7 Land Contamination

7.1 Introduction

7.1.1 This section presents the potential land contamination implications associated with the Project.

7.2 Environmental Legislation, Plans, Standards, and Guidelines

7.2.1 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.

7.3 Assessment Methodologies

7.3.1 Land contamination assessment was carried out according to the abovementioned EIAO-TM, Guidance Note, Practice Guide and Guidance Manual.

7.3.2 Site appraisals, including site walkovers and desktop review, were conducted to identify the potentially contaminating activities that may pose adverse impact to the Project. Site walkovers were conducted within the works sites and works areas of the Project (i.e. the Project Area) to review the general site conditions and to identify any sources of land contamination (or ‘hotspots’). For the desktop review, the following information was reviewed:

· Selected aerial photographs and topographic maps held by the Lands Department (LandsD); and

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

7.3.3 Based on the site appraisals, soil and groundwater sampling and testing at the potentially contaminated areas have been proposed. A Contamination Assessment Plan (CAP), detailed findings of the site appraisals and the proposed site investigation (SI) works, was prepared and enclosed in Appendix 7.1.

7.3.4 As reported in the CAP, all the identified potentially contaminated areas within the Project Area are currently in operation, the SI works and the subsequent assessment / remediation works are therefore proposed to be carried out after decommissioning but prior to the construction works at the concerned areas. For these concerned areas, review of the initial contamination, possible remediation methods, potential insurmountable impacts, SI requirements as well as the tentative timeframe for subsequent submissions were presented in the CAP (Appendix 7.1 refers).

7.4 Description of the Environment

7.4.1 The Project, including the viaduct, stations and the associated works areas / works sites, with a total area of approximately 25 hectares, is located in the southern part of Tuen Mun. The current land uses of the Project mainly comprises a recycling station, a swimming pool, open car parks, parks / gardens, vegetated land, vacant land, river channel and road. The Project Area is shown in Figure No. C1502/C/TME/ACM/M50/102.

7.4.2 The surrounding environment of the Project is urbanized, with existing land uses comprising mainly high-density residential developments [Residential (Group A)], Government, Institution or Community (G/IC), Green Belt (GB) and Open Space (O).

7.4.3 The Project also includes an offsite construction works area at Mong Wing Street, which is currently used as site office for the project “Tuen Mun - Chek Lap Kok Link (TM-CLKL)”, to support the construction of the Project. This works area would be handed over by Highways Department in 2024 tentatively. This offsite works area will only be used as site office, material storage for pre-cast unit (non-dusty material) and temporary tree nursery, and there would be no excavation works, earthworks and stockpiling of dusty materials to be conducted at this works area. The entire area was paved with intact concrete in good condition and the site photos are shown in the CAP (Appendix 7.1 refers). Hence, no potential land contamination implication associated with this offsite construction works area is anticipated for the Project. The proposed offsite temporary works area is shown in Figure No. C1502/C/TME/ACM/M50/103.

7.5 Identification of Potential Land Contamination Concern

General

7.5.1 Site appraisals were carried out in the period between January and June 2021 with site walkovers conducted in January, February and May 2021. Findings of the site appraisals were detailed in the CAP (Appendix 7.1 refers) and are summarised below.

Review of Historical Land Uses

7.5.2 A review of historical aerial photographs was undertaken to evaluate the likelihood of potential contamination associated with past land uses within the Project Area. A summary of the historical land uses is presented in Table 7.1 below. The historical photographs are shown in Annex A of the CAP (Appendix 7.1 refers).

Table 7.1 Summary of Historical Land Uses of the Project Area

Year	Description
1963	The Project Area was occupied by open waters.
1973	Reclamation works and reclaimed land were observed in the north and the east of the Project Area. The nullah was modified to the existing configuration in the north of the Project Area.
1983	Reclaimed land was observed in the centre and south of the Project Area. Tuen Mun Park and Tuen Mun 3rd Village Temporary Housing Area were observed. The nullah was largely modified to the existing configuration except for the southwest of the Project Area.
1993	A suspected industrial facility with electrical substation (Site TME-S1) was observed in the centre of the Project Area. The area appeared to be concrete paved. An open storage (Site TME-S2) was observed in the south of the Project Area. A cargo working area was also observed in the south of the Project Area. The area appeared to be concrete paved with containers, construction materials and barging point for cargo handling. The existing Tuen Mun Swimming Pool, garden, playground and existing Wong Chu Road were observed. The Tuen Mun River Channel was modified to the existing configuration. Tuen Mun 3rd Village Temporary Housing Area was replaced by the existing Tuen Mun Park.
2003	The suspected industrial facility (Site TME-S1) was replaced by an open storage. The open storage (Site TME-S2) was replaced by an existing open car park, vegetated land and vacant land. The cargo working area was replaced by an existing open car park. A construction site was observed in the northern portion of the Project Area. The existing Construction Industry Training Authority (CITA) / Construction Industry Council (CIC) Tuen Mun Training Ground was observed in the central portion of the Project Area. The existing open car park, a construction site and a temporary structure were also observed in the central portion of the Project Area. The existing Wu King Road Garden, Wu Shan Recreation Playground, Tuen Mun Promenade and public toilet were observed in the south of the Project Area.
2013	The existing Pui To Road (South) Rest Garden and Hoi Wong Road Garden were observed in the north of the Project Area. A site office was observed in the central portion of the Project Area.
2020	The open storage (Site TME-S1) was turned into the existing Tuen Mun Community Green Station. The site office was vacated. Tuen Mun River (Eastern Bank) Garden was observed. An existing works site was observed within Tuen Mun Park.

7.5.3 Based on the review, apart from the former suspected industrial facilities / open storage (Site TME-S1) and the former open storage (Site TME-S2), no other historical potentially contaminating land uses were identified within the Project Area.

Site Geology

7.5.4 The Project Area, generally flat with levels varying from +4.5 mPD to +10.8 mPD, is largely located on land reclaimed previously in the early 1970-80s.

7.5.5 According to the preliminary borehole records of ground investigation (GI) works under this Project, the general thickness of reclamation fill ranges from 2m to 14.7m. The Project Area is generally further underlain by marine deposit with thickness ranging from 2m to 9.5m and / or alluvium with thickness ranging from 1.7 m to 9m. Colluvium of approximately 0.5m in thickness is also anticipated. In-situ decomposed rock (i.e. Grade IV/V materials) is anticipated with thickness ranging from 0.2m to 34.8m. Engineering rockhead is anticipated to be situated at -9.4 mPD to -40.1 mPD.

Information from Government Authorities

7.5.6 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 Project Area.

7.5.7 According to the replies from EPD and FSD, there were no records of spillage/ leakage of chemicals record within Project Area.

7.5.8 A total of 2 DG records and 1 incident record were reported by FSD but all concerned locations are outside the Project Area. In addition, there are 5 valid and 3 invalid registered CWPs identified within the Project Area. The relevant details are presented in the CAP (Appendix 7.1 refers).

Site Reconnaissance

7.5.9 Site walkovers were conducted in January, February and May 2021 to investigate any contaminative issues associated with current land uses and activities within the Project Area.

7.5.10 Based on the findings of site walkovers, the Project Area is mainly occupied by non-contaminating land uses including Wong Chu Road, public car parks, gardens / parks / promenade, Tuen Mun Swimming Pool, Tuen Mun Community Green Station, Tuen Mun Ferry Pier Public Toilet, Tuen Mun River Channel, vacant land and vegetated land. No potentially contaminating land uses / activities (e.g. vehicle maintenance activity) were observed in these areas during the site walkovers.

7.5.11 In addition, a portion of the existing Construction Industry Council (CIC) Tuen Mun Training Ground is within the Project Area. Given that the identified concerned areas i.e. the chemical / chemical waste storage areas were located outside the Project Area (refer to Appendix 7.1 for details), potential land contamination issue associated with the operation of the CIC Tuen Mun Training Ground to the Project is not anticipated.

7.5.12 Nevertheless, the electrical substation (No. 08271-1) at Tuen Mun Swimming Pool (Site TME-S3) and the diesel generator in the works site of Contract No. DC/2018/09 Rehabilitation of Trunk Sewers in Tuen Mun at Tuen Mun Park (Site TME-S4) were identified with potential land contamination concerns during the site walkovers. The potentially contaminating activities identified within the concerned areas are detailed in Table 7.2.

Summary of Site Appraisal

7.5.13 Based on findings of the site appraisal, the following four facilities / areas were identified with potential land contamination concerns:

· Tuen Mun Community Green Station (former open storage, former suspected industrial land use and former electrical substation) (Site TME-S1);

· Wu Shan Road Car Park (STT No. MX16007) and land in the vicinity (former open storage) (Site TME-S2);

· Electrical substation (No. 08271-1) at Tuen Mun Swimming Pool (Site TME-S3); and

· Diesel generator in Works site of Contract No. DC/2018/09 (Site TME-S4).

7.5.14 Further site investigation (SI) works is considered necessary to confirm any land contamination in the above concerned facilities / areas. The corresponding sampling and testing strategies are presented in Section 7.6.

7.5.15 Site appraisal findings of the facilities / areas with potential land contamination concerns are shown in Table 7.2. The photographic records, including the site layout plans, are shown in Figure Nos. C1502/C/TME/ACM/M55/017, 019, 020 and 022 in the CAP (Appendix 7.1 refers).

Table 7.2 Summary of Potential Land Contamination Issues within the Project Area

Site ID / Concerned Site (Affected Land Lot No. / Address)¹	Current Land Use	Site Observation / Current Potentially Contaminating Activities	Corresponding Photographic Record Reference in the CAP in Appendix 7.1	Other Past Potential Contaminating Land Use / Activities	Approx. Site Area (m²)	Any Potential Land Contamination Issues?	Potential COCs	Future Land Uses	RBRGs Land Use Scenario³
TME-S1 Tuen Mun Community Green Station (GLA-TTM 717)	Recycling station	The Tuen Mun Community Green Station is located in the central portion of the Project Area. As reported by the site representative and observed during the site walkover, the site mainly consists of an office (comprising an office area, an activity room and a toilet) in the centre, a garden in the south, a warehouse and a storage yard for the temporary storage of recyclables (e.g. paper, plastics and aluminum cans) in the northern portion of the site. Except for the landscaped areas, the entire site was paved with no stains / stressed vegetation observed. A chemical waste storage room for temporary storage of spent fluorescent lamp tubes and batteries was observed in the west of the warehouse. As reported by the site representative, the spent fluorescent lamp tubes and batteries are delivered off-site regularly for recycling. A hydraulic waste baler was also observed in the northwest of the warehouse. Based on site observations and information reported by the site representative, hydraulic oil is used for the operation of the baler and the oil is stored in the hydraulic oil tank within the baler machine at least 2 m above ground level. The entire warehouse was paved with intact concrete in good condition with no signs of oil stains / chemical spillage observed. No potentially contaminating activities were observed at the site during the site walkover. Based on EPD information, a valid CWP record registered for government facility was identified for the site. Based on FSD/EPD information, there were no DG / fire incident / spillage records for the site.	C1502/C/TME/ACM/M55/020	Open storage (year 2003 to 2019) Suspected industrial land use & electrical substation (year 1993 to 2002)	2,760	Yes · Potential land contamination issues associated with past land uses. · Given the storage of spent batteries and fluorescent lamps in the chemical waste storage room was only temporary as these chemical wastes are reportedly delivered off-site regularly, and the hydraulic oil tank is located within the baler machine at least 2m above ground level, and the entire warehouse was paved with concrete in good conditions with no signs of oil stains / chemical spillages observed, no potential land contamination issues associated with these two areas to the Project are anticipated.	Metals, VOCs, SVOCs, PCRs and PCBs	Viaduct and railway station	Industrial
TME-S2 Wu Shan Road Car Park (STT No. MX16007) and land in the vicinity	Open car park and vegetated land	An open car park is located in the south of the Project Area, which was largely concrete paved. No vehicle maintenance activities were observed at the site. The site also comprises vegetated land. No potentially contaminating activities were identified at the site during the site walkover. Based on FSD/EPD information, there were no DG / chemical wastes / fire incident / spillage records for the site.	Photo 0966, 2506, 0970 and 2522 in C1502/C/TME/ACM/M55/022	Open storage (year 1993 to 2002)	7,220	Yes²	Metals, VOCs, SVOCs, and PCRs	Riverside open space and potential underground car park	Lower of Industrial or Public Park
TME-S3 Tuen Mun Swimming Pool (GLA-TM 47)	Swimming pool, squash courts, car park and garden	The site mainly comprises swimming pool facilities (e.g. pools and changing rooms), a plant room (comprising water boilers, water pumps and tanks, a refuse store and chemical storage rooms for the storage of sodium chloride (common salt), sodium hypochlorite (bleach) and a small amount of alum), a fire service water tank, Tuen Mun Swimming Pool Squash Courts (comprising 2 courts and site offices), car park and a garden. As reported by the site representatives, only the chemicals stored in the chemical storage rooms are used in the plant room. No potentially contaminating activities were observed in these areas during the site walkover. An electrical substation (No. 08271-1) (Site TME-S3) is located within the plant room in the south of the Tuen Mun Swimming Pool. The substation was concrete paved and housed a transformer (approx. 5m²) containing transformer oil. The transformer was situated on raised concrete foundation in good condition with no oil stains observed. Based on information from EPD, FSD and site representatives, there were no DG / chemical wastes / fire incident / spillage records for the site.	C1502/C/TME/ACM/M55/019	N/A	35,660 Transformer: 5 m²	Yes Concerned area: · Transformer (5 m²) · No land contamination issues anticipated for the plant room given the chemicals identified (sodium chloride, sodium hypochlorite and alum) are not considered as land contaminants.	Metals, VOCs, SVOCs, PCRs and PCBs	Viaduct and railway station / Residential	Urban Residential
TME-S4 Works site of Contract No. DC/2018/09 (Portion of GLA-TM 106)	Works site	A works site of Contract No. DC/2018/09 Rehabilitation of Trunk Sewers in Tuen Mun is located within Tuen Mun Park in the east of the Project Area. The works site mainly comprises a works area for rehabilitation of underground trunk sewers in the north, a material storage area (for construction materials and equipment) and a chemical dosing unit in the south of the site. Apart from the works area, the remaining areas of the works site was part of the existing paved cycling track. The cycling track was noted to be in good condition with no stains / stressed vegetation observed. Based on site observations and as reported by the site representative, no vehicle refueling or vehicle / equipment maintenance activities are carried out on site. Based on site observations and information provided by the site representatives, wastewater treatment chemicals including Clarifloc, polyaluminum chloride (PAC) and sodium bisulfite are stored in the chemical dosing unit and are used on site. These chemicals were stored in plastic drums with metal drip trays within the chemical dosing unit in the east of the works site. The metal drip trays and paved cycling track in the vicinity were in good condition with no signs of stains / spillage observed. A 60 L diesel generator was observed in the west of the works site. The generator was located on the existing raised planter of approximately 0.3 m above ground level along the Tuen Mun River Channel and was provided with a metal drip tray. The drip tray was observed to be intact and in good condition with no signs of oil stains / spillages in the vicinity of the generator. As reported by the site staff, diesel and lubricating oils are used for operation of the generator and are delivered to site as and when required for refueling of the generator. All lubricating oils and spent lubricating oils were reportedly stored off-site at another works site outside the Project Area. No chemical waste / chemical waste storage areas were observed on site during the site walkover. Based on EPD information, 1 valid CWP record registered for construction was identified for the site. Based on information from FSD, EPD and site representatives, there were no DG / fire incident / chemical spillage records for the site.	Photo 2624, 6970, 7456, 7461 and 7463 in C1502/C/TME/ACM/M55/017	N/A	420 Diesel generator: 3 m²	Yes Concerned area: · Diesel generator (3 m²) · The wastewater treatment chemicals (Clarifloc, PAC and sodium bisulfite) are not considered as land contaminants.	Metals, VOCs, SVOCs, and PCRs	Cycling track / footpath	Lower of Industrial or Public Park

Notes:

1. Refer to Figure Nos. C1502/C/TME/ACM/M55/026 to 028 of the CAP (Appendix 7.1 refers) for locations of the sites.

2. Potential land contamination impact associated with Site TME-S2 to the Project is not anticipated if no excavation works would be proposed at the site, subject to confirmation of the engineering design plan in later stage of the Project.

3. Where a site would be developed into more than one land use in the future, the most stringent RBRGs has been adopted.

N/A: Not Applicable

Table 7.3 Sampling and Testing Plan

Site ID (Approx. Area)	Hotspot (Approx. Area)	Grid Size (m)	Proposed Number of Sampling Location	Rationale	Sampling Method	Sampling Matrix / Depth⁽¹⁾		Testing Parameters⁽²⁾
Site ID (Approx. Area)	Hotspot (Approx. Area)	Grid Size (m)	Proposed Number of Sampling Location	Rationale	Sampling Method	Sampling Matrix / Depth⁽¹⁾		VOC	SVOC	Metals	PCRs	PCBs
TME-S1 Tuen Mun Community Green Station / Former Industrial Facility (2,760 m²)	Whole area of former industrial facility (2,760 m²)	14	16 Borehole ID: ENV-BH01 – BH16 (refer to Figure No. C1502/C/TME/ACM/M55/029 of the CAP in Appendix 7.1 for sampling locations)	Sampling to target the existing site. A grid sampling approach based on EIA recommendations and the Practice Guide with specified grid size was adopted for the sampling strategy. Sampling location ENV-BH16 was proposed to target the former electrical substation (approx. 55 m²).	Borehole to 2m below the ground-water table or 6m bgl	Soil	(i) 0.5m bgl; (ii) 1.5m bgl; (iii) 3.0m bgl; and (iv) above GW level if present or if no GW encountered, 6m bgl.	Full List	Full List	Full List	Full List	ü (ENV-BH16 only)
	Whole area of former industrial facility (2,760 m²)	14			Borehole to 2m below the ground-water table or 6m bgl	GW	If present⁽³⁾	Full List	Full List	Mercury only	Full List	ü (ENV-BH16 only)
TME-S2⁽⁴⁾ Wu Shan Road Car Park (STT No. MX16007) (7,220 m²)	Whole area of former open storage (7,220 m²)	17	31 Borehole ID: ENV-BH18 – BH48 (refer to Figure No. C1502/C/TME/ACM/M55/030 of the CAP in Appendix 7.1 for sampling locations)	Sampling to target the existing site. A grid sampling approach based on the Practice Guide with specified grid size was adopted for the sampling strategy.	Borehole to 2m below the ground-water table or 6m bgl	Soil	(i) 0.5m bgl; (ii) 1.5m bgl; (iii) 3.0m bgl; and (iv) above GW level if present or if no GW encountered, 6m bgl.	Full List	Full List	Full List	Full List	-
	Whole area of former open storage (7,220 m²)	17			Borehole to 2m below the ground-water table or 6m bgl	GW	If present⁽³⁾	Full List	Full List	Mercury only	Full List	-
TME-S3 Tuen Mun Swimming Pool (35,660 m²)	1 transformer on concrete foundation (5 m²)	-	1 Borehole ID: ENV-BH17 (refer to Figure No. C1502/C/TME/ACM/M55/029 of the CAP in Appendix 7.1 for sampling location)	Sampling to target the transformer located in the electrical substation.	Borehole to 2m below the ground-water table or 6m bgl	Soil	(i) 0.5m bgl; (ii) 1.5m bgl; (iii) 3.0m bgl; and (iv) above GW level if present or if no GW encountered, 6m bgl.	Full List	Full List	Full List	Full List	ü
TME-S3 Tuen Mun Swimming Pool (35,660 m²)	1 transformer on concrete foundation (5 m²)	-			Borehole to 2m below the ground-water table or 6m bgl	GW	If present⁽³⁾	Full List	Full List	Mercury only	Full List	ü
TME-S4 Works site of Contract No. DC/2018/09 (420 m²)	1 diesel generator (3 m²)	-	1 Borehole ID: ENV-BH49 (refer to Figure No. C1502/C/TME/ACM/M55/031 of the CAP in Appendix 7.1 for sampling location)	Sampling to target the hotspot area at the existing diesel generator.	Borehole to 2m below the ground-water table or 6m bgl	Soil	(i) 0.5m bgl; (ii) 1.5m bgl; (iii) 3.0m bgl; and (iv) above GW level if present or if no GW encountered, 6m bgl.	Full List	Full List	Full List	Full List	-
	1 diesel generator (3 m²)	-			Borehole to 2m below the ground-water table or 6m bgl	GW	If present⁽³⁾	Full List	Full List	Mercury only	Full List	-

Notes:

(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) No SI works is required if there would be no excavation works proposed at the site under the Project, subject to confirmation of the engineering design plan in later stage of the Project. The relevant design plans will be provided to EPD for review and agreement should the SI works would not be proceeded in the future.

7.7 Evaluation of Environmental Impacts

7.7.1 Based on the findings of site appraisals, a total of four facilities / area were identified with potential land contamination concerns within the Project Area and intrusive SI works were considered necessary. However, as the concerned sites are still in operation, it would not be feasible to carry out the proposed SI works under the EIA Study.

7.7.2 The potential land contamination concerns for the concerned sites were associated with handling and storage of hazardous substances. Apart from the former open storage areas / suspected industrial facility (Site TME-S1 and TME-S2), the scale of operation of the remaining concerned area was considered small (approximately 3 to 5 m²). For the former open storage, the site appeared to be largely used for construction materials storage and it is likely that only a small portion of the site is used for the handling / storage of hazardous substances (if any). As reported by EPD and FSD, there were no records of spillages / leakages accidents of chemicals / dangerous goods within the Project Area. It is therefore considered that the contamination (if indeed present) would unlikely be extensive within the Project Area.

7.7.3 Land contamination assessment including intrusive SI works and, if required, remediation works would need to be carried out at a later stage of the Project (refer to Section 7.8 below for details) and should follow EPD’s Guidance Manual, Guidance Note and Practice Guide. Any soil/groundwater contamination would be identified and properly treated prior to the commencement of construction works under the Project. The potential COCs identified include metals, VOCs, SVOCs, PCRs and PCBs and there are commercially available technologies that could tackle these COCs.

7.7.4 Given the above, land contamination impacts are considered not insurmountable to the future occupants if the recommended actions as outlined in Section 7.8 were followed and contaminated soil and groundwater (if any) were properly treated using appropriate remediation methods and according to EPD’s agreed Remediation Action Plan (RAP).

7.8 Mitigation of Adverse Environmental Impacts

Recommended Further Works

7.8.1 As the concerned facilities within the Project Area are still in operation, it would not be feasible to carry out the proposed SI works under the EIA Study. Moreover, as the demolition of concerned facilities and construction works at the concerned areas will not commence until 2023, there could be changes in the operation or changes in land use within the Project Area which may cause further contamination issues. Therefore, site re-appraisal and submission of supplementary CAP(s) should be carried out for the whole Project Area at a later stage of the Project in order to address any new contamination issues caused by the (i) changes in operation of the identified potentially contaminated site and (ii) changes of land use within the Project Area. The associated SI works and any necessary remediation action are recommended to be carried out after the operation of concerned area(s) has ceased but prior to the commencement of construction works at the concerned area(s).

7.8.2 The site re-appraisal and submission of supplementary CAP(s) should be carried out prior to the commencement of the SI works. Supplementary CAP(s), presenting findings of the review, the latest site conditions and updated sampling strategy and testing protocol, should be submitted to EPD for approval. The SI works should be carried out according to EPD’s approved supplementary CAP(s). Following completion of SI works and receipt of laboratory test results, 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, RAP(s) which provides details of the remedial actions for the identified contaminated soil and / or groundwater should be submitted to EPD for approval.

7.8.3 Remediation action, if necessary, will be carried out according to EPD approved RAP(s) and Remediation Report(s) (RR(s)) will be submitted after completion of the remediation action. The RR(s) should be endorsed by EPD prior to the commencement of construction works at the respective identified contaminated areas (if any).

Possible Remediation Measures

7.8.4 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 5.2 of the CAP (Appendix 7.1 refers).

Mitigation Measures for Remediation Works

7.8.5 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;

· 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;

· 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.

7.9 Evaluation of Residual Environmental Impacts

7.9.1 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 7.8 were followed and contaminated soil and groundwater (if any) were properly treated using appropriate remediation methods and according to EPD’s approved RAP.

7.10 Conclusion

7.10.1 Site appraisals, in the form of desktop review and site walkovers, were conducted between January 2021 and February 2022 to identify any current/historical potentially contaminating and uses within the Project Area. Based on the findings of site appraisals, a total of four facilities / areas were identified with potential land contamination concerns within the Project Area.

7.10.2 A sampling and testing programme, targeting the potential hotspots identified within the Project Area was proposed and documented in the CAP. As the concerned facilities are still in operation and the demolition and construction works will not commence until 2023, there could be change in site activities and land uses within the Project Area prior to development which may cause further contamination issues. Further site appraisal, associated SI works and any necessary remediation action are recommended to be carried out after site operation has ceased but prior to the commencement of construction works at the concerned area(s).

7.10.3 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.

7.10.4 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 surmountable to future occupants.