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Civil Engineering and Development Department and Planning Department |
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Contamination Assessment Plan |
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Rpt
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Contents
1.5 Statutory
Legislation and Evaluation Criteria
2.2 Topography,
Geology and Hydrology
2.3 Previous
Site Investigation
2.4 Other
Relevant Information
2.6 Future
Landuse and Activities
3 Potentially
Contaminated Sites
3.1 Potentially
Contaminated Sites with “A” Rating
3.2 Surveyed
Sites with “B” and “U” Ratings
4 Potential
Health Risk and Environmental Impacts
4.1 Potential
Impact on Receptors
4.2 Health
Risk to Site Workers
4.3 Contaminated
Groundwater Disposal
4.4 Potential
Health Risks to Future Users of the Site
5.1 Proposed
Site Investigation
6.1 Possible
Remediation Methods
6.2 Surmountability
of the Potentially Contaminated Sites
Figures
Figure 1.1 NENT
NDA Project Boundaries
Figure 1.2.1 Locations of
Schedule 2 Designated Projects in KTN NDA
Figure 1.2.2 Locations of
Schedule 2 Designated Projects in FLN NDA
Figure 1.2.3 Location of
Schedule 2 Designated Project along Fanling Bypass
Figure 2.1.1 Existing Land Use
in Kwu Tung North NDA
Figure 2.1.2 Existing Land Use
in Fanling North NDA
Figure 2.2.1 KTN – Recommended
Outline Development Plan
Figure 2.2.2 FLN – Recommended
Outline Development Plan
Figure 3.1.1 Locations of
Potentially Contaminated Sites (“A” Rating) in Kwu
Tung North
Figure 3.1.2 Locations of
Potentially Contaminated Sites (“A” Rating) in Fanling
North
Figure 3.1.3 Locations of
Potentially Contaminated Sites (“A” Rating) along Fanling
Bypass
Figure 5.1.1 Locations of
Potentially Contaminated Sites at Government Lot in Kwu
Tung North
Figure 5.1.2 Location of
Potentially Contaminated Site at Government Lot in Fanling
North
Figure 5.2.1a Location of Potentially
Contaminated Site at Government Lot in Kwu Tung North
(KTN-23b)
Figure 5.2.1b Locations of Proposed Boreholes at
Government Lot in Kwu Tung North (KTN-23b)
Figure 5.2.2b Locations of Proposed Boreholes at
Government Lot in Kwu Tung North (KTN-35a)
Figure 5.2.3b Location of Proposed Boreholes at
Government Lot in Kwu Tung North (KTN-77,78)
Figure 5.2.4a Locations of Potentially Contaminated
Site at Government Lot in Fanling North (FLN-9a)
Figure 5.2.4b Locations of Proposed Boreholes at
Government Lot in Fanling North (FLN-9a)
Appendices
Geological Profile for NDA Sites
Copy of Letter to Fire Services Department and the Formal Reply of FSD
Copy of Letter to Environmental Protection Department and the Formal Reply of EPD
Site Appraisal Findings of previous NENT EIA Study (June 2003)
Typical Details of Proposed Groundwater Monitoring Well
The Planning and Development Study on North East New Territories (NENT Study, CE64/96) commenced in 1998 had identified areas in Kwu Tung North (KTN), Fanling North (FLN) and Ping Che/Ta Kwu Ling (PC/TKL) to be suitable for New Development Areas (NDAs). The NENT Study also confirmed the feasibility of NDAs based on the findings and recommendations from the technical assessments on various aspects including planning, environmental and engineering. In 2003, having regard to the housing demand at the time, the Government decided to shelve the NDAs proposal in the interim pending a comprehensive review of Hong Kong’s overall planning under the Study on Hong Kong 2030: Planning Vision and Strategy (HK2030 Study).
The HK2030 Study carried out by the Planning Department (PlanD) completed in 2007 was a comprehensive review of Hong Kong’s territorial development strategy for formulating a broad planning framework to guide the future development of Hong Kong up to 2030. It recommended proceeding with KTN, FLN and PC/TKL NDAs (i.e. NENT NDAs) as well as Hung Shui Kui NDA to address long-term housing demand and to provide job opportunities. NENT NDAs and Hung Shui Kui NDA were included as one of ten major infrastructure projects in the 2007-08 Policy Address. .
Further to the recommendations for NDAs in HK2030 Study, the Civil Engineering and Development Department (CEDD) and PlanD jointly commissioned the North East New Territories New Development Areas Planning and Engineering Study - Investigation (the Project) to formulate updated development proposals for NENT NDAs. The Project aims to review and update the findings and recommendations of the NENT Study, and to formulate revised proposals for NENT NDAs.
Section 3.4.9.4 of the EIA Study Brief No.: ESB-176/2008 for the NENT NDAs project dated January 2008 issued by the EPD specified that a land contamination assessment shall be undertaken and that a Contamination Assessment Plan (CAP) shall be submitted to the EPD for endorsement prior to conducting the assessment.
The NENT NDAs under this Study including Kwu Tung North (KTN) NDA, and Fanling North (FLN) NDA covering a total area of about 612ha as shown in Figure 1.1.
It should be noted that the development boundaries of the NDAs have been readjusted and fine-tuned during the planning stage. The Study Area outlined in Figure 1.1 is reference to the revised Recommended Outline Development Plan (RODP) of NENT NDAs study.
1.2.1 Kwu Tung North (KTN) NDA
The KTN NDA covers an area of about 450 ha. It is located to the west and northwest respectively of the proposed FLN NDA and the existing Fanling/Sheung Shui New Town. It is generally bounded by the Shek Sheung River in the east, Castle Peak Road and the Fanling Highway in the south, Tit Hang in the west and Tai Shek Mo (Crest Hill) in the north.
Long
The majority of KTN NDA lies on a relatively flat area
within the central and southern parts where the main developed areas are
located. They involve mixed land
uses which comprise small residential developments, scattered villages,
agricultural lands, rural areas and rural industries including vehicle repair,
construction material storage, container storage etc. In particular, Yin Kong Tsuen and Ho Sheung Heung are the
recognised villages within KTN NDA.
They are located at the southern end of
Within the northern portion of KTN NDA, the elevation of the topography rises gradually as a series of east-west striking hills to Fung Kong Shan. A number of smaller valleys branch off through this high ground in a northeast to southwest orientation. The Lo Wu Classification Range is located near to the northern end of KTN NDA, and the Ma Tso Lung Restored Landfill is located at the north-western end of KTN NDA.
1.2.2 Fanling North (FLN) NDA
The FLN NDA covers an area of about 164 ha. It is located immediately to the north of the established Fanling/Sheung Shui New Town and to the southeast of the proposed KTN NDA. It is generally bounded by Wa Shan in the north, the Ma Wat River in the east, Ma Sik Road and Tin Ping Road in the south, Ng Tung River in the southwest and Sheung Yue River in the west.
The majority of FLN NDA lies on a relatively flat area with mixed land uses which comprise agricultural and rural areas with scattered villages, some small isolated buildings and residential developments. Rural industries including vehicle repair and material storage are concentrated on the two sides of Jockey Club Road with FLN NDA. There is no recognized village in FLN NDA.
Sheung Shui Slaughter House and Shek Wu Hui Sewage Treatment Works are located at the western end, and Sheung Shui Water Treatment Works is located immediately to the north of FLN NDA. San Wai Barracks and San Wai/Tai Ling Firing Range are located to the north-east of FLN NDA.
1.2.3 Ping Che / Ta Kwu Ling (PC/TKL) NDA
PC/TKL NDA, which is previously included as a part of the NDAs, would be subject to replanning and would be proceeded at a later stage. Thus, there will not be a revised RODP for PC/TKL NDA at this juncture and no EIA and contamination assessment would be required in this context.
The planning study for the NENT NDAs is a Designated Project (DP) under Item 1 of Schedule 3 of EIAO - Engineering feasibility study of urban development projects with a study area covering more than 20 ha or involving a total population of more than 100,000.
In addition, the following work components also fall under various Schedule 2 DP categories as summarized in Table 1.1a and Table 1.1b. The locations of the Schedule 2 Designated Projects are shown in Figures 1.2.1 – 1.2.3.
Table 1.1a - Schedule 2 Designated Projects
in KTN NDA
Item |
Work Component |
Schedule 2 DP Category |
|
1 |
San Tin Highway and Fanling Highway Kwu Tung Section Widening (between San Tin Interchange
and Po Shek Wu Interchange) (Major Improvement) |
A1 |
A road which is an expressway, trunk road, primary distributor road or
district distributor road including new roads, and major extensions or
improvements to existing road |
2 |
Castle Peak Road Diversion (Major Improvement) |
A1 |
A road which is an expressway, trunk road, primary distributor road or
district distributor road including new roads, and major extensions or
improvements to existing road. |
3 |
KTN NDA Road P1 and P2 (New Road) and associated new Kwu Tung Interchange (New Road) and Pak Shek Au Interchange Improvement (Major Improvement) |
A1 |
A road which is an expressway, trunk road, primary distributor road or
district distributor road including new roads, and major extensions or
improvements to existing road. |
4 |
KTN NDA Road D1 to D5 (New Road) |
A1 |
A road which is an expressway, trunk road, primary distributor road or
district distributor road including new roads, and major extensions or
improvements to existing road. |
5 |
New Sewage Pumping Stations (SPS) in KTN NDA |
F3 |
A sewage pumping station---(b) with an installed capacity of more than
2000 m3 per day and a boundary of
which is less than 150 m from an existing or planned residential area or
educational institution. |
6 |
Proposed railway station
and associated facilities in KTN NDA (To be conducted under other separated
studies). |
A2 |
A railway and its associated stations. |
7 |
Utilization of Treated Sewage Effluent |
F4 |
An activity for the reuse of treated sewage
effluent from a treatment plant |
Table 1.1b - Schedule 2 Designated Projects
in FLN NDA
Item |
Work Component |
Schedule 2 DP Category |
|
7 |
Utilization of Treated Sewage Effluent |
F4 |
An activity for the reuse of treated sewage
effluent from a treatment plant |
8 |
Po Shek Wu Interchange Improvement (Major
Improvement) |
A1 |
A road which is an expressway, trunk road,
primary distributor road or district distributor road including new roads,
and major extensions or improvements to existing road |
9 |
Fanling Bypass Western Section (New Road) |
A1 |
A road which is an expressway, trunk road,
primary distributor road or district distributor road including new roads, and
major extensions or improvements to existing road |
10 |
Fanling Bypass Eastern Section (New Road) |
A1 |
A road which is an expressway, trunk road,
primary distributor road or district distributor road including new roads, and
major extensions or improvements to existing road. |
11 |
Shek Wu Hui Sewage Treatment Works - Further Expansion at FLN NDA |
F1 |
Sewage treatment works with an installed
capacity of more than 15,000 m3 per day. |
12 |
Reprovision of temporary wholesale market in FLN NDA. |
N3 |
A wholesale market. |
13 |
New Sewage Pumping Stations (SPSs) in FLN
NDA |
F3 |
A sewage pumping station---(b) with an
installed capacity of more than 2000 m3 per day and a boundary of which is
less than 150 m from an existing or planned residential area or educational
institution. |
The purpose of this Contamination Assessment Plan (CAP) is to provide information, guidance and instruction to characterise land contamination and identify where any contamination is or may be present during the construction and operation of the NENT NDAs. The objectives of this CAP are:
· To provide an account of the land use within project site boundary and relevant past land use history in relation to possible land contamination;
· To identify areas of potential contamination and the associated impacts, risks or hazards; and
· To identify the chemical of concern and scoping of requirements for sampling and laboratory testing of soil and groundwater samples.
This CAP is prepared in accordance with the following Technical Memorandum and Guidance Notes:
· Annex 19 of the TM-EIAO, Guidelines for Assessment of Impact On Sites of Cultural Heritage and Other Impacts (Section 3 : Potential Contaminated Land Issues), EPD, 1997;
· Guidance Notes for Investigation Remediation of Contaminated Sites of Petrol Filling Stations, Boatyards, and Car Repairing/Dismantling Workshops, EPD, 1999 (i.e. superseded in August 2011);
· Guidance Manual for Use of Risk-Based Remediation Goals (RBRGs) for Contaminated Land Management, EPD, 2007.
· Guidance Notes for Contaminated Land Assessment and Remediation EPD, 2007 ; and
· Practice Guide for Investigation and Remediation of Contaminated Land, EPD, 2011
In accordance with EPD’s Guidance Note for Contamination Land Assessment and Remediation, a contamination assessment evaluation should:
· provide a clear and detailed account of the present use of the land and the relevant past land history, in relation to possible land contamination;
· identify areas of potential contamination and associated impacts, risks or hazards; and
· submit a plan to evaluate the actual contamination conditions for soil and/or groundwater, if required.
The EPD’s Guidance Notes include a summary of the general steps of a detail contamination assessment study.
Under the Annex 19 of the TM-EIAO, consideration shall be given to a number of potentially contaminating historical land uses, including oil installations, gas works, metal workshops, car repair and dismantling workshops, as having the potential to cause or have caused land contamination. All of these land uses have been identified either adjacent to, or within the NDAs area and work area boundary.
This CAP has been prepared to set out the requirements for a baseline contamination evaluation of the NDAs area and work areas. A Contamination Assessment Report (CAR) will be prepared following site investigation activities. If significant contamination is identified in the CAR, a Remediation Action Plan (RAP) will be developed to deal with these areas during excavation works for the Project. The RAP should follow the contents requirements as specified in the EPD’s Practice Guide for Investigation and Remediation of Contaminated Land. A remediation Report (RR) will be prepared to demonstrate adequate clean-up and submitted to EPD for endorsement prior to the commencement of any construction/ development works within the NDAs.
A desktop study has been conducted to review past and present landuses, activities and installations in the vicinity of the NDAs boundary and the associated Designated Projects (i.e. details given in Section 1.3) that may pose potential for land contamination.
Existing information from historical land contamination site investigations and other contamination reports for areas located within the vicinity of the NDA boundary have been reviewed, including the following:
· Hong Kong Ordinance Survey Maps from various years;
· Relevant Outline Zoning Plans (OZPs) for Kwu Tung, Sheung Shui and Fanling;
·
· Relevant aerial photos from 1963;
· Landuse information from the District Land Offices (DLO) in Yuen Long (DLO Yuen Long) and Fanling (DLO North);
·
“Mapping
· “Sheung Shui to Lok Ma Chau Spurline Contaminated Land Assessment, Contamination Assessment Report (CAR) and Remediation Action Plan (RAP) Final (May 2002) with Addendum (August 2002) (2141/913)”, MTR, 2002; and
· “Environmental Impact Assessment Report for Planning and Development Study on North East New Territories”, CEDD and PlanD”, 2003.
2.1.1 Review of Aerial Photographs and Historical Landuse
The development history of the study areas and the associated Designated Projects was reviewed with the aid of the historical aerial photographs in Appendix A. It should be noted that except the southern section of Fanling Bypass, all Schedule 2 Designated Projects are located within the NDAs.
The current and historical contamination concerns within the NDA study areas and the southern section of Fanling Bypass have been identified and are discussed below:
Kwu Tung
North (KTN) NDA
·
Year
1963
The aerial
photograph for the northern extent of the Kwu Tung
North Development Area is missing in 1963.
The southern extent of the development area is dominated by agricultural
fields with village housing concentrated along the main access roads in Fung
Kong and Tung Fong, Shek Tsa
Long and Pak Shek Au. The
·
Year
1972
The aerial
photograph in 1972 shows that there is a hill range in the north of the
development area which is undeveloped, in contrast, the flat land between the
hill slopes is used as agricultural land.
As was the case in 1963, the dominant land use in 1972 is
agricultural. Since 1963 there has
been further development of the existing villages and these are more apparent
in 1972 with the majority of development occurring in the south of the
development area.
·
Year
1982
The aerial
photograph for the northern extent of the development area is missing in
1982. However, the southern
section, particularly by
·
Year
1993
By 1993
more residential development has occurred throughout the development area with
agricultural land remaining in the eastern extent. Large plots of land have also been
developed as storage and parking facilities.
·
Year
2001
By 2001
the
·
Year
2008
There has
been little change between 2001 and 2008 in the Kwu
Tong North development area; residential and light industrial development
remains scattered throughout the area.
Fanling North (FLN) NDA
·
Year
1963
The aerial
photograph for the northern extent of the Fanling
North Development Area is missing in 1963.
However, the photograph for the southern section shows that in 1963 the
majority of the land was used for agricultural purposes with much of the flat
land divided into fields. The Ng
Tung River runs through the length of the flat (flood plain land) in the
development area. Hill slopes are
located in the central section of the development area and these remain as
grassland or scrubland. Village
houses are evident and these are concentrated at the foot of the slopes and in
village clusters scattered through-out the development area. Small access roads connect the villages
to the fields and river crossings.
·
Year
1972
Little has
changed between 1963 and 1972 in Fanling North; the
main use of the land remains as agricultural within the flood plain of the Ng
Tung River, although there is increased housing in the south of the development
area.
·
Year
1982
Little has
changed between 1972 and 1982 in Fanling North; the
main use of the land remains as agricultural within the flood plain of the Ng
Tung River, although there is increased housing in the south of the development
area.
·
Year
1993
By 1993
the majority of the land remains in agricultural use. However, the villages have increased in
size, particularly in the south.
Some agricultural land has been cleared; this is in the north of the
development area and is focused along the main road and river. The land has been cleared and replaced
with hard standing ground that is used for storage and trailer parking.
·
Year
2001
By 2001,
large areas of land have been cleared and are no longer used for agricultural
fields. These clearance activities
have been concentrated along the river corridor and to the north a sewage
treatment works has been constructed.
Village buildings are now scattered throughout the development
area.
·
Year
2008
By 2008
the Ng Tung River has been channelized and there are a number of road and river
crossings. The previously cleared land is now also used for storage and parking
capacity. The sewage treatment
works in the north of the development area has also been expanded.
Fanling
Bypass
·
Year
1963
The
photograph shows that in 1963 the majority of land was composed of agricultural
land and village type buildings. Few temporary structures were found to the
south of Fanling Highway.
·
Year
1972
There has
been little change between 1963 and 1972 near the development area; the main
use of the land remains agricultural and residential.
·
Year
1982
There has
been little change between 1972 and 1982 near the development area; the main
use of the land remains agricultural and residential. The number of temporary
structures to the south of Fanling Highway increased
as compared with those in 1972.
·
Year
1993
By 1993
most of the agricultural land had changed into industrial uses with an
increased number of temporary structures and parked trailers found in the
photos.
·
Year
2001
There has
been little change between 1993 and 2001 near the development area; the main
use of the land remains industrial.
·
Year
2008
No
significant change between 2001 and 2008. Only an increased number of parked
trailers was found within the industrial areas.
The following
sections provide an overview of the topography, geology and hydrology of the
NDAs and the geology of Fanling Bypass alignment.
2.2.1 Kwu Tung North (KTN NDA)
Topography
The KTN NDA is located to the west of Fanling / Sheung Shui New Town and east of San Tin in the North New Territories. It is bounded to th east by the Shek Sheung River and section of Ng Tung River and to the north by the Frontier Closed Area Boundary. The Fanling Highway, from Fanling to Yuen Long and Tuen Mun fringes the site at the south. The Sheung Yue River also fringes the site from the central south boundary. The KTN NDA has an area of some 450 ha.
The general area lies in a large valley and flood plain feature extending from Shenzhen, People’s Republic of China (P.R.C) in the north to Fanling. A number of smaller valleys branch off through the high ground in a northeast to southwest orientation. The majority of the topographic features in this part of the northern New Territories are strongly structurally controlled and often faults related. Geological structures such as foliations developed above underlying San Tin Thrust faults control not only the location and elevation of valleys and floodplains but also the positions for soil/rock deposition in the basin of low-lying areas.
The south-eastern part (
The other low-lying ground within the site area is
built-up/ cottage area and is higher than the
The site is bounded to the southwest, northwest and northeast by high ground. Hadden Hill in the southwest peaks at an elevation of about +222mPD. The hills to the west and northwest of the site peak at about + 100mPD to + 134mPD, whereas the hills towards the northeast of the site (Tai Shek Mo) peak at about +183mPD.
Within KTN NDA, the site is rural in character and it
comprises villages and rural industrial uses (vehicle repair, construction
materials storage site, etc.) which intermix with active and inactive
agriculture, horticulture and fish farming. On both sides of
There are cultural resources within the site including the
historical buildings of the Sin Wai Nunnery,
Geology
Based on the currently available data it is found that majority of the KTN NDA is generally underlain by a layer of fill that generally of 2m thick, where the alluvium of up to 10m thick has been accumulated around the downstream side of Long Valley. Significant fill bodies are present at west (near a sports field at Fong Kong), with a thickness of up to 14m due to the completed designated filling area. Pockets of colluviums, average 1.5m thick but locally up to 11m thick, and thin lenses of pond deposits, typically about 0.5m thick, are occasionally encountered above the alluvium. These superficial deposits are typically underlain by decomposed fine to coarse ash tuff, schistose tuff or sedimentary rocks of few to 85m thick.
The anticipated rockhead level generally varies in accordance with the topography, ranging between approximately -40mPD to +10mPD across the flood plain area of the NDA site, up to +100mPD at hilly regions. According to the recent ground investigation under the current NENT NDA study, the lower rockhead levels (-40mPD to -25mPD) are encountered near the north-easterly San Tin thrust fault in the eastern KTN NDA, the north-south-trending trough at the central NDA and in the vicinity of the Sheung Yue River. Corestones within decomposed rocks are only occasionally encountered and appear to be uncommon within this Site. The geological section of KTN NDA is included in Appendix B
Hydrology
KTN NDA is located within the catchment boundary of Sheung Yue River. Sheung Yiu River runs from southwest to northeast direction along the eastern side of the proposed KTN NDA. Based upon past history, the flooding occurred in the low lying areas, especially near junction of Sheung Yue River with Ng Tung River.
The section of Sheung Yue River between Ng Tung River and Castle Peak Road is designed to provide a 1 in 50 year flood protection. Whereas, the upstream section is designed to provide a flood protection of 1 in 2 years.
Under the existing condition, the majority of the runoff from development site is discharged to Sheung Yue River with small catchment on west drain to Chau Tau Channel.
The flooding condition within the Kwu Tung North area will be improved considerably after the completion of the ongoing drainage improvement works recommended under the Drainage Master Plan Study in North New Territories.
2.2.2 Fanling North (FLN NDA)
Topography
FLN NDA is located immediately to the north of the developed areas of Fanling / Sheung Shui New Town. It is bounded to the south by Ma Sik Road and Po Wan Road. The northern boundary of the site is bounded by hills of Ma Tau Leng, Wa Shan and Cham Shan. The Ng Tung River also meanders through the area from the southeast to the west into Shek Sheung River. The FLN NDA has an area of around 180 ha.
The general area lies in a large valley and flood plain feature extending from Shenzhen (P.R.C) in the north to Tai Po at the head of Tolo Harbour towards the southeast. The site is bound to the north and northeast by high ground. Wa Shan towards the north of the area peaks at an elevation of about +140mPD approximately. A number of smaller valleys branch off through the high ground in a northeast to southwest orientation.
The majority of the topographic features in this part of
the northern
Unlike the variable land use within KTN NDA, private agricultural lots that are held under block government leases dominate the whole of FLN NDA. Few building lots are found in the NDA. Low village-type residential structures are dotted over the agricultural land. Industrial usage such as open storage of vehicles and repair workshops can also be found within the NDA.
Geology
The FLN NDA is generally underlain by fill of few to 6m thick in general, followed by a generally 6m to 8m thick of alluvial deposits. These superficial deposits are then underlain by relatively thick residual soil and decomposed tuff and metamorphosed tuff of up to 85m thick. Based on the available drillholes records, rockhead levels in the area appear to vary between +5mPD to deeper than -50mPD. However, it should be noted that confirmed bedrock was not encountered with the majority of the available borehole records. A local zone of corestones, comprising highly to moderately decomposed coarse ash tuff, was encountered above the rockhead near the east of Man Shek Tong Ancestral Hall. The thickness of this corestone zone is about 9m. The geological section of FLN NDA is included in Appendix B.
Hydrology
From the upland areas to the north there are a number of streams which cross through the site, prior to joining the Ng Tung River. Ng Tung River has been trained and providing a 1 in 50 year flood protection after river training works.
Under the existing condition, there are a series of urban catchments within Fanling and Sheung Shui, which are discharged to the Ng Tung River, whose outfall drainage comprising open channels and box culverts, crossing through the NDA.
Some low-lying areas remain to flood prone even after the completion of the river training works. This is because Ng Tung River constructed with embankments, which in low-lying areas will be at a higher level than the surrounding areas. The water level along the channel under extreme conditions may raise up above the existing ground levels whilst remaining in bank, which may result in flood water being retained behind embankments until the peak channel water levels subside.
2.2.3 Fanling Bypass
Topography,
Geology and Hydrology
The Fanling Bypass area is generally covered by about 2m thick of fill, followed by 2m to 8m alluvium. The composition of alluvium consists of about 4m thick alluvial sand and then cobbles are followed. In-situ soil of completely decomposed tuff is encountered below the alluvium layer, with thickness about 10m to 30m. Moderately to slightly decomposed tuff is encountered as bedrock underneath. As reviewed from previous ground investigation records, the groundwater regime in this area is about 1m to 4m below existing ground level.
As far as the KTN NDA is concerned, a number of potential land contamination sites have been identified (i.e. refer to Section 3). It is revealed that during the construction of the Lok Ma Chau (LMC) Spur Line (i.e. the railway run through KTN NDA), the environmental site investigation was conducted in accordance with the Environmental Permit of the LMC Spur Line as those potential land contamination sites were not accessible for environmental SI during the Spur Line EIA Stage. Besides the concerned area during the land contamination assessment conducted during the construction of the mentioned project, we have also identified the remaining sites that will require land contamination sampling. No other previous land contamination study for FLN NDA is found.
Based on the findings of the corresponding Contamination Assessment Report (CAR) and Remediation Action Plan (RAP) Final (May 2002) with Addendum (August 2002) (2141/913) (Binnie May 2002), some of the potentially contaminated sites within the vicinity of the LMC Spur Line alignment have been assessed. However, the site survey revealed that various industrial activities were still in operation at most of the assessed sites, namely KTN-14, KTN-15, KTN-88 and KTN-89. Therefore these sites will be further assessed in this CAP.
Nevertheless, 2 assessed sites namely KTN-29,30,30a and KTN-30b have been excluded from further assessment in this CAP as these 2 sites have been assessed and remediated during the development and construction of LMC Spur Line. These 2 sites are fenced off as Spur Line Restricted Areas since the completion of remediation/ construction of LMC Spur Line. Site KTN-29,30,30a has been reserved for the development of future Spur Line Kwu Tung Station. Spur Line Emergency Access Point is located in site KTN-30b. No industrial activity was seen in these 2 sites during the site survey.
The aforementioned sites are shown in the figure attached in Appendix D.
Acquisition of
other relevant information from Fire Services Department (FSD)
and Environmental Protection Department (EPD) was summarized below:
2.4.1 Fire Services Department
The Fire Services
Department (FSD) has been contacted in January and
February 2011 for
(i)
The
records of Dangerous Goods License(s), and
(ii)
The
reported accidents of spillage/leakage within the surveyed sites.
Based on the
information provided by FSD on 11 February 2011 and 3
March 2011 respectively (as shown in Appendix C1), there is only one location used
for storage of dangerous goods (i.e. 163 Ho Sheung
Heung Road, Sheung Shui,
New Territories) which is adjacent to KTN-48. Further site survey was conducted
and confirmed that the aforesaid storage location is Lo Wu Correctional
Institution.
2.4.2 Environmental Protection Department
The Environmental
Protection Department (EPD) has been contacted in January 2011 for
(i)
The
records of Chemical Waste Producers Registration, and
(ii)
The
reported accidents of spillage/leakage within the surveyed sites.
Based on the
information provided by EPD on 22 February 2011, lists of chemical waste
production registration records and illegal wastewater discharge records are
given in Appendix C2. A comparison table between
surveyed sites with the records are also presented in Appendix C2 for
easy reference.
Site surveys have been conducted in May to June 2009 to confirm findings of desktop study and to
identify any other land uses within the NDA boundaries (i.e. include the
associated Designated Projects and southern section of Fanling
Bypass) which may have the potential
for causing soil and groundwater contamination. The surveyed sites have also
been re-visited from July 2012 to September 2012 to ensure the information
given in this CAP is up-to-date.
2.5.1 Pre-Survey Preparation
In order to carry out the site surveys more effectively for these 2 NDAs, the following documents and information have been referred and comprehensively reviewed before conducting the site survey:
· Previous NENT Study, Technical Paper 13 Environmental Impact Assessment Study (TP13), Annex H - Contamination Assessment Plan (June 2003);
· Existing land uses plan; and
· Aerial photographs of Year 2008.
A field based site appraisal has been undertaken in the NDA areas and the southern section of Fanling Bypass in year 2003, as part of the previous NENT EIA Study. The site appraisal findings provided a preliminary understanding regarding the distribution of various potentially contaminating land uses in NDAs. All appraised sites located within the current NDA boundaries have been visited during the site survey, and their current land use status was also updated. The specific details of the potentially contaminating land uses identified in the site appraisal are given in Appendix C3.
It should be noted that some appraised sites are located outside the current NDA boundaries, and therefore no site survey was carried out for these appraised sites.
In additional to the site appraisal findings of year 2003, the existing land uses plans and aerial photographs of year 2008 also facilitate the site survey as they illustrate the current land use patterns in the two NDAs. Special attentions have been paid for the following land use categories during the site survey:
· Commercial use;
· Industrial use;
· Open storage;
· Warehouse; and
· Open car park.
Nevertheless, the areas of all other land use categories have also been visited for locating any potentially contaminating land uses that were not included in the existing land uses plans and TP13. The existing land use plans are shown in Figures 2.1.1 - 2.1.2.
2.5.2 Site Survey Results
Due to the limited access of the private lot sites, the site survey was mainly conducted by visual inspection from the entrance and / or boundary of sites. The details of each surveyed site, including the site description, information of OZPs / GSMs / historical aerial photos review, other relevant information obtain from FSD and EPD, site survey observations and site layout plan are given in Appendix D.
It should be noted that the surveyed sites (i.e. with assigned site number) shown in the figures of Appendix D were considered with certain potential of land contamination. On the other hand, the areas of the unnumbered areas / sites shown in the figures of Appendix D were dominated by woodland, grassland, agricultural land, ponds, natural and channelized streams, residential blocks, schools and village type development. All these unnumbered areas / sites have been visited during the site survey, and no potentially contaminating activity was found. Therefore, number was not assigned for these areas / sites in order to distinguish the surveyed sites with potentially contaminating land uses from other areas.
2.5.3 Contamination Rating System
The major scale
site survey effort identified around 300 sites at the proposed NDAs and
southern section of Fanling Bypass, which during the
site survey exhibited visible evidence of contamination which was suspected to
be derived from the particular land uses. The specific land uses which were
identified as potentially contaminating sources include:
· Vehicle repair and maintenance yards / workshops;
· Car junk yards:
· Trailer /container storage yards;
· Scrap yards and metal recycling facilities;
· Petrol stations;
· Concrete batching plants;
· Metal workshops;
· Saw mills;
· Construction material and open storage areas; and
· Uncontrolled dumping; and
· Several types of manufacturing facilities (electronic, umbrella, chemical manufacturing etc)
The details of the
potentially contaminating land uses are summarized in Appendix D. In
order to determine those activities which pose the potential for contamination,
a contamination rating was determined based on visual evidence and available
historical records such as historical aerial photos and TP13’s findings to
evaluate the potential contamination of the site. The EPD’s
Practice Guide for Investigation
and Remediation of Contaminated Land
has been used to determine those activities which pose the potential for
contamination. The rating categories used in the preliminary site evaluation
are as follows:
· “A” rating indicates a significant potential for land contamination, with visual evidence and supplement with the historical records to suggest the potential for soil and groundwater contamination (i.e. spillage / leakage of oils and / or chemicals, heavy oil stains on the ground, burn pits, areas of uncontrolled dumping etc);
· “B” rating indicates a low potential for land contamination, with no major concerns observed during the site survey; and
· “U” rating indicates the site was limited for access for visual inspection during the survey and the potential for land contamination could not be evaluated.
The ratings “A” and
“B” are based on visual inspection (i.e. conducted from the entrance and / or
boundary of the site) and available historical records such as historical
aerial photos and TP13’s findings.
2.6 Future Landuse and Activities
The RBRGs have developed four
different post-restoration land uses, namely “Urban Residential”, “Rural
Residential”, “Industrial” and “
The revised RODP of NDAs is given in Figures 2.2.1 - 2.2.2, which
consisted of different facilities, such as residential buildings, education
institutions, outdoor sport facilities, commercial, mixed development, police
facilities, primary and district distributors, sewage treatment works, sewage
pumping stations, wholesale market, railway, pedestrian walkway, open space,
car park and various of public utilities etc. The relevant RBRGs
for the identified contaminated sites should be decided with reference to the
revised RODP of NDAs. The most relevant RBRG
corresponding to its future land use should be adopted in assessing its land
contamination level.
Corresponding RBRGs
landuse of the associated facilities are defined and
given in Table 2.1.
Table
2.1 Post-restoration
land use and RBRGs land use
Landuse |
Corresponding RBRGs
Landuse |
Commercial / Residential · Urban High Rise ·
Low Rise in
Rural Area |
Urban Residential Rural Residential |
Commercial /
Business & Office |
Urban Residential |
School |
Rural Residential |
|
Lower of |
Warehouse
& Storage |
Industrial |
Government,
Institution & Community Facilities |
Urban Residential |
Road
including Pedestrian Walkway |
Lower of Industrial or |
Railway |
Industrial |
Open Space |
|
Public
Utilities |
Industrial |
Nevertheless, if the future land uses is changed after the approval of this CAP or in doubt during the assessment (i.e. interpretation of the soil and groundwater testing results), the most stringent set of RBRGs should be adopted.
3 Potentially Contaminated Sites
Potentially contaminated sites within the NDAs (i.e. include the locations of the associated Designated Projects) and along the southern section Fanling Bypass have been identified based on the selected historical aerial photos, information of TP13 and existing land uses plans, and the information collected during site survey.
The details of the surveyed sites are given in Appendix D. It is recommended that intrusive site investigations are carried out on the identified sites with a contamination rating “A” (i.e. potentially contaminated sites). Locations of the sites with “A” rating are given in Figures 3.1.1 - 3.1.3 and summarised in Tables 3.1 - 3.3.
Further site appraisal will be carried out by Project Proponent (PP)’s appointed consultants once site access is available (e.g. after land redemption) for the sites with “A” rating, in order to identify the presence of “hot spots” for intrusive site investigation.
The PP/ PP’s appointed consultants should also liaise with DLO of Lands Department to find out if a “Decontamination” clause had been incorporated into the land lease/ tenancy agreement of the sites with potential land contamination as identified in this CAP which requires the responsible lessee/ tenant to undertake a land contamination assessment including decontamination works (if any). If the “Decontamination” clause exists, the PP/ PP’s appointed consultants should identify the responsible party (i.e. name of relevant government department, land lessee/ occupier/ owner, etc.) for undertaking the land contamination assessment including land decontamination works for each of the identified sites.
The PP’s consultants should prepare a supplementary CAP to summarise the relevant findings regarding the “Decontamination” clause and the further site appraisal. A supplementary CAR, RAP and RR for contaminations other than As (which will follow the recommendations of the HRA) should also be prepared by the PP’s and submit to EPD for approval prior to the commencement of the proposed development at these sites.
Although many of the sites are not identified as potentially contaminated sites (e.g. the sites with rating “B”) or cannot be accessed for visual inspection (e.g. the sites with rating “U”) during the course of this EIA Study, these sites are still in operation and the proposed development of these sites will only commenced in a number of years later. Change of the land usage (e.g. change to use as chemical storage area, dismantling workshop, etc) may occur in these sites, which may cause potential land contamination. Hence, once the individual site is handed over to the PP for development, the PP’s appointed consultants should revisit these sites to assess the latest site situation. If any of these sites are found to have sign of potential land contamination, the PP’s appointed consultants are required to prepare and submit the supplementary CAP to EPD prior to the commencement of SI works. Following on from the submission of CAP and completion of SI, the PP’s appointed consultants would prepare CAR, RAP and RR for contaminations other than As (which will follow the recommendations of the HRA) to EPD for approval prior to the commencement of the proposed development at these sites.
In order to avoid errors and misplacement of documents, the PP’s appointed consultants should submit the supplementary CAP, CAR, RAP and RR as mentioned in Sections 3.1 and 3.2 in separate packages (e.g. one package for one project/development area) instead of one set of report which includes all of the concerned sites as mentioned in aforementioned sections.
Prior to the commencement of any proposed construction works, the PP’s appointed consultants should prepare a Remediation Report (RR) and submit to EPD to demonstrate that the decontamination work is adequate and is carried out in accordance with the endorsed CAR and RAP. Information such as soil treatment/disposal records (including trip tickets), confirmatory sampling results, photographs and, if applicable, certification of independent checker should be included in the aforesaid RR.
No construction works should be carried out before the endorsement of the RR given by EPD.
If the proposed development / construction works of any individual site(s) is categorized as Designated Project under EIAO, the CAP and CAR/ RAP shall be documented in the EIA Study Report of the Designated Project(s).
Table 3.1 Potentially
Contaminated Landuse (“A” Rating Sites) at KTN NDA
Site No.* |
Location |
|
Potentially Sources of Contamination |
Approximate
Area (m²) |
Recommended No. of Boreholes(i) |
Future Landuse |
Corresponding RBRGs |
KTN-1 |
Tsuen Kee, vehicle repair and car dump (paved)
(North of Castle Peak Road) |
Vehicle Repair and Car Dump |
Possible spillage/ leakage of fuels and oils
during maintenance and demolishing activities |
1,878 |
12 |
AGR, GB |
Public Park |
KTN-2a |
Kin Lik metal recycling (partially paved)
(North of Castle Peak Road) |
Metal Workshop |
Possible spillage/ leakage of fuels and oils
during metal cutting/welding activities |
639 |
4 |
AGR, A |
Public Park |
KTN-4a |
Yat Fai
vehicle repairing workshop (partially paved) (North of Castle Peak Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
770 |
5 |
AGR, A |
Public Park |
KTN-5 |
Tong Kee, vehicle repair (AGREBA) (partially paved) (North of Castle Peak Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
2,637 |
13 |
A, OU, Road network within revised RODP |
Lower of
Industrial or Public Park |
KTN-5b |
Hai Sai Mechanical Equipment (paved) (North of
Castle Peak Road) |
Maintenance of Forklift |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
881 |
5 |
Road network
within revised RODP |
Lower of Industrial
or Public Park |
KTN-5e |
Kam Tat fuel
filling station (illegal??) (partially paved) |
Temporary fuel
filling station |
Possible spillage/ leakage of fuels during
filling operation |
646 |
4 |
A, Road network
within revised RODP |
Lower of Industrial
or Public Park |
KTN-5n |
Eastern Yard
Development Co. Ltd (partially paved) |
Vehicle Repair |
Possible
spillage/ leakage of fuels and oils during maintenance activities |
527 |
3 |
O, Road network
within revised RODP |
Lower of Industrial
or Public Park |
KTN-6 |
Sam Luen vehicle repair (small scale) (partially paved) |
Vehicle Repair |
Possible
spillage/ leakage of fuels and oils during maintenance activities |
607 |
3 |
Road network
within revised RODP |
Lower of Industrial
or Public Park |
KTN-7,8 |
Kam Shing, vehicle repair and car dump
(partially paved to paved), refuelling station (Side road, north of Castle
Peak Road) |
Vehicle Repair and Fuel Filling |
Possible spillage/ leakage of fuels and oils
during maintenance and filling activities |
5,163 |
17 |
Commercial,
Research & Development/OU |
Urban Residential
|
KTN-16 |
Computer waste recycling yard (partially paved) (South of Ho Sheung Heung Road) |
Electronic Waste
Recycling |
Possible spillage/ leakage of acid and
metal-containing liquid during demolishing and recycling activities |
5,482 |
18 |
A, R2 |
Urban Residential
|
KTN-16a |
Fu Shing / Fu Ton vehicle repair workshop
(partially paved) (South of Ho Sheung Heung Road) |
Vehicle Repair |
Possible
spillage/ leakage of fuels and oils during maintenance activities |
1,620 |
10 |
A, R2 |
Urban Residential
|
KTN-16c |
Heavy Equipment
Maintenance workshop (unpaved) (South of Ho Sheung
Heung Road) |
Excavator
Maintenance |
Possible
spillage/ leakage of fuels and oils during maintenance activities |
1,526 |
9 |
A, R2, Road
network within revised RODP |
Urban Residential |
KTN-18 |
Vehicle repair and maintenance workshop, (unpaved), (North of |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
1,974 |
12 |
Commercial, Research &
Development/OU |
Urban Residential
|
KTN-18a |
Vehicle repair and maintenance workshop (unpaved ground with some metal
sheet) (North of Castle Peak Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
456 |
3 |
Commercial, Research &
Development/OU |
Urban Residential
|
KTN-19-23 |
Vehicle and heavy equipment repair and maintenance, car dump (unpaved)
(North of Castle Peak Road) |
Vehicle Repair and Car Demolish |
Heavy staining of soil in several locations,
vehicle parts, fuel drums, refuelling operations, tires and scrap metal |
4,002 |
14 |
Commercial,
Research & Development/OU |
Urban Residential |
KTN-23b |
Chung Hing Hong, petrol station (partially
paved) Shell Gas (North of Castle Peak Road) |
Fuelling Area/ Fuel Storage |
Possible spillage/ leakage of fuel during filling
activity |
203 |
3 |
A |
Public Park |
KTN-25 |
Vehicle repair and maintenance workshop, (unpaved), (South of |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
1,092 |
6 |
R2 |
Urban Residential
|
KTN-26a |
Abandoned Vehicle Repair
Workshop (paved) , (South of Ho Sheung Heung
Pai Fung Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
218 |
3 |
A, Road network within
revised RODP |
Lower of
Industrial or Public Park |
KTN-26b |
Heavy vehicle repair and maintenance workshop (partially paved) (South
of Ho Sheung Heung Pai
Fung Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
761 |
5 |
A, R2, Road
network within revised RODP |
Urban Residential
|
KTN-28c |
Hang Fai, vehicle repair and maintenance (unpaved) (East of Ho Sheung Heung Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
5,981 |
20 |
Commercial,
Research & Development/OU |
Urban Residential |
KTN-28h |
Shing Kee Metal Works (paved) (North of Castle
Peak Road) |
Metal Workshop |
Possible spillage/ leakage of fuels and oils
during metal cutting/welding activities |
483 |
3 |
Commercial, Research & Development/OU |
Urban Residential |
KTN-31c |
Open storage and car park (unpaved) (South of Ma Tso Lung Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
2,481 |
12 |
O, R1c |
Urban Residential
|
KTN-34 |
Tsuen Kee Transportation Company, container yard
with minor vehicle repair activity. Limited access. (West of Ho Sheung Heung Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
3,699 |
14 |
R2, O |
Urban Residential
|
KTN-34a |
Wah Yan Hong Chemical Factory (1974), (paved) (West of Ho Sheung Heung Road) |
Chemical Processing and Storage |
Possible spillage/ leakage of chemicals
during operation. |
1,494 |
9 |
R2, O, Road
network within revised RODP |
Urban Residential |
KTN-34b |
Lai Cheong, Metal Workshop (paved) |
Metal Workshop |
Possible spillage/ leakage of fuels and oils
during metal cutting/welding activities |
545 |
3 |
R2, O |
Urban Residential
|
KTN-35a |
Vehicle repair and maintenance (partially paved) (North of Ma Tso Lung
Road) |
Vehicle Repair |
Potential spillage/ leakage of fuels and
oils during maintenance activities |
632 |
4 |
PRH, O |
Urban Residential
|
KTN-35c |
Wo Fat
vehicle repair (unpaved) (West of Ho Sheung Heung
Road) |
Vehicle Repair |
Potential spillage/ leakage of fuels and
oils during maintenance activities |
1,394 |
8 |
E, PRH, O, Road network within revised RODP |
Rural Residential
|
KTN-36 |
Sun Wing Lee heavy equipment maintenance workshop (Ho Sheung Heung Pai Fung Road) |
Heavy Equipment Repair |
Possible spillage/ leaking of fuels &
oils during maintenance activities |
2,349 |
12 |
R2 |
Urban Residential
|
KTN-37 |
Industrial Estate (i.e. several large warehouse, Hip Chun metal
workshop, Tak Fung waste recycling yard, Chun Hing
warehouse, Yee Fu logistic and warehouse, Wing Chun logistic) (West of Ho Sheung Heung Pai Fung
Road) |
Industrial Estate |
Possible spillage/ leaking of fuels, oils
and chemical during various industrial and maintenance activities |
8,254 |
28 |
GB, R2, Road
network within revised RODP |
Urban Residential
|
KTN-38 |
Heavy Truck Parking (partially paved) and Vehicle Maintenance Workshop
(paved) (West of Ho Sheung Heung Road) |
Vehicle Repair |
Potential spillage/ leakage of fuels and
oils during maintenance activities |
10,377 |
29 |
A, GB, R2, O,
Road network within revised RODP |
Urban Residential
|
KTN-39 |
Hop Cheong, Vehicle Repair and Maintenance (since 2003) (West of Ho Sheung Heung Road) |
Vehicle Repair |
Potential spillage/ leakage of fuels and
oils during maintenance activities |
959 |
6 |
A, R2, Road network
within revised RODP |
Urban Residential
|
KTN-40 |
Wah Fung Hong, Sun Lun, scrap metal (paved)
(West of Ho Sheung Heung Road) |
Metal Recycling |
Possible spillage/ leakage of fuels, oils or
other chemical during recycling and packing process |
3,758 |
14 |
A, R2, Road
network within revised RODP |
Urban Residential
|
KTN-40a |
Open parking
with maintenance workshop (partially paved) (West of Ho Sheung
Heung Road) |
Vehicle Repair |
Potential spillage/
leakage of fuels and oils during maintenance activities |
2,485 |
12 |
R2, Road network
within revised RODP |
Urban Residential
|
KTN-41 |
Unistress Concrete Products (HK) Limited. Paul Y warehouse and open storage
with equipment maintenance workshop (partially paved) (West of Ho Sheung Heung Road) |
Heavy Equipment Repair |
Possible spillage/ leaking of fuels &
oils during maintenance activities |
20,478 |
31 |
A, R2, Road
network within revised RODP |
Urban Residential
|
KTN-51b |
Vehicle
repairing workshop (partially paved) (To the south of Lo Wu Firing Range) |
Vehicle Repair |
Potential spillage/ leakage of fuels and
oils during maintenance activities |
1,021 |
6 |
A, GB, Gr |
Urban Residential |
KTN-51d |
Storage of heavy equipment (unpaved) (To the south of Lo Wu Firing
Range) |
Scrap Metal Storage and equipment maintenance |
Possible spillage/ leakage of fuels, oils
and other chemicals during maintenance activities |
535 |
3 |
Gr |
Urban Residential |
KTN-52a |
Abandoned
temporary structures with a chimney (partially paved) (To the south of Lo Wu
Firing Range) |
Scrap Metal Storage and equipment maintenance |
Possible spillage/ leakage of fuels, oils
and other chemicals during maintenance activities |
835 |
5 |
Gr |
Urban Residential |
KTN-54 |
Fuel filling
station (paved) (To the south of Lo Wu Firing Range) |
Fuel filling and storage of oil drums |
Potential spillage/ leakage of fuels and
oils during operation |
952 |
6 |
A, Gr, Road network within revised RODP |
Urban Residential |
KTN-58c |
Waste recycling
workshop (partially paved) (Next to the Lo Wu Firing Range) |
Waste metal and
plastic recycling |
Potential spillage/ leakage of fuels, oils and
other chemicals during operation |
890 |
6 |
OU, Road network
within revised RODP |
Lower of
Industrial or Public Park |
KTN-64b |
Lik Hang
Engineering with metal workshop (partially paved) (North of Ma Tau Lung Road) |
Scrap Metal Storage and equipment maintenance |
Possible spillage/ leakage of fuels, oils
and other chemicals during maintenance activities |
1,051 |
6 |
O |
Public Park |
KTN-69 |
Metal Workshop (paved) (East of Ma Tso Lung Road) |
Metal Workshop |
Possible spillage/ leakage of fuels and oils
during metal cutting/welding activities |
1,721 |
11 |
E |
Rural Residential |
KTN-74a |
Construction materials and equipments (unpaved) (East of Ma Tso Lung
Road) |
Open Storage |
Possible spillage/ leakage of fuels, oils
and other chemicals from previous and current storage |
549 |
3 |
PRH |
Urban Residential
|
KTN-74b |
Ka Cheung maintenance yard (unpaved) (East of Ma Tso Lung Road) |
Construction Equipment Maintenance |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
693 |
4 |
PRH |
Urban Residential
|
KTN-74e |
Vehicle repair and maintenance yard (paved) (East of Ma Tau Lung Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
901 |
6 |
PRH |
Urban Residential
|
KTN-77 |
Container trailer park with vehicle repairing workshop (unpaved).
Metal workshop (unpaved). (area behind
saw mills) (Behind Saw Mills KTN-76) |
Heavy Vehicle Parking and Repairing. Painting of Metal on Unpaved
Ground |
Possible spillage/ leakage of fuels, oils
and other chemicals during previous storage and dumping activities (i.e. oil
stain observed in some area) |
5,421 |
18 |
O, PRH |
Urban Residential |
KTN-78 |
Combine with 77 |
||||||
KTN-81 |
Po Wing, vehicle repair and maintenance (partially paved) (East of Ma
Tau Lung Road) |
Vehicle Repair and Demolish |
Possible spillage/ leakage of fuels and oils
during maintenance and demolishing activities |
2,751 |
13 |
R2, RR4 |
Rural Residemtial |
KTN-84 |
Shun Hai, trailer park, repair and
maintenance activities (paved) (North of Castle Peak Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
5,526 |
19 |
A, G, Road
network within revised RODP |
Urban Residential |
KTN-88 |
Car Vehicle and Trailer Parking Area (partially paved) (part of the site within the vicinity
of LMC Spur Line) |
Trailer parking
lot |
Possible spillage/ leakage of fuels and oils of vehicle. |
3,123 |
13 |
A, GB, Road
network within revised RODP |
Lower of
Industrial or Public Park |
KTN-92c |
Open storage (unpaved, grassland) (Next to Ho Sheung
Heung Village) |
Heavy Equipment Parking and Oil Drums Storage |
Possible spillage/ leakage of fuels and
oils during filling activities |
1,815 |
11 |
R2, Road network within revised RODP |
Urban Residential |
KTN-101 |
3 units of vehicle repairing and demolishing workshops (partially
paved) (North of Castle Peak Road) |
Vehicle Repair and Demolish |
Possible spillage/ leakage of fuels and oils
during maintenance and demolishing activities |
1,063 |
6 |
CDA, E, Road network
within revised RODP |
Rural Residential |
Note *: Permission for access the Sites KTN-23b, KTN-35a, KTN-77 and
KTN-78 has been granted for selecting the hotspot locations (e.g. borehole
locations for intrusive SI). Intrusive site investigation will be carried out
at these sites after liaison with the land user and formal permission for
Intrusive SI is granted.
Note (i): Except
Sites KTN-23b, KTN-35a and KTN-77,78 (i.e. these sites have been accessed and hotspots
have been identified), determination of the number of boreholes for other sites
is based on Table 2.1 of the Practice Guide for Investigation and
Remediation of Contaminated Land (PG) as summarized below:
Area of Site (m2) |
Min Number of Sampling Points |
100 |
3 |
500 |
3 |
1,000 |
6 |
2,000 |
12 |
4,000 |
14 |
5,000 |
17 |
8,000 |
28 |
10,000 |
29 |
30,000 |
32 |
90,000 |
35 |
Total recommended no. of boreholes is 490.
Table 3.2 Potentially
contaminated landuse (“A” Rating Sites”) at FLN NDA
Site No.* |
Location |
|
Potentially Sources of Contamination |
Approximate
Area (m²) |
Recommended No. of Boreholes(i) |
Future Landuse |
Corresponding RBRGs |
FLN-9a |
Luen Fat, vehicle repairing workshop (paved) (To the east of Woodland
Crest) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
343 |
3 |
Road network within revised RODP |
Lower of Industrial or Public Park |
FLN-10 |
Kee Cheong,
vehicle repairing workshop (paved) (To the east of Woodland Crest) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
306 |
3 |
Road network within revised RODP |
Lower of Industrial or Public Park |
FLN-11, 12, 13 |
Hing Yau Hon container yard (paved) (Man Kam To Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
13,995 |
29 |
IC, OU, G |
Urban Residential |
FLN-18 |
Yiu Wah
vehicle repairing workshop (partially paved) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities. |
1,144 |
7 |
OU, G |
Urban Residential |
FLN-18a |
Chung Kee, Choi Kee
and other 2 Vehicle Repairing Workshops. (unpaved to partially paved) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities. |
4,272 |
15 |
OU |
Public Park |
FLN-18c |
Hor Lung A/C,
Electronic, |
A/C, |
Possible spillage/ leakage of fuels and oils
during maintenance activities. |
321 |
3 |
OU |
Public Park |
FLN-23 |
2 Vehicle Repairing Workshops and 1 Illegal Petrol Filling Station.
(partially paved) (Man Kam To Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
2,831 |
13 |
OU |
Public Park |
FLN-23a |
Tat Wo, car repairing/maintenance (partially
paved) (Man Kam To Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
1,536 |
9 |
O, OU |
Public Park |
FLN-27a |
Parking Lot with Vehicle Repairing Workshop (partially paved) (To the
east of Man Kam To Road) |
Parking with Heavy Oil Staining |
Possible spillage/ leakage of fuels and oils
of vehicle. |
537 |
3 |
G |
Urban Residential |
FLN-27c |
Tai Keung Machinery (unpaved) (To the east of Man Kam To Road) |
Machinery Repairing |
Possible spillage/ leakage of fuels and oils
during repairing activities |
995 |
6 |
G |
Urban Residential |
FLN-28 |
Former Kit Wing vehicle repairing workshop (paved) (no operation)
(access limited) (To the east of Man Kam To Road) |
Vacant with Oil staining |
Possible contamination from the past
activities. (e.g. spillage/ leakage of fuels and oils during maintenance activities) |
162 |
3 |
G, O, Road network within revised RODP |
Urban Residential |
FLN-29a |
Sin Tat vehicle parking lot (partially paved) (To the east of Man Kam
To Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
1,144 |
7 |
G |
Urban Residential |
FLN-29b |
Ho Wah, vehicle repairing workshop (paved) (To the east of Man Kam To
Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
265 |
3 |
G |
Urban Residential |
FLN-29c |
Transportation company with in-house vehicle repairing workshop
(partially paved) (To the east of Man Kam To Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
492 |
3 |
G |
Urban Residential |
FLN-29d |
Logistic Company (paved) with parking lot beyond the loading bay
(unpaved) |
Trailer Park with Oil Staining |
Possible spillage/ leakage of fuels and oils
of vehicle. |
4,371 |
15 |
G, Road network within revised RODP |
Urban Residential |
FLN-29f |
Kwong Ming vehicle repairing Workshop (partially paved) (To the east of Man
Kam To Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
1,792 |
11 |
Road network within revised RODP |
Lower of Industrial or Public Park |
FLN-30 |
Yhet Hing vehicle repairing workshop (partially
paved) (To the east of Man Kam To Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
107 |
3 |
G, O, Road network within revised RODP |
Urban Residential |
FLN-30c |
Yee Hop Heavy Equipment Maintenance Workshop (unpaved) |
Equipment Maintenance |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
1,390 |
8 |
G, Road network within revised RODP |
Urban Residential |
FLN-31a |
Lung Sum vehicle repairing Workshop (partially paved) ( |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
790 |
5 |
G |
Urban Residential |
FLN-34 |
Fu Wah vehicle repairing workshop (partially paved) (Man Kam To Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
735 |
4 |
Road network within revised RODP |
Lower of Industrial or Public Park |
FLN-35 |
Kai Wan vehicle repairing workshop (unpaved) (Man Kam To Road) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
4,545 |
16 |
G |
Urban Residential |
FLN-37 |
Waste Recycling Workshop (partially paved) (Man Kam To Road) |
Waste metal and plastic recycling |
Potential spillage/ leakage of fuels, oils
and other chemicals during operation |
3,236 |
13 |
O, OU |
Public Park |
FLN-41 |
Large container yard with few maintenance workshops (unpaved) |
Containers Yards |
Possible spillage/ leakage of fuels and oils
of vehicle. |
65,634 |
34 |
O, PRH, OU, G,
Road network within revised RODP |
Urban Residential |
FLN-42 |
Vehicle Repairing Workshop (unpaved) |
Vehicle Repair |
Possible spillage/ leakage of fuels and oils
during maintenance activities |
986 |
6 |
AGR, G |
Urban Residential |
Note *: Permission for access the Site FLN-9a has been granted for
selecting the hotspot locations (e.g. borehole locations for intrusive SI).
Intrusive site investigation will be carried out at this site after liaison
with the land user and formal permission for detail SI is granted.
Note (i): Except Site FLN-9a (i.e. this site has
been accessed and hotspots have been identified), determination of the number
of boreholes is based on Table 2.1 of the Practice
Guide for Investigation and Remediation of Contaminated Land (PG) as
summarized below:
Area of Site (m2) |
Min Number of Sampling Points |
100 |
3 |
500 |
3 |
1,000 |
6 |
2,000 |
12 |
4,000 |
14 |
5,000 |
17 |
8,000 |
28 |
10,000 |
29 |
30,000 |
32 |
90,000 |
35 |
Total recommended no. of boreholes is 222.
Table 3.3 Potentially
Contaminated Landuse (“A” Rating Sites) along
Southern Section of Fanling Bypass
Site No.* |
Location |
Current |
Potentially Sources of Contamination |
Approximate Area (m²) |
Recommended No of Boreholes(i) |
Future Landuse |
Correspoding RBRGs |
FLB-5 |
K. Lee Engineering
Ltd. (paved) |
Vehicle Repair |
Possible spillage/
leakage of fuels and oils during maintenance activities |
3,033 |
13 |
Road network (FLB) |
Lower of Industrial or
Public Park |
FLB-14 |
Kin Yip Motors
(Operated by Cross Trade Investment Ltd), Car repairing workshop (paved) |
Vehicle Repair |
Possible spillage/
leakage of fuels and oils during maintenance activities |
498 |
3 |
Road network (FLB) |
Lower of Industrial or
Public Park |
FLB-17 |
Existing Caltex Petrol
Station (paved) |
Fuelling Area/ Fuel
Storage |
Possible spillage/
leakage of fuel during filling activity |
770 |
5 |
Road network (FLB) |
Lower of Industrial or
Public Park |
FLB-19 |
Car repairing workshop
(paved) |
Vehicle Repair |
Possible spillage/
leakage of fuels and oils during maintenance activities |
368 |
3 |
Road network (FLB) |
Lower of Industrial or
Public Park |
Note *: No permission was granted for access the site in FLB.
Note(i): Determination
of the number of boreholes is based on Table 2.1 of the Practice Guide for Investigation and Remediation of Contaminated Land
(PG) as summarized below:
Area of Site (m2) |
Min Number of Sampling Points |
100 |
3 |
500 |
3 |
1,000 |
6 |
2,000 |
12 |
4,000 |
14 |
5,000 |
17 |
8,000 |
28 |
10,000 |
29 |
30,000 |
32 |
90,000 |
35 |
Total
recommended no. of boreholes is 24.
The selection of chemicals of concern (COCs) for the potentially contaminated sites should be based on the historical land use and the information collected during the site survey with reference to RBRGs and EPD’s Practice Guide for Investigation and Remediation of Contaminated Land (the Practice Guide).
As mentioned in Sections 3.1 and 3.2, once any of the sites is handed over to PP, the PP’s appointed consultants should further appraise the sites with “A” rating and revisit the sites with “B” or “U” rating to identify the presence of “hot spots” for intrusive site investigation. Therefore, the PP’s appointed consultants will take the latest site appraisal information into consideration for selecting the site specific COCs with reference to RBRGs and the Practice Guide. All these latest information and proposed site specific COCs should be included in the supplementary CAP and submit to EPD for approval prior to the commencement of intrusive site investigation.
A generic analysis proposal corresponding to different types of potentially contaminating activities is given in Table 3.4 for reference. In case the type of activities reveal from the site re-appraisal (i.e. for “A” rating sites) or site re-visit (i.e. for “B” or “U” rating sites) cannot be found in Table 3.4, reference should be made to Appendix E “Chemical Contaminants Listed by Industrial Type” of Australian Standard 4482.1-2005 “Guide to the investigation and sampling of sites with potentially contaminated soil Part 1: Non-volatile and semi-volatile compounds”.
3.4.1 COCs for Accessible Government Lot Areas
As only four government lot areas are accessible and allowed for intrusive site investigation (i.e. refer to Section 5.1.1) throughout the NDAs at this stage, it is proposed to use a board testing approach, including Volatile Organic Chemicals (VOCs), Semi-volatile Organic Chemicals (SVOCs), metals and Petroleum Carbon Ranges (PCRs) for these 4 accessible government lot sites in order to gather as much data as possible. Polychlorinated Biphenyls (PCBs) and Cyanide are also proposed for site KTN-77,78 due to the worse site observation. The gathered data could provide the Project Proponent (PP) a preliminary picture and understanding of land contamination level/extent of other potentially contaminated sites with similar industrial activities.
Table 3.4 Generic
Analysis Proposal
Type of
Activities Based upon Site Surveys in 2009 |
Potentially
Polluting Activities |
Potential
Source of Contamination |
Possible
Contaminants |
Key Chemicals
of Concern (COCs) |
Motor vehicle/
equipment depot, repairing, service centre |
Release of oils
and fuels and lubricants from vehicles, vehicle and equipment maintenance and
refuelling. Use of chemicals and solvents in maintenance activities. Motor
vehicle painting and storage and disposal of wastes. |
Vehicle maintenance, scrap vehicle parts, fuels and lubricants storage |
Heavy metals, hydrocarbon (fuel, oils, lubricants), solvent or
degreasers, paint and battery acid. |
Metals(1)
(e.g. chromium, copper, lead, manganese, nickel, zinc), PCRs(2),
VOCs(3) (e.g. acetone, BTEX, MTBE, and trichloroethene) and SVOCs(4)
(e.g. PAHs), |
Car junk yards |
Release of oils
and fuels and lubricants from vehicles, vehicle and equipment maintenance and
refuelling. Use of chemicals and solvents in maintenance activities. Motor vehicle
painting and storage and disposal of wastes. |
Vehicle maintenance, scrap vehicle parts, fuels and lubricants storage |
Heavy metals, hydrocarbon (fuel, oils, lubricants), solvent or
degreasers, paint and battery acid. |
Metals (e.g.
chromium, copper, lead, manganese, nickel, zinc), PCRs,
VOCs (e.g. acetone, BTEX,
MTBE, and trichloroethene)
and SVOCs (e.g. PAHs), |
Trailer
/container storage yards |
Release of oils
and fuels and lubricants from vehicles, vehicle and equipment maintenance and
refuelling. Use of chemicals and solvents in maintenance activities. Motor
vehicle painting and storage and disposal of wastes. |
Vehicle maintenance, scrap vehicle parts, fuels and lubricants storage |
Heavy metals, hydrocarbon (fuel, oils, lubricants), solvent or
degreasers, paint. |
Metals (e.g.
chromium, copper, lead, manganese, nickel, zinc), PCRs,
VOCs (e.g. acetone, BTEX,
MTBE, and trichloroethene)
and SVOCs (e.g. PAHs), |
Scrap yards and
metal recycling facilities |
Waste oils and
fuels and lubricants from scrap vehicles/ machinery, transformers, scrap
metals, vehicle and equipment maintenance and refuelling. Storage and
disposal of wastes. |
Mechanical machinery, scrap metals and debris storage, maintenance
activities. |
Heavy metals, hydrocarbon (fuel, oils, lubricants), solvent or
degreasers. |
Metals (full
list), VOCs (e.g. acetone, BTEX,
MTBE and trichloroethene),
PCRs, SVOCs (e.g. PAHs), and PCBs. |
Petrol filling
stations |
Leaks from pipework, tanks and offset fill pipes. Spills during
customer refuelling, filling underground storage tanks and over filling of
portable containers. |
Petrol station fuel tanks / drums, possible vehicle maintenance. |
Heavy metals, hydrocarbon (fuel, oils, lubricants), solvent or
degreasers. |
Metals (e.g.
lead), PCRs, VOCs (e.g. BTEX and MTBE), and SVOCs (e.g. PAHs). |
Concrete and
asphalt production |
Storage and
transfer of residues from physical conversion of earthen materials by sorting,
mixing, and grinding. |
Mechanical machinery, maintenance activities, fuel and lubricants
storage. |
Heavy metals, hydrocarbon (fuel, oils, lubricants), solvent or
degreasers. |
VOCs (e.g. BTEX), PCRs, and SVOCs. |
Steel mills/ metal workshops |
Use of metals
and chemicals for manufacturing, equipment maintenance and cleaning, storage,
treatment and disposal of wastes. |
Mechanical machinery, foundry metal works, scrap metals and debris
storage, fuel and lubricants storage. |
Heavy metals, hydrocarbon (fuel, oils, lubricants-cutting and coating
oils), solvent or degreasers, paints. |
Metals (full
list), PCRs, VOCs (e.g. BTEX), SVOCs (e.g. phenol, and PAHs). |
Saw mills |
Timber cutting and
shaping activities, mechanical machinery, fuels and lubricants storage. |
Timber cutting and shaping activities, mechanical machinery, fuels and
lubricants storage. |
Wood treatment chemical, hydrocarbons (fuel, oils, lubricants-cutting
and coating oils) |
Metals (e.g.
lead, chromium, copper, zinc), PCR, VOCs, and SVOCs. |
Construction material and open storage areas |
Loading,
unloading and storage of goods, fuel storage and transfer, maintenance of
equipment and vehicles. |
Fuels, lubricants and various kinds of chemical storage |
Heavy metals, hydrocarbon (fuel, oils, lubricants), various chemicals. |
Metals (full
list), PCRs, VOCs and SVOCs. |
Uncontrolled dumping |
Storage of general construction waste, vehicle and machinery parts,
paints, fuels, oils, metals and batteries. |
General construction waste, vehicle and machinery parts, paints,
fuels, oils, metals, batteries. |
Heavy metals, hydrocarbon (fuel, oils, lubricants-cutting and coating
oils), paint, organic solvents, acids, lubricants and unidentified
contaminants. |
Metals (full
list), PCRs, VOCs, SVOCs, free cyanide, and PCBs. |
Chemical manufacturing/ processing plants, dangerous goods stores |
Spillages and accidents related to storage of chemicals, manufacturing
process, equipment maintenance and cleaning, storage, treatment and disposal
of wastes. |
Mechanical manufacturing equipments for chemicals and various kinds of
chemical storage |
Heavy metals, hydrocarbon (fuel, oils, lubricants), various chemicals,
organic solvents, acids |
Dependent on the
materials handled, stored, used and produced on site but would generally
include PCRs, VOCs, and SVOCs. |
Industrial estate |
Release of oils
and fuels and lubricants from mechanical machinery, equipment maintenance and
refuelling. Use of chemicals and solvents in maintenance activities. Storage
of foundry metal works, scrape metals, debris, fuel and lubricants. |
Mechanical machinery, foundry metal works, scrap metals and debris
storage, fuel and lubricants storage. |
Heavy metals, hydrocarbon (fuel, oils, lubricants), solvent or
degreasers, paint, battery acid, lubricants and unidentified contaminants. |
Metals (full
list), PCRs, VOCs, SVOCs, free cyanide, and PCBs. |
Several types of manufacturing facilities (electronic, umbrella, chemical manufacturing etc) |
Release of oils
and fuels and lubricants from mechanical machinery, equipment maintenance and
refuelling. Use of chemicals and solvents in maintenance activities. Storage
of chemicals for various manufacturing processes. |
Mechanical machinery, paint spraying, fuels and lubricants storage, a
range of chemicals associated with various manufacturing processes. |
Paints, organic solvents and degreasers, acids, lubricants (cutting
and coating oils), various kinds of chemicals. |
Metals (full
list), PCRs, VOCs, SVOCs, free cyanide, and PCBs. |
(1) In RBRGs, metals include antimony, arsenic, barium, cadmium, chromium III, chromium VI, cobalt, copper, lead, manganese, mercury, molybdenum, nickel, tin and zinc.
(2) Petroleum carbon ranges (PCRs) include C6 – C8, C9 – C16 and C17 – C35.
(3) Volatile organic chemicals (VOCs) include BTEX (benzene, toluene, ethylbenzene, and total xylenes), MTBE (methy tert-butyl ether), acetone, bromodichloromethane, 2-butanone, chloroform, methylene chloride, styrene, tetrachloroethene, and trichloroethene.
(4) Semi-volatile organic chemicals (SVOCs) include polyaromatic hydrocarbons (PAHs) [acenaphthene, acenaphthylene, anthracene, benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene, dibenzo(a,h)anthracene, fluoranthene, fluorene, indeno(1,2,3-cd)pyrene, naphthalene, phenanthrene and pyrene], bis-(2-ethylhexyl)phthalate, hexachlorobenzene, and phenol.
4 Potential Health Risk and Environmental Impacts
The potential impacts to the Project from contaminated soil and groundwater are judged to be as follows:
· Health risks to site workers;
· Disposal of contaminated soils, where encountered;
· Disposal of contaminated groundwater, where encountered; and
· Potential health risks to future users of the sites.
Site construction workers may become exposed to contaminated soils and groundwater during earth moving operations and the laying of pipelines or underground services. The main exposure routes for site construction workers are accidental direct ingestion of contaminated materials through poor hygiene and eating or smoking on site, or through direct contact with potentially toxic or harmful contaminants in excavated soil.
Where excavations for NENT NDAs take place below the groundwater table, there may be a need to dewater the pits for safety and construction purposes. Where dewatering takes place through layers of contaminated material or where any contaminated soil is being excavated, the groundwater may become contaminated, thereby requiring appropriate handling and disposal. The proposed remediation method and disposal arrangement of the contaminated groundwater will be presented and addressed in the RAP, which will be submitted to EPD for approval during the course of this EIA Study, or in the supplementary RAP, which will be submitted to EPD for approval after the handover of those sites with no access during the course of this EIA Study.
Depending on the level of contamination encountered, and subject to the findings of the aforesaid RAP, groundwater will need to be disposed of in an appropriate manner, comply with the WPCO.
During the operational phase, there is little potential for impacts associated with contaminated soils. However, maintenance workers may come into contact with such materials, at which time all of the above mentioned impacts may be applicable. However, if contaminated material is identified during the construction stage, it is expected that appropriate remedial measures will have been undertaken either to ensure this material is mitigated or removed, or to ensure that future, direct contact with in-situ materials is avoided.
Potentially contaminated sites have been identified in Section 3 based on desktop study and site survey. Further site investigation is required to confirm and quantify the presence of soil and groundwater contamination within NDAs. Location of potentially contaminated sites in relation to the NDA boundary and landuse activities has been referenced for the selection of sampling points.
5.1.1 Site Investigation in Accessible Government Lot Areas
Due to the limitation of access in private land lot areas (i.e. refer to Section 5.1.2), sampling will be carried out at first in those potential land contamination sites within accessible government lot areas. There are three sites at KTN NDA (Sites KTN-23b, KTN-35a, and KTN-77,78), and one at FLN NDA (Site FLN-9a). Observed activities at the sites included car repair/ maintenance, petrol refilling, open storage and workshop. They are shown in Figures 5.1.1 - 5.1.2.
With permission from the site operators of government lot areas, photos were taken to identify the land contamination hot spot of government lot sites, of which are shown in Figures 5.2.1a - 5.2.4b. The landuse description of all potential contaminated sites is summarized in Tables 3.1 – 3.4.
Totally, there are 15 sampling locations for the CAP (see Table 5.1 and Figures 5.2.1a - 5.2.4b for details). Assignment of the sampling points and locations are mainly based on the observed hot spots (e.g. stain areas) during the site visits. The historical drilling records in the nearby locations of the proposed boreholes are taken into reference to decide the termination levels of each borehole. The historical drillhole records are given in Appendix F. Nevertheless, the on-site Land Contamination Specialist will decide the appropriate depths for sampling on a point by point basis.
It should be noted that a stand-alone CAP for the abovementioned four accessible government lot areas had been submitted and approved by EPD on 30 September 2009.
5.1.2 Site Investigation in Private Land Lot Areas
The permission for access and drilling works in private land lot areas have been discussed with the private land owners / site operators, but not successful. Therefore, the site investigation will be carried out in private lot areas after these areas are resumed and accessible. The PP’s appointed consultants should refer to Section 3.3 for the detailed submission requirement.
5.2.1 Future Site Investigation for Accessible Government Lot Areas
Since the four accessible potentially contaminated government lot areas mentioned in Section 5.1.1 are still in operation and any propose remediation works after intrusive site investigation at this stage will only be carried out in a number of years later. Hence, the proposed site investigation for the four accessible potentially contaminated government lot areas during this EIA study will only serve as a preliminary assessment of the current site situation. After each of these four areas are handed over to the PP, the PP’s appointed consultants should revisit the areas to assess the latest site situation, review the available information, carry out further site investigation, and submit an updated SI report to EPD for approval. Also, the PP’s appointed consultants are required to submit the supplementary CAP to EPD prior to the commencement of SI works. Following on from the submission of CAP and completion of SI, the PP’s appointed consultants would prepare CAR, RAP and RR for contaminations other than As (which will follow the recommendations of the HRA) for all of these four accessible potentially contaminated government lot areas prior to the commencement of the proposed development at these four sites. The PP’s appointed consultants should refer to Section 3.3 for the detailed submission requirement.
5.2.2 Future Site Investigation for Inaccessible Government and Private Lot Areas
The PP’s appointed consultant should also assess the land contamination level of the inaccessible government and private lots areas once these areas are resumed and become accessible. Supplementary information such as locations of hotspots, sampling strategy and testing protocol for these areas will be prepared and submitted to EPD for approval and SI & soil/groundwater sampling works will be carried out accordingly. Also, the Project Proponent (PP)’s appointed consultants should prepare and submit the supplementary CAP, CAR, RAP and RR to EPD for approval prior to the commencement of the proposed development at these sites.
In order to avoid errors and misplacement of documents, the PP’s appointed consultants should submit the supplementary CAP, CAR, RAP and RR in separate packages (e.g. one package for one project/development area) instead of one set of report which includes all of the concerned inaccessible sites. The PP’s appointed consultants should refer to Section 3.3 for the detailed submission requirement.
Table 5.1 Sampling
Strategy for the Four Accessible Government Lot Areas
Locations |
Coordinates |
Sampling Strategy |
Estimated No. of Samples (1) |
||||
NDA |
Site ID |
Borehole No. |
Easting |
Northing |
Termination Level for Environmental Sampling (bgl)
(mbgl) (1) |
Frequency of Sampling Analysis (2) |
|
Kwu Tung North |
KTN-23b (Figures 5.1.1, 5.2.1a & 5.2.1b) |
KTN 23b-1 |
828497 |
840470 |
14.20 - (Drillhole Record at (E828509.67, N840339.42) in Jan 95
was referred. (i.e. ALLUVIUM ended at Saprolite
layer of 14.10mbgl) |
Drilling of a borehole and collection of
soil samples at depths of 0.5, 1.5 & 3.0, and then at 3.0m intervals to
the termination level for environmental sampling. One groundwater sample if
encountered. |
6 soil + 1 water samples |
KTN 23b-2 |
828504 |
840458 |
6 soil + 1
water samples |
||||
KTN-35a,b (Figure 5.1.1, 5.2.2a & 5.2.2b) |
KTN 35a-1 |
828455 |
841025 |
6.45 - (Drillhole Record at (E828480.29,
N841189.88) in April 97 was referred. (i.e. COLLUVIUM
ended at Saprolite layer of 6.45mbgl) |
4 soil + 1 water samples |
||
KTN 35a-2 |
828468 |
841029 |
4 soil + 1 water samples |
||||
KTN-77,78 (Figures 5.1.1. 5.2.3a & 5.2.3b) |
KTN 77,78-1 |
827968 |
840911 |
1.50 + 4.50 = 6.00 (Drillhole Record at (E827999.14, N840957.17) in Nov/Dec
97 was referred. Owing to the
relative thin COLLUVIUM layer ended at Saprolite layer of 1.5m, it is recommended to extend the
Termination Level into the first layer of Saprolite
(Grade V slightly gravelly sandy SILT/CLAY) from 1.5 to 6.0m |
4 soil + 1
water samples |
||
KTN 77,78-2 |
827983 |
840935 |
4 soil + 1
water samples |
||||
KTN 77,78-3 |
827989 |
840916 |
4 soil + 1
water samples |
||||
KTN 77,78-4 |
828003 |
840921 |
4 soil + 1
water samples |
||||
KTN 77,78-5 |
828021 |
840941 |
4 soil + 1
water samples |
||||
KTN 77,78-6 |
828023 |
840925 |
4 soil + 1
water samples |
||||
KTN 77,78-7 |
828014 |
840917 |
4 soil + 1
water samples |
||||
KTN 77,78-8 |
828025 |
840907 |
4 soil + 1
water samples |
||||
Fanling North |
FLN-9a (Figure 5.1.2, , 5.2.4a & 5.2.4b) |
FLN 9a-1 |
832062 |
840917 |
10.3 - (Drillhole Record at (E832033, N840928) in
Aug 88 was referred. (i.e. ALLUVIUM stopped at Saprolite
layer of 10.3mbgl) |
5 soil + 1
water samples |
|
FLN 9a-2 |
832073 |
840915 |
5 soil + 1
water samples |
||||
FLN 9a-3 |
832075 |
840906 |
5 soil + 1
water samples |
(1)
The proposed Termination
Levels for Environmental Sampling and Estimated No. of Samples are just for
reference purpose. The exact termination levels and no. of soil/ groundwater
samples of each borehole should be decided by the on-site Land Contamination Specialist.
(2)
Historical drillhole records indicated that the water levels in the
nearby areas of proposed boreholes are approximately ranged from 2 to 5 mbgl, hence, it is very likely to encounter the groundwater
table of each proposed borehole.
5.3.1 General
The sampling work will be undertaken following appropriate protocols, to minimise the potential for cross-contamination between samples and between different sampling locations. The soil sampling methods are based on techniques developed by USEPA. These methods include decontamination procedures, sample collection, preparation and preservation, and chain-of-custody documentation.
For general land contamination assessments, samples are collected by drillholes as the sampling depth will often exceed 3.0m. This will minimise the chance of cross-contamination between samples that are often observed when using the trial pit method. When conducting the intrusive investigations, care will be taken to avoid underground utilities.
Samples for laboratory testing will be taken with clean stainless steel hand tools and clean latex gloves and placed in rigid containers made of a material that is non-reactive with the likely contaminants.
In addition to the samples collected for laboratory analysis, a strata log will be kept for record of additional data to aid in the interpretation of results. Information on the general structure of the subsurface strata including grain size, colour, and wetness, and the depth and thickness of each soil/rock layer will be noted. The presence of any foreign material such as metals, wood, or plastics is also to be recorded.
All field personnel should wear adequate personal protective equipment when working in potential contaminated areas.
5.3.2 Decontamination Procedures
Equipment in contact with the ground shall be thoroughly decontaminated between each sampling event to minimize the potential for cross contamination. The equipment shall be decontaminated by steam cleaning, then washed with phosphate-free detergent and finally rinsed with water. Only clean water shall be used for drilling.
A clean area immediately adjacent to the sample location should be established, using a clean plastic sheet, on which all cleaned, and foil wrapped equipment may be placed.
During sampling and decontamination activities, disposable latex gloves shall be worn to prevent the transfer of contaminants from other sources. Disposable accessories, such as latex gloves, will be discarded after use.
5.3.3 Soil Sampling
Drillhole sampling
Drilling of borehole and collection of soil samples should be conducted at depths of 0.5m, 1.5m & 3.0m, and then at 3.0m intervals to the base. The on-site Land Contamination Specialist will decide the appropriate depths for sampling on a point by point basis.
Sufficient sample (see Table 5.2) should be placed in a pre-cleaned glass sample jar. The jar lid should be covered with laboratory solvent washed aluminium foil and lids. The jar must be filled with no void space (or otherwise if specified by the lab) for samples to be tested for VOCs. Each sample jar should be labelled. Records should be made of the details of the sampling location and other pertinent data. A chain-of-custody form should be completed for the samples. All samples should be stored on ice in portable ice chests between 2oC – 4oC whilst in the field or in transit.
Trial pit sampling
Trial pits should be constructed on site for soil and groundwater sampling if drilling sampling is not feasible. Trial pits can be constructed either manually or by an excavator, as judged as suitable by the site investigation contractor. Exact location of soil sampling should be determined on site by the on-site Land Contamination Specialist based on observation. The trial pits should be constructed to allow soil samples to be collected at:
· 0.5m below ground
· Level immediate above the groundwater level; and
· Level in between (i) and (ii) above for each sampling point.
Inspection of soil should be made at 0.5m intervals. The maximum depth of the trial pit would be 3m below ground level.
5.3.4 Groundwater Sampling
Groundwater samples shall be collected at each drillhole when groundwater is encountered. Historical drillhole records indicated that the water levels in the nearby areas of proposed boreholes are approximately ranged from 2 to 5 mbgl, hence, it is very likely to encounter the groundwater table of each proposed borehole. Anyhow, the on-site Land Contamination Specialist will decide whether the groundwater sample should be collected in accordance with the actual geological situation of the borehole.
Each sample shall be truly representative of the groundwater at the point from which it is taken, without dilution or contamination by water from other sources or by other material. A groundwater monitoring well shall be installed at each drillhole, and upon completion of installation of monitoring wells, approximately five times volumes of well shall be flushed to remove silt and drilling fluid residue from the wells. The wells shall then be allowed to stand for a day to permit groundwater conditions to equilibrate. Groundwater level and thickness of free product layer, if present, shall be measured by dip meter and interface probe respectively, before groundwater samples are taken. Moreover, prior to groundwater sampling, the sampling wells shall be purged (at least three times volumes of well) to remove fine-grained materials and to collect freshly refilled groundwater samples. After purging, one groundwater sample shall then be collected at each sampling well with a Teflon bailer. Field measurement of temperature and pH shall also be taken for each of the samples. The free products, if present, shall also be sampled to allow identification by the laboratory. Typical details of proposed groundwater monitoring well is shown in Appendix G.
If the permeability of the surrounding strata and storage is low, dewatering by pumping may dry up the hole, in which case the on-site Land Contamination Specialist will decide whether the requirement to pump out three times the liquid volume is to be waived.
After the dewatering process (and allowing groundwater to percolate back into the hole if it has been pumped dry), enough quantity of groundwater sample shall be collected from each drillhole, and then stored in different sample containers for analysis. Immediately after collection, samples shall be transferred to labelled sample containers containing the necessary preservatives (supplied by the laboratory). Samples shall be stored between 2oC – 4oC, and delivered to the laboratory within 24 hours. All samples shall be collected under chain-of-custody protocols.
5.3.5 Sample Size and Handling Criteria
Recommended sample size, sample containers and preservative procedures for each chemical analysis of the soil and groundwater have been summarized in Table 5.2. The containers shall be marked with sampling point codes and the depths at which the samples were taken. Samples shall be stored between 2oC – 4oC, and delivered to the laboratory within 24 hours.
Table
5.2 Summary
of Sample Handling Criteria
Analytical
Parameters |
Sample
Size |
Sample
Container |
Preservation |
Notes |
Soil Sampling |
||||
All major analyses in soil sample |
2 X 500g |
Glass Jar with Teflon Lined Lid |
Refrigeration at 2oC – 4oC |
The soil jar must be filled to minimise
headspace when volatiles are to be determined. |
Groundwater
Sample |
||||
Metals |
250ml |
Clear Plastic Bottle |
Nitric
Acid (HNO3) Refrigeration at 2oC – 4oC |
For Dissolved Metals the sample must be
filtered prior to acidification. |
PCRs (C6 – C8)
& VOCs |
2 X 40ml |
Glass Vial with Teflon Lined Lid |
Hydrochloric
Acid (HCl) Refrigeration at 2oC – 4oC |
The vials must be filled for zero
headspace. |
|
||||
PCRs (C9 – C16) |
1L |
Amber Glass Bottle with Teflon Lined Cap |
Refrigeration at 2oC – 4oC |
- |
PCRs (C17 – C35) |
||||
SVOCs |
||||
PCBs |
5.3.6 Analytical Programme and Parameters
Depends on the specific site activities, the PP’s appointed consultants should select and propose testing parameters in the supplementary CAP after the site re-appraisal / re-visit with reference to the general analysis proposal in Section 3.4 and Table 3.5. The soil and groundwater samples should be analysed by a HOKLAS accredited laboratory in accordance with analytical method given in Table 5.3.
· Volatile Organic Chemicals (VOCs):
· BTEX: benzene, toluene, ethylbenzene, and total xylenes
· MTBE: methyl tert-butyl ether
· VOCs other than BTEX and MTBE: acetone, bromodichloromethane, 2-butanone, chloroform, methylene chloride, styrene, tetrachloroethene, and trichloroethene
· Semi-volatile Organic Chemicals (SVOCs):
· PAHs: acenaphthene, acenaphthylene, anthracene, benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(g.h.i)perylene, benzo(k)fluoranthene, chrysene, dibenzo(a,h)anthracene, fluoranthene, fluorene, indeno(1,2,3-cd)pyrene, naphthalene, phenanthrene, and pyrene
· SVOCs other than PAHs: bis-(2-ethylhexyl)phthalate, hexachlorobenzene, and phenol
· Metals: antimony, arsenic, barium, cadmium, chromium III, chromium VI, cobalt, copper, lead, manganese, mercury, molybdenum, nickel, tin, zinc
· Petroluem Carbon Ranges (PCRs): Carbon Ranges C6-C8, C9-C16 and C17-C35
·
Polychlorinated
Biphenyls (PCBs)
· Cyanide: Cyanide, free (i.e. only for soil samples)
Table 5.3 Method
of Analysis for Soil and Groundwater Samples
Parameter |
Referenced
Analytical Method |
Reporting Limit
for Soil (mg/kg) |
Reporting Limit
for Groundwater (mg/L) |
VOCs |
|||
Acetone |
USEPA Method 8260 |
5 |
0.05 |
Benzene |
0.2 |
0.005 |
|
Bromodichloromethane |
0.1 |
0.005 |
|
2-Butanone |
5 |
0.05 |
|
Chloroform |
0.05 |
0.005 |
|
Ethylbenzene |
0.5 |
0.005 |
|
Methyl tert-Butyl
Ether |
0.5 |
0.005 |
|
Methylene Chloride |
0.5 |
0.05 |
|
Styrene |
0.5 |
0.005 |
|
Tetrachloroethene |
0.04 |
0.005 |
|
Toluene |
0.5 |
0.005 |
|
Trichloroethene |
0.1 |
0.005 |
|
Xylenes (Total) |
1.5 |
0.015 |
|
SVOCs |
|||
Acenaphthlene |
USEPA Method 8270 |
0.5 |
0.002 |
Acenaphthene |
0.5 |
0.002 |
|
Anthracene |
0.5 |
0.002 |
|
Benzo(a)anthracene |
0.5 |
- |
|
Benzo(a)pyrene |
0.5 |
- |
|
Benze(b)floranthene |
1.0 |
0.004 |
|
Benzo(g,h,i)perylene |
0.5 |
- |
|
Benzo(k)fluoranthene |
1.0 |
0.004 |
|
Bis-(2-Ethylhexyl)phthalate |
5.0 |
- |
|
Chrysene |
0.5 |
0.002 |
|
Dibenzo(a,h)anthracene |
0.5 |
- |
|
Fluoranthene |
0.5 |
0.002 |
|
Fluorene |
0.5 |
0.002 |
|
Hexachlorobenzene |
0.2 |
0.004 |
|
Indeno(1,2,3-cd)pyrene |
0.5 |
- |
|
Naphthalene |
0.5 |
0.002 |
|
Phenanthrene |
0.5 |
0.002 |
|
Phenol |
0.5 |
- |
|
Pyrene |
0.5 |
0.002 |
|
Metals |
|||
Antimony |
USEPA Method 6020A |
1 |
- |
Arsenic |
1 |
- |
|
Barium |
0.5 |
- |
|
Cadmium |
0.2 |
- |
|
Chromium III |
0.5 |
- |
|
Chromium VI |
0.5 |
- |
|
Cobalt |
0.5 |
- |
|
Copper |
1 |
- |
|
Lead |
1 |
- |
|
Manganese |
0.5 |
- |
|
Mercury |
0.05 |
0.0001 |
|
Molybdenum |
1 |
- |
|
Nickel |
1 |
- |
|
Tin |
0.5 |
- |
|
Zinc |
1 |
- |
|
PCRs |
|||
C6-C8 |
USEPA Method 8015 |
5 |
0.02 |
C9-C16 |
200 |
0.5 |
|
C17-C35 |
500 |
0.5 |
|
PCBs |
USEPA Method 8080 |
0.1 |
0.0001 |
Cyanide,
free |
USEPA Method 9010A |
1 |
- |
A HOKLAS accredited (or equivalent) testing laboratory shall be appointed to conduct chemical analysis for the soil and groundwater samples. All laboratory tests shall be made in accordance with Guidance Manual for Use of Risk-Based Remediation Goals for Contaminated Land Management. The RBRGs for soil and soil saturation limits, and RBRGs for groundwater and groundwater solubility limits are given in Appendix H.
5.3.7 Analytical Programme and Parameters for the Four Accessible Government Lot Areas
The soil and groundwater samples collected at the sampling points of 4 accessible government lot areas should be analyzed for parameters in accordance with sampling and testing schedule shown in Table 5.4 and analysed by a HOKLAS accredited laboratory in accordance with analytical method given in Table 5.3.
Table 5.4 Sampling
and Testing Schedule for the Four Accessible Government Lot Areas
Locations |
Existing Landuse |
Testing Parameters |
||||||
VOCs |
SVOCs |
Metals |
PCRs |
Cyanide |
PCBs |
|||
Kwu Tung North |
KTN-23b |
Chung Hing Hong, petrol station |
√ |
√ |
√ |
√ |
|
|
KTN-35a |
Vehicle repairing workshops |
√ |
√ |
√ |
√ |
|
|
|
KTN-77,78 |
Container trailer park |
√ |
√ |
√ |
√ |
√ |
√ |
|
Fanling North |
FLN-9a |
Luen Fat, vehicle repairing workshop |
√ |
√ |
√ |
√ |
|
|
5.3.8 Toxicity Characteristic Leaching Procedure Test
It is
envisaged that the likely scale of contamination should be very much localized,
if found. The volume of soil expected to require cleanup should be of small
quantities. Landfill disposal may be a practical option and should be
considered as the last resort. Additional tests in terms of Toxicity
Characteristic Leaching Procedure (TCLP) would be
required to meet the criteria for disposal to landfills. Hence, surplus soil
samples obtained during the site investigation would be stored for subsequent TCLP tests if identified necessary.
Landfill
disposal Criteria for Contaminated Soil is show in Table
5.5.
Table 5.5 Landfill
Disposal Criteria for Contaminated Soil
Parameter |
TCLP Limit (ppm) |
Referenced Analytical
Method |
Detection Limit (mg/L) |
Cadmium |
10 |
USEPA Method 1311 and 6020A |
0.2 |
Chromium |
50 |
1 |
|
Copper |
250 |
1 |
|
Nickel |
250 |
1 |
|
Lead |
50 |
1 |
|
Zinc |
250 |
1 |
|
Mercury |
1 |
0.2 |
|
Tin |
250 |
1 |
|
Silver |
50 |
1 |
|
Antimony |
150 |
1 |
|
Arsenic |
50 |
1 |
|
Beryllium |
10 |
1 |
|
Thallium |
50 |
1 |
|
Vanadium |
250 |
1 |
|
Selenium |
1 |
0.2 |
|
Barium |
1000 |
1 |
Ref: EPD’s Practice Guide for Investigation and Remediation of
Contaminated Land
5.3.9 Quality Control and Quality Assurance (QA/QC)
A proper
QA/QC program shall be established to ensure that the data collected are
accurate and representative of actual soil and groundwater conditions. The QA/QC programme shall include the
following:
·
1
duplicate per 20 samples;
·
1
equipment blank per 20 samples;
·
1
field blank per 20 samples; and
·
1
trip blank per trip for the analysis of volatile parameters.
5.3.10 Sample Handling, Packaging and Transport
The soil
and groundwater sampling shall be conducted by an experienced sampling
technician (provided by the G.I. Contractor), and the
appropriate procedures shall be adhered to. Sampling methodologies are based on
the techniques developed by the USEPA. Collection
tools shall be cleaned thoroughly before, in-between and after sampling. Special care shall be taken to prevent
any cross contamination of the samples during collection, handling, and
storage.
Sample
containers shall be laboratory cleansed, airtight, and made of glass or other
suitable materials with Teflon-lined lids to ensure that the container does not
react with the sample or absorb contaminants. Care shall be taken when recording and
labeling the sample information on the containers. Information such as the date/time,
sample point codes, depths, and any other relevant data shall be included. Samples shall be stored in an icebox (at
about 2oC – 4oC) immediately after collection and
labeled, until they can be transported to the laboratory for analysis.
After
endorsement of the CAP by EPD, site investigation will be conducted and then
the Contamination Assessment Report (CAR) will be prepared. The CAR will
present the findings of the site investigation where site access can be
obtained and evaluate the level and extent of potential contamination. The CAR
will evaluate the potential environmental and human health impacts based on the
extent of potential contamination identified. If remediation is required, a
Remediation Action Plan (RAP) will be prepared. The objectives of the RAP will
be:
·
To
undertake further site investigation where required;
·
To
evaluate and recommended appropriate remedial measures for the contaminated
soil and groundwater identified in the assessment;
·
To
recommend good handling practices for the contaminated soil and groundwater
during all stages of the remediation works;
·
To
recommend approximate handling and disposal measures; and
·
To
formulate optimal and cost-effective mitigation and remedial measures for the EPD’s agreement.
A
Remediation Report (RR) to demonstrate adequate clear-up shall be prepared and
submitted to EPD for endorsement prior to the commencement of any construction/
development works within the NDAs. No construction/ development works shall be
carried out before the endorsement of the RR.
The
supplementary CAP, CAR, RAP and RR mentioned in Section
5.2 should also follow the above submission procedures.
The possible contaminants that might be found in the potentially contaminated sites include volatile and semi-volatile organic compounds, metals and petroleum carbon ranges (PCRs).
Consideration of Remediation Methods for Contaminated
Soil
Soil remediation options applicable to the subject contaminants should be addressed based on the following criteria:
· Technical and cost effectiveness;
· Technology development status;
· Environmental benefits and dis-benefits;
· Commercial availability;
· Experience; and
· Expertise requirement.
6.1.1 Remediation Methods for Contaminated Soil
Common
treatment technologies that were screened for the targeted soil contaminants
are presented in Table 6.1 below.
The technologies are classified into removal, biological treatment, and
physical / chemical treatment.
Table 6.1 Treatment
Technologies for Contaminated Soil with VOCs / SVOC / Metals / PCRs
Technology |
In-situ Treatment |
Ex-situ Treatment |
|
Biological
Treatment |
·
Natural
Attenuation ·
Soil
Venting |
· Biopiling · Landfarming |
|
Physical / Chemical Treatment |
·
Electrokinetic Separation ·
Thermal
Desorption ·
Permeable
Reactive Barrier |
· Solidification/Stabilization · Soil Washing · Incineration |
|
Removal |
NA |
· Excavation and
Landfill Disposal |
The
applicability / environmental benefits and limitations / environmental dis-benefits of the above remediation techniques for VOCs / SVOC / metals / PCRs contaminated soil are detailed in Table
6.2.
In
assisting the formulation of appropriate remedial measures, the Practice Guide
issued by EPD suggest the following factors to be taken into consideration when
evaluating different available remediation methods:
· Degree and extent of the contamination;
· Anticipated future use of the site;
· Nature of the contaminants;
· Soil characteristics; and
· Time available for remediation.
The PP’s appointed consultants should take the aforementioned factors into consideration when formulating the remediation strategy after land resumption and completion of intrusive SI as mentioned in Section 5.2.
It should be noted that the “Excavation and Landfill Disposal” (i.e. off-site disposal of the treated contaminated soil) should only be considered as the last resort. Prior agreement to the proposed disposal arrangement should be sought from the Waste Facilities Management Group, and Waste Policy and Service Group of the EPD.
6.1.2 Remediation
Methods for Contaminated Groundwater
The applicability, limitations and environmental benefits and disbenefits of different remediation techniques for VOCs / SVOC / Mercury / PCRs contaminated groundwater are described in Table 6.3.
Table 6.2 List of
Soil Remediation Technologies for VOCs / SVOC / Metals / PCRs Contaminated
Soil
Remediation Option |
Descriptions |
Applicability / Environmental Benefits |
Limitations / Environmental Dis-benefits |
Biopiling |
An Ex-situ
bioremediation method that facilitates bacterial growth in contaminated soil
and degradation of waste into harmless products. |
·
Effective to PCRs and other wide range of organic contaminants with
some successful local case studies, e.g. decontamination works at the Cheoy Lee Shipyard at Penny’s Bay, reclamation works at
North Tsing Yi Shipyard site, decommissioning of
Kwan Chung Incinerator. · Most cost-effective for large volumes of
contaminated soil · All materials and equipment commercially available ·
Can be designed to
be a closed system; vapour emissions can be controlled |
·
Labour-intensive;
considerable maintenance required ·
Time-consuming (~12
months period) and not cost-effective for treating small soil samples. ·
Space required for biopile construction |
Soil Venting |
An In-situ bioremediation
method using indigenous bacterial degradation of contaminants. Bacterial
activity enhanced by air flow inducement (using extraction or injection wells)
and, if required, by adding nutrients. |
·
Very effective to PCRs ·
Suitable for
remediation in built up areas as wells can be placed between and/or below
buildings ·
Applicable to
extensive contamination in large sites ·
Uses readily
available equipment; easy to install ·
Vapour emissions
can be controlled but not to the extent of biopiling
depending on underground soil in-situ properties |
·
Effectiveness
hindered by underground soil features e.g. soil moisture content,
permeability, etc. ·
Potential air
emission to the sensitive receivers ·
Large area
requirement for system development |
Solidification /
Stabilization |
Ex-situ immobilization
technique treating contaminated soil by mixing soil with binding agents, e.g.
cement so as to physically bind contaminants into stable mass. |
·
Applicable to
clean-up inorganic contaminants such as heavy metals. ·
Solidification/stabilization
are used on certain contaminated sites in Hong Kong and successfully
demonstrated treatment method for inorganic contaminated soil, e.g.
decontamination works at the Cheoy Lee Shipyard at
Penny’s Bay, reclamation works at North Tsing Yi
Shipyard site, decommissioning of Kwan Chung Incinerator, and few isolated
sites identified in the Deep Bay Link project. |
·
Effective in
reducing presence of organic contaminants ·
Possible hindrance
of large boulders in mixing process. Soil sorting necessary prior to
treatment. |
Electrokinetic Separation |
This In-situ method uses electrochemical
and electrokinetic processes to desorb
and remove metals and polar organics from soil. Low intensity direct current
is applied to the soil to mobilize the charged species. |
·
Applicable to treat
soil with low permeability and heavily contaminated with metals. |
·
Effectiveness
dependent on moisture content of soil and decreases with moisture content
less than 10%. ·
Require further
treatment for removal of desorbed contaminants and thus increase cost of
remediation. ·
Variability of
electrical conductivity in soil may be induced by presence of anomalies such
as large gravels and insulating material. This may reduce treatment
effectiveness. |
Excavation and Landfill
Disposal |
Ex-situ method whereby contaminants
are removed by excavation of the contaminated soil and direct disposal to
landfill |
·
Most simple and
quickest way to dispose of large volume of contaminated soil. ·
Contamination is
removed definitely. ·
Higher certainty of
success. ·
Wide experience in
Hong Kong. ·
Applicable to all
waste or mixture that meet land disposal restriction treatment standards. ·
Common practice for
shallow, highly-contaminated soils. |
·
Pre-treatment may
be required for contaminated soil to meet landfill disposal criteria ·
Landfill space
limited and valuable. ·
Indirect costs to
the landfill management on monitoring and maintenance. ·
Potential long-term
liabilities to landfill ·
Need large volume
of clean backfill materials ·
No access to the
working site until completion of backfilling ·
Least desirable
management option. |
Thermal Desorption |
A
method to increase the volatility of contaminants by applying heat to the
contaminated soil so that the contaminants can be removed / separated from
the soil matrix. |
·
Low temperature thermal
desorption systems are targeted for soils contaminated with VOCs, SVOCs and fuel
components. ·
PAHs, PCBs, and pesticides
can be treated with high temperature thermal desorption. ·
Less polluting
method when compared with incineration. |
·
Have varying degrees
of effectiveness against the full spectrum of organic contaminants ·
Processor unit can
potentially be venerable to highly abrasive feed ·
Reaction time can
vary with feed content as a result of binding of contaminants |
Incineration |
Ex-situ or in-situ
treatment of contaminated soils and hazardous materials by incinerating in
order to break down contaminants. |
·
Applicable to soil
contaminated with hazardous wastes such as dioxins, PCBs, and chlorinated
hydrocarbons. ·
Wide experience in
Hong Kong. ·
Common practice for
highly-contaminated soils. |
·
Process produces
ash residues which contains volatile heavy metals ·
Ash residues
leaving the combustion unit requires gas treatment prior to release ·
Contaminants can
react to each other forming more volatile and toxic compounds which may
require breaking down in a caustic quench |
Table 6.3 List
of Groundwater Remediation Technologies for VOCs / SVOC / Mercury / PCRs
Contaminated Groundwater
Remediation Option |
Descriptions |
Applicability and Environmental Benefits |
Limitations and Environmental Disbenefits |
Vapour extraction / Groundwater extraction |
Vacuum is applied to well(s) above water table to recover vapour phase
and residual hydrocarbons and to help maintain high water table. Free product
and / or groundwater is recovered from wells by pumps. |
·
Low to moderately
permeable materials (silts and silty sands). Often
used to enhance recovery of hydrocarbons. |
·
Water and vapour
treatment is typically required ·
Phase separation is
required ·
Initial startup times are longer than other conventional methods ·
Moderate to large
capital investment, medium to high operation and maintenance costs |
Permeable Reactive Barriers |
In-situ treatment of contaminated water by means of engineering and
use of reactive materials. |
·
Applicable to
groundwater contaminated with volatile organic compounds, metals, and
radioactive contaminants. ·
Common method for
reducing chlorinated contaminants such as TCE and PCE. Effective method for immobilizing metals such as uranium, chromium and
arsenic. |
·
Method only applies
to relatively shallow aquifers ·
Treatment
effectiveness is highly dependent on groundwater chemistry / flow rate,
ground geochemistry, site topography, seasonal changes in hydrogeological
conditions. |
Vapour extraction / Groundwater extraction |
Vacuum is applied to well(s) above water table to recover vapour phase
and residual hydrocarbons and to help maintain high water table. Free product
and / or groundwater is recovered from wells by pumps. |
·
Low to moderately
permeable materials (silts and silty sands). Often
used to enhance recovery of hydrocarbons. |
·
Water and vapour
treatment is typically required ·
Phase separation is
required ·
Initial startup times are longer than other conventional methods ·
Moderate to large
capital investment, medium to high operation and maintenance costs |
Dual phase (liquid and vapour) recovery |
Both liquids and vapours are recovered from same well. Groundwater
production is minimized, and water table is stabilized. |
·
Generally low
permeability materials (clay, clayey silts, silts, silty
/ clayey sands). Requires surface seal (either naturally occurring clay or
man-made) to prevent short-circuiting of vacuum. ·
High vacuum
increases groundwater and product recovery. ·
Minimizes drawdown
and “smearing” of product. ·
Expedites site
cleanup by recovering all hydrocarbon phases. |
·
Usually requires
vapour and groundwater treatment ·
Phase separation is
required ·
Longer initial startup time ·
Higher capital
costs |
Skimming systems |
Free product is recovered from a pit or trench without recovering
groundwater |
·
Applicable to
settings in which the amount of free product is small and exists in permeable
conduits such as utility bedding or buried underground open structures. ·
Low cost and simple
operation and maintenance. ·
Ideal for shallow
groundwater level and soil excavation works. |
·
Recovery rates
depend on pit/trench size ·
Frequent media
replacement ·
Requires manual
adjustment |
The contamination problem at the potentially contaminated sites would not be considered insurmountable in the supportive view of the following factors:
· The sizes of the potentially contaminated sites are relatively small;
· The extent of potential contamination are relatively localized;
· The possible contaminants are relatively generic and easily remediated;
· Remediation methods available in the market are well established; and
· Local remediation experience is sufficient to deal with the nature of the possible contaminants.
At this stage, the land resumption programme has yet been confirmed as the planning and engineering feasibility study is still in progress, but it is expected the resumption programme would be divided into different distinct development or works packages. Therefore, the contamination assessment programme is expected to span the entire duration of the works packages, as access to potentially contaminated sites is granted. The assessment will comprise of the following activities:
· Preparation and submission of supplementary CAP to EPD for endorsement;
· Mobilization of the SI Contractor (pending private property access arrangements) and contracting analytical laboratory;
· Field sampling programme (number of days in field depends on number of sites and sampling locations to be employed);
· Analytical programme / laboratory turnaround (normal turnaround time is expected 10 days to two weeks depending upon the number of samples);
· Assessment and reporting of results in a draft supplementary CAR, including, if required, development of supplementary RAP (estimate minimum of three weeks) for contaminations other than As; and
· Preparation and submission of supplementary RR after the completion of remediation works.
A tentative programme for land contamination assessment and remediation work after land resumption is shown in Figure 7.1. It should be noted that the tentative programme is for general reference only and the actual time span will be subject to the actual site condition of each concerned sites.