Report

7 Land Contamination

7.1 Legislation, Standards and Guidelines

7.1.1 General

7.1.1.1 The relevant legislation, standards and guidelines applicable to the Study for the assessment of land contamination include:

· Annex 19 of the Technical Memorandum on Environmental Impact Assessment Process (TM-EIAO), Guidelines for Assessment of Impact On Sites of Cultural Heritage and Other Impacts (Section 3: Potential Contaminated Land Issues), Environmental Protection Department (EPD), 1997;

· Guidance Note for Contaminated Land Assessment and Remediation, EPD, 2007;

· Guidance Manual for Use of Risk-Based Remediation Goals (RBRGs) for Contaminated Land Management, EPD, 2007; and

· Practice Guide for Investigation and Remediation of Contaminated Land, EPD, 2011.

7.1.2 Environmental Impact Assessment Ordinance (EIAO) (Cap. 499), Technical Memorandum on Environmental Impact Assessment Process (TM-EIAO)

7.1.2.1 Under Annex 19 of the TM-EIAO, a number of potentially contaminating historical and present landuses 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. Nevertheless, any other potential contaminating activities/ installations/ facilities within the boundary of the Project should be identified and considered based on professional judgement.

7.1.3 Guidance Note for Contamination Land Assessment and Remediation

7.1.3.1 In accordance with EPD’s Guidance Note for Contamination Land Assessment and Remediation, a contamination assessment evaluation should:

· Provide a clear and detailed account of the present landuse and the relevant past land history, in relation to possible land contamination;

· Identify areas of potential contamination and associated impacts, risks or hazards; and

· Submit a plan to evaluate the actual contamination conditions for soil and/or groundwater, if required.

7.1.4 Guidance Manual for Use of Risk-Based Remediation Goals (RBRGs) for Contaminated Land Management

7.1.4.1 The Guidance Manual introduces the risk-based approach in land contamination assessment and presents instructions for comparison of soil and groundwater data to the RBRGs for 54 chemicals of concern commonly found in Hong Kong. The RBRGs were derived to suit Hong Kong conditions by following the international practice of adopting a risk-based methodology for contaminated land assessment and remediation and were designed to protect the health of people who could potentially be exposed to land impacted by chemicals under four broad post restoration land use categories. 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 (C_sat) (mg/kg)
Chemical	Urban Residential (mg/kg)	Rural Residential (mg/kg)	Industrial (mg/kg)	Public Park (mg/kg)	Soil Saturation Limit (C_sat) (mg/kg)
VOCs
Acetone	9,590	4,260	10,000*	10,000*	***
Benzene	0.704	0.279	9.21	42.2	336
Bromodichloromethane	0.317	0.129	2.85	13.40	1,030
2-Butanone	10,000*	10,000*	10,000*	10,000*	***
Chloroform	0.132	0.0529	1.54	253	1,100
Ethylbenzene	709	298	8,240	10,000	138
Methyl tert-Butyl Ether	6.88	2.80	70.1	505	2,380
Methylene Chloride	1.30	0.529	13.9	128	921
Styrene	3,220	1,540	10,000*	10,000*	497
Tetrachloroethene	0.101	0.0444	0.777	1.84	97.1
Toluene	1,440	705	10,000*	10,000*	235
Trichloroethene	0.523	0.211	5.68	69.4	488
Xylenes (Total)	95.0	36.8	1,230	10,000*	150
SVOCs
Acenaphthene	3,510	3,280	10,000*	10,000*	60.2
Acenaphthylene	2,340	1,510	10,000*	10,000*	19.8
Anthracene	10,000*	10,000*	10,000*	10,000*	2.56
Benzo(a)anthracene	12.0	11.4	91.8	38.3
Benzo(a)pyrene	1.20	1.14	9.18	3.83
Benzo(b)fluoranthene	9.88	10.1	17.8	20.4
Benzo(g,h,i)perylene	1,800	1,710	10,000*	5,740
Benzo(k)fluoranthene	120	114	918	383
Bis-(2-Ethylhexyl)phthalate	30.0	28.0	91.8	94.2
Chrysene	871	919	1,140	1,540
Dibenzo(a,h)anthracene	1.20	1.14	9.18	3.83
Fluoranthene	2,400	2,270	10,000*	7,620
Fluorene	2,380	2,250	10,000*	7,450	54.7
Hexachlorobenzene	0.243	0.220	0.582	0.713
Indeno(1,2,3-cd)pyrene	12.0	11.4	91.8	38.3
Naphthalene	182	85.6	453	914	125
Phenanthrene	10,000*	10,000*	10,000*	10,000*	28.0
Phenol	10,000*	10,000*	10,000*	10,000*	7,260
Pyrene	1,800	1,710	10,000*	5,720
Metals
Antimony	29.5	29.1	261	97.9
Arsenic	22.1	21.8	196	73.5
Barium	10,000*	10,000*	10,000*	10,000*
Cadmium	73.8	72.8	653	245
Chromium III	10,000*	10,000*	10,000*	10,000*
Chromium VI	221	218	1,960	735
Cobalt	1,480	1,460	10,000*	4,900
Copper	2,950	2,910	10,000*	9,790
Lead	258	255	2,290	857
Manganese	10,000*	10,000*	10,000*	10,000*
Mercury	11.0	6.52	38.4	45.6
Molybdenum	369	364	3,260	1,220
Nickel	1,480	1,460	10,000*	4,900
Tin	10,000*	10,000*	10,000*	10,000*
Zinc	10,000*	10,000*	10,000*	10,000*
Dioxins / PCBs
Dioxins (I-TEQ)	0.001	0.001	0.005	0.001
PCBs	0.236	0.226	0.748	0.756
Petroleum Carbon Ranges
C6 - C8	1,410	545	10,000*	10,000*	1,000
C9 - C16	2,240	1,330	10,000*	10,000*	3,000
C17 - C35	10,000*	10,000*	10,000*	10,000*	5,000
Other Inorganic Compounds
Cyanide, free	1,480	1,460	10,000*	4,900
Organometallics
TBTO	22.1	21.8	196	73.5

Notes:

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

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

[3] * indicates a 'ceiling limit' concentration.

[4] *** indicates that the Csat value exceeds the 'ceiling limit' therefore the RBRG applies.

Table 7.2 RBRGs for groundwater and solubility limit

Chemical	Risk-Based Remediation Goals (RBRGs) for Groundwater			Solubility Limit (mg/L)
Chemical	Urban Residential (mg/L)	Rural Residential (mg/L)	Industrial (mg/L)	Solubility Limit (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
Dioxins / 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.

7.1.5 Practice Guide for Investigation and Remediation of Contaminated Land

7.1.5.1 The EPD’s Practice Guide for Investigation and Remediation of Contaminated Land includes a summary of the general steps of a contamination assessment study, which include site appraisal, site investigation and remediation.

7.2 Description of the Environment

7.2.1.1 As discussed in Section 2, the works area of the Project is located at north-eastern coast of Tung Ping Chau facing towards Ping Chau Hoi. It overlaps mostly with Tung Ping Chau Marine Park. Plover Cove (Extension) Country Park is located at more than 70m to the west of the Project. Part of the works area is currently occupied by Tung Ping Chau Public Pier of approximately 98m long and 5.5m wide which would be subject to pier improvement works under the Project. The adjacent area of the Project is generally rural in character with Tai Tong, Lei Uk, Chan Uk, Sha Tau and Lam Uk located in the vicinity to more than 210m away. According to Draft Ping Chau Outline Zoning Plan (OZP) No. S/NE-PC/1, the existing Tung Ping Chau Public Pier encroaching the works area is located within an area zoned as “Other Specified Uses” annotated “Pier” (“OU(Pier)”). The proposed new pier falls outside the boundary of the OZP. The areas in proximity to the existing pier are currently zoned as “Coastal Protection Area” (“CPA”), “Green Belt” (“GB”) and Village Type Development (“V”). Figure 1.1 shows the works area of the Project.

7.3 Assessment Methodology

7.3.1 Overview

7.3.1.1 A land contamination assessment has been conducted according to the following procedures. The procedures listed below are further discussed in the following sections.

· Identification of potentially contaminated sites;

· Identification of potential for future land contamination; and

· Recommending necessary mitigation measures, if necessary.

7.4 Identification of Potentially Contaminated Sites

7.4.1 General

7.4.1.1 To minimise the work areas and potential environmental impacts, the total area of the proposed site boundary/works area has been reduced 1.14ha from 2.16ha in the Project Profile to 1.02ha in the EIA Report. Within the latest works area, a desktop review of historical aerial photos, activities and relevant incidents in the works area was conducted to identify any potentially contaminated sites. After the desktop review had been completed, site walkover surveys were conducted to ground truth the findings. A summary of the key procedures to identify potentially contaminated sites is given below.

· Review of aerial photographs;

· Review of other relevant information; and

· Site surveys.

7.4.2 Aerial Photographs and Historical Land Uses

7.4.2.1 The aerial photos from Year 1945 to Year 2018 were reviewed to identify any historical land uses with potential of land contamination within the works area. The review indicated that the works area comprises mainly the sea by nature.

7.4.2.2 The findings from reviewing the aerial photographs between 1945 and 2018 showing the works area of the Project are summarized in Table 7.3 and the aerial photographs are given in Appendix 7.1.

Table 7.3 Historical land use of the Project

Year	Description
1945	· First aerial photograph recorded the works area of the Project. · The works area was the sea by nature. · Neither pier nor other artificial structures were identified within the works area.
1973	· The earliest aerial photograph recorded the presence of the pier. · The landside of the Project was surrounded by cultivated farmland and sea.
1999	· No significant change in land uses within the works area was observed as compared with those in Year 1973.
2008	· Pier was improved by widening the rubble causeway. · No significant change in land uses within the works area was observed as compared with those in Year 1999.
2018	· The recent aerial photograph recorded the works area. · No significant change in land uses within the works area was observed as compared with those in Year 2008.

7.4.3 Other Relevant Information

Fire Services Department

7.4.3.1 Fire Services Department (FSD) was contacted in February 2020 for:

· The records of Dangerous Goods License(s); and

· The reported accidents of spillage/leakage within the boundary of the Project.

7.4.3.2 Based on the latest information provided by FSD in 17 March 2020, neither records of dangerous goods licence nor incidents of spillage/leakage of dangerous goods were found within the boundary of the Project. Copy of FSD’s correspondence is provided in Appendix 7.2.

Environmental Protection Department

7.4.3.3 EPD was contacted in February 2020 for:

· The records of Chemical Waste Producers Registration; and

· The reported accidents of spillage/leakage within the boundary of the Project.

7.4.3.4 Based on the information provided by EPD in 5 March 2020, there are neither registered Chemical Waste Producers nor chemical spillage/ leakage records within the boundary of the Project. Copy of EPD’s correspondence is provided in Appendix 7.2.

7.4.4 Site Survey

7.4.4.1 Site walkover surveys were conducted in July and August 2018 to ground truth the findings of the desktop research and to identify any other potentially contaminated areas. Possible contaminants, if any, would be identified in accordance with EPD’s Practice Guide for Investigation and Remediation of Contaminated Land.

7.4.4.2 Photo records of the site walkover surveys are shown in Appendix 7.3 and descriptions are provided in Table 7.4 below. The site walkover checklist is given in Appendix 7.4.

Table 7.4 Descriptions of site photos

Photo ID	Description
Photo 1	The photo shows the existing pier from the southeast to the pier. The side view of the pier with landing steps can be observed. By site observation, there were neither oil stains nor land contaminating activities. No signs of land contamination were observed.
Photo 2	The photo shows the existing pier from the northeast to the pier. Another side view of the pier with landing steps can be observed. By site observation, there were neither oil stains nor land contaminating activities. No signs of land contamination were observed.
Photo 3	The photo shows the rocky shore from the southwest of the pier. By site observation, there were neither oil stains nor land contaminating activities. No signs of land contamination were observed.
Photo 4	The photo shows the concrete-paved pier walkway from the landside towards the seaside. By site observation, there were neither oil stains nor land contaminating activities. No signs of land contamination were observed.
Photo 5	The photo shows the concrete-paved pier walkway from the seaside towards the landside. By site observation, there were neither oil stains nor land contaminating activities. No signs of land contamination were observed.

7.4.4.3 The existing pier is a straight solid concrete pier of about 98m long and 5.5m wide. A pitched roof cover, a navigation light, a few signs and 5 bollards are located on the pier. Two sets of 1m high galvanised steel tubular railing are installed on each side along the existing pier. During the site walkover survey, neither oil stains, chemical containers nor land contaminating activities were identified at the existing pier or the proposed works area at the landside. No signs of land contamination were observed.

7.4.5 Summary

7.4.5.1 Based on the review of the aerial photos, the information from EPD and FSD and the findings from ground-truthing, no potentially contaminated areas have been identified in the Project Site.

7.5 Conclusion

7.5.1.1 This land contamination assessment has examined the potential contaminative land uses within the boundary of the Project, and their potential impacts to future use.

7.5.1.2 Based on the desktop review findings of the aerial photos, the information collected during site surveys as well as the information provided by EPD and FSD, no potential land contamination issue is identified within the boundary of the Project site. Further site investigation or mitigation measures are therefore not required.