Contents
8.2 Environmental Legislations and Evaluation Criteria
8.3 Assessment Approach and Methodology
8.4 Description of the Environment
8.5 Remediation Measures and Validation
8.6 Environmental Monitoring & Audit (EM&A)
8.7 Evaluation of Residual Impact
TABLES
Table 8.1 Risk-Based Remediation Goals (RBRGs) for Soil and the Soil Saturation Limit
Table 8.2 Risk-Based Remediation Goals (RBRGs) for Groundwater and Solubility Limit
Table 8.3 Summary of Historical Aerial Photographs at the PDA
Table 8.4 Summary of Historical Aerial Photographs at the Associated Off-site Works Area
Table 8.6 Full List of Chemicals of Concern
Table 8.7 Post-Restoration Land Uses and the Corresponding RBRGs
Table 8.8a Potential Soil Remediation Options
Table 8.8b Potential Groundwater Remediation Options
FIGURES
Figure 8.1 Delineation of Sub-Area 1 to Sub-Area 4 at Fanling Golf Course
Figure 8.2 Notional Layout Plan of Proposed Housing Development at Sub-Area 1
Figure 8.3 Land Use Activities at Sub-Area 1
Figure 8.4 Land Use Activities at Sub-Areas 2 and 3
Figure 8.5 Land Use Activities at Sub-Area 4
Figure 8.6 Land Use Activities Outside the Project Development Area
Figure 8.7 Proposed RBRGs Land Use at Sub-Area 1
Figure 8.8 Proposed RBRGs Land Use at Sub-Areas 2 to 4
APPENDIX
Appendix 8.1 Contamination Assessment Plan (CAP)
Appendix 8.2 Geochemical Atlas of Hong Kong – Arsenic in Stream Sediment
(a) Sections 3.1 and 3.2 (Potential Contaminated Land Issues) of the 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) set out the general approach and methodology for assessment of land contamination issues, predominantly historical land uses, associated with a project or proposal.
(b) EPD’s Practice Guide for Investigation and Remediation of Contaminated Land, August 2011 (Practice Guide) presents the standard investigation methods and remediation strategies for the range of potential contaminated sites and contaminants typically encountered in Hong Kong. It sets out the requirements for planning and implementation for the contaminated land investigation, interpretation of the investigation results using the Risk-Based Remediation Goals (RBRGs), outlining the contaminated land assessment, planning and implementation of remediation actions, and reporting the remediation works;
(c) EPD’s Guidance Note for Contaminated Land Assessment and Remediation, August 2007 (Guidance Note) sets out the requirements for proper assessment and management of potentially contaminated sites that are typically found in Hong Kong. It provides guidelines on how site assessments should be conducted and analysed and suggests practical remediation measures that can be adopted for the remediation of contaminated sites; and
(d) EPD’s Guidance Manual for Use of Risk-Based Remediation Goals for Contaminated Land Management, December 2007 (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. The RBRGs were derived to suit Hong Kong’s conditions by following international best practices of adopting a risk-based methodology for contaminated land assessment and remediation. They are designed to protect the health of people who could potentially by exposed to land impacted by any of the above-mentioned chemicals of concern under four broad post-restoration land use categories. In addition, the RBRGs served as the remediation targets if remediation is necessary. The RBRGs for soil and groundwater for the four post-restoration land use categories are presented in Table 8.1 and Table 8.2, respectively.
Table 8.1 Risk-Based Remediation Goals (RBRGs) for Soil and the Soil Saturation Limit
Chemical |
Risk-Based Remediation Goals for Soil |
Soil
Saturation |
|||
Urban Residential (mg/kg) |
Rural Residential (mg/kg) |
Industrial (mg/kg) |
Public Parks (mg/kg) |
||
VOCs |
|||||
Acetone |
9.59E+03 |
4.26E+03 |
1.00E+04 |
1.00E+04 |
*** |
Benzene |
7.04E-01 |
2.79E-01 |
9.21E+00 |
4.22E+01 |
3.36E+02 |
Bromodichloromethane |
3.17E-01 |
1.29E-01 |
2.85E+00 |
1.34E+01 |
1.03E+03 |
2-Butanone |
1.00E+04 |
1.00E+04 |
1.00E+04 |
1.00E+04 |
*** |
Chloroform |
1.32E-01 |
5.29E-02 |
1.54E+00 |
2.53E+02 |
1.10E+03 |
Ethylbenzene |
7.09E+02 |
2.98E+02 |
8.24E+03 |
1.00E+04 |
1.38E+02 |
Methyl tert-Butyl Ether |
6.88E+00 |
2.80E+00 |
7.01E+01 |
5.05E+02 |
2.38E+03 |
Methylene Chloride |
1.30E+00 |
5.29E-01 |
1.39E+01 |
1.28E+02 |
9.21E+02 |
Styrene |
3.22E+03 |
1.54E+03 |
1.00E+04 |
1.00E+04 |
4.97E+02 |
Tetrachloroethene |
1.01E-01 |
4.44E-02 |
7.77E-01 |
1.84E+00 |
9.71E+01 |
Toluene |
1.44E+03 |
7.05E+02 |
1.00E+04 |
1.00E+04 |
2.35E+02 |
Trichloroethene |
5.23E-01 |
2.11E-01 |
5.68E+00 |
6.94E+01 |
4.88E+02 |
Xylenes (Total) |
9.50E+01 |
3.68E+01 |
1.23E+03 |
1.00E+04 |
1.50E+02 |
SVOCs |
|||||
Acenaphthene |
3.51E+03 |
3.28E+03 |
1.00E+04 |
1.00E+04 |
6.02E+01 |
Acenaphthylene |
2.34E+03 |
1.51E+03 |
1.00E+04 |
1.00E+04 |
1.98E+01 |
Anthracene |
1.00E+04 |
1.00E+04 |
1.00E+04 |
1.00E+04 |
2.56E+00 |
Benzo(a)anthracene |
1.20E+01 |
1.14E+01 |
9.18E+01 |
3.83E+01 |
N/A |
Benzo(a)pyrene |
1.20E+00 |
1.14E+00 |
9.18E+00 |
3.83E+00 |
N/A |
Benzo(b)fluoranthene |
9.88E+00 |
1.01E+01 |
1.78E+01 |
2.04E+01 |
N/A |
Benzo(g,h,i)perylene |
1.80E+03 |
1.71E+03 |
1.00E+04 |
5.74E+03 |
N/A |
Benzo(k)fluoranthene |
1.20E+02 |
1.14E+02 |
9.18E+02 |
3.83E+02 |
N/A |
bis-(2-Ethylhexyl)phthalate |
3.00E+01 |
2.80E+01 |
9.18E+01 |
9.42E+01 |
N/A |
Chrysene |
8.71E+02 |
9.19E+02 |
1.14E+03 |
1.54E+03 |
N/A |
Dibenzo(a,h)anthracene |
1.20E+00 |
1.14E+00 |
9.18E+00 |
3.83E+00 |
N/A |
Fluoranthene |
2.40E+03 |
2.27E+03 |
1.00E+04 |
7.62E+03 |
N/A |
Fluorene |
2.38E+03 |
2.25E+03 |
1.00E+04 |
7.45E+03 |
5.47E+01 |
Hexachlorobenzene |
2.43E-01 |
2.20E-01 |
5.82E-01 |
7.13E-01 |
N/A |
Indeno(1,2,3-cd)pyrene |
1.20E+01 |
1.14E+01 |
9.18E+01 |
3.83E+01 |
N/A |
Naphthalene |
1.82E+02 |
8.56E+01 |
4.53E+02 |
9.14E+02 |
1.25E+02 |
Phenanthrene |
1.00E+04* |
1.00E+04* |
1.00E+04* |
1.00E+04* |
2.80E+01 |
Phenol |
1.00E+04* |
1.00E+04* |
1.00E+04* |
1.00E+04* |
7.26E+03 |
Pyrene |
1.80E+03 |
1.71E+03 |
1.00E+04 |
5.72E+03 |
N/A |
Metals |
|||||
Antimony |
2.95E+01 |
2.91E+01 |
2.61E+02 |
9.79E+01 |
N/A |
Arsenic |
2.21E+01 |
2.18E+01 |
1.96E+02 |
7.35E+01 |
N/A |
Barium |
1.00E+04* |
1.00E+04* |
1.00E+04* |
1.00E+04* |
N/A |
Cadmium |
7.38E+01 |
7.28E+01 |
6.53E+02 |
2.45E+02 |
N/A |
Chromium III |
1.00E+04* |
1.00E+04* |
1.00E+04* |
1.00E+04* |
N/A |
Chromium VI |
2.21E+02 |
2.18E+02 |
1.96E+03 |
7.35E+02 |
N/A |
Cobalt |
1.48E+03 |
1.46E+03 |
1.00E+04 |
4.90E+03 |
N/A |
Copper |
2.95E+03 |
2.91E+03 |
1.00E+04 |
9.79E+03 |
N/A |
Lead |
2.58E+02 |
2.55E+02 |
2.29E+03 |
8.57E+02 |
N/A |
Manganese |
1.00E+04* |
1.00E+04* |
1.00E+04* |
1.00E+04* |
N/A |
Mercury |
1.10E+01 |
6.52E+00 |
3.84E+01 |
4.56E+01 |
N/A |
Molybdenum |
3.69E+02 |
3.64E+02 |
3.26E+03 |
1.22E+03 |
N/A |
Nickel |
1.48E+03 |
1.46E+03 |
1.00E+04* |
4.90E+03 |
N/A |
Tin |
1.00E+04* |
1.00E+04* |
1.00E+04* |
1.00E+04* |
N/A |
Zinc |
1.00E+04* |
1.00E+04* |
1.00E+04* |
1.00E+04* |
N/A |
Dioxins / PCBs |
|
|
|
|
|
Dioxins (I-TEQ) |
1.00E-03 |
1.00E-03 |
5.00E-03 |
1.00E-03 |
N/A |
PCBs |
2.36E-01 |
2.26E-01 |
7.48E-01 |
7.56E-01 |
N/A |
Petroleum Carbon Ranges |
|||||
C6 - C8 |
1.41E+03 |
5.45E+02 |
1.00E+04* |
1.00E+04* |
1.00E+03 |
C9 - C16 |
2.24E+03 |
1.33E+03 |
1.00E+04* |
1.00E+04* |
3.00E+03 |
C17 - C35 |
1.00E+04* |
1.00E+04* |
1.00E+04* |
1.00E+04* |
5.00E+03 |
Other Inorganic Compounds |
|||||
Cyanide, free |
1.48E+03 |
1.46E+03 |
1.00E+04* |
4.90E+03 |
N/A |
Organometallics |
|||||
Tributyltin oxide (TBTO) |
2.21E+01 |
2.18E+01 |
1.96E+02 |
7.35E+01 |
N/A |
Notes: (1) N/A indicates that RBRG could not be calculated because the toxicity or physical / chemical values were unavailable, or the condition of Henry’s Law Constant > 1.00E-05 was not met for the inhalation pathway. (2) For Dioxins, the clean-up 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”. (3) Soil saturation limits for petroleum carbon ranges taken from the Canada-Wide Standards for Petroleum Hydrocarbons in Soil, CCME 2000. (4) * indicates a ‘ceiling limit’ concentration. (5) *** indicates that the Csat value exceeds the ‘ceiling limit’ therefore the RBRG applies. |
Table 8.2 Risk-Based Remediation Goals (RBRGs) for Groundwater and Solubility Limit
Chemical |
Risk-Based Remediation Goals for Groundwater |
Solubility
Limit |
||
Urban Residential (mg/L) |
Rural Residential (mg/L) |
Industrial (mg/L) |
||
VOCs |
||||
Acetone |
1.00E+04* |
1.00E+04* |
1.00E+04* |
*** |
Benzene |
3.86E+00 |
1.49E+00 |
5.40E+01 |
1.75E+03 |
Bromodichloromethane |
2.22E+00 |
8.71E-01 |
2.62E+01 |
6.74E+03 |
2-Butanone |
1.00E+04* |
1.00E+04* |
1.00E+04* |
*** |
Chloroform |
9.56E-01 |
3.82E-01 |
1.13E+01 |
7.92E+03 |
Ethylbenzene |
1.02E+03 |
3.91E+02 |
1.00E+04* |
1.69E+02 |
Methyl tert-Butyl Ether |
1.53E+02 |
6.11E+01 |
1.81E+03 |
*** |
Methylene Chloride |
1.90E+01 |
7.59E+00 |
2.24E+02 |
*** |
Styrene |
3.02E+03 |
1.16E+03 |
1.00E+04* |
3.10E+02 |
Tetrachloroethene |
2.50E-01 |
9.96E-02 |
2.95E+00 |
2.00E+02 |
Toluene |
5.11E+03 |
1.97E+03 |
1.00E+04* |
5.26E+02 |
Trichloroethene |
1.21E+00 |
4.81E-01 |
1.42E+01 |
1.10E+03 |
Xylenes (Total) |
1.12E+02 |
4.33E+01 |
1.57E+03 |
1.75E+02 |
SVOCs |
||||
Acenaphthene |
1.00E+04* |
7.09E+03 |
1.00E+04* |
4.24E+00 |
Acenaphthylene |
1.41E+03 |
5.42E+02 |
1.00E+04* |
3.93E+00 |
Anthracene |
1.00E+04* |
1.00E+04* |
1.00E+04* |
4.34E-02 |
Benzo(a)anthracene |
N/A |
N/A |
N/A |
N/A |
Benzo(a)pyrene |
N/A |
N/A |
N/A |
N/A |
Benzo(b)fluoranthene |
5.39E-01 |
2.03E-01 |
7.53E+00 |
1.50E-03 |
Benzo(g,h,i)perylene |
N/A |
N/A |
N/A |
N/A |
Benzo(k)fluoranthene |
N/A |
N/A |
N/A |
N/A |
bis-(2-Ethylhexyl)phthalate |
N/A |
N/A |
N/A |
N/A |
Chrysene |
5.81E+01 |
2.19E+01 |
8.12E+02 |
1.60E-03 |
Dibenzo(a,h)anthracene |
N/A |
N/A |
N/A |
N/A |
Fluoranthene |
1.00E+04* |
1.00E+04* |
1.00E+04* |
2.06E-01 |
Fluorene |
1.00E+04* |
1.00E+04* |
1.00E+04* |
1.98E+00 |
Hexachlorobenzene |
5.89E-02 |
2.34E-02 |
6.95E-01 |
6.20E+00 |
Indeno(1,2,3-cd)pyrene |
N/A |
N/A |
N/A |
N/A |
Naphthalene |
6.17E+01 |
2.37E+01 |
8.62E+02 |
3.10E+01 |
Phenanthrene |
1.00E+04* |
1.00E+04* |
1.00E+04* |
1.00E+00 |
Phenol |
N/A |
N/A |
N/A |
N/A |
Pyrene |
1.00E+04* |
1.00E+04* |
1.00E+04* |
1.35E-01 |
Metals |
||||
Antimony |
N/A |
N/A |
N/A |
N/A |
Arsenic |
N/A |
N/A |
N/A |
N/A |
Barium |
N/A |
N/A |
N/A |
N/A |
Cadmium |
N/A |
N/A |
N/A |
N/A |
Chromium III |
N/A |
N/A |
N/A |
N/A |
Chromium VI |
N/A |
N/A |
N/A |
N/A |
Cobalt |
N/A |
N/A |
N/A |
N/A |
Copper |
N/A |
N/A |
N/A |
N/A |
Lead |
N/A |
N/A |
N/A |
N/A |
Manganese |
N/A |
N/A |
N/A |
N/A |
Mercury |
4.86E-01 |
1.84E-01 |
6.79E+00 |
N/A |
Molybdenum |
N/A |
N/A |
N/A |
N/A |
Nickel |
N/A |
N/A |
N/A |
N/A |
Tin |
N/A |
N/A |
N/A |
N/A |
Zinc |
N/A |
N/A |
N/A |
N/A |
Dioxins / PCBs |
||||
Dioxins (I-TEQ) |
N/A |
N/A |
N/A |
N/A |
PCBs |
4.33E-01 |
1.71E-01 |
5.11E+00 |
3.10E-02 |
Petroleum Carbon Ranges |
||||
C6 - C8 |
8.22E+01 |
3.17E+01 |
1.15E+03 |
5.23E+00 |
C9 - C16 |
7.14E+02 |
2.76E+02 |
9.98E+03 |
2.80E+00 |
C17 - C35 |
1.28E+01 |
4.93E+00 |
1.78E+02 |
2.80E+00 |
Other Inorganic Compounds |
||||
Cyanide, free |
N/A |
N/A |
N/A |
N/A |
Organometallics |
||||
Tributyltin oxide (TBTO) |
N/A |
N/A |
N/A |
N/A |
Notes: (1) N/A indicates that RBRG could not be calculated because the toxicity or physical/chemical values were unavailable, or the condition of Henry’s Law Constant>1.00E-05 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. |
· Desktop review to investigate the current and past land uses in the PDA for potentially contaminating activities and chemicals, and surrounding area with the aid with historical aerial photographs and maps;
· History of development applications and approvals for the site;
· Site inspection to identify the current land uses in the PDA as well as to verify the potential contamination areas and hotspots;
· Information provided by site representative; and
· Consideration on the land use changes.
· Hong Kong Geological Survey Maps (GSMs);
· Relevant aerial photographs and maps;
· Relevant Outline Zoning Plans (OZPs);
· Records of dangerous goods, chemical wastes, chemical spillage/leakage from FSD and EPD;
· Hong Kong Historic Maps – Reference 1922 (https://www.hkmaps.hk/map.html?1922);
· Mapping Hong Kong – A Historical Atlas, Government Information Services, 1992;
· Geochemical Atlas of Hong Kong (Sewell, 1999); and
· “North East New Territories New Development Areas Planning and Engineering Study – Investigation”, CEDD and PlanD, 2007, EIA Report No. AEIAR-175/2013.
Review of Historical and Current Information
Table 8.3 Summary of Historical Aerial Photographs at the PDA
Year |
Height (Feet) |
Photo Reference Number |
Site Description |
1922 |
N/A |
HK Maps (extracted from Hong Kong Historic Maps – Reference 1922) |
The Proposed Development Area (PDA) already used as a golf course, which is present day ‘Old Course’. “Club House” and “Golf Course” were observed on a printed map. Land use in the surrounding areas include Ping Kong Village which has a settlement history dating back to the Late Ming–Early Qing dynasty (in orange). |
1945 |
20,000 |
681_4-3117 |
Fan Kam Road has been established. The PDA remains unchanged serving as a golf course. Agricultural land observed along the eastern side and southwest tip of PDA; settlement of Ping Kong Village shown clearly. The surrounding areas of the PDA are of agricultural use surrounded by dense vegetation and residential (village). |
1954 |
29,200 |
V81A_550-0046 |
Additional fairways were constructed between 1945 to 1954 in Sub-Areas 1 to 4. The golf course is more prominent, and the boundary is similar to present day. Some vegetation removal was observed in north of Sub-Area 1 (in turquoise). Site clearance activities observed in yellow where present day Tai Lung Experimental Farm is located. |
1961 |
30,000 |
F42_625-0029 |
No change to the land use activities within the PDA. Some structures observed in the area north of Sub-Area 1 (in turquoise). Surrounding areas included agricultural land and residential. Early establishment (a building) of AFCD’s Tai Lung Experimental Farm (in blue) and scattered buildings in present day On Po Village (in yellow) observed. |
1969 |
N/A |
1969-1762 |
Development of fairways in the Fanling Golf Course (Eden Course) in progress. No change to the land use activities within the PDA. The surrounding areas remained as agricultural land. |
1973 |
6,000 |
CN0625 |
Development of fairways in the FGC New Course completed. Some site clearance activities observed at present day parking lot in Sub-Area 1. |
1974 |
12,500 |
10017 |
No change to the land use activities within the PDA. Surrounding areas remained as agricultural land and residential. |
1976 |
12,500 |
16328 |
PDA undergoing changes to create additional fairway located south of present day parking lot in Sub-Area 1. No other development observed in Sub-Area 2 to Sub-Area 4 and no changes to the surrounding areas. |
1978 |
12,500 |
24505 |
Completion of the additional fairway and parking lot repaved in Sub-Area 1. No construction activities observed in Sub-Area 2 to Sub-Area 4. Land uses remain unchanged in the surrounding areas. |
1983 |
10,000 |
52299 |
The Fanling Pumping Station (constructed in 1983) and associated Substation have been established in Sub-Area 2 of the PDA, in addition to the tennis courts observed in Sub-Area 1. No construction activities are observed in Sub-Area 3 and Sub-Area 4. Scattered temporary structures (present day On Po Village in orange) observed next to southeast border of Sub-Area 2. |
1986 |
10,000 |
A07957 |
Private property observed in the northern part of Sub-Area 1. Surrounding areas remain as agricultural land and residential usage. |
1992 |
10,000 |
A32969 |
Staff quarters observed in the northern part of Sub-Area 1, whilst no changes to the surrounding areas. |
1997 |
10,000 |
CN19248 |
No change to the land use activities within the PDA. Construction of the North District Hospital has been completed. |
2008 |
8,000 |
CW80471 |
Removal of vegetation on the tennis court observed. Turf loss in the fairway in Sub-Area 3 observed (in blue). Land use activities surrounding the PDA include residential and agricultural land. A school (Elegantia College) was observed and according to historical sources it was founded in 2002. Site clearance activities observed (in turquoise) north of school site to make way for high-rise residential. According to historical sources, the construction of Tai Lung Veterinary Laboratory (in yellow) commenced in 2000 and completed in 2001. |
2016 |
7,000 |
E008323C |
PDA resembles to present day. Tennis court in Sub-Area 1 is repaved; new greens observed in Sub-Area 3. Surrounding areas are predominately occupied by buildings and structures, consisted of agricultural (Tai Lung Experimental Farm), residential (public housing, hospital, On Po Village and Ping Kong Village). No major changes to the PDA observed from year 2008 to current date. |
Table 8.4 Summary of Historical Aerial Photographs at the Associated Off-site Works Area
Height (Feet) |
Photo Reference Number |
Site Description |
|
1945 |
20,000 |
681_4-3117 |
North of Fan Kam Road Fanling Highway was observed surrounded by grassland and some densed vegetation. East Rail Line is located further north of Fanling Highway, which according to historical sources, the Sheung Shui Station opened in 1930. Ping Kong Road and Po Kin Road The area mainly consisted of farmland and grassland. |
1954 |
29,200 |
V81A_550-0046 |
North of Fan Kam Road No change in land use was observed and remained as a road. Fanling Highway was observed surrounded by grassland Ping Kong Road and Po Kin Road A road was observed (Ping Kong Road) and the surrounding area mainly consisted of agricultural land and grassland. Some vegetation and grassland were removed along Ping Kong Road. |
1986 |
10,000 |
A07957 |
North of Fan Kam Road No change in land use was observed and remained as a road. Ping Kong Road and Po Kin Road No change in land use. A road was observed extended east to Po Kin Road. According to historical sources, Choi Po Court and Choi Yuen Estate (public housing) were constructed between 1981 and 1985. |
1997 |
10,000 |
CN19248 |
North of Fan Kam Road No change in land use was observed and remained as a road. Ping Kong Road and Po Kin Road No change in land use was observed and remained as a road. The North District Hospital was observed and according to historical sources, the hospital opened in 1998. |
2016 |
7,000 |
E008323C |
North of Fan Kam Road No change in land use was observed and remained as a road. Resembles to present day and site inspection observations. Ping Kong Road and Po Kin Road No change in land use was observed and remained as a road. Resembles to present day and site inspection observations. |
Current and Future Land Use
Ping Kong Road and Po Kin Road (Drainage System)
North of Fan Kam Road (Sewerage System)
Site Geology
(a) Lam Construction Co. Ltd in 1980 (Report No. 2891);
(b) Gammon (HK) Limited in 1986 (Report No. 48321 and 48322);
(c) I-P Foundations Limited in 1998 (Report No. 30567); and
(d) Driltech Ground Engineering in 2014 (Report No. 60803).
(a) Completely decomposed granite / volcanic rock or completely weathered pyroclastic rock was encountered throughout the entire borehole depth until termination. This comprised of pink, brown, grey, yellow, dense silt or clay, with occasional rock fragments.
(b) Colluvium was also encountered at depths of 0 to 12 metres below ground level (mbgl) undertaken by Gammon (HK) Limited in 1986 before the layer of granite. Colluvium comprised of brownish yellow cobbles, gravel and clay.
(a) Tuff was encountered throughout the entire borehole depth until termination. This comprised of grain size ranging from ash, silt, sand to gravel. Occasional quartz and manganese oxide veins were found.
(b) Colluvium was encountered at the southernmost borehole location, at depths around +33 to +27 metres below Principal Datum (mPD). Colluvium comprised of red, brown and dark grey silty clay.
(c) Fill was also encountered at the southernmost borehole location, at depths around +35 to +34 mPD.
(a) Terraform-FGS, HKHA 100 of 1998 Stage 2 Study of Slope No. 2SW-A/R28 at Choi Yuen Estate (Report No. 38262);
(b) Lam Construction Co., Ltd, PWD Contract 613/79 MCA/TPF/81/21 Site Investigation for Fanling Bypass (Report No. 3352);
(c) Enpack (Hong Kong) Limited, GE/97/13 Fanling/Sheung Shui Development Formation and Servicing in Area 36, Fanling, Ground Investigation (Report No. 28128);
(d) Chung Shun Boring Eng. Co., Ltd., HKHA Contract No. 20070032 Central Servicing Term Contract for Ground Investigation Works (2007-2009) Public Rental Housing Development at Sheung Shui Area 36 West – Feasibility (Report No. 50647);
(e) Gammon (Hong Kong) Limited, HKHA Contract No. 98 of 1981 W.O. 181 Shek Wu Hui Area 27c (Report No. 05939 & 04590);
(f) Gammon (Hong Kong) Limited, Contract 446/81 WOQ 7/2/7.38, Future Increase in Water Supply from China Stage I & II 2200mm Dia. Pipeline from Sheung Shui to Tau Pass (Report No. 03428); and
(g) Impact Foundations (HK) Ltd., HK-BU-294 Tai Po, Fanling and Shek Wu Hui Development (Report No. 03067A).
(a) Fill was encountered as the top layer of strata consisting of sand and occasional gravels under the concrete layer, if present. The depths of the fill strata generally reached 2 to 3 mbgl.
(c) Completely to highly decomposed granite / volcanic rock was encountered as the bottom layer of strata i.e., below alluvium, until termination depth. This comprised of pink, brown, grey, yellow, dense silt or clay, with occasional rock fragment.
(a) Fill as the top layer of strata, ranged a thickness of 1.0 to 2.5 m.
(b) Alluvium was encountered as the second layer of strata below Fill, on Ping Kong Road, which ranged a thickness of 0.5 to 1.5 m.
(c) Tuff was encountered as the last layer of strata in all boreholes. This comprised of grain size ranging from ash, silt, sand to gravel. The thickness of Tuff encountered ranged from 37 to 54 m, until termination depth.
(d) Colluvium was encountered at the southernmost borehole location, at depths around +33 to +27 mPD. Colluvium comprised of red, brown and dark grey silty clay.
(e) Fill was also encountered at the southernmost borehole location, at depths around +35 to +34 mPD.
Table 8.5 Land Use Activities and Corresponding Chemicals of Concern at the Proposed Development Area
Sub-Area |
Type of Activities Based upon Site Inspection in May 2020 |
Potentially Polluting Activities |
Approximate Area |
Potential Chemicals of Concern |
|
Sub-Area 1 |
Private properties |
Golf course with historical application of fertilisers, pesticides and herbicides |
5,958 m2 |
- Pesticides and herbicides - VOCs / SVOCs - Metals (full suite) - Dioxins / PCBs - PCRs - Cyanide - TBTO |
|
Tennis Court and Staff Quarters |
2,432 m2 |
|
|||
Outdoor car park |
10,260 m2 |
|
|||
Golf course (turf grasses, fairways, teeways and tree foliage) |
89,239 m2 |
|
|||
Total Potentially Contaminated Area in Sub-Area 1# |
107,889 m2 / 11 ha |
||||
Sub-Area 2 |
Golf course (turf grasses, fairways, teeways and tree foliage) |
Golf course with historical application of fertilisers, pesticides and herbicides |
69,161 m2 (7 ha) |
- Pesticides and herbicides - VOCs / SVOCs - Metals (full suite) - Dioxins / PCBs - PCRs - Cyanide - TBTO |
|
Sub-Area 3 |
85,000 m2 (8.5 ha) |
|
|||
Sub-Area 4 |
50,726 m2 (5.1 ha) |
|
|||
Total Potentially Contaminated Area in Sub-Areas 2 to 4 |
204,887 m2 (20.5 ha) |
||||
Total Potentially Contaminated Areas at PDA |
32 hectares (ha) |
Note: # includes developable and non-developable areas
Chemicals of Concern
Table 8.6 Full List of Chemicals of Concern
Pesticides and herbicides (Total Pesticides)[1] |
Total pesticides consist of organochlorine pesticides, organophosphorus pesticides and triazine pesticides, with details listed below: Organochlorine pesticides –alpha-BHC, beta-BHC, gamma-BHC, delta-BHC, Heptachlor, Aldrin, Heptachlor epoxide, cis-hlordane, Endosulfan 1, trans-Chlordane, Dieldrin, 4.4`-DDE, Endrin, Endosulfan 2, 4.4`-DDD, Endrin aldehyde, Endosulfan sulfate, 4.4`-DDT, Endrin ketone, Methoxychlor, Cypermethrins(total), Hexachlorobenzene (HCB) Organophosphorus pesticides – Dichlorvos, Monocrotophos, Dimethoate, Diazinon, Chlorpyrifos-methyl, Parathion-methyl, Malathion, Fenthion, Chlorpyrifos, Parathion, Pirimphos-ethyl, Chlorfenvinphos (E), Chlorfenvinphos (Z), Bromophos-ethyl, Fenamiphos, Prothiofos, Ethion, Carbophenothion, Azinphos Methyl Triazine pesticides – Atrazine, Simazine |
|
VOCs |
Acetone, Benzene, Bromodichloromethane, 2-Butanone, Chloroform, Ethylbenzene, Methyl- tert-Butyl Ether, Methylene Chloride, Styrene, Tetrachloroethene, Toluene, Trichloroethene, Xylenes (total) |
|
SVOCs |
Acenaphthene, Acenaphthylene, Anthracene, Benzo(a)anthracene, Benzo(a)pyrene, Benzo(b)fluoranthene, Benzo(g,h,i)perylene, Benzo(k)fluoranthene, bis-(2-Ethylhexyl)phthalate, Chrysene, Dibenzo(a,h)anthracene, Fluoranthene, Fluorene, Hexachlorobenzene, Indeno(1,2,3-cd)pyrene, Naphthalene, Phenanthrene, Phenol, Pyrene |
|
Metals (full suite) |
Antimony, Arsenic, Barium, Cadmium, Chromium III, Chromium VI, Cobalt, Copper, Lead, Manganese, Mercury, Molybdenum, Nickel, Tin, Zinc |
|
Dioxins / PCBs |
Dioxins, PCBs |
|
PCRs |
Petroleum Carbon Ranges: C6 to C8, C9 to C16, and C17 to C35 |
|
Other Inorganic Compounds |
Cyanide (free) |
|
Organometallics |
TBTO |
· Urban residential – sites located in an urban area where main activities involve habitation by individuals. The typical physical setting is high-rise residential building situated in a housing estate where amenity facilities such as landscaped yards and children playground. The receptors are residents who stay indoors most of the time, if not for a short duration each day where they may come in direct contact with soil at landscaping or play areas within the estate.
· Rural residential – Sites located in a rural area where main activities involve habitation by individuals. These sites typically have village-type houses or low-rise residential blocks surrounded by open space. The receptors are rural residents who stay at home and spend some time each day outdoor engaging in gardening works or participating in light sport activities. The degree of contact with soil under the rural setting is more than urban setting in terms of the intensity and frequency of contact.
· Industrial – any sites where activities involve the manufacturing, chemical or petrochemical processing, storage or raw materials, transport operations, energy production or transmission. Receptors include those at sites where part of the operation is carried out directly on the subject land and the workers are more likely to be exposed to the soil than those working in multi-storey factory buildings.
· Public parks – receptors include individuals and well-being who frequent parks and play areas where there is contact with soil in lawns, walkways, gardens and play areas. Parks are considered to be predominately hard covered with limited areas of landscaped soil. Furthermore, buildings are unlikely to be constructed in public parks.
Table 8.7 Post-Restoration Land Uses and the Corresponding RBRGs
Land Use |
Corresponding RBRGs Land Use |
Grid IDs |
|||
Sub-Area 1
|
Public housing site made up of: - high rise residential buildings - social welfare facilities - public transport interchange (PTI) - amenity areas - footpaths and access roads School site (special school) |
Urban residential or Rural residential, whichever more stringent |
1-1 to 1-51 |
||
Sub-Area 2 (Figure 8.7 and Figure 8.8) |
Open space made up of: - recreational facilities and ancillary facilities (with minimal new structure/change to existing site conditions) |
Urban residential or Rural residential, whichever more stringent
|
2-1 to 2-9 |
||
Open space made up of: - recreational facilities - tree transplanting |
Public parks |
2-10 to 2-31 |
|||
Sub-Area 3 |
Open space made up of: - recreational facilities - tree transplanting |
Public parks |
3-1 to 3-41 |
||
Sub-Area 4 |
Open space (no works to be carried out in Sub-Area 4) |
Public parks |
4-1 to 4-26 |
||
Site Investigation
Task |
Tentative Date |
Supplementary CAP(s) |
Q2 2023 |
Site Investigation Works[1] |
Q3 2023 |
Submission of CAR and RAP (if required) |
Q4 2023 |
Submission of RR (if required) |
TBD |
Note:
[1] Arsenic Assessment Plan (AAP) will be prepared and submitted to EPD after site investigation (if required).
TBD – to be determined: remediation programme subject to contamination extent and remediation method(s) chosen
· Site characteristics (i.e., site hydrogeology, soil and groundwater chemical characteristics);
· Site constraints (i.e., available space, surrounding areas);
· Nature and level of contamination;
· Extent and area of contamination;
· Cost effectiveness;
· Experience and expertise requirement; and
· Time available to carry out remediation works.
· Set remediation objectives and goals;
· Formulate optimal and cost-effective mitigation and remedial measures for the contaminants identified in the contamination assessment;
· Specify remediation monitoring and measurements to monitor remediation progress and to confirm completion of the remediation (i.e., validation); and
· Propose good handling practices for the contaminated materials during all stages of the remediation works and appropriate disposal measures.
· Background information (i.e., background of the project, regulatory and other requirements, summary of site history, and contamination sources);
· A summary of site investigation findings, nature, levels and extent of contamination on site;
· The objectives of the RAP, goals and remediation targets;
· The proposed remediation actions (i.e., general description of the remediation methods, treatment and handling, equipment, verification and confirmation sampling and testing, other monitoring and audit requirements, and equipment decontamination procedure);
· An implementation schedule for remediation with appropriate actions and milestones. The criteria to be used to assess the effectiveness of the remediation activities should be included; and
· A health and safety section in the RAP to include health and safety risks identification and control measures required during the remediation, monitoring and measurement activities.
· Background information (i.e., background of the project, regulatory and other requirements, future land use of the site and land use classifications assessed, and the summary of the on-site contamination);
· Description of the remediation programme carried out (i.e., additional investigation, pilot testing, remediation, monitoring and measurements, and decommissioning of plants and equipment);
· Remediation monitoring results (i.e., field measurements and observations, samples laboratory test results, QA/QC results);
· Soil disposal records and certification by the Independent Checker (if applicable); and
· Conclusions, recommendations and other supplementary information.
Table 8.8a Potential Soil Remediation Options[2]
Remediation Category |
Remediation Method |
Type of Contaminants |
Description |
Applicability |
Limitations |
Physical-chemical |
Cement Solidification / Stabilisation |
Inorganic compounds, including radionuclides, heavy metals.
|
Ex-situ immobilisation technique treats contaminated soil by mixing soil with binding agents. |
· Applicable to soils · Solidification has been used on certain contaminated site in Hong Kong and demonstrated as a successful treatment method for inorganic contaminated soil. |
· The effectiveness reduces with the presence of organic contaminants · Large boulders may hinder the mixing process. Soil sorting is necessary before the treatment taken place · The process may result in volume increase · Pilot test is required to set the appropriate ratio of cement to soil for complete immobilisation |
Physical-chemical |
Soil Vapour Extraction (SVE), also referred to as in-situ Soil Venting |
Effective to petroleum hydrocarbons such as PCRs. |
In-situ bioremediation method that make use of indigenous bacteria to degrade contaminants. The bacteria activities will be enhanced by inducing air flow and adding nutrients if necessary. |
· Applicable to soils · Suitable for remediation in built up areas as the wells can be placed between and below buildings. · Applicable to large sites. · Equipment can be installed easily. · Vapour emissions can be controlled. |
· Usually applied for cases with large area of organic contaminated soil · May induce air emission to the sensitive receivers · Large space is required · Generally utilised to remove the more volatile petroleum products such as gasoline and aviation fuel. It can also be used to reduce the mobility and hazard of diesel, kerosene, and some heating oils by removing the more volatile fractions from the soil |
Physical-chemical |
Soil Washing / Flushing |
Inorganic compounds, including radioactive contaminants, heavy metals, PCBs, VOCs, SVOCs, free cyanide, fuels and pesticides |
Water-based process for scrubbing soils ex-situ to remove contaminants. |
· Applicable to coarse-grained organic or inorganic-contaminated soils |
· Required further treatment and disposal for residual · Complex waste mixtures make formulating washing fluid difficult · Effectiveness of soil washing treatment depends on the soil particle size. Fine soil particle may require a polymer in addition to be removed from the washing fluid · Maybe less cost-effective |
Biological |
Biopiling / Bioremediation |
Non-halogenated volatiles and semi-volatiles, fuel hydrocarbons, residues of coke and some pesticides, and organometallic compounds (TBTO). |
Bioremediation method that bacteria grow in the piled contaminated soil and degrade the waste into harmless products. |
· Applicable and most cost-effective for large volumes of contaminated soil. · Vapour emission can be controlled as it can be designed to be a closed system. · Effective method to utilise microbes and plants to eliminate the pesticide residues |
· Large space is required for biopile construction · Time-consuming as it usually takes one year |
Biological |
Bioventing |
Petroleum products including gasoline, jet fuels, kerosene and diesel fuel. Non-halogenated solvents, some pesticides and wood preserves, among other organic compounds. |
In-situ bioremediation process that promotes aerobic biodegradation of organic contaminants in soil by providing oxygen to existing soil microorganisms. |
· Proven successful in remediating soils contaminated by petroleum hydrocarbons, non-chlorinated solvents, some pesticides and other organic compounds |
· Low levels of humidity and permeability may limit bioventing efficiency · Effectiveness of the process may be affected by the soil moisture content |
Biological |
Phytoremediation[3] |
Radionuclides, hydrophobic organic compounds, BTEX, PAHs, organometallic compounds (TBTO), heavy metals and pesticides. |
Bioremediation process that uses various types of plants to remove, transfer, stabilise, and/or destroy contaminants in the soil and groundwater. |
· Applicable to soils, groundwater and surface water |
· The contaminating material should be present within the root zone to be accessible to the roots · Large space is required to grow plants · Time-consuming as it usually takes one year |
Remediation Category |
Remediation Method |
Type of Contaminants |
Description |
· Applicability |
· Limitations |
Thermal |
Thermal Incineration |
Explosives and residues, particularly chlorinated hydrocarbons, PCBs and dioxins, free cyanide, semi-volatiles, and pesticides. |
Utilises flame and high temperature to cause the organic and some of the metal wastes to be converted from solids or liquids into hot gases. |
· Applicable to soils
|
· High energy costs · Volatile metals such as arsenic, cadmium, chromium, lead and mercury are not destroyed by the combustion, thus being some of them present in the ashes or released in the gases · Require residual management for inorganic materials |
Thermal |
Thermal Desorption |
All types of organic contaminants. The target contaminants include SVOCs, PAHs, PCBs, heavy metals and pesticides. |
Utilises heat to increase the volatility of contaminants such that they can be removed (separated) from the solid matrix (typically soil, sludge or filter cake). |
· Thermal desorption has varying degrees of effectiveness against the full spectrum of organic contaminants · Thermal methods can be particularly useful for dense nonaqueous phase liquids (DNAPLs) or light nonaqueous phase liquids (LNAPLs) |
· Effectiveness depends on the contaminant · Clay, silty soils and high humic content soils increase reaction time as a result of binding of contaminants. Highly abrasive feed potentially can damage the processor unit |
Table 8.9b Potential Groundwater Remediation Options [4] & [5]
Remediation Category |
Remediation Method |
Type of Contaminants |
Description |
Applicability |
Limitations |
Chemical |
In-situ chemical oxidation and chemical reduction |
Depends on contaminant and method chosen but applicable to metals, PCRs, PAHs, PCBs, dioxins, VOCs / SVOCs and pesticides
|
Groundwater is treated in place without extraction from the aquifer. In situ treatment technologies can destroy, immobilize or remove contaminants |
· Applicable to soil and groundwater |
· Site specific – depends on the contaminant present and method chosen · Very specialised contractors required · Chemical methods require the handling of large quantity of hazardous oxidising chemicals · Some COCs are resistant to oxidation |
Physical |
Containment |
Metals |
Applicable for containing contamination in groundwater in place, avoids need for pump and treat. |
· Applicable to soil and groundwater · In-situ treatment technologies such as chemical oxidation and chemical reduction, and permeable reactive barriers |
· Long-term monitoring and maintenance required · Treatment in the future cannot be ruled out · This method does not lessen toxicity, mobility, or volume of hazardous wastes, but does mitigate migration |
Physical |
Permeable Reactive Barrier |
Metals, PCRs, PAHs, PCBs, dioxins, free cyanide, VOCs / SVOCs and pesticides |
Groundwater is treated in place without extraction from the aquifer |
· Water flows through reactive material to reduce contamination levels and risk to receptors down stream of site |
· Applies to relatively shallow aquifers · Effectiveness of the treatment is influenced by groundwater chemistry / flow rate, ground geochemistry, site topography, seasonal changes in hydrogeological conditions |
Physical |
Pump and Treat |
Metals, PCRs, PAHs, PCBs, dioxins, free cyanide, VOCs / SVOCs and pesticides |
Extract and convey groundwater to an above-ground treatment system to remove the contaminants |
· Most common clean up method to remove contaminants from groundwater · Also applicable to plumes in groundwater |
· Above-ground treatment system required |
Biological |
Phytoremediation[6] |
Radionuclides, hydrophobic organic compounds, BTEX, PAHs, organometallic compounds (TBTO), heavy metals and pesticides. |
Bioremediation process that uses various types of plants to remove, transfer, stabilise, and/or destroy contaminants in the soil and groundwater. |
· Applicable to soils, groundwater and surface water |
· The contaminating material should be present within the root zone to be accessible to the roots · Large space is required to grow plants · Time-consuming as it usually takes one year |
[1] Source: Full list of pesticides and herbicides available for analysis provided by ALS Technichem (HK) Pty Ltd (HOKLAS-accredited)
[2] Teresa Castelo-Grande, Paulo A. Augusto, Paulo Monteiro, Angel M. Estevez & Domingos Barbosa (2010): Remediation of soils contaminated with pesticides: a review, International Journal of Environmental Analytical Chemistry, 90:3-6, 438-467.
[3] Views from relevant authorities (i.e., WPG/EPD) would be sought and presented in the Remediation Action Plan (RAP) if remediation is required; and subject to EPD’s agreement.
[4] Remediation Methods Applied in Overseas Cases, extracted from Table 4.2 of EPD’s Practice Guide for Investigation and Remediation of Contaminated Land.
[5] How Superfund Addresses Groundwater Contamination, USEPA <https://www.epa.gov/superfund/how-superfund-addresses-groundwater-contamination>.
[6] Views from relevant authorities (i.e., WPG/EPD) would be sought and presented in the Remediation Action Plan (RAP) if remediation is required; and subject to EPD’s agreement.