8              Land Contamination

8.1          Introduction

8.1.1       Contaminated land refers to the land which has been polluted by hazardous substances as a result of industrial operations carried out on site over a number of years. These contaminants, if present, may pose hazardous risks or cause adverse effects to the land users and the nearby environment. The implications of land contamination associated with the proposed road improvement works were assessed in accordance with Section 3.4.7 of the EIA Study Brief.

8.2          Environmental Legislation, Standards & Guidelines

8.2.1       Relevant legislation, standards and guidelines applicable to this assessment of land contamination include:

Ÿ   Environmental Impact Assessment Ordinance (EIAO) (Cap. 499), Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM), Section 3 (Potential Contaminated Land Issues) of Annex 19 of the ‘Guidelines for Assessment of Impact on Sites of Cultural Heritage and Other Impacts’

Ÿ   The Guidance Note for Contaminated Land Assessment and Remediation (Guidance Note) sets out the requirements for proper assessment and management of potentially contaminated sites such as oil installations (e.g. oil depots, petrol filling stations), gas works, power plants, shipyards/boatyards, chemical manufacturing/processing plants, steel mills/metal workshops, car repairing/dismantling workshops and scrap yards. 

Ÿ   The Practice Guide for Investigation and Remediation of Contaminated Land (Practice Guide).  This guide outlines typical investigation methods and remediation strategies for the range of potential contaminants typically encountered in Hong Kong.

Ÿ   The Guidance Manual for Use of Risk-Based Remediation Goals for Contaminated Land Management (Guidance Manual) presents the risk based approach for contamination assessment and instructions for comparison of soil and groundwater data with Risk-Based Remediation Goals (RBRGs) for 54 chemicals of concern commonly found in Hong Kong.  The RBRGs were derived to suit Hong Kong conditions and were designed to protect the health of people who could potentially be exposed to land impacted by chemicals under four broad post-restoration land use categories.  RBRGs also serve as the remediation targets if remediation is necessary. The RBRGs for soil and groundwater are given in Tables 8.1 and 8.2.

Table 8.1               Risk-Based Remediation Goals (RBRGs) for Soil & Soil Saturation Limit

Chemical

 

Risk-Based Remediation Goals (RBRGs) for Soil

Soil Saturation Limit (Csat)

Urban Residential

Rural Residential

Industrial

Public Parks

(mg/kg)

(mg/kg)

(mg/kg)

(mg/kg)

(mg/kg)

VOCs 

Acetone

9,590

4,260

10,000*

10,000*

***

Benzene

0.704

0.279

9.21

42.2

336

Bromodichloromethane

0.317

0.129

2.85

13.4

1,030

2-Butanone

10,000*

10,000*

10,000*

10,000*

***

Chloroform

0.132

0.0529

1.54

253

1,100

Ethylbenzene

709

298

8,240

10,000*

138

Methyl tert-Butyl Ether

6.88

2.80

70.1

505

2,380

Methylene Chloride

1.30

0.529

13.9

128

921

Styrene

3,220

1,540

10,000*

10,000*

497

Tetrachloroethene

0.101

0.0444

0.777

1.84

97.1

Toluene

1,440

705

10,000*

10,000*

235

Trichloroethene

0.523

0.211

5.68

69.4

488

Xylenes (Total)

95.0

36.8

1,230

10,000*

150

SVOCs

Acenaphthene

3,510

3,280

10,000*

10,000*

60.2

Acenaphthylene

2,340

1,510

10,000*

10,000*

19.8

Anthracene

10,000*

10,000*

10,000*

10,000*

2.56

Benzo(a)anthracene

12.0

11.4

91.8

38.3

--

Benzo(a)pyrene

1.20

1.14

9.18

3.83

--

Benzo(b)fluoranthene

9.88

10.1

17.8

20.4

--

Benzo(g,h,i)perylene   

1,800

1,710

10,000*

5,740

--

Benzo(k)fluoranthene

120

114

918

383

--

Bis-(2-Ethylhexyl)phthalate

30.0

28.0

91.8

94.2

--

Chrysene

871

919

1,140

1,540

--

Dibenzo(a,h)anthracene

1.20

1.14

9.18

3.83

--

Fluoranthene

2,400

2,270

10,000*

7,620

--

Fluorene

2,380

2,250

10,000*

7,450

54.7

Hexachlorobenzene

0.243

0.220

0.582

0.713

--

Indeno(1,2,3-cd)pyrene

12.0

11.4

91.8

38.3

--

Naphthalene

182

85.6

453

914

125

Phenanthrene

10,000*

10,000*

10,000*

10,000*

28.0

Phenol

10,000*

10,000*

10,000*

10,000*

7,260

Pyrene

1,800

1,710

10,000*

5,720

 --

Metals 

Antimony

29.5

29.1

261

97.9

--

Arsenic

22.1

21.8

196

73.5

--

Barium

10,000*

10,000*

10,000*

10,000*

--

Cadmium

73.8

72.8

653

245

--

Chromium III

10,000*

10,000*

10,000*

10,000*

--

Chromium VI   

221

218

1,960

735

--

Cobalt

1,480

1,460

10,000*

4,900

--

Copper

2,950

2,910

10,000*

9,790

--

Lead

258

255

2,290

857

--

Manganese

10,000*

10,000*

10,000*

10,000*

--

Mercury

11.0

6.52

38.4

45.6

--

Molybdenum

369

364

3,260

1,220

--

Nickel

1,480

1,460

10,000*

4,900

--

Tin

10,000*

10,000*

10,000*

10,000*

--

Zinc

10,000*

10,000*

10,000*

10,000*

--

Dioxins / PCBs 

Dioxins (I-TEQ)

0.001

0.001

0.005

0.001

--

PCBs

0.236

0.226

0.748

0.756

--

Petroleum Carbon Ranges 

C6 - C8

1,410

545

10,000*

10,000*

1,000

C9 - C16

2,240

1,330

10,000*

10,000*

3,000

C17 - C35

10,000*

10,000*

10,000*

10,000*

5,000

Other Inorganic Compounds

Cyanide, free

1,480

1,460

10,000*

4,900

-- 

Organometallics

TBTO

22.1

21.8

196

73.5

 --

Notes:

(1)   For Dioxins, the cleanup levels in USEPA Office of Solid Waste and Emergency Response (OSWER) Directive of 1998 have been adopted. The OSWER Directive value of 1 ppb for residential use has been applied to the scenarios of "Urban Residential", "Rural Residential", and "Public Parks", while the low end of the range of values for industrial, 5 ppb, has been applied to the scenario of "industrial".

(2)   Soil saturation limits for petroleum carbon ranges taken from the Canada-Wide Standards for Petroleum Hydrocarbons in Soil, CCME 2000.

(3)    * indicates a 'ceiling limit' concentration.

(4)    *** indicates that the Csat value exceeds the 'ceiling limit' therefore the RBRG applies.

 

Table 8.2               Risk-Based Remediation Goals (RBRGs) for Groundwater and Solubility Limit

Chemical

Risk-Based Remediation Goals (RBRGs) for Groundwater

Groundwater

Solubility Limit

Urban Residential

Rural Residential

Industrial

(mg/L)

(mg/L)

(mg/L)

(mg/L)

VOCs 

Acetone

10,000*

10,000*

10,000*

***

Benzene

3.86

1.49

54.0

1,750

Bromodichloromethane

2.22

0.871

26.2

6,740

2-Butanone

10,000*

10,000*

10,000*

***

Chloroform

0.956

0.382

11.3

7,920

Ethylbenzene

1,020

391

10,000*

169

Methyl tert-Butyl Ether

153

61.1

1,810

***

Methylene Chloride

19.0

7.59

224

***

Styrene

3,020

1,160

10,000*

310

Tetrachloroethene

0.250

0.0996

2.95

200

Toluene

5,110

1,970

10,000*

526

Trichloroethene

1.21

0.481

14.2

1,100

Xylenes (Total)

112

43.3

1,570

175

SVOCs

Acenaphthene

10,000*

7,090

10,000*

4.24

Acenaphthylene

1,410

542

10,000*

3.93

Anthracene

10,000*

10,000*

10,000*

0.0434

Benzo(a)anthracene

--

--

--

--

Benzo(a)pyrene

--

--

--

--

Benzo(b)fluoranthene

0.539

0.203

7.53

0.0015

Benzo(g,h,i)perylene   

--

--

--

--

Benzo(k)fluoranthene

--

--

--

--

Bis-(2-Ethylhexyl)phthalate

--

--

--

--

Chrysene

58.1

21.9

812

0.0016

Dibenzo(a,h)anthracene

--

--

--

--

Fluoranthene

10,000*

10,000*

10,000*

0.206

Fluorene

10,000*

10,000*

10,000*

1.98

Hexachlorobenzene

0.0589

0.0234

0.695

6.20

Indeno(1,2,3-cd)pyrene

--

--

--

--

Naphthalene

61.7

23.7

862

31.0

Phenanthrene

10,000*

10,000*

10,000*

1.00

Phenol

--

--

--

--

Pyrene

10,000*

10,000*

10,000*

0.135

Metals

Antimony

--

--

--

--

Arsenic

--

--

--

--

Barium

--

--

--

--

Cadmium

--

--

--

--

Chromium III

--

--

--

--

Chromium VI   

--

--

--

--

Cobalt

--

--

--

--

Copper

--

--

--

--

Lead

--

--

--

--

Manganese

--

--

--

--

Mercury

0.486

0.184

6.79

--

Molybdenum

--

--

--

--

Nickel

--

--

--

--

Tin

--

--

--

--

Zinc

--

--

--

--

PCBs 

Dioxins (I-TEQ)

--

--

--

--

PCBs

0.433

0.171

5.11

0.031

Petroleum Carbon Ranges 

C6 - C8

82.2

31.7

1,150

5.23

C9 - C16

714

276

9,980

2.80

C17 - C35

12.8

4.93

178

2.80

Other Inorganic Compounds 

Cyanide, free

--

--

--

--

Organometallics 

TBTO

--

--

--

--

Notes:

(1)   Blank indicates that RBRG could not be calculated because the toxicity or physical/chemical values were unavailable, or the condition of Henry's Law Constant > 0.00005 was not met for the inhalation pathway.

(2)   Water solubilities for Petroleum Carbon Range aliphatic C9-C16 and greater than C16 generally are considered to be effectively zero and therefore the aromatic solubility for C9-C16 is used.

(3)  * indicates a 'ceiling limit' concentration.

(4)   *** indicates that the solubility limit exceeds the 'ceiling limit' therefore the RBRG applies.

8.3          Assessment Methodologies

8.3.1       The following tasks have been undertaken to identify any potentially contaminated areas:

Ÿ     Desktop study to review the current and historical land uses; and

Ÿ     Site inspection to identify potentially contaminated areas as necessary.

8.3.2       To facilitate the land contamination assessment, the following sources of information have also been collated and reviewed:

Ÿ     Aerial photographs from Survey and Mapping Office of Lands Department;

Ÿ     Information of chemical waste producer registration and spillage or release of chemical and/or chemical wastes from Environmental Protection Department (EPD);

Ÿ     Information of dangerous goods from Fire Services Department (FSD);

Ÿ     Photographs from site inspection; and

Ÿ     Relevant approved EIA report

8.4          Description of the Environment

8.4.1       The road improvement works will be conducted at Junction of (J/O) Lin Tak Road / Sau Mau Ping Road, at J/O Clear Water Bay Road / On Sau Road and J/O Clear Water Bay Road / New Clear Water Bay Road and at J/O New Clear Water Bay Road near Shun Lee Tsuen Road. The location and extent of these Sites are shown in Figure 2.2 to 2.4.

8.5          Site Appraisal

Acquistition of Information from Relevant Government Departments

8.5.1       EPD and FSD have been contacted for (i) history of chemical waste producers registration; (ii) spillage or release of chemical and/or chemical wastes within the Sites; (iii) records of dangerous goods storage license; (iv) reported accidents of spillage/leakage of dangerous goods (DGs).

8.5.2       EPD and FSD’s replies on the request had been received and attached in Appendix 8.1. All the information provided is summarized below.

Environmental Protection Department

8.5.3       According to the information provided by EPD, there are no records of accidents of chemical spillage/leakage at the Sites. 

8.5.4       There were two records of registered chemical waste producers located in the Sites. All the registrations were terminated and no record of waste produced. Details of the chemical waste producers are provided in Appendix 8.1.

Fire Services Department

8.5.5       According to the information provided by FSD, there are no DGs stored at the Sites and FSD has no records of accidents of spillage/leakage of DGs. FSD’s reply is provided in Appendix 8.1.

Review of Aerial Photographs

8.5.6       A review of historical maps of Hong Kong and aerial photographs has been undertaken. The aim of this review is to evaluate the likelihood of contamination associated with any apparent land use changes at the subject locations. Since the approved EIA report for “Agreement No. CE 18/2012 (CE) Development of Anderson Road Quarry – Investigation” has already reviewed the aerial photographs between 1963 and 2011 and the review findings show that no potential land contamination activities were anticipated in the Sites. Therefore, aerial photos after 2011 are reviewed in this EIA Study. The review result is summarized below and a list of aerial photographs reviewed has been provided in Table 8.3. Selected aerial photos are provided in Appendix 8.2 for reference.

 

Table 8.3               Review of Aerial Photographs

Sites

Year

Photograph Reference No.

J/O Lin Tak Road / Sau Mau Ping Road

2014

CS53539

J/O Clear Water Bay Road / On Sau Road and J/O Clear Water Bay Road / New Clear Water Bay Road

2014

CS53546

J/O New Clear Water Bay Road near Shun Lee Tsuen Road

2014

CS49232

8.5.7       Comparing the latest available aerial photographs taken in Year 2014 with the aerial photos in the approved EIA report, there are no significant changes of land use and activity at the Sites “J/O Lin Tak Road / Sau Mau Ping Road” and “J/O Clear Water Bay Road / On Sau Road and J/O Clear Water Bay Road / New Clear Water Bay Road”. For the Site, “J/O New Clear Water Bay Road near Shun Lee Tsuen Road”, the slope formation works in Year 2011 were shown to be completed in Year 2014. Besides, no other significant changes of land use and activity are observed within the Site.

Site Inspection

8.5.8       Site inspection was carried out on 8 May 2015.  During the site inspection, the Sites are in normal operation and no land contamination activities were observed. Site inspection photos are shown in Figure 8.1 to Figure 8.3.  

8.6          Identification of Sensitive Receptors

8.6.1       Onsite construction workers are considered to have the potential to be exposed to potentially contaminated materials during the decommissioning and construction stages.

8.7          Prediction and Evaluation of Environmental Impacts

8.7.1       Based on the findings from the desktop studies and site inspection, no historical contaminative land uses / activities were identified. Thus, no adverse environmental impacts on land contamination are anticipated.

8.8          EM&A Requirements

8.8.1       Since no land contamination impact is anticipated, no EM&A requirements are required.

8.9          Conclusions

8.9.1       Based on the findings of site appraisal within the Sites, adverse land contamination impact arising from Project is not anticipated and thus, no Contamination Assessment Plan / Contamination Assessment Report / Remediation Assessment Plan and EM&A are required to be prepared.