TABLE OF CONTENTS

8 Land Contamination.. 8-1

8.1 Introduction. 8-1

8.2 Environmental Legislation, Plans, Standards, and Guidelines. 8-1

8.3 Description of the Environment 8-2

8.4 Assessment Methodologies. 8-2

8.5 Baseline Condition. 8-3

8.6 Identification of Potential Environmental Impacts. 8-6

8.7 Site Investigation Plan. 8-16

8.8 Evaluation of Environmental Impacts. 8-22

8.9 Mitigation of Adverse Environmental Impacts. 8-22

8.10 Evaluation of Residual Environmental Impacts. 8-24

8.11 Conclusion. 8-24

LIST OF Appendices

Appendix 8.1 Contamination Assessment Plan

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.

8.1.2 The implications of land contamination associated with the works areas within the Scheme Boundary were assessed in accordance with TM-EIAO. This section summarises the site appraisal results from the Contamination Assessment Plan (CAP) (Appendix 8.1 refers), recommendation of possible remediation works and overall findings and recommendations relevant to this EIA study.

8.2 Environmental Legislation, Plans, Standards, and Guidelines

8.2.1 The relevant environmental legislation guidelines and standards on land contamination include the following:

· Section 3 (Potential Contaminated Land Issues) of Annex 19 “Guidelines for Assessment of Impact on Sites of Cultural Heritage and Other Impacts” of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM).

· “Guidance Note for Contaminated Land Assessment and Remediation” (Guidance Note)

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. In addition, this Guidance Note provides guidelines on how site assessments should be conducted and analyzed and suggests practical remedial measures that can be adopted for the cleanup of contaminated sites.

· “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.

· “Guidance Manual for Use of Risk-based Remediation Goals for Contaminated Land Management” (Guidance Manual)

Guidance Manual introduces a risk based approach to land contamination assessment and presents instructions for comparison of soil and groundwater data to the 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 follow a risk-based methodology for contaminated land assessment and remediation, 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. The RBRGs also serve as the remediation targets if remediation is necessary.

8.3 Scheme Boundary of the Project

Description of the Environment

8.3.1 The area within Scheme Boundary of the Project is approximately 2,100 m long and 315m wide located on a land reclaimed previously in the early 1990’s. Before that time, the area was the original coastline at the north shore of Lantau Island as revealed from the aerial photo in 1982 as shown in Annex 2.1 in the CAP (Appendix 8.1 refers). The Scheme Boundary consists of a 30-hectare SHD which currently provides maintenance and supporting services to the existing TCL, AEL and DRL. Construction works areas for Tuen Mun - Chek Lap Kok Link (TM-CLKL) within Scheme Boundary are located to the south of SHD between the existing tracks area and North Lantau Highway, while the existing Siu Ho Wan Sewage Treatment Works (SHWSTW) is located to the south-east of SHD.

Works Areas of the Project

8.3.2 The components of the works areas within Scheme Boundary for supporting and facilitating the construction and operation of the Project are summarized below with the location and components of the works areas within the Scheme Boundary with the extent of proposed works (including excavation and track works) are shown in Figure Nos. NEX1062/S/SHD/ACM/Z10/019 - 022 in the CAP (Appendix 8.1 refers).

(i) Tentative Major Works Area

· Stage 1 to Stage 4 SHD Replanning Works;

· Proposed SHO and associated trackworks area;

· Provision of sewerage network to the existing Siu Ho Wan Sewage Treatment Works (SHWSTW); and

· Western access road connecting to Tai Ho Interchange and local access including vehicular access ramp and staircase as mean of escape (MoE) located to the west of reprovisioned SHD.

(ii) Temporary Works Area (i.e. areas other than item (i) above and within the Scheme Boundary)

8.3.3 For the purpose of this land contamination assessment, the proposed works extent within the Scheme Boundary is divided into (a) existing SHD (i.e. Stage 1 to Stage 4 SHD Replanning Works) and (b) proposed works areas that fall outside the existing SHD.

8.4 Assessment Methodologies

8.4.1 The first step was to identify and assess any potentially contaminated sites within the proposed works extent within the Scheme Boundary. The following tasks have been undertaken to identify and evaluate the potential land contamination impacts:

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

· Site reconnaissance to identify the potentially contaminated areas.

8.4.2 In addition, the following sources of information have been collated and reviewed:

· Selected aerial photographs;

· Hong Kong Geological Survey Map (Series HGM20) – Sheet No. 10 (1:20,000);

· Records on dangerous goods (DGs), chemical wastes and chemical spillage/leakage incidents from Fire Services Department (FSD) and Environmental Protection Department (EPD);

· Records and photographs obtained during site inspection; and

· Geotechnical review under Consultancy Agreement No. NEX/1062.

8.5 Baseline Condition

Review of Historical Aerial Photos

8.5.1 Selected historical aerial photographs between year 1982 and 2016 of the Scheme Boundary have been reviewed in order to ascertain any historical land uses with the potential of land contamination. A summary of the historical land uses is presented in Table 8.1 below. The historical photographs are shown in Annex 2.1 of the CAP (Appendix 8.1 refers).

Table 8.1 Summary of Historical Land Uses of the Scheme Boundary

Year	Description
1982	The Scheme Boundary was located in open sea and no reclamation was observed.
1993	Reclamation was observed in progress.
2000	Land reclamation completed and SHD, railway tracks, slip road from North Lantau Highway to the western entrance of SHD, North Lantau Highway, Sham Shui Kwok Drive and Cheung Tung Road were observed.
2015	The existing Siu Ho Wan Sewage Treatment Works was observed to the east of the SHD at Cheung Tung Road.
2016	The construction works areas for Tuen Mun - Chek Lap Kok Link (TM-CLKL) were observed to the south of SHD between the existing tracks area and North Lantau Highway.

Site Geology

8.5.2 According to the findings of the geotechnical review under Consultancy Agreement No. NEX/1062, there are a total of 339 existing boreholes located in / at the vicinity of the Scheme Boundary. Based on the existing borehole records, the typical thickness of reclamation fill ranges from 3m to 25m. Marine deposit is also anticipated with thicknesses ranging from 0m to 10m. On the other hand, alluvium ranges in thickness from 0m to 21m and colluvium ranges in thickness from 0.5m to 2.6m. In-situ decomposed rock (i.e. Grade IV/V materials) is anticipated with the thicknesses ranging from 1m to 33m. Engineering rockhead is anticipated to be situated at +2.7mPD to -57.1mPD.

Information from Government Authorities

8.5.3 EPD and FSD were contacted for (i) records on any spillage / leakage of chemicals, (ii) records of DG and (iii) records of Chemical Waste Producer(s) within the existing SHD and proposed works areas that fall outside SHD and within the Scheme Boundary.

Existing SHD

8.5.4 According to the replies given by EPD and FSD, there were no records of spillage/ leakage of chemicals / DGs reported at the SHD.

8.5.5 There are Chemical Waste Producers (CWPs) and DGs records within the SHD and details are presented in Section 2.3 of the CAP (Appendix 8.1 refers). Based on the records, the relevant chemicals of concern (COCs) identified include metals, volatile organic chemicals (VOCs), semi-volatile organic chemicals (SVOCs) and petroleum carbon ranges (PCRs).

Proposed Works Areas That Fall Outside the Existing SHD and within Scheme Boundary

8.5.6 According to the replies from EPD and FSD, there were no records of spillage/ leakage of chemicals / DGs reported and DGs record within the proposed works areas that fall outside the existing SHD and within Scheme Boundary.

8.5.7 For CWP record, according to the replies from EPD, there are only 2 registered CWPs within or near the proposed works area: (i) existing SHWSTW and (ii) Gammon Construction Limited (for the construction of Tuen Mun – Chek Lap Kok Link (TM-CLKL) project).

8.5.8 For the existing SHWSTW, there are 2 active CWPs records available in EPD office. No land contamination issue was anticipated for the construction of proposed provision of sewerage network within the existing SHWSTW as the proposed provision of sewerage network only pass through existing road and landscaped area inside SHWSTW where no chemical wastes are stored.

8.5.9 It is checked at EPD office that there are 4 active CWPs records for TM-CLKL project that are in the vicinity of the Scheme Boundary but the premises addresses of these 4 active CWPs records fall well outside of the Scheme Boundary and no chemical waste storage at the TM-CLKL project area is anticipated within the Scheme Boundary.

Site Reconnaissance

8.5.10 Site walkovers were conducted in April and June 2016, and January 2017 to investigate any contaminative issues associated with current land uses and activities within the proposed works extent in the Scheme Boundary.

Existing SHD

8.5.11 During the site walkovers, the following facilities / areas that may pose concern were identified in proposed works extent in the existing SHD. According to the SHD operator, there is no change or relocation of these facilities, areas and activities since the operation of SHD:

· Permanent Way Depot Building (AB1);

· Dangerous Goods Storage (AB2);

· Substation (AB3);

· Waste Collection Facility (AB4);

· Covered Storage Facility (AB5);

· Locomotive and MIV Repair Facility (AB6);

· Flash Butt Welding Facility (AB7);

· Paint Shop (AB8);

· Track Machine Shed (AB9);

· Traction Substation (AB11);

· Central Chiller Compound (AB15);

· Central Plant Building (AB16);

· Overhead Line Office and Workshop (AB21);

· Underfloor Wheel Lathe Facility (AB22);

· Wash Control Facility (East) (AB23);

· Water Wash Control Facility (West) (AB24); and

· Main Depot Building (MDB).

8.5.12 Site appraisal findings of these facilities / areas, including the necessity for site investigation works, are summarized in Table 2.6 of the CAP (Appendix 8.1 refers) while the location of the facilities / areas is presented in Figure Nos. NEX1062/S/SHD/ACM/Z10/019 to NEX1062/S/SHD/ACM/Z10/022 in the CAP (Appendix 8.1 refers).

8.5.13 Apart from the aforementioned facilities / areas, the other areas within the existing SHD are mainly composed of guard houses, railway tracks, asphalt / concrete-paved roads, vehicle parking areas (paved with intact concrete) and landscaped areas. Furthermore, according to the SHD operator, there is no change or relocation of these facilities, areas and activities since the operation of SHD. No historical and current potentially polluting activities nor stains, chemicals and stressed vegetation were observed in these areas. Thus, no land contamination issue is anticipated in other areas within the existing SHD.

Proposed Works Areas That Fall Outside the Existing SHD and within Scheme Boundary

8.5.14 The proposed works areas that fall outside the existing SHD and within Scheme Boundary are mainly comprises of railway tracks, i.e. AEL/TCL, landscaped areas and roads (i.e. section of North Lantau Highway and Cheung Tung Road and a slip road connecting to the western entrance of the SHD and the North Lantau Highway). No contaminating land use was identified and thus no land contamination issue was identified within these areas.

8.5.15 Apart from the above, part of the proposed works areas were within the project area of the Tuen Mun - Chek Lap Kok Link (TM-CLKL) to the southeast of SHD and within the existing SHWSTW (for the proposed provision of sewerage network) to the east of SHD. No stains and stressed vegetation were observed. No land contaminating activities were reported or observed and thus no land contamination issue was identified in these areas.

8.5.16 The photo records of the site walkover for the works areas that fall outside the existing SHD and within the Scheme Boundary are presented in Figure Nos. NEX1062/S/SHD/ACM/Z10/042 and 043 in the CAP (Appendix 8.1 refers).

Future Land Uses and Activities

8.5.17 Land contamination assessment on the potentially contaminated sites would need to be evaluated against the RBRGs and if there were presence of non-aqueous phase liquid (NAPL), soil saturation (C_sat) / solubility limits, as stipulated in Table 2.1 and Table 2.2 of the Guidance Manual.

8.5.18 The RBRGs were developed based on a risk assessment approach to suit the local environmental conditions and community needs in Hong Kong. Decisions on contaminated soil and groundwater remediation are based on the nature and extent of the potential risks that are posed to human receptors as a result of exposure to chemicals in the soil and/or groundwater. RBRGs were developed for four different land use scenarios as below reflecting the typical physical settings in Hong Kong under which people could be exposed to contaminated soil and groundwater:

· Urban residential

· Rural residential

· Industrial

· Public parks

8.5.19 Based on the site appraisal, there are facilities / areas within the existing SHD that may pose land contamination concern and would require further site investigation works. The ground level of the area within the existing SHD will be developed for the reprovisioned SHD operation/maintenance facilities and new SHO (refer to Figure Nos. NEX1062/S/SHD/ACM/Z10/023 and 024 in the CAP (Appendix 8.1 refers). As such the RBRGs for “Industrial” land use scenarios are considered to be appropriate for the assessment.

Table 8.2 Summary of the Future Land Use of the Concerned Areas and Corresponding RBRGs

Area ID	Concerned Area	Future Land Use	RBRGs for the Relevant Land Use Category
AB2	Whole area of Dangerous Goods Storage (AB2)	Reprovisioned SHD operation / maintenance facilities and new SHO	Industrial
AB3	Two transformers with bund walls	Reprovisioned SHD operation / maintenance facilities	Industrial
AB6	Maintenance area and underground diesel tank	Reprovisioned SHD operation / maintenance facilities	Industrial
AB8	Paint workshop, paint storage and chemical waste storage area	Reprovisioned SHD operation / maintenance facilities and new SHO	Industrial
AB9	Whole area of track machine shed (AB9)	Reprovisioned SHD operation / maintenance facilities	Industrial
Transformers located outside AB11	Three transformers with secondary containments	Reprovisioned SHD operation / maintenance facilities and new SHO	Industrial
AB16	Four transformers with bund walls	Reprovisioned SHD operation / maintenance facilities	Industrial
AB22	Area below ground floor	Reprovisioned SHD operation / maintenance facilities	Industrial
MDB	Maintenance workshop and two transformers with bund walls	Reprovisioned SHD operation / maintenance facilities	Industrial

8.6 Identification of Potential Environmental Impacts

8.6.1 Based on the site appraisal results, 9 facilities / areas (i.e. AB2, AB3, AB6, AB8, AB9, Transformers located outside AB11, AB16, AB22 and MDB) within the existing SHD have been identified as potentially contaminated and require further site investigation. Details of the aforementioned facilities / areas are summarized in Table 8.3 and the corresponding sampling and testing strategies are presented in Section 8.7. No land contamination issue is anticipated in the areas outside the existing SHD and within the Scheme Boundary.

Table 8.3 Summary of Facilities / Areas with Land Contamination Concern within the Proposed Works Extent

Name of Facility / Area (Area ID)	Approx-imate Area (m^2)	Observations	Concerned Area (m^2)	Proposed Sampling ID	Chemical Of Concerns^(1)	Possible Remediation Methods^(2)	Future Land Use	Relevant RBRGs Land Use Scenario	Reference Figure
Dangerous Goods Storage (AB2)	390	· No report of spillage or leakage of dangerous goods was reported from EPD and FSD records. · Chemicals, such as acid, alkaline, thermic starter, oxygen cylinders, acetylene cylinders, kerosene and thinner, were stored with secondary containments to prevent spillage and leakage in the Dangerous Goods Storage. · According to site representative, drip trays were placed under the floor in the buildings to collect oil spillage / leakage as a preventive measure. · All the dangerous goods store rooms were locked and managed by staffs from relevant departments. · No stain was observed on the floors, except the floor in chemical waste storage. · There is a chemical waste storage area located in the Dangerous Goods Storage. During the site visit, 7 drums of spent rag with oil and 2 drums of spent lubrication oil / grease were placed on drip trays. Furthermore, 6 cans of spent paint with thinner were stored in a shelf.	Whole area of Dangerous Goods Storage (approximately 390m^2)	AB2 BH1 – BH6 (refer to Figure NEX1062/S/SHD/ACM/Z10/046 of the CAP in Appendix 8.1 for borehole location)	Full list of Metals, PCRs, VOCs and SVOCs.	Biopiling, Solidification / Stabilisation, Permeable Reactive Barriers	Relocated SHD operation / maintenance facilities and new SHO	Industrial	Figure No. NEX1062/S/SHD/ACM/Z10/026 of the CAP in Appendix 8.1
Substation (AB3)	550	· The building floor was concrete paved and the concrete was in good condition. · Two transformers (labelled as TX01 and TX02) with bund walls (approximately 10m^2 each) were observed. The bund walls were in good condition and oil absorbing wipes were observed under the transformers. However, oil stains were observed within the bund wall. · Apart from transformers, the Substation was mainly comprises of switch rooms.	Two transformers with bund walls (approximately 10m^2 each)	Two transformers locations AB3 – BH1 to BH2 (refer to Figure NEX1062/S/SHD/ACM/Z10/047 of the CAP in Appendix 8.1 for borehole location)	Full list of Metals, PCRs, VOCs, SVOCs and PCBs	Biopiling, Solidification / Stabilisation, Permeable Reactive Barriers	Relocated SHD operation / maintenance facilities and new SHO	Industrial	Figure No. NEX1062/S/SHD/ACM/Z10/027 of the CAP in Appendix 8.1
Locomotive and MIV Repair Facility (AB6)	1,380	· Parts storage area and office area was observed. · Maintenance area (approximately 1,050m^2) of electric engineering trains was observed and oil stains were observed in the maintenance bays. · An underground 10,000L diesel tank and filling pumps were observed at the eastern end of the maintenance area (referring to as the diesel storage located at open ground of depot in the DGs Storage License). As confirmed by the SHD operator, apart from the abovementioned underground diesel tank, there are no other aboveground / underground diesel tanks presented within the SHD (Appendix 8.1 refers). · According to the site representative, AB6 was previously used for repairing / maintaining and fuelling diesel-fuelled engineering trains. Although the diesel-fuelled engineering trains were replaced by the electric engineering trains, the underground diesel tank is still in use for the operations of the SHD. · The floor of the facility was concrete paved and the concrete was in good condition.	Maintenance area (approximately 1,050m^2) and underground diesel tank	Maintenance area including observed oil stains AB6 BH1 – BH7 (refer to Figure NEX1062/S/SHD/ACM/Z10/048 of the CAP in Appendix 8.1 for borehole location) Underground diesel tank AB6 SS1 – SS5 (refer to Figure NEX1062/S/SHD/ACM/Z10/048 of the CAP in Appendix 8.1 for sampling location)	Maintenance area Full list of Metals, PCRs, VOCs and SVOCs. Underground diesel tank Full list of Metals, PCRs, VOCs and SVOCs.	Biopiling, Solidification / Stabilisation, Permeable Reactive Barriers	Relocated SHD operation / maintenance facilities and new SHO	Industrial	Figure No. NEX1062/S/SHD/ACM/Z10/030 of the CAP in Appendix 8.1
Paint Shop (AB8)	750	· The building floor was concrete paved and the concrete was in good condition. · Paint workshop was observed. · Cabinets for paint storage and chemical waste were observed. The paints were tidily placed on the shelves. · No stains were observed.	Paint workshop, paint storage and chemical waste storage area (approximately 670m^2)	AB8 BH1 – BH4 (refer to Figure NEX1062/S/SHD/ACM/Z10/049 of the CAP in Appendix 8.1 for borehole location)	Full list of Metals, PCRs, VOCs and SVOCs.	Biopiling, Solidification / Stabilisation, Permeable Reactive Barriers	Relocated SHD operation / maintenance facilities and new SHO	Industrial	Figure No. NEX1062/S/SHD/ACM/Z10/032 of the CAP in Appendix 8.1
Track Machine Shed (AB9)	880	· Maintenance platform and track area were observed in the building and two rail grinding trains which were used to maintain tracks were parked in the track area. · According to the site representative, AB9 is used to maintain the rail grinding trains and unload the metal scraps collected during rail grinding from the trains. · Oil stains were observed on the floor of the maintenance platform and the track area.	Whole area of track machine shed (approximately 880m^2)	Track Machine Shed including observed oil stains AB9 BH1 – BH5 (refer to Figure NEX1062/S/SHD/ACM/Z10/050 of the CAP in Appendix 8.1 for borehole location)	Full list of Metals, PCRs, VOCs and SVOCs.	Biopiling, Solidification / Stabilisation, Permeable Reactive Barriers	Relocated SHD operation / maintenance facilities and new SHO	Industrial	Figure No. NEX1062/S/SHD/ACM/Z10/033 of the CAP in Appendix 8.1
Transformers located outside Traction Substation (AB11)	1,680	· Three transformers (labelled as TX03 to TX05) with secondary containments were observed outside the AB11. · The areas of TX03, TX04 and TX05 with secondary containments are approximately 10m^2, 10m^2 and 30m^2 respectively. · Oil stains were observed within the secondary containments. · Apart from the three transformers, AB11 will be retained and no works (including excavation works) will be carried out within the area.	Three transformers with secondary containments (TX03: approximately 10m^2; TX04: approximately 10m^2; TX05: approximately 30m^2)	Three transformer locations AB11 BH1 –BH3 (refer to Figure NEX1062/S/SHD/ACM/Z10/051 of the CAP in Appendix 8.1 for borehole location)	Full list of Metals, PCRs, VOCs, SVOCs and PCBs	Biopiling, Solidification / Stabilisation, Permeable Reactive Barriers	Relocated SHD operation / maintenance facilities and new SHO	Industrial	Figure No. NEX1062/S/SHD/ACM/Z10/034 of the CAP in Appendix 8.1
Central Plant Building (AB16)	950	· General storage room was observed, no storage of chemical/ fuels/ oils and no stains were observed inside the room. · Apart from the general storage room, AB16 was comprises of switch rooms. · Four transformers (labelled as TX06 to TX09) were situated separately in a bund wall area of approximately 10m^2. The bund walls were in good condition and oil absorbing wipes were observed under the transformers. However, oil stains were observed within the bund wall areas.	Four transformers with bund walls (approximately 10m^2 each)	Four transformer locations AB16 BH1 –BH4 (refer to Figure NEX1062/S/SHD/ACM/Z10/052 of the CAP in Appendix 8.1 for borehole location)	Full list of Metals, PCRs, VOCs, SVOCs and PCBs	Biopiling, Solidification / Stabilisation, Permeable Reactive Barriers	Relocated SHD operation / maintenance facilities	Industrial	Figure No. NEX1062/S/SHD/ACM/Z10/036 of the CAP in Appendix 8.1
Underfloor Wheel Lathe Facility (AB22)	260	· No operation was observed during site visit. · Four wheel lathing machines were found below ground floor (approximately 100m^2) while lockers and some inert materials were observed at the ground floor. · Oil stains were observed around the lathing machines. · The floor of the facility was paved with intact concrete.	Area below ground floor (approximately 100m^2)	AB22 TP1 – TP3 (refer to Figure NEX1062/S/SHD/ACM/Z10/053 of the CAP in Appendix 8.1 for trial pit location)	Full list of Metals, PCRs, VOCs and SVOCs.	Biopiling, Solidification / Stabilisation, Permeable Reactive Barriers	Relocated SHD operation / maintenance facilities	Industrial	Figure No. NEX1062/S/SHD/ACM/Z10/038 of the CAP in Appendix 8.1
Main Depot Building (MDB)	26,680	· The MDB comprised warehouse and maintenance workshop for trains. · A warehouse (approximately 6,210m^2) was found in the middle portion of the main depot building. New parts / accessories of the train were stored on shelves. Folk lifts and their designated parking areas were observed. The warehouse was paved with intact concrete and no stains were observed. · Maintenance and repairing activities of trains were observed in the workshop (approximately 20,470m^2). The floor of the workshop was paved with intact concrete, however, oil stains were observed. · Chemicals and chemical wastes were temporary stored in designated cabinets or storage areas with secondary containments in the workshop. · Two transformers (labelled as TX10 and TX11) with bund walls (approximately 10m^2 each) were observed. The bund walls were in good condition and oil absorbing wipes were observed under the transformers. However, oil stains were observed within the bund wall.	Maintenance workshop (approximately 20,470m^2) and two transformers with bund walls (approximately 10m^2 each)	Maintenance workshops including observed oil stain MDB BH1 – BH35 Two transformer locations MDB BH36 – BH37 (refer to Figure NEX1062/S/SHD/ACM/Z10/054 of the CAP in Appendix 8.1 for borehole location)	Maintenance workshops Full list of Metals, PCRs, VOCs and SVOCs. Transformers Full list of Metals, PCRs, VOCs, SVOCs and PCBs	Biopiling, Solidification / Stabilisation, Permeable Reactive Barriers	Relocated SHD operation / maintenance facilities	Industrial	Figure No. NEX1062/S/SHD/ACM/Z10/041 of the CAP in Appendix 8.1

Note:

(1) - Metals include antimony, arsenic, barium, cadmium, chromium III, chromium VI, cobalt, copper, lead, manganese, mercury, molybdenum, nickel, tin and zinc.

- Petroleum carbon ranges (PCRs) include C6 – C8, C9 – C16 and C17 – C35.

- Volatile organic chemicals (VOCs) include BTEX (benzene, toluene, ethylbenzene, and total xylenes), MTBE (methyl tert-butyl ether), acetone, bromodichloromethane, 2-butanone, chloroform, methylene chloride, styrene, tetrachloroethene, and trichloroethene.

- 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.

- PCBs - Polychlorinated biphenyls.

(2) Details of possible remediation method(s) for the COCs are listed in Section 6.2 of the CAP (Appendix 8.1 refers).

8.7 Site Investigation Plan

8.7.1 Based on the desktop review and site observation, a total of 76 sampling locations are proposed to study the vertical profile of possible contamination in the concerned areas within the proposed works extent.

8.7.2 The regular grid pattern recommended in the Practice Guide is adopted for the concerned areas, except few small-scale potential contamination sources (e.g. underground diesel tank and transformers). The sampling and testing plan is presented in Table 8.4 while the sampling locations are shown in Figure Nos. NEX1062/S/SHD/ACM/Z10/044 to NEX1062/S/SHD/ACM/Z10/054 in the CAP (Appendix 8.1 refers).

8.7.3 However, the concerned areas listed in Table 8.4 are still in operation and undertaking the site investigation (SI) works at this stage is not feasible due to significant impact to the existing SHD operations and the need for maintaining the depot function to support existing operating railway lines, SI works are therefore recommended to carry out after decommissioning of the concerned areas.

Table 8.4 Sampling and Testing Plan

Area ID (Approx. Area)	Concerned Area (Approx. Area)	Grid Size (m)	Proposed Number of Sampling Location	Sampling Method	Sampling Matrix / Depth^(1)		Testing Parameters^(2)
							VOC	SVOC	Metals	PCRs	Other
AB2 (390m^2)	Whole area of AB2 (390m^2)	11	6 Borehole ID: AB2 BH1 – BH6 (refer to Figure NEX1062/S/SHD/ACM/Z10/046 of the CAP in Appendix 8.1 for borehole location)	Borehole to 2m below the groundwater table or 6m bgl	Soil	0.5m bgl, 1.5m bgl, 3.0m bgl, and further at 3.0m intervals upon encountering groundwater or 6m bgl whichever is shallower, and above GW level if present.	Full List	Full List	Full List	Full List	-
					GW	If present^(3)	Full List	Full List	Mercury	Full List	-
AB3 (550m^2)	TX01 and TX02 with bund walls (10m^2 each)	-	2 Borehole ID: AB3 BH1 – BH2 (refer to Figure NEX1062/S/SHD/ACM/Z10/047 of the CAP in Appendix 8.1 for borehole location)	Borehole to 2m below the groundwater table or 6m bgl	Soil	0.5m bgl, 1.5 m bgl, 3.0m bgl, and further at 3.0m intervals upon encountering groundwater or 6m bgl whichever is shallower, and above GW level if present.	Full List	Full List	Full List	Full List	PCBs
					GW	If present^(3)	Full List	Full List	Mercury	Full List	PCBs
AB6 (1,380m^2)	Maintenance area (1,050m^2)	13	7 Borehole ID: AB6 BH1 – BH7 (refer to Figure NEX1062/S/SHD/ACM/Z10/048 of the CAP in Appendix 8.1 for borehole location)	Borehole to 2m below the groundwater table or 6m bgl	Soil	0.5m bgl, 1.5m bgl, 3.0m bgl, and further at 3.0m intervals upon encountering groundwater or 6m bgl whichever is shallower, and above GW level if present.	Full List	Full List	Full List	Full List	-
					GW	If present^(3)	Full List	Full List	Mercury	Full List	-
	Underground diesel tank	-	5 Sampling ID: AB6 SS1 - SS5 (refer to Figure NEX1062/S/SHD/ACM/Z10/048 of the CAP in Appendix 8.1 for sampling location)	Hand tools^(4)	Soil	Side walls at mid-depth of tank and 0.5m below the bottom of tank or its casing	Full List	Full List	Full List	Full List	-
AB8 (750m^2)	Paint workshop, paint storage and chemical waste storage area of AB8 (670m^2)	13	4 Sampling ID: AB8 BH1 – BH4 (refer to Figure NEX1062/S/SHD/ACM/Z10/049 of the CAP in Appendix 8.1 for borehole location)	Borehole to 2m below the groundwater table or 6m bgl	Soil	0.5m bgl, 1.5m bgl, 3.0m bgl, and further at 3.0m intervals upon encountering groundwater or 6m bgl whichever is shallower, and above GW level if present.	Full List	Full List	Full List	Full List	-
					GW	If present^(3)	Full List	Full List	Mercury	Full List	-
AB9 (880m^2)	Whole area of AB9 (880m^2)	13	5 Borehole ID: AB9 BH1 – BH5 (refer to Figure NEX1062/S/SHD/ACM/Z10/050 of the CAP in Appendix 8.1 for borehole location)	Borehole to 2m below the groundwater table or 6m bgl	Soil	0.5m bgl, 1.5m bgl, 3.0m bgl, and further at 3.0m intervals upon encountering groundwater or 6m bgl whichever is shallower, and above GW level if present.	Full List	Full List	Full List	Full List	-
					GW	If present^(3)	Full List	Full List	Mercury	Full List	-
Transformers located outside AB11	TX03 and TX04 with secondary containments (10m^2 each) and TX05 with secondary containment (30m^2)	-	3 Borehole ID: AB11 BH1 – BH3 (refer to Figure NEX1062/S/SHD/ACM/Z10/051 of the CAP in Appendix 8.1 for borehole location)	Borehole to 2m below the groundwater table or 6m bgl	Soil	0.5m bgl, 1.5m bgl, 3.0m bgl, and further at 3.0m intervals upon encountering groundwater or 6m bgl whichever is shallower, and above GW level if present.	Full List	Full List	Full List	Full List	PCBs
					GW	If present^(3)	Full List	Full List	Mercury	Full List	PCBs
AB16 (950m^2)	TX06 to TX09 with bund walls (10m^2 each)	-	4 Borehole ID: AB16 BH1 – BH4 (refer to Figure NEX1062/S/SHD/ACM/Z10/052 of the CAP in Appendix 8.1 for borehole location)	Borehole to 2m below the groundwater table or 6m bgl	Soil	0.5m bgl, 1.5m bgl, 3.0m bgl, and further at 3.0m intervals upon encountering groundwater or 6m bgl whichever is shallower, and above GW level if present.	Full List	Full List	Full List	Full List	PCBs
					GW	If present^(3)	Full List	Full List	Mercury	Full List	PCBs
AB22 (260m^2)	Area below ground floor (100m^2)	-	3 Trial Pit ID: AB22 TP1 – TP3 (refer to Figure NEX1062/S/SHD/ACM/Z10/053 of the CAP in Appendix 8.1 for trial pit location)	Trial pit to 3m below below ground level (bgl)	Soil	0.5m bgl, 1.5m bgl, 3.0m bgl, and above GW level if present.	Full List	Full List	Full List	Full List	-
					GW	If present^(3)	Full List	Full List	Mercury	Full List	-
MDB (26,680m^2)	Maintenance Workshop (20,470m^2)	25.5	35 Borehole ID: MDB BH1 – BH35 (refer to Figure NEX1062/S/SHD/ACM/Z10/054 of the CAP in Appendix 8.1 for borehole location)	Borehole to 2m below the groundwater table or 6m bgl	Soil	0.5m bgl, 1.5m bgl, 3.0m bgl, and further at 3.0m intervals upon encountering groundwater or 6m bgl whichever is shallower, and above GW level if present.	Full List	Full List	Full List	Full List	-
					GW	If present^(3)	Full List	Full List	Mercury	Full List	-
	TX10 and TX11 with bund walls (10m^2 each)	-	2 Borehole ID: MDB BH36 – BH37 (refer to Figure NEX1062/S/SHD/ACM/Z10/054 of the CAP in Appendix 8.1 for borehole location)	Borehole to 2m below the groundwater table or 6m bgl	Soil	0.5m bgl, 1.5m bgl, 3.0m bgl, and further at 3.0m intervals upon encountering groundwater or 6m bgl whichever is shallower, and above GW level if present.	Full List	Full List	Full List	Full List	PCBs
					GW	If present^(3)	Full List	Full List	Mercury	Full List	PCBs

Note:

(1) bgl = Below ground level; GW = groundwater

(2) – Full list refers to the parameters as shown in Table 2.1 – RBRGs for Soil & Soil Saturation Limit and Table 2.2 – RBRGs for Groundwater and Solubility Limit under VOCs, SVOCs, Metals and PCRs in the Guidance Manual.

– Volatile organic chemicals (VOCs) include BTEX (benzene, toluene, ethylbenzene, and total xylenes), MTBE (methyl tert-butyl ether), acetone, bromodichloromethane, 2-butanone, chloroform, methylene chloride, styrene, tetrachloroethene, and trichloroethene.

– 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. Since RBRG value of Benzo(a)anthracene, Benzo(a)pyrene, Benzo(g,h,i)perylene, Benzo(k)fluoranthene, bis-(2-Ethylhexyl)phthalate, Dibenzo(a,h)anthracene, Indeno(1,2,3-cd)pyrene and Phenol were not available for groundwater, the captioned chemicals parameters would not be tested in groundwater sample

– Metals include antimony, arsenic, barium, cadmium, chromium III, chromium VI, cobalt, copper, lead, manganese, mercury, molybdenum, nickel, tin and zinc.

– Petroleum carbon ranges (PCRs) include C6 – C8, C9 – C16 and C17 – C35.

– PCBs - Polychlorinated biphenyls.

(3) Samples will only be collected if groundwater is encountered during SI works.

(4) Details refer to Section 3.2.4 of the CAP (Appendix 8.1 refers).

8.8 Evaluation of Environmental Impacts

8.8.1 The relevant land contamination issues within the areas of existing SHD identified as potentially contaminated are considered to be surmountable due to the following factors:

· The size of individual sites and related operation scale are relatively small and the extent of any potential contamination is anticipated to be localised rather than widespread

Based on the site appraisal, the potentially contaminating activities in the concerned areas are mainly train / equipment maintenance and associated chemical handling/storage and the activities are localised within the existing SHD.

In addition, the concerned areas are not large scale polluting installations / facilities such as oil depots and power plants and majority of the concerned areas are relatively small in scale. Therefore, the contamination extent, if any, caused by the operations of the concerned area are anticipated to be localised.

· The chemical species identified are readily treatable using establish physical, chemical and biological techniques

Based on the site appraisal, the potential COCs include metals, VOCs, SVOCs, PCRs and PCBs. Remediation methods that have demonstrated to effectively treat the aforementioned soil and groundwater contaminants include biological treatment and physical / chemical treatment. Details of the treatment methods are provided in Section 6.2 of the CAP provided in Appendix 8.1.

· Local remediation experience is sufficient to deal with the nature of the possible contaminants

Soil contaminated with the abovementioned COCs had successfully been remediated in Hong Kong using proven remediation techniques. Notable local remediation projects include the followings:

§ Decommissioning of Kai Tak Airport North Apron;

§ Decontamination works at the Cheoy Lee Shipyard;

§ Reclamation works at North Tsing Yi Shipyard site; and

§ Decommissioning of Kwai Chung Incinerator.

8.8.2 In view of the above factors, any soil / groundwater contamination would be identified and properly treated according to the approved Remediation Action Plan(s) (RAP).  Remediation Report(s) (RRs) demonstrating the completion of remediation works at the area(s) (if any) confirmed with contamination will be prepared and submitted to EPD for approval prior to the commencement of construction works at the contaminated areas.

8.9 Mitigation of Adverse Environmental Impacts

Recommended Further Works

8.9.1 Since the concerned areas within the existing SHD are still in operation and undertaking the SI works at this stage is not feasible due to significant impact to the existing SHD operations and the need for maintaining the depot function to support existing operating railway lines, therefore, the SI works and any necessary remediation action are recommended to be carried out after decommissioning of concerned areas but prior to construction works at the concerned area. Further assessment and, if required, remediation should follow EPD’s Guidance Manual, Guidance Note and Practice Guide and should include the following:

· Prior to the commencement of the SI works, review the CAP provided in Appendix 8.1 to confirm whether the proposed SI works (e.g. sampling locations, testing parameters etc.) are still valid and to confirm the appropriate RBRGs land use scenario for the development;

· Should any changes in operation which lead to any new or the relocation of contamination hotspots or occurrence of spillage or accident be found in the review, supplementary CAP(s), presenting the findings of the review, the latest site conditions and updated sampling strategy and testing protocol, should be submitted to EPD for endorsement;

· The SI works should be carried out according to EPD’s approved CAP(s);

· Contamination Assessment Report(s) (CAR(s)) should be prepared to present the findings of the SI works and to discuss the presence, nature and extent of contamination. If contamination is identified in the CAR(s), Remediation Action Plan(s) (RAP(s)) which provides details of the remedial actions for the identified contaminated soil and/or groundwater should be developed prior to construction works at the concerned area. Submission to EPD for endorsement of supplementary CAP(s), CAR(s) and, if required, RAP would be carried out in stages according to the programme of SHD Replanning Works.

· If required, carry out soil/groundwater remediation works according to EPD agreed RAP(s) and submit Remediation Report(s) (RR(s)) afterwards for EPD agreement. The remediation works should be completed and RR(s) demonstrating the completion of remediation works at the area(s) (if any) confirmed with contamination will be prepared and submitted to EPD for approval prior to the commencement of construction works at the contaminated areas.

Possible Remediation Measures

8.9.2 According to the Practice Guide, the need to remediate the concerned areas would be determined based on the findings of the SI presented in the CAR and the actual nature, level and extent of contamination can only be evaluated through SI. The appropriate remediation methods should be selected in the RAP based on the SI findings. The possible remediation methods and the selection criteria are detailed in Section 6.2 of the CAP provided in Appendix 8.1.

Mitigation Measures for Remediation Works

8.9.3 Mitigation measures for the remediation works would depend on the nature / extent of contamination and the method of treatment. The mitigation measures will be recommended in the RAP and would typically include the following:

· Excavation profiles must be properly designed and executed with attention to the relevant requirements for environment, health and safety;

· Establish and maintain a Health and Safety Plan with the information below before commencement of the SI:

(a) Instruction of works on work procedures, safe practices, emergency duties, and applicable regulations;

(b) Regularly scheduled meetings of the workers in which the possible hazards, problems of the job, and related safe practices are emphasized and discussed;

(c) Good housekeeping practices; and

(d) Availability of and instruction in the location, use and maintenance of personal protective equipment.

· Excavation shall be carried out during dry season as far as possible to minimise contaminated runoff from contaminated soils;

· Supply of suitable clean backfill material (or treated soil) after excavation;

· Stockpiling site(s) shall be lined with impermeable sheeting and bunded. Stockpiles shall be fully covered by impermeable sheeting to reduce dust emission. If this is not practicable due to frequent usage, regular watering shall be applied. However, watering shall be avoided on stockpiles of contaminated soil to minimise contaminated runoff;

· Vehicles containing any excavated materials shall be suitably covered to limit potential dust emissions or contaminated wastewater run-off, and truck bodies and tailgates shall be sealed to prevent any discharge during transport or during wet conditions;

· Speed control for the trucks carrying contaminated materials shall be enforced;

· Vehicle wheel and body washing facilities at the site’s exit points shall be established and used; and

· Pollution control measures for air emissions (e.g. from biopile blower and handling of cement), noise emissions (e.g. from blower or earthmoving equipment), and water discharges (e.g. runoff control from treatment facility) shall be implemented and complied with relevant regulations and guidelines.

8.10 Evaluation of Residual Environmental Impacts

8.10.1 Recommended further works for the proposed works extent within the Scheme Boundary would need to follow EPD’s Guidance Manual, Guidance Note and Practice Guide and any soil / groundwater contamination would be identified and properly treated prior to the development. Land contamination impacts are therefore considered surmountable to future occupants if the recommended actions as outlined in Section 8.9 were followed and contaminated soil and groundwater (if any) were properly treated using appropriate remediation methods and according to EPD’s approved RAP.

8.11 Conclusion

8.11.1 This land contamination assessment examined the potential contaminative land uses and their potential impacts to future land use within the Scheme Boundary.

8.11.2 Based on the findings from desktop review and site reconnaissance, 9 facilities / areas within the existing SHD have been identified as potentially contaminated. Findings of the desktop review and site reconnaissance as well as the proposed soil and groundwater sampling and testing strategy are presented in the CAP enclosed in Appendix 8.1. Other than the concerned areas, no other land contamination issue were identified within the Scheme Boundary.

8.11.3 Since the concerned areas are still in operation and undertaking the SI works at this stage is not feasible due to significant impact to the existing SHD operations and the need for maintaining the depot function to support existing operating railway lines, the SI works are recommended to be carried out after decommissioning of the facilities but prior to construction works at the concerned areas. If required, carry out soil/groundwater remediation works according to EPD agreed RAP(s) and submit Remediation Report(s) (RR(s)) afterwards for EPD agreement. The remediation works should be completed and RR(s) demonstrating the completion of remediation works at the area(s) (if any) confirmed with contamination will be prepared and submitted to EPD for approval prior to the commencement of construction works at the contaminated areas.

8.11.4 The recommended further works, including the submission of Supplementary CAP(s), CAR(s) / RAP(s) and RR(s), would need to follow EPD’s Guidance Manual, Guidance Note and Practice Guide and according to Section 8.9 of this report.

8.11.5 With the implementation of the recommended further works for the concerned areas, any soil / groundwater contamination would be identified and properly treated prior to construction works at the concerned areas. Land contamination impacts are therefore considered not insurmountable to future occupants.