7
land contamination
7.1.1.1
This section presents the
potential land contamination implications associated with the Project.
7.2.1.1
The relevant environmental
legislation guidelines and standards on land contamination aspect 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)
The 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 analysed and suggests practical remedial measures that can be
adopted for the clean-up of contaminated sites.
·
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)
The
Guidance Manual introduces the risk-based approach in land contamination
assessment and present 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 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.
7.3.1.1
Land contamination assessment
was carried out according to the abovementioned EIAO-TM, Guidance Note,
Practice Guide and Guidance Manual.
7.3.1.2
A site appraisal, including
site walkover and desktop review, was conducted to identify the potentially
contaminating activities that may pose adverse impact to the Project. Site walkover was conducted within 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:
·
Aerial photographs and
topographic maps held by the Lands Department;
·
Hong Kong Geological Survey Map
(Series HGM20) – Sheet No. 7 (1:20,000);
·
Records on dangerous goods,
chemical wastes, chemical spillage/leakage and fire incidents from the
identified potentially contaminated sites from Environmental Protection
Department (EPD) and Fire Services Department (FSD); and
·
Relevant ground investigation (GI)
reports from the Civil Engineering and Development Department (CEDD) civil
engineering library.
7.3.1.3
If potentially contaminated
land use(s) were identified within the Project Area, the potential land
contamination impacts arising from the Project would be evaluated and
appropriate mitigation measures would be recommended. If necessary, Contamination Assessment Plan
(CAP), Contamination Assessment Report (CAR) and Remediation Action Plan (RAP)
would be submitted to EPD for endorsement.
Any contaminated soil and/or groundwater should be treated according to
EPD’s approved RAP. A Remediation Report
(RR), demonstrating adequate clean-up, should be submitted to EPD for
endorsement prior to the commencement of any development or redevelopment works
within the Project Area.
7.4.1.1
The Project includes the
construction of a dual 2-lane trunk road of about 2.6km connecting Shing Mun
Tunnel Road and Tsing Sha Highway in the northwest with Sha Tin Road in the
southeast. The location of the Project
is shown in Figure
1.1.
7.4.1.2
As shown in the site location
plan provided in Figure
1.1, the Project Area is located on a generally flat terrain and is
mainly bounded by residential buildings and undeveloped vegetated land to the
north, residential / industrial buildings and the Hong Kong Heritage Museum to
the south, residential buildings, roads and the Shing Mun River Channel to the
east and west.
7.4.1.3
Based on the latest engineering
design and as shown in Figure 2.3.1,
Figure 2.3.2,
Figure 2.3.3
& Figure
2.3.4, the Project would include construction of at-grade roads,
depressed roads, underpasses as well as piers of elevated roads where soil
excavation would be anticipated. In addition, a section of the proposed elevated road
(approximately 30m in length) in the central part of the Project and along Man
Lam Road to the north of the Shing Mun River Channel, would be above the
Caltex-Tai Wai Petrol Filling Station (refer to Figure 2.3.2).
Based on the latest design, the proposed road works, including the
piers, will not encroach into the petrol filling station and the petrol station
will be retained under the Project.
7.5
Identification of Potential Land
Contamination Concern
7.5.1
General
7.5.1.1
Site appraisal was carried out
in the period from June 2019 to June 2020 with site walkovers conducted in February
2020. Findings of the site appraisal are
summarized below.
7.5.2.1
A comprehensive land
contamination assessment was conducted under the approved EIA Report for Trunk
Road T4 in Sha Tin (Register
No.: AEIAR-084/2005).
The assessment was conducted in accordance with the EIAO-TM as well as
EPD’s guidelines. The Dutch Ministry of Housing, Planning
and Environmental Soil and Groundwater Standards (1994) (the Dutch
Guidelines) were used as the reference criteria for the classification of
contaminated materials, with Dutch B level as the cleanup target for
soil.
7.5.2.2
The assessment area of the
approved EIA Report largely covered the current Project Area (refer to Figure 7.1). The assessment included desktop study (e.g.
review of aerial photographs, survey maps and relevant information from Lands
Department, EPD and FSD), site reconnaissance and preliminary site
investigation (SI). The site
reconnaissance and preliminary SI works were conducted in September 2003.
7.5.2.3
Based on the approved EIA
report, apart from an open car park adjacent to Che Kung Miu Station (Site A)
(refer to Figure 7.1),
no other potentially contaminated sites were identified in the original
alignment. The preliminary SI works was
conducted at Site A in September 2003.
Three boreholes were constructed for the preliminary SI works with a
total of 9 soil samples collected. The
collected soil samples were tested by an HOKLAS accredited laboratory for heavy
metals (chromium, copper, lead and zinc), total petroleum hydrocarbons,
polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethylbenzene, xylene
(BTEX) and solvents (halogenated and non-halogenated). Based on the laboratory analytical results,
no exceedances in the Dutch B levels for all the tested parameters were found
in the collected samples. The laboratory
analytical results are summarised in Appendix 7.1. For the purpose of this assessment, the
relevant RBRGs under the
current EPD’s Guidance Manual are also presented in Appendix 7.1.
As the future land uses of the Project are roads, cycling tracks, pedestrian
walkways and footbridges, the RBRGs of Lower
of Industrial or Public Park land use scenario is adopted for this assessment. According to the laboratory analytical results, there is no
exceedance of relevant RBRGs in the collected samples.
7.5.2.4
According to the approved EIA
report and the laboratory analytical results, no contaminated sites (including
Site A) were identified within the assessment area for the original alignment as
of Year 2003.
7.5.3
Review of Historical Land Uses
7.5.3.1
A review of aerial photographs in
the period after the approval of EIA Report has been undertaken to evaluate the
likelihood of potential contamination associated with past land uses within the
Project Area. Findings of the review are
summarized in Table 7.1 and the reviewed aerial photographs are provided
in Appendix 7.2.
Table 7.1 Aerial
Photographs Reviewed
|
Year
|
Reference
of Aerial Photos in Appendix 7.2 (Photo Reference Number)
|
Site
Description
|
|
1963
|
AP1,
AP2 (#1963_0480)
|
The Project Area was largely occupied by
agricultural land, village houses and vegetation. The Shing Mun River and
Tai Po Road were also observed.
|
|
1973
|
AP3
(#03251), AP4 (#03249)
|
Reclamation
was in progress and the Shing Mun River Channel was under modification to
the present configuration. The existing Lion Rock Tunnel Road was observed. No significant land use changes were
observed in the remaining areas of the Project Area.
|
|
1983
|
AP5
(#51133, #51152);
AP6
(#51152, #51171)
|
Tai
Chung Kiu Temporary Housing Area and Sha Tin Tau Temporary Housing Area
(Site A) were observed on both sides of Shing Mun River Channel near Lion
Rock Tunnel Road. The existing Tai Po Road was widened and the existing Che
Kung Miu Road and Shing Wan Road were observed. The construction site for
the existing Sha Tin Road was also observed in the south of the Project
Area.
|
|
1993
|
AP7
(#A34663, #A34684);
AP8
(#A34684, #A34707)
|
The
Tai Chung Kiu Temporary Housing Area was demolished and an open car park was
observed. The Shing Mun Tunnel Road and Chung Ling Road were also observed in the northern portion of the Project Area. No significant
land use changes were observed in the remaining areas of the Project Area.
|
|
2003
|
AP9 (#CW47503);
AP10
(#CW47592; #CW47611)
|
The
Project Area remained largely occupied by roads, farmland and vegetation.
The Temporary Housing Area in Site A was demolished and an open was observed.
The existing Caltex-Tai Wai Petrol Filling Station was noted within the
central portion of the Project Area.
|
|
2013
|
AP11
(#CS45680; #CS45683);
AP12
(#CS45206; #CS45680)
|
The existing
Tsing Sha Highway was observed in the northern portion of the Project Area. Site depots were observed adjacent to Che
Kung Miu Station (previously open car park in Site A).
No
significant land use changes were observed in the remaining areas of the
Project Area.
|
|
2018
|
AP13 (#E039205C;
#E039208C; #E039211C; #E049616C; #E049619C; #E049623C);
AP14
(#E049623C; #E049627C; #E049631C; #E039205C; #E039199C; #E039196C)
|
No
significant land use changes were observed in the Project Area.
|
Source of aerial photographs:
Survey and Mapping Office, Lands Department
7.5.3.2
Based on the review of aerial
photographs, similar to the approved EIA report, the Project Area had been
mainly occupied by roads, agricultural land, residential uses, open car park and
vegetation. No potential land contamination issues were identified in these
areas. A potentially contaminating land use (the Caltex-Tai Wai Petrol Filling
Station) was identified within the Project Area. However, as discussed in Section 7.4.1.3,
the proposed road alignment and piers will not encroach into the Caltex-Tai Wai
Petrol Filling Station and the petrol filling station will be retained under
the Project. Two site depots were observed adjacent to Che Kung Miu station
since 2013. Based on findings of the site walkover (refer to Section 7.5.6.4),
the site depots had been used as site offices / car park only.
7.5.3.3
Based on the above, no
historical potential land contamination issues were identified within the
Project Area.
7.5.4
Site Geology
7.5.4.1
The superficial geology of the
Project Area generally comprises Quaternary deposits and fill materials. Fill
material is likely to be encountered within the urban areas in Shatin.
Reclamation fills of various ages will be encountered near the river bank of
Shing Mun River. According to the
archival GI records, local marine deposits which mainly comprising thin layer
sand materials, are likely to be encountered near Heritage Museum and Shatin
Park Area. A large extent of Alluvium is encountered in Shatin valleys and
natural drainage lines on the hillsides, extending towards the Tolo Harbour.
The deposit generally composes of interbedded clay, silt, sand, gravel,
cobbles. Colluvium, which consists of
silt, sand, gravel or cobbles, occurs widely in the valleys or incised streams
of the uphill of Shing Mun River and Shek Mun Area.
7.5.4.2
According to the published
1:20,000 Geological Map (Sheet No.7), the dominant rock types likely to be
encountered within the Project Area are Jurassic Shatin Granite (Jkt_gc), with
some minor Late Jurassic East Lantau Rhyodacite (Jkd_rf) and Needle Hill
Granite (Jkn_gf) intrusions on the west of the Tolo Channel fault and generally
underlain along Shing Mun Tunnel Road;
and Cretaceous Shui Cheun O Granite (Kcs_gm & Kcs_gc) with dykes of
Cretaceous Tei Tong Tsui Quartz Monzonite (Klt_mq) are dominant on the east of
the Tolo Channel fault, where situated at the central part of Shing Mun River
area and near the hillside of Shatin Road.
7.5.4.3
The Sha Tin Granite (Jkt_gc)
comprises a coarse-grained central core surrounded by medium- to fine-grained
lithologies. The coarse-grained granite is texturally uniform comprising large
crystals of quartz, alkali feldspar and plagioclase forming a subhedral
granular texture. Interstitial aggregates of brown biotite are a distinctive
feature of the granite and are especially conspicuous in the coarse-grained
rocks. Porphyritic fine-grained lithologies are commonly observed close to the
boundaries of the pluton.
7.5.4.4
The Shui Chuen O Granite
(Kcs_gm & Kcs_gc) is dominantly porphyritic and fine to medium grained and
is commonly weakly deformed. Phenocrysts of perthitic orthoclase and strained
quartz are set in a subhedral-granular matrix of strained quartz, weakly zoned
plagioclase, and chloritized biotite.
7.5.5
Information from Government
Departments
7.5.5.1
The EPD and FSD were contacted
for (i) records of any spillage / leakage of chemicals, (ii) records of Dangerous
Goods (DG) and (iii) records of Chemical Waste Producer(s) (CWPs) and (iv)
records of reported fire incidents within the Project Area.
7.5.5.2
EPD and FSD’s replies on the
request have been received and attached in Appendix 7.3.
The information is summarized below.
Environmental Protection Department
7.5.5.3
Based on the reply given by EPD
on 28 June 2019, there is no record of spillage / leakage of chemical wastes or
chemicals within the Project Area.
7.5.5.4
Further to the EPD’s reply,
visit to EPD’s Southorn Centre Office was undertaken on 3 April 2020 to review
the available CWP records. No CWP
records were found within the Project Area.
Fire Services Department
7.5.5.5
Based on the reply from FSD on
22 July 2019, there are 2 DG license records identified within the Project
Area. The records are likely to be associated with the Caltex-Tai Wai Petrol
Filling Station situated in the central part of the Project Area (refer to Figure 2.3.2). Details of the DG licenses are summarized in Table
7.2. As discussed in Section
7.4.1.3, the Caltex-Tai Wai Petrol Filling Station will be retained under
the Project. Potential land
contamination issues associated with the storage of DG in the petrol filling
station are therefore not anticipated.
7.5.5.6
Furthermore, based on the reply
from FSD, there was a ‘No.1 Alarm Fire’ incident reported at the Transport City
Building on 10 March 2017. As the
concerned building is situated 30 m to the southwest of the Project Area (refer
to Figure 2.3.2),
the incident was not expected to pose any potential land contamination issues
to the Project Area.
Table 7.2 Summary of Dangerous
Goods License Information
|
Location
|
Type of DG
|
Quantity
|
Storage Method
|
|
Caltex-Tai Wai Petrol Filling Station
|
Petrol
|
45,000 Litres
|
Underground Tank in Petrol Filling Station
|
|
Diesel Oil
|
45,000 Litres
|
7.5.6
Site Reconnaissance
7.5.6.1
Site walkover was conducted on
20 and 25 February 2020 to investigate any contaminative issues associated with
current land uses and activities within the Project Area. Findings of the site walkover, including the
photographic records and site layout plan, are shown in Figure 7.2, Figure 7.3, Figure 7.4, Figure 7.5 & Figure 7.6. Site walkover checklists are provided in Appendix 7.4.
7.5.6.2
Based on the site walkover, the
Project Area was mainly occupied by non-contaminating land uses including
roads, footpaths / cycling tracks, subways, car parks, refuse collection point,
playground / sitting-out area, MTR East Rail, the Shing Mun River Channel, open
area, agricultural land and vegetation (refer to Figure 7.2, Figure 7.3, Figure 7.4, Figure 7.5 & Appendix 7.4). No potentially contaminating land uses /
activities were observed in these areas.
7.5.6.3
The Caltex-Tai Wai Petrol
Filling Station was observed in the central portion of the Project Area (refer
to Photo No. 2806 in Figure 7.3)
and was inaccessible
for detailed site walkover. However, based on
peripheral observations, the site was paved with intact concrete in good
condition and as discussed in Section 7.4.1.3, the petrol filling
station will be retained under the Project.
Potential land contamination issues associated with the operation of the
Petrol Filling Station to the Project are therefore not anticipated.
7.5.6.4
There are two site depots
located adjacent to Che Kung Miu Station in the central portion of the Project
Area. The northern site depot is currently operated by CEDD under Contract No.
NE/2017/05 Road Widening and Retrofitting Noise Barriers on Tai Po Road (Sha
Tin Section) and the southern site depot is currently operated by the Highways
Department (HyD) and China
Road & Bridge Corporation (contractors). Based on
information provided by the site representatives and site observations, the
site depots are used for site offices and car parking only with no vehicle
maintenance activities carried out on site. No potentially contaminating
activities were identified, and no chemical / oil storage or stressed
vegetation were observed within the sites. The concrete paved ground was noted
to be in good condition with no oil stains observed. As reported by the site representatives,
there had been no major change in site operations at the two site depots for
the last 5 years. Based on the above, potential land contamination issues
associated with the operation of the site depots to the Project are not
anticipated. Findings of the site walkover, including the photographic records
are shown in Figure 7.6.
Questionnaires were conducted with available site representatives and the site
walkover checklists with site layout plans are provided in Appendix 7.4.
7.6.1.2
From the above, no land
contamination impact arising from the Project is anticipated and mitigation
measures are considered not necessary. No further site investigation (SI) works
at the Project Area is required.
7.9.1.1
A site appraisal, in the form of desktop review and site walkover, was
conducted from June 2019 to June 2020 to identify any current/historical
potentially contaminating and uses within the Project Area.
7.9.1.2
Based on the findings of the site appraisal, no adverse land
contamination impact arising from Project is anticipated. No further SI works
at the Project Area is required.