10 Land Contamination Assessment

10.1 Introduction

This Section presents the assessment of potential land contamination impact associated with the construction and operation of the Project. The assessment identifies the potential sources of land contamination, summarises the intrusive site assessment findings, and reviews the need for mitigation measures and monitoring and audit programme to minimize potential environmental implications from the Project, and assesses the potential residual impacts after the implementation of the mitigation measures (if required).

A site appraisal of the Project Site was carried out to identify potential sources of land contamination from sources located within or adjacent to the Project Site. A Contamination Assessment Plan (CAP) was prepared outlining a programme for the intrusive site investigation to determine presence and extent (if any) of contamination at the Project Site. The CAP was approved by the EPD in December 2009.

The land contamination site investigation was carried out in accordance with the CAP in January 2010. Upon completion of the site investigation, a Contamination Assessment Report (CAR) was prepared detailing the investigation programme, on-site observations, and the results of the soil sampling and testing. The CAR was submitted to the EPD in March 2010.

This land contamination assessment has been undertaken in accordance with the requirements of Section 3.4.7 of the EIA Study Brief and makes reference to the CAP, dated October 2009 and the CAR, dated March 2010 (a copy of which including the CAP is provided in Annex F).

10.2 Legislative Requirements and Evaluation Criteria

Section 3.4.7 (ii) of the EIA Study Brief requires the EIA study to address likely issues associated with the land contamination within the study boundary and, if any, the boundaries of all associated areas of the Project. The brief requires the contamination impact to be evaluated and assessed as stipulated in Sections 3 of Annex 19 of the Technical Memorandum on the Environmental Impact Process (EIAO-TM), issued under Section 16 of the EIAO. Annex 19 of the EIAO-TM: Guidelines for Assessment of Impact on Sites of Cultural Heritage and Other Impacts provides guidance on contamination assessment of potential contaminated land.

The assessment of land contamination sources and the potential impacts to particular development projects are guided by the EPD’s Guidance Manual for Use of Risk-based Remediation Goals (RBRGs) for Contaminated Land Management (the RBRG Guidance Manual), the associated Guidance Note for Contaminated Land Assessment and Remediation, and the EPD’s Guidance Notes for Investigation and Remediation of Contaminated Sites of Petrol Filling Stations, Boatyards, and Car Repair/Dismantling Workshop. The RBRGs were developed for four different post-restoration land-use scenarios. The Project Site is classified as a Rural Residential Site under the RBRGs.

RBRGs for soil, used in conjunction with associated Soil Saturation Limits (C_sat), set the remediation goals for soil. Detected concentrations of Chemicals of Concern (COCs) in soil at the Project Site will be compared to the RBRG values for Rural Residential Land Use and the associated C_sat values.

The following legislation, documents and guidelines may also cover or have some bearing upon the assessment contamination and the handling, treatment and disposal of contaminated materials (if any) for the Project.

· Waste Disposal Ordinance (Cap 354);

· Waste Disposal (Chemical Waste) (General) Regulation (Cap 354);

· Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes, EPD (1992);

· Water Pollution Control Ordinance (WPCO) (Cap 358); and

· Technical Memorandum on Standards for effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters.

10.3 Site Conditions

The following sections describe the Project Site and the environmental settings, and is contained in the CAP in Annex F and referenced as deemed necessary.

10.3.1 Site Environmental Setting

The Project Site comprises an approximately 4.5 km long section of the Shenzhen River and is located at the boundary of Shenzhen and Hong Kong. The Project Site is predominantly rural. To the west of the river within the Shenzhen Special Economic Region, schools, residential dwellings and a sewage treatment works have been identified. The area which is located to the east of the Project Site within the Hong Kong SAR is predominately rural with mainly village houses, farm lands and undeveloped lands.

10.3.2 Description of Existing Conditions

A review of the available information, including a review of aerial photographs, historical maps, and historical contamination study in the Project area and the nearby area, was conducted for potential sources of land contamination that may impact the Project Site. Two site surveys were also undertaken by ERM, the first of which was undertaken on 30 July 2009 and the second site survey on 7 August 2009, as detailed in the CAP. During the surveys, the area was inspected for evidence of any of the following characteristics:

· open burning;

· areas of dead or stressed vegetation;

· areas of stained soil;

· recent soil disturbances;

· on site disposal of municipal or hazardous wastes;

· oil slicks or discoloration on surface waters;

· storage and handling of chemicals, oils and other materials;

· abnormal odours; and,

· indications of presence of septic tanks or underground storage tanks (UST).

In the vicinity of the Project Site, a few potential commercial and industrial developments were identified. These included an abandoned poultry farm, a non-operating industrial facility with an air emission stack, a police station with a dangerous goods store and a pumping station for the Ping Yuen River (River Ganges) as listed in Table 10.1.

Table 10.1 Potential Commercial and Industrial Developments Identified in the Vicinity of the Project Site during Site Survey

Site	Description ^(a)	Approximate Distance to Project Site (m)	Potential Contaminants
1	Abandoned poultry farm.	40	-
2	Abandoned poultry/livestock farm.	50	-
3	A nursery - storage of fertilizers in the field, the area is not paved but is covered by plastic sheets structure.	100	Fertilizers and pesticides
4	Fenced off area with buildings and an air emission stack. Next to this area were large buildings in fenced off area. Information from a local villager indicates that the site was a bean curd sheets/sticks manufacturing plant. It appears that it was not in operation for some times. It is not sure about the type of fuel to be used for the operation of the plant (charcoal/woods or diesels).	Partly within the Project Site	Petroleum hydrocarbons, volatile organic compounds
5	Police station with dangerous goods store. Opposite police station was a fire station. An emergency generator was installed in a plant room within the police station building. An above ground diesel tank (about 250 litre with a drip tray) was provided within the plant room. The plant room was paved and there is no sign of oil spillage. A Dangerous Goods (DG) store contains Types 4 and 5 DG in containers. The room is paved and with no sign of chemical spillage	75	Petroleum hydrocarbons, volatile organic compounds
6	River Ganges water pumping station.	10	Petroleum hydrocarbons
Note: (a) Sites were identified through aerial photographs, survey maps and site surveys.

Locations of these facilities are shown in Figure 10.1 and photographs taken during the site survey are presented in the CAP (Annex F).

10.4 Potential Sources of Land Contamination at the Site

Based on the historical uses of the Project Site and the environmental setting described above, the following potential existing on-site sources of land contamination that could affect the Project Site have been identified. They are described in the following sections.

10.4.1 Potential Existing Sources

The results of the desktop review and the site surveys indicated six (6) potential sites with land contamination concerns.

Site 1 is located at about 40 m from the Project Site. The location of this establishment was identified through a review of aerial photographs and verified by site visit. Although access into the site was not available, based on the nature of its setting and the building arrangements, the facility was identified to be an abandoned poultry farm. Given the previous use of the site and that the site is located at about 170 m from the Project area, no further contamination investigation for this area was recommended.

Site 2 is located adjacent to the Project Site. The location of this establishment was identified through a review of aerial photographs. ERM visited this site on 7 August 2009 and identified that it was for poultry/ livestock farm uses. The facility was abandoned and most of the buildings/sheds were damaged. No potential land contamination sources were identified within the site.

Site 3 is a nursery which is located at approximately 100 m from the Project Site. Site survey found that fertilizers stored in bags were stored on site. The fertilizer storage at this site was not considered to be a significant off site source that could cause significant on-going contamination at the Project Site. No further contamination investigation for these areas was recommended.

Site 4 is a potential industrial site identified in the first site visit, partly located within the Project Site. Restricted site access meant that the potential contaminations from this site could not be confirmed during the site surveys and no information was available through previous investigations or historical maps/photographs. During the second site visit on 7 August 2009, a local villager informed the study team that the site was formally used for production of bean curd sheets and sticks. However, the type of fuels (eg charcoals/woods or diesel) used for the production cannot be determined. The potential for land contamination at this site cannot be excluded. Further contamination investigation for this area was recommended.

Site 5 is the Ta Kwu Ling Police Station which has a DG store and an oil storage tank. It is located at about 75 m from the Project Site. The above ground oil storage tank (about 250 L with a drip tray) was installed within the plant room of the emergency genset. The plant room is paved and with no sign of oil spillage. Types 4 and 5 DG are stored in containers and the DG store is paved and with no sign of chemical spillage. The potential for land contamination of the Project Site due to the operation of the DG store and the above ground oil storage tank was considered low. No further contamination investigation in this site was recommended.

Site 6 is a water pumping station (located adjacent to the Project Site) for the Ping Yuen River (River Ganges). As the Ping Yuen River has been widened, the pumping station is seldom used. Four small above ground transformers were found on site (two within the pumping station site and two at the CLP substation next to the pumping station) which are mounted on a paved area. No visual evidence of leakage of transformers oil at the pumping station site and CLP substation site was observed. It is confirmed by DSD that no emergency generator or underground fuel storage tank is provided in the pumping station. The operations of the water pumping station and the CLP substation were not considered to be significant off site sources that could cause significant on-going contamination at the Project Site. No further contamination investigation for these areas was recommended.

In addition to the industrial and commercial sites identified above, the Shenzhen River receives discharges from the nearby areas and contamination at the river bank from long-term deposition of pollutants from the river cannot be excluded. However, as the river bank data from the 1998 Study([1]) indicated that river bank soil down stream are not polluted, further contamination investigation along the river bank was not recommended.

The above sites and requirements for further investigation have been summarised in Table 10.2.

Table 10.2 Potential Sources of Contamination

Site	Description	Distance to Project Site (m)	Potential Impacts to Project Site?	Further Investigation Required?
1	Abandoned poultry farm.	170	No	No
2	Abandoned poultry/livestock farm.	65	No	No
3	A nursery with storage of fertilizers in the field. The area is not paved but is covered by plastic sheets structure.	170	No	No
4	Fenced off area with buildings and an air emission stack. Next to this area were large buildings in fenced off area.	Partly within the Project Site	Yes	Yes
5	Ta Kwu Ling Police Station with an above ground diesel oil storage tank and DG within the paved rooms of the station.	90	No	No
6	River Ganges water pumping station.	90	No	No
7	Shenzhen River.	0 - 10	No	No

10.4.2 Potential Future Source

It is not considered that the future operations of the Project are likely to cause on-going contamination of the underlying ground.

10.5 Land Contamination Site Investigation

The site investigation adjacent to Site 4 was undertaken on 21 January 2010 in accordance with the investigation programme and methodology described in the CAP and the results are presented in the CAR.

10.5.1 Sampling Locations

Site investigation was carried out at one (1) sampling location, namely BH1, located immediately adjacent to Site 4 and within the Project Site (see Figure 10.2), as presented in the CAR. Soil samples collected were visually inspected and checked for olfactory evidence of potential contamination.

The site investigation involved the use of a trial pit to investigate and determine the presence of soil contamination. Soil samples were taken from 0.5 m, 1.5 m and 2.95 m ([2]) below the ground surface (bgs) for analysis of metals (Antimony, Arsenic, Barium, Cadmium, Chromium III, Chromium VI, Cobalt, Copper, Lead, Manganese, Mercury, Molybdenum, Nickel, Tin and Zinc), total petroleum hydrocarbons (TPH), benzene, toluene, ethylbenzene and xylenes (BTEX) and polycyclic aromatic hydrocarbons (PAHs).

No groundwater sample was collected during the site investigation due to the absence of groundwater at the maximum excavation depth of 2.95 m (bgs).

10.5.2 Soil Analytical Results

Soil samples analytical results are presented in Table 10.3 and summarised in Table 10.4, as required under the RBRG Guidance Manual.

The detailed results of the laboratory analysis of the soil samples with the QA/QC information are presented in the CAR (see Annex F).

All analytical results of soil samples were below the RBRG standard for Rural Residential Land Use.

Table 10.3 Soil Data Summary and Comparison to RBRGs and C_sat (mg/kg)

Chemical	Frequency of detection (x/y) ^(b)	Range of detected conc. (mg/kg)	LOR	RBRG (mg/kg)^(b)	C_sat (mg/kg)	Maximum concentration exceeds
Chemical	Frequency of detection (x/y) ^(b)	Range of detected conc. (mg/kg)	LOR	RBRG (mg/kg)^(b)	C_sat (mg/kg)	RBRG	C_sat
Metals
Antimony	0/4	BRL	1	29.1	N/A	None	N/A
Chromium (VI)	0/4	BRL	1	218	N/A	None	N/A
Chromium (III)	4/4	8 – 18	1	10,000	N/A	None	N/A
Arsenic	4/4	9 – 21	1	21.8	N/A	None	N/A
Barium	4/4	21 - 52	1	10,000	N/A	None	N/A
Cadmium	1/4	BRL – 0.2	0.2	72.8	N/A	None	N/A
Cobalt	4/4	1 – 2	1	1,460	N/A	None	N/A
Copper	4/4	7 – 30	1	2,910	N/A	None	N/A
Lead	4/4	29 – 47	1	255	N/A	None	N/A
Manganese	4/4	34 – 182	1	10,000	N/A	None	N/A
Mercury	0/4	BRL	0. 2	6.52	N/A	None	N/A
Molybdenum	4/4	1 – 2	1	364	N/A	None	N/A
Nickel	4/4	3 – 7	1	1,460	N/A	None	N/A
Tin	4/4	1 – 2	1	10,000	N/A	None	N/A
Zinc	4/4	24 - 774	1	10,000	N/A	None	N/A
TPH
C₆-C₈	0/4	BRL	20	545	N/A	None	N/A
C₉-C₁₆	0/4	BRL	200	1,330	N/A	None	N/A
C₁₇-C₃₅	0/4	BRL	500	10,000	N/A	None	N/A
BTEX
Benzene	0/4	BRL	0.1	0.279	336	None	None
Toluene	0/4	BRL	0.5	705	235	None	None
Ethylbenzene	0/4	BRL	0.5	298	138	None	None
Xylenes (Total)	0/4	BRL	0.5 - 1	36.8	150	None	None
PAHs
Various	0/4	BRL	0.5 - 1	Var	Var	None	None
Notes: (a) Table based on Standard Form 3.2 of the RBRG Guidance Manual (b) x = number of samples above laboratory reporting limit, y = number of samples analysed (c) RBRG for rural residential land use was used for this Project (d) LOR = Level of reporting (e) N/A = not applicable (no C_sat values were available for these parameters) (f) BRL = Below reporting limit (g) Var. = various RBRG and C_sat\ values for individual compound

Table 10.4 Soil Analytical Results (mg/kg)

Chemical	LOR	RBRG	C_sat	Sample ID
Chemical	LOR	RBRG	C_sat	BH1 0.5m	BH1 1.5m	BH1 2.95m	BH1 DUP
Metals
Antimony	1	29.1	N/A	BRL	BRL	BRL	BRL
Chromium (VI)	1	218	N/A	BRL	BRL	BRL	BRL
Chromium (III)	1	10,000	N/A	14	18	8	15
Arsenic	1	21.8	N/A	9	21	11	21
Barium	1	10,000	N/A	47	51	21	52
Cadmium	0.2	72.8	N/A	0.2	BRL	BRL	BRL
Cobalt	1	1,460	N/A	2	2	1	2
Copper	1	2,910	N/A	30	11	7	11
Lead	1	255	N/A	40	46	29	47
Manganese	1	10,000	N/A	182	57	34	62
Mercury	0. 2	6.52	N/A	BRL	BRL	BRL	BRL
Molybdenum	1	364	N/A	1	2	1	2
Nickel	1	1,460	N/A	7	6	3	5
Tin	1	10,000	N/A	2	2	1	2
Zinc	1	10,000	N/A	774	35	24	32
TPH
C₆-C₈	20	545	N/A	BRL	BRL	BRL	BRL
C₉-C₁₆	200	1,330	N/A	BRL	BRL	BRL	BRL
C₁₇-C₃₅	500	10,000	N/A	BRL	BRL	BRL	BRL
BTEX
Benzene	0.1	0.279	336	BRL	BRL	BRL	BRL
Toluene	0.5	705	235	BRL	BRL	BRL	BRL
Ethylbenzene	0.5	298	138	BRL	BRL	BRL	BRL
Xylenes (Total)	0.5 - 1	36.8	150	BRL	BRL	BRL	BRL
PAHs
Various	0.5 - 1	Var	Var	BRL	BRL	BRL	BRL
Notes: (a) LOR = Level of reporting (b) RBRG values for Rural Residential land use were used for comparisons of results (c) Var. = various RBRG and Csat\ values for individual compound (d) BRL = below reporting levels (e) N/A = not applicable (no C_satvalues were available for these parameters) (f) DUP = Duplicate sample

10.6 Land Contamination Impact Assessment

Based on the analytical results, soil samples collected from BH1 do not exceed the RBRG (Rural Residential Land Uses) limits for the parameters tested. The field observations made during the site investigation works did not record any evidence of discolouration, odours or the presence of non-aqueous phase liquids (NAPLs).

Overall the results indicate no significant contamination in the soils to be excavated. No further testing or remediation is required.

10.7 Land Contamination Mitigation Measures

Based on the above investigation results, no mitigation measures are required during the construction and operation of the Project.

10.8 Residual Environmental Impacts

There will not be any residual impacts associated with the construction and operation of Project.

10.9 Environmental Monitoring and Audit

Based on the above investigation results, no further investigation is warranted.

As no potential risks to receptors anticipated, no environmental monitoring and audit programme is deemed necessary.

10.10 Conclusions

In the vicinity of the Project area, a few potential commercial and industrial developments were identified during the site surveys. These included abandoned poultry/livestock farms, a plant nursery, a non-operating industrial facility with an air emission stack, a police station with a dangerous goods store, and a pumping station for the Ping Yuen River. The potential land contamination risks of these facilities to the Project area were assessed and identified only one site (Site 4) required intrusive site investigation to confirm if the soil is contaminated. Based on the soil analytical results, it is concluded that there is no significant contamination at BH1. All results were below the respective RBRGs – Rural Residential for the parameters tested. As no groundwater was present at the sampling depth of 3 m (bgs), groundwater samples were not retrieved. There is no risk to humans from the handling of the excavated soil and therefore no further assessment or remediation of soil is required.

As the result of the above, no potential impact from the contaminated soil is anticipated.

([1]) Regulation of Shenzhen River Stage III EIA Study, 1998.

([2]) A large boulder was present at 2.95 which rendered the material not suitable for lab analysis.