7.               Land Contamination Impact

7.1             Introduction

7.1.1        This chapter presents a land contamination assessment for the potential existing brown field sites to be affected by the Project according to the EIAO. The assessment includes Investigating whether the sites contain land contamination materials, ground investigation, assessment and mitigation measures or any treatment works required before carrying the civil works for the WYLH.  The aim of this land contamination assessment is to identify major concerns pertaining to potential land contamination in the study area based on the proposed design.

 

7.2             Relevant Legislations, Standards & Guidelines 

7.2.1        The relevant legislations, standards and guidelines applicable to the present study for the assessment of land contamination include:

·         Annex 19 of the EIAO-TM, Guidelines for Assessment of Impact On Sites of Cultural Heritage and Other Impacts (Section 3 : Potential Contaminated Land Issues), EPD, 2023

·         Guidance Note for Contaminated Land Assessment and Remediation (Guidance Note), EPD, April 2023;

·         Guidance Manual for Use of Risk-based Remediation Goals (RBRGs) for Contaminated Land Management (Guidance Manual), EPD, April 2023; and

·         Practice Guide for Investigation and Remediation of Contaminated Land (Practice Guide), EPD, April 2023.

 

Environmental Impact Assessment Ordinance (Cap. 499), Technical Memorandum on Environmental Impact Assessment Process

7.2.2        Under Annex 19 of the EIAO-TM, a number of potentially contaminating historical land uses should be considered, including oil installations, gas works, metal workshops, car repair and dismantling workshops, which have the potential to cause or have caused land contamination.

Guidance Note for Contamination Land Assessment and Remediation

7.2.3        The Guidance Note sets out the EPD requirements for the assessment and management of potentially contaminated sites, provides guidelines on how site assessments should be conducted and suggests practical remedial measures that can be adopted for the remediation of a contaminated site.

 

Guideline Manual for Use of Risk-Based Remediation Goals

7.2.4        The Guidance Manual provides the background of the use of the Risk-Based Remediation Goals (RBRGs) and presents instructions for the comparison of soil data that is collected to the appropriate RBRGs.

7.2.5        The RBRGs have developed four different post-restoration land uses, namely "Urban Residential", Rural Residential", "Industrial" and "Public Parks", to reflect actual settings in which people could be exposed to contaminated soil or groundwater. Definitions of post-restoration land uses are given in EPD's Guidance Manual for Use of Risk-Based Remediation Goals for Contaminated Land Management.

7.2.6        The assessment criteria will make reference to the EPD’s Guidance Note for Contaminated Land Assessment and Remediation, and Guidance Manual for Use of Risk-Based Remediation Goals for Contaminated Land Management.  Reference was made to the RBRGs criteria for assessing the extent of land contamination in the present site based on the proposed future land use. The RBRGs also serve as the remediation targets if remediation is necessary. The RBRGs for soil and groundwater are given in Table 7.1 and Table 7.2 respectively.

Table 7.1 RBRGs for Soil & Soil Saturation Limit

Chemical

Risk-Based Remediation Goals (RBRGs) for Soil

Soil Saturation Limit (Csat)

Urban Residential

Rural Residential

Industrial

Public Park

(mg/kg)

(mg/kg)

(mg/kg)

(mg/kg)

(mg/kg)

Volatile Organic Chemicals (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

Semi-Volatile Organic Chemicals (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 / Polychlorinated Biphenyls (PCBs)

Dioxins (I-TEQ)

0.001

0.001

0.005

0.001

PCBs

0.236

0.226

0.748

0.756

Petroleum Carbon Ranges (PCRs)

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



 

Table 7.2 Risk-Based Remediation Goals (RBRGs) for Groundwater and Solubility Limit

Chemical

Risk-Based Remediation Goals (RBRGs) for 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>0.00001 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.

 

Practice Guide for Investigation and Remediation of Contaminated Land

7.2.7        The Practice Guide outlines the process for conducting land contamination assessments and remediation projects in Hong Kong. The Practice Guide presents the standard investigation methods and remediation strategies for the range of potential contaminated sites and the contaminants that are typically encountered in Hong Kong.

 

7.3             Assessment Methodology

7.3.1        The land contamination assessment area is referred to Figure 7.1. The assessment includes three stages, namely:

Stage 1 – Site Appraisal

 

The scope of Site Appraisal includes the following as desktop studies:

 

·         Conduct desktop review and site description;

·         Identify the Project Site’s future land use in regard to the RBRGs;

·         Review past and present land use within the Project Site Boundary and activities that may lead to potential land contamination;

·         Review aerial photographs of the Project Site;

·         Review chemical spillage/ leakage records from EPD, FSD and LandsD;

·         Review dangerous goods license and records from FSD;

·         Review nearby chemical waste producers; and

·         Conduct site walkover to evaluate current conditions and identify areas of potential concern.

 

Stage 2 – Contamination Assessment Plan (CAP)

 

·         Propose the sampling strategy for site investigation;

·         Design sampling method for the site investigation; and

·         Prepare the CAP to EPD for endorsement.

 

Stage 3 – Site Investigation (SI) Works

 

·         Monitor and supervise Site Investigation works based on the agreed CAP;

·         Advise on the contamination assessment schedule, investigation procedures and methodologies;

·         Review analytical results of the soil and groundwater samples; and

·         Prepare and submission of Contamination Assessment Report (CAR) for EPD’s endorsement.

 

Stage 4 – Remediation Action Plan (RAP) and Remediation Report (RR)

If contamination is identified at the Site, the following will be conducted:

·         Propose the required remediation works;

·         Identify the environmental, health and safety requirement during remediation;

·         Prepare the Remediation Action Plan (RAP) for EPD’s endorsement

·         Carry out remediation works as agreed with EPD; and

·         Prepare the RR for EPD’s endorsement

 

7.3.2        A Contamination Assessment Plan (CAP) has been prepared under this EIA study. The CAP is presented in Appendix 7.1.

 

7.4             Review of EIA reports

7.4.1        The approved EIA reports under the EIAO will also be reviewed, including:

·         Agreement No. CE 98/98 Widening of Yuen Long Highway between Lam Tei and Shap Pat Heung Interchange Preliminary Design and Ground Investigation Assignment (EIA Report AEIAR-059/2002 Widening of Yuen Long Highway between Lam Tei and Shap Pat Heung Interchange);

·         Agreement No. CE 109/98 – Deep Bay Link – Investigation and Preliminary Design (EIA Report AEIAR-064/2002 Deep Bay Link);

·         Agreement No. CE 2/2011 (CE) Hung Shui Kiu New Development Area Planning and Engineering Study – Investigation (EIA Report AEIAR-203/2016 Hung Shui Kiu New Development Area);

·         Agreement No. CE 35/2012 (CE) Planning and Engineering Study for Housing Sites in Yuen Long South – Investigation (EIA Report AEIAR-215/2017 Housing Sites in Yuen Long South).

Information of the adjacent feasibility studies and investigation assignments, including:

·         Agreement No. CE 19/2015 (TP) Preliminary Land Use Study for Lam Tei and the Adjoining Areas – Feasibility Study (WP6 – Preliminary Feasibility Assessments for Preferred Land Use Option);

·         Agreement No. CE51/2016 (HY) Route 11 (between North Lantau and Yuen Long) – Feasibility Study (Preliminary Environmental Review Report);

·         Agreement No. CE 75/2017 (CE) Site Formation and Infrastructure Works for Public Housing Developments at Long Bin, Yuen Long – Investigation, Design and Construction (Preliminary Environmental Review Report);

·         Agreement No. CE 92/2017 (CE) Site Formation and Infrastructure Works for Public Housing Development near Tan Kwai Tsuen, Yuen Long Investigation, Design and Construction (Preliminary Environmental Review Report);

·         Agreement No. CE 11/2020 (CE) Site Formation and Infrastructure Works for Proposed Public Housing Developments at Ping Shan South, Yuen Long, Lam Tei North and Nai Wai, Tuen Mun – Feasibility Study.

 

7.5             Description of the Environment

Geological Condition

7.5.1        Geological map suggests that the alignment is underlain by granite and metasedimentary rock, which geological boundaries are inferred near LTQ and TSWWI by existing the boreholes. The metasedimentary rock may be more susceptible to the weathering, and thus the differential weathering profile or abruptly changing of the rockhead profile may be occurred in the lithological boundary. The rockhead variation form -15mPD to +8mPD and from - 4mPD to -24mPD are identified near LTQ and TSWWI respectively, and variation in the rockhead profile will be considered in the viaduct and foundation works design. In addition, different presumed allowable vertical bearing pressure for granite (Category I) and metasedimentary rock (Category II) will be considered in reference to the BD Code of Practice for Foundations.

7.5.2        Review of Historical Land Use

7.5.3        In order to identify any past land uses which may have the potential for causing land contamination, the development history of the Assessment Area has been reviewed with the aid of selected historical aerial photos between 1963 and 2022. The aerial photographs for the Project Boundary Area are shown in Appendix A of the CAP and the findings are summarised in Table 7.3.

Table 7.3 Summary of the findings of Aerial Photographs

Year of Aerial Photos

Observations

1963

The Project area comprised of mainly rural residential houses and agricultural land. Part of the land comprised of natural terrain.

1973

No significant change in land use was observed compared with Year 1963 except more village houses are formed.

1982

No significant change in land use was observed compared with Year 1973.

1993

Yuen Long Highway was under construction within the Project area. Some industrial buildings appeared including Hop Hing Building and its oil factory, Forefront Cyber Centre and Hang Sun Chemical Manufacturing Limited which are next to the project boundary. Part of the agricultural land was replaced by scattered industrial activities next to the project boundary.

2001

Construction of Yuen Long Highway has been finished and was in operation. Most of the agricultural land were replaced by industrial activities and residential houses.

2011

No significant change in land use was observed compared with Year 2001.

2019

No significant change in land use was observed compared with Year 2011.

2022

No significant change in land use was observed compared with Year 2019.

Source of historical aerial photographs: Survey and Mapping Office, Lands Department.

 

7.5.4        As shown in the Table 7.3, Yuen Long Highway were historically occupied as farmland and village housing from 1963 until early 1990s. The construction of Yuen Long Highway has started in 1993 and it has been finished and in operation in 2000s. Since then, there is no significant change of land use within the Project Boundary. 

7.6             Information Request from Government Departments

7.6.1        Supporting information has been requested in order to identify any historical leakage, chemical spillage, dangerous goods stores or accidents within the Site.

7.6.2        According to the reply from EPD on 12 June 2023, there was no record indicating historical leakage and spillage of chemicals found within the project site boundary.

7.6.3        According to the reply from Fire Services Department (FSD) on 30 June 2023, there was no dangerous goods license nor leakage of dangerous goods found at the Site during its operation. 14 no. of fire incidents have been recorded within the project site boundary, which include traffic accident, rubbish fire, vegetation fire and one electric fire. All the recorded fire incidents has no encroachment into Project Site Area.

7.6.4        A record checking has been conducted on 11 May 2023 at EPD office for the registration of chemical waste producers of the Site and its surrounding industrial buildings. The chemical waste producers are summarized in Table 7.4.

Table 7.4 Registration of Chemical Waste Producer Record

No.

Chemical Waste Producer

Address

Location within Site Boundary

Business Type

Valid (Y/N)

1

Hop Hing Oil Investment Limited

 

Hop Hing Building, 9 Ping Tong Street East, Tong Yan San Tsuen

No

Trading and Manufacturing

Y

2

Hop Hing Oil Refinery Limited

Flat C&D, 2/F, Hop Hing Building, 9 Ping Tong Street East, Tong Yan San Tsuen, Yuen Long, N.T.

No

Edible oils manufacturing

Y

3

Hip Hing Oil Factory Limited

Flat E&F, 2/F, Hop Hing Building, 9 Ping Tong Street East, Tong Yan San Tsuen, Yuen Long, N.T.

No

Edible Oil Manufacturing

Y

4

Wasserbel Testing Laboratory Limited

2/F, Flat D, Hop Hing Building, Ping Tong Street East, Lot 2024 DD 121, Tong Yan San Tsuen, N.T

No

Chemical Testing

Y

5

Hang Sun Chemical Manufacturing Limited

396 Tan Kwai Tsuen, Hung Shui Kiu, Yuen Long, N.T.

No

Manufacturing of Foam Rubber

N

6

Evergreen Oils & Fats Limited

Flat C, 2/F, Hop Hing building, Lot 2024 DD121 Ping Tong Street East, Tong Yan San Tsuen, NT.

No

Edible Oils Manufacturer

N

7

Wasserbel Testing Laboratory Limited

2/F, Flat D, Hop Hing Building, Ping Tong Street East, Lot 2024 DD 121, Tong Yan San Tsuen, N.T

No

Chemical Testing

N

8

Tak Cheong Investment (HK) Limited

G/F, No. 3 Tong Tai Road, Tong Yan San Tsuen, Yuen Long, N.T.

No

Car Repairing

N

Note: The information is provided by EPD. The validity of the records as of 2 March 2023.

 

7.6.5        According to the chemical waste producer record, currently there are no valid record within the project site boundary. There are 4 valid records and 4 expired records at the immediate vicinity of the project site boundary, however, the Project area will not encroach into these existing facilities.

 

7.7             Site Walkover

7.7.1        Site walkovers were conducted in May 2023 to confirm the existing condition of the site. However, detailed site appraisal at each individual premise within the Assessment Area was restricted as the majority of the sites surveyed are private land of which most were still in operation. Therefore, access to the aforementioned premises was infeasible for both inspection and site investigation due to the ongoing operations, as both site survey and site investigation would both involve the suspension of operations on site. Peripheral inspections (i.e. from the entrance and / or boundary of the premises) was conducted in order to provide a general view of the Assessment Area Details of the site walkover checklists are presented in Appendix C of the CAP. The potentially contaminating lands are presented in Figure 4.1, 4.1a and 4.1b of CAP.

 

7.8             Identification of Potentially Contaminated Sites

Potential Contaminated Sites

7.8.1        According to Section 2.3.1 of EPD’s Practice Guide for the Investigation and Remediation of Contaminated Land, through site survey and desktop review such as the review of aerial photographs and information from Government Departments such as FSD and EPD, areas which may have potential to cause soil and groundwater contamination have been identified. Sites identified to have records of dangerous goods and chemical waste producers are considered as potentially contaminated sites. Furthermore, specific land uses which were identified as potentially contaminating sources include the below.

·         Open storage;

·         Warehouse;

·         Vehicle maintenance;

·         Metal works;

·         Waste recycling;

·         Construction material and equipment storage;

·         Concrete batching plant; and

·         Chemical store; and

·         Dangerous Goods Stores; and

·         Chemical Waste Producers.

7.8.2        Based on the desktop review of preliminary project alignment, location base maps, relevant findings of land contamination assessment in EIA studies, feasibility studies and investigation assignments at the development sites adjacent to the Project, the potential contaminated areas are indicated in Figure 4.1, 4.1a and 4.1b of CAP.

7.8.3        Making reference to the EPD’s Practice Guide for Investigation and Remediation of Contaminated Land, the key COCs and remediation methods associated with the identified potentially contaminating land uses are identified and summarised in Table 7.5.

Table 7.5 Potentially COCs and Possible Remediation Methods for the identified potentially contaminating land uses

Identified Potentially Contaminating Land Use

Potentially Contaminating Activities

COCs

Possible Remediation Methods

Vehicle maintenance

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.

Metals (e.g. chromium, copper, lead, manganese, nickel, zinc), PCRs, VOCs (e.g. acetone, BTEX, MTBE, and trichloroethene) and SVOCs (e.g. PAHs).

Stabilisation/ Solidification, Biopile, Permeable Reactive Barriers

Open storage / Warehouse / Construction material storage / Open car park

Loading, unloading and storage of goods, fuel storage and transfer, maintenance of equipment and vehicles.

Metals (full list), PCRs, VOCs and SVOCs

Stabilisation/ Solidification, Biopile, Permeable Reactive Barriers

 

7.9             Site Investigation Plan

Proposed Site Investigation for Potentially Contaminated Landuses

7.9.1        As the majority of the sites within the Assessment Area are still in operation, site access for appraisal is limited. Sampling should be carried out in these sites once access is available. As detailed in the CAP in Appendix D, 10 potentially contaminated sites were identified. Based on the latest information, site C1 to C7 are currently under work area of CEDD contract no. YL/2022/01. The environmental sampling of these sites will be conducted by relevant contractors under YL/2022/01. Sites C8 and C9 are currently under Yuen Long South Stage 2B works areas. Similar to C1 to C7, the environmental sampling of these areas will be conducted by the relevant contractors under Yuen Long South Stage 2B. Hence, a total of 8 boreholes have been recommended at Site C10 for SI under this Project. It should be noted, however, that the CAP has determined the approach for SI based on the best available current information and thus the actual sampling and testing strategies could be subject to change after a detailed site walkover is undertaken.

Proposed Re-appraisal for Potentially Contaminated Landuses

7.9.2        Further site appraisal will be carried out by Project Proponent (PP)’s appointed consultants once site access is available (e.g. after land resumption), in order to identify the presence of “potential contaminant” for intrusive site investigation and confirm the evaluation of the contaminated site in initial land contamination assessment.

7.9.3        The PP’s consultants should prepare a supplementary CAP to summarise the relevant findings of the further site appraisal at Site C10. The supplementary CAP for Site C1 to C7 and C8 to C9 will be prepared by the relevant contractors under YL/2022/01 and Yuen Long South Stage 2B respectively. After approval of the supplementary CAP and upon completion of the SI works, if any, the PP should prepare a CAR to present findings of the SI works. If contamination has been identified, a RAP should be prepared to formulate appropriate remedial measures to deal with the contamination identified. Following completion of any necessary remediation works, a RR should be prepared to demonstrate adequate clean-up and submit to EPD for approval prior to the commencement of any development works at the contaminated sites.

 

7.10          Evaluation of Land Contamination Impacts

7.10.1      The contamination problem in the land uses that are identified as potentially contaminated would not be considered insurmountable in the supportive view that any contaminated soil should be remediated by the Project Proponent based on the factors below:

Size and Scale of Individually Surveyed Sites

7.10.2      Based on the current alignment design, site survey and desktop review, only small portions of potential contaminated site has encroached the current site alignment. The total encroachment of the potentially contaminated sites is less than 2700m2 which is approximately 1.3% of the total area of the current site alignment. In addition, due to site access issues, only peripheral site inspections were undertaken. As such, the site inspections were unable to determine the site activities and what type of goods are stored within these sites. For example, it is difficult to access the contamination potential for a warehouse as the warehouse containing household supplies is unlikely to have any contamination potential whereas a warehouse containing chemicals is likely to.  

Chemical of Concern

 

7.10.3      Based on the COC’s identified in this site appraisal (including metals, VOCs, SVOCs, PCRs and PCBs), it is considered that the remediation measures outlined in Table 7.5 have been demonstrated to effectively treat such contamination, both in soil and groundwater.

Local remediation experience

 

Soil contaminated with the abovementioned COCs had successfully been remediated in Hong Kong using proven remediation techniques. Such examples range from the decontamination works at the Cheoy Lee Shipyard to the decommissioning of the Kwai Chung Incinerator.

 

7.11          Submission Requirement of CAR, RAP and RR

Submissions Requirements of further works

7.11.1      After endorsement of the supplementary 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.

Possible Remediation Measures

7.11.2      According to the Practice Guide, the need to remediate the contaminated area and the nature, level and extent of contamination would be determined based on the findings of the SI works to be presented in the CAR(s).  The appropriate remediation methods should be selected based on the findings of the SI works and would be presented in the RAP(s).

7.11.3      A Remediation Report (RR) to demonstrate adequate remediation shall be prepared and submitted to EPD for endorsement prior to the commencement of any construction/ development works within the Project Site. No construction/ development works shall be carried out before the endorsement of the RR.

 

Tentative Programme Schedule of submissions

7.11.4      According to the current programme, land resumption will be arranged in Q3 2024 upon Scheme Authorisation (Q2 2024). 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 CAR, including, if required, development of supplementary RAP (estimate minimum of three weeks) for contaminations; and

·         Preparation and submission of RR after the completion of remediation works.

 

Table 7.6 Tentative Programme Schedule of Submissions

 

Submission Item

Tentative Schedule

Supplementary CAP

Q3 2024

Contamination Assessment Report 

Q4 2024

Remediation Assessment Plan (RAP)*

Q4 2024

Remediation Assessment Report (RR)*

Q1 2025

*Note: The RAP and RR are only required when contamination is identified after conducting the SI and field sampling works.

 

 

7.12          Environmental Acceptability of Schedule 2 Designated Projects

7.12.1      The identified potentially contaminated sites under Schedule 2 DP and the findings are summarised in Table 7.3 of CAP. As the land contamination potential of the sites listed in Table 7.3 of CAP have been assessed under the EIA (referred to Section 7.10), the land contamination issue within these sites are considered surmountable. Prior to the commencement of construction of the DP works, the recommended actions proposed in Section 7.9 shall be carried out for the concerned sites listed in Table 7.3 of CAP. Any soil/groundwater contamination would be identified and properly treated prior to the development of the concerned sites after land resumption. No residual land contamination impact is anticipated and thus it is considered environmentally acceptable if the recommended actions are followed.

 

 

7.13          Conclusion and Recommendation

7.13.1      This land contamination assessment examined the potential contaminative land use within the Project site alignment. The assessment involved desktop review, site surveys, the proposed environmental SI and their potential impacts to future land use.

7.13.2      Majority of the potentially contaminated sites could not be accessed to inspect the site conditions during site walkover at the time of preparing the EIA report and permission could not be obtained from the site owners/ operators to carry out the site investigation works. As such, this land contamination assessment on the potential land contamination was conducted based on desktop review, review of historical aerial photos and a number of peripheral site surveys. Based on desktop review and peripheral site surveys, a total of 10 potentially contaminated sites were identified and some of which are existing warehouse, open area storage and vehicle maintenance workshop. In addition, as the sites are still in operation, it is considered not suitable to carry out the SI at this stage as there may be change in land use prior to construction for both potentially contaminated sites and other surveyed sites. In view of this, further site visits to these potentially contaminated sites are proposed once future development of these sites is confirmed and that site access is available in order to identify the need for SI for any additional hot spots as a result of the on-going land contaminating activities.

7.13.3      For further works after land resumption, re-appraisal would be required for the other surveyed sites, findings from the re-appraisal will be presented in a supplementary CAP. Upon approval of the supplementary CAP and completion of the SI works, a CAR would be prepared to present findings of the SI works. If contamination has been identified, a RAP would be prepared to recommend specific remediation measures. Upon completion of the remediation works, if any, a RR would also be prepared to demonstrate that the clean-up works are adequate. The CAR, RAP and RR would be submitted to EPD for approval prior to commencement of any construction works.