10.1
Contaminated land refers to the land which
has been polluted by hazardous substances as a result of industrial operations
carried out on site over a number of years.
These contaminants, if present, may pose hazardous risks or cause
adverse effects to the land users and the nearby environment.
10.2
The implications of land contamination
associated with the Project and its
works areas have been assessed with reference to the EIA Study Brief. This section summarises the
site appraisal results from the Contamination Assessment Plans (CAPs) and site
investigation results as reported in the Contamination Assessment Report (CAR),
together with overall findings and recommendations relevant to the EIA.
Environmental Legislation,
Standards and Guidelines
10.3
The relevant environmental legislation guidelines and standards on
land contamination include the following:
(i)
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).
(ii)
Guidance Note for Contaminated Land
Assessment and
Remediation” (Guidance Note 1)
Guidance Note 1
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
cleanup of contaminated sites.
(iii)
Guidance Notes for Investigation and
Remediation of Contaminated Sites of Petrol Filling Stations, Boatyards and Car
Repair /Dismantling Workshop” (Guidance
Note 2)
Guidance Note 2
specifically sets out guidance for land contamination assessment and
remediation for sites previously used for petrol filling stations,
boatyards and vehicle repair/dismantling workshops.
(iv)
Guidance Manual for Use of Risk-based
Remediation Goals for
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
10.4
The first step was
to identify and assess any potentially contaminated sites within the Project area. The following tasks have been undertaken to
identify and evaluate the potential land contamination
impacts associated with the Project:
·
Desktop study to
review the current and historical land uses;
·
Acquisition of
information related to potential land contamination from Environmental
Compliance Division of Environmental Protection Department (EPD) and Fire Services Department (FSD); and
·
Site reconnaissance
to identify the existing land uses and potential sources of
contamination.
10.5
In addition, the
following sources of information have been collated and reviewed:
·
Selected aerial photographs from Lands Department;
·
·
Information on
dangerous goods for potentially contaminated areas from Fire Services Department (FSD);
·
Records and
photographs obtained during site visit; and
·
Previous ground investigation (GI) reports
from Civil Engineering and Development Department (CEDD).
10.6
Based on the desktop review and site appraisal results, a Contamination
Assessment Plan (CAP) was prepared specifying the sampling and testing requirements for the soil and groundwater samples.
The
CAP was approved by EPD
on 8 October 2009 and is presented in Appendix
10.1.
10.7
Subsequent to the approval of the CAP, some
proposed sampling locations were relocated. An additional assessment area, Mong Kok Freight Terminal, was
also included. To address the adjustments to the Site Investigation (SI) plan
due to these changes, a Supplementary CAP was prepared. The Supplementary CAP was approved by EPD on
11 March 2010 and is presented in Appendix 10.2 (the “approved
Supplementary CAP”).
10.8
Another change subsequent to the approval of
the above-mentioned CAPs involved minor shift of the Project alignment at the
section from Portal 1A to Chatham Road Interchange (CRI). As such, the SI plan
for one of the Assessment Areas (i.e. Area 1) in the approved CAP is slightly
modified to accommodate the alignment and works changes. A Supplementary CAP for the revised alignment
was, therefore, submitted to EPD which was endorsed on 23 November 2010
(attached as Appendix 10.3).
10.9
Sampling and laboratory testings
were proposed for areas identified to have high potential for contamination
(potential hotspots). After completion of the SI works, the soil and
groundwater analytical results were compared against the adopted RBRGs. Due to site constraints, SI works were conducted in different stages as described in the
abovementioned CAPs.
10.10 All SI works have been completed.
The nature, level and extent of land contamination are evaluated and the
findings documented in the Contamination Assessment Report (CAR) which has been
submitted to EPD for endorsement. The CAR is
presented in Appendix 10.4.
Description of the Environment
10.11 The latest Project
boundary and the alignment are indicated in Figure no.
NEX2213/C/361/ENS/M50/501. The assessment areas for land contamination
under this Project were divided into five geographic categories which are shown in Figure nos.
NEX2213/C/361/ENS/M57/505 and NEX2213/C/361/ENS/M57/506.
Area 1[1]:
Works Area North of the Covered Section of Hung Hom
Freight Terminal (HFT)
10.12 Area 1 generally covers the section of the proposed Project alignment
starting from the tunnel near Oi Man Estate extending
south-easterly through the Chatham
Road Interchange to the works area north of
the covered section of HFT, but excludes the locomotive running shed and the
underground storage tanks (USTs) in the northeast.
Area 2: Works Area within the Covered Section of
HFT
10.13 Area 2 includes the covered section of HFT, the locomotive running shed and the USTs in the northeast.
The proposed alignment passes through the existing HFT (approx. area 100,000 m2) and major construction works in this area
include cut-and-cover tunnel construction, modification, reprovisioning, construction and
demolition of facilities in support of
the railway construction works.
Area 3: Works Area South of the Covered Section of
HFT
10.14 Area 3 generally covers the area south of the covered section of HFT, including the International Mail Centre (interfacing with the project area of SCL – Tai Wai to Hung Hom Section), Hung Hom Freight Yard (HFY), and the cargo pier at Hung Hom waterfront. The
Area 4[2]:
Supporting Works Area east of Hung Hom Station (HUH)
10.15 Area 4 includes the supporting works areas for ancillary purposes such as site offices and
stockpiling are also proposed under the Project. They are all located to the northeast/east of
the HFT.
Area 5: Mong Kok Freight Terminal (MFT)
10.16
Area 5 is the Mong Kok Freight Terminal (MFT), mainly covering Mong Kok East station, which will be used as an additional works area
for modification of buildings and facilities of the existing goods yard.
Identification of Potential Environmental Impacts
Identification of Impact Sources
10.17 The identification of potentially contaminated sites within the Project areas has been completed through the site appraisal
exercise. Potentially contaminated sites were
identified in Areas 1-3 and the details are summarised in Table 10.1 below. For Area 4, no works will be
carried out according to the latest design. No SI works will, therefore, be carried
out. Since the current land use of Area 5 is drinks storage without historic
potential land uses recorded, and no potentially contaminated site was
identified during site appraisal, no intrusive SI is proposed.
Table 10.1 Potentially Contaminated
Sites Identified under the Latest Design
|
Site ID |
|
Planned Post-Restoration Land Use |
Reference Figure |
|
Area 1 |
|||
|
1-10 |
Open storage for
construction materials (previously a D.G. store for paint) |
Railway
facilities |
|
|
1-18 |
Emergency
generator and associated fuel tank |
Railway facilities |
|
|
1-22 |
MTR railway operations (Historic railway
maintenance facility area) |
Railway facilities |
|
|
Area 2 |
|||
|
2-02 |
Locomotive traverser |
Railway
facilities |
|
|
2-04 |
Locomotive running
shed (A sampling
location southeast of the locomotive running shed was not excavated to the
proposed depth; underground structures were encountered during excavation) |
To be demolished and adapted
for railway facilities |
|
|
2-05 |
USTs for diesel
storage |
To be demolished and adapted
for railway facilities |
|
|
2-06 |
Aboveground
lubricating oil storage tank |
To be demolished and adapted
for railway facilities |
|
|
2-07 |
Fuel
dispensers/pump islands |
To be demolished and adapted
for railway facilities |
|
|
2-08 |
Part of the
railway tracks in HFT |
Railway
facilities |
|
|
2-09 |
D.G. store
containers |
Railway facilities |
|
|
Area 3 |
|||
|
L17 |
International Mail
Centre ·
D.G. store ·
Chemical storage ·
Emergency generator room ·
Fuel tank room ·
Open car park (previously open storage with unknown purposes) |
Facilities and buildings in
this site will be demolished to accommodate construction of SCL - Mong Kok East to Hung Hom Section and SCL – Tai Wai to Hung Hom
Section |
|
|
3-02 |
Container stacker
refuelling and maintenance area at HFY |
Railway facilities |
|
Identification of
Sensitive Receptors
10.18 Onsite construction
workers have the potential to be exposed to potentially contaminated materials during
the decommissioning stage. The principle exposure pathways for onsite workers include:
l
Direct ingestion
of contaminated soil through eating, drinking or smoking onsite; and
l
Dermal contact
with contaminated soil.
10.19 Through the correct implementation of occupational health and safety
guidelines and correct use of personal protective equipment these potential
pathways can be successfully managed.
10.20 Other potential sensitive receptors include water bodies and other
humans working or travelling near the sites and during the intrusive
investigation and remediation work stages.
During these stages there is a potential to generate dust emissions and
water discharges that have the potential to affect the surrounding sensitive
receivers (e.g. human receivers and water bodies). However, adoption of
appropriate work practices and precautionary measures during investigation and remediation works will ensure that
these risks can be successfully managed.
Prediction
and Evaluation of Environmental Impacts
Site Investigation
Results
10.21 SI works at identified hotspots have been conducted. A summary of the SI status and
findings is provided in Table 10.2 below:
Table 10.2 Summary of SI Status
and Findings
|
Site ID |
SI Status |
No. of Borehole/
Trial Pits Sampled |
No. of Sample Tested* |
Compliance to Industrial RBRGs |
|
Area 1 |
|
|||
|
1-10 |
Completed |
1 |
11 |
All samples tested indicated
compliance |
|
1-18 |
Completed |
1 |
3 |
All
samples tested indicated compliance |
|
1 - 22 |
Completed |
6 |
40 |
All samples tested indicated
compliance |
|
Area 2 |
|
|||
|
2-02 |
Completed |
1 |
8 |
All samples tested indicated
compliance |
|
2-04, 2-06 and 2-07** |
Completed |
10 |
110 |
All samples tested indicated
compliance |
|
2-05 |
Completed |
3 |
15 |
All samples tested indicated
compliance |
|
2-08 |
Completed |
5 |
24 |
All samples tested indicated
compliance |
|
2-09 |
Completed |
1 |
8 |
All samples tested indicated
compliance |
|
Area 3 |
|
|||
|
L17 |
Completed |
4 |
20 |
All samples tested indicated
compliance |
|
3-02 |
Completed |
2 |
12 |
All samples tested indicated
compliance |
|
Total |
34 |
251 |
- |
|
Notes:
*: Number of tested soil and groundwater (if encountered) samples. Number
of duplicate soil samples is not included in this table.
**: SI for Sites 2-04, 2-06, and 2-07 were carried
out collectively.
10.22 A total of 231 soil samples and 20 groundwater samples were collected at 34 locations identified as potentially contaminated sites.
According to the analytical results, no exceedances
of the RBRGs (industrial) were found among all soil and groundwater samples
collected.
Remediation Actions and
Precautionary Measures to Be Undertaken during Construction
Review of Remediation Options, Method and Target
10.23 Based on SI results of the soil and
groundwater samples, no exceedance of the adopted
RBRG guidelines has been confirmed at the identified potentially contaminated sites;
therefore no remediation actions are needed for these sites.
Summary of Proposed
Precautionary Measures to Be Undertaken during Construction
10.24 Although no exceedance
was found, to be conservative,
precautionary measures such as visual inspection are recommended during
construction for the sites of which only preliminary SI has been carried
out. The inspection process should involve a visual observation of excavated soils
for discolouration and the presence of oils, together with identifying the presence
of odours, which may also indicate soil and/or groundwater contamination.
10.25 The following is a summary of proposed precautionary measures to be carried out during construction:
Site ID 1-18: Emergency Generator and the
Associated Fuel Tank
10.26 Due to site constraints, only a trial pit was conducted
outside the identified hotspots, i.e. the emergency generator and its
associated fuel tank rooms. Visual
inspection for the presence of contamination should therefore be carried out during construction of the cut and cover tunnel in the
proximity of this site and attention paid to potential contamination due to the historic
and current operation.
Site ID 1-22: Historical Railway Maintenance
Facility
10.27 Due to site constraints, three out of six boreholes could only be constructed to 3 to 6.5m. At the time of cut and cover railway construction, an inspection should consider visual evidence of potential contamination due to its past operation.
Site ID 2-02: Locomotive Traverser
10.28 Due to site constraints, only one borehole for preliminary screening for
potential land contamination was conducted.
Visual inspection should be carried out for soil and groundwater (if encountered) especially during cut and cover tunnel construction in part of this site and attention paid to potential contamination due to the historic and
current operation as a locomotive traverse for which lubricating oil is used for regular
maintenance.
Site ID 2-05: Underground Storage Tanks
10.29 Due to site constraints, three borehole
locations were sampled around the UST. Visual inspection should be carried out
during demolition of the USTs to confirm whether a leakage or spillage of
stored fuel had occurred and caused soil contamination.
Site ID: 2-08: Railway Tracks inside Hung Hom Freight Terminal
10.30 Five boreholes were proposed for preliminary
screening of potential land contamination.
Visual inspection should be carried out along the
railway tracks area where construction works will be carried out, to look for
signs of potential contamination due to past and current operations for
marshalling.
Site ID 2-09: D.G. Store
10.31 Due to site constraints, SI was conducted
outside of the D.G. storage containers.
Visual inspection for the presence of contamination should therefore be
carried out during the construction of the cut and cover tunnel in the proximity of this site.
Site ID L17: International
Mail Centre
10.32 Due to site constraints, only two trial pits
were sampled outside the identified hotspots namely the emergency generator and the associated fuel tank as well as the D.G. store. Visual inspection on the presence of contamination should therefore be carried out onsite where building demolition, road works and
construction of a cooling tower under this Project and an interfacing project (SCL – Tai Wai to Hung Hom Section) will be carried
out.
Site ID 3-02: Hung Hom
Freight Yard (HFY)
10.33 Since the HFY used to contain a refuelling and lubrication area for container stackers, should this
land use have caused contamination at the HFY, the contamination has the potential to
migrate to where intrusive works including cut and cover tunnel construction and building of the NOV will be carried out.
However, due to site
constraints, only preliminary assessment of potential land contamination was
carried out between the hotspot and the future cut-and-cover construction
area. Visual inspections should
therefore be carried out during the construction of this building.
10.34 If soil discolouration or the presence of oil/unnatural odour is noted during visual inspection, sampling and testing should also be undertaken to verify the presence
of contamination. Should concentrations
of COCs exceed the adopted RBRGs, remediation works should be undertaken with
reference to the CAR and RAP. A Remediation Report (RR) will
then be prepared and submitted to EPD to demonstrate that the decontamination
work is adequate and has been carried out in accordance with the endorsed CAR
and RAP. Information such as soil
treatment/disposal records (including trip tickets), confirmatory sampling
results and photographs will be included in the RR. No construction work will be carried out
prior to endorsement of the RR by EPD.
Potential
Remediation Works
10.35 If land contamination is identified, a RAP
detailing the proposed remediation works will be prepared. In order to
minimise environmental impacts arising from the handling of potentially
contaminated materials, the following environmental precautionary measures are
recommended to be utilised during the course of any required site remediation:
·
Excavation profiles
must be properly designed and executed with attention to the relevant
requirements for environment, health and safety;
·
Excavation should be
carried out during dry season as far as possible to minimise contaminated
runoff from contaminated soils;
·
Supply of suitable
clean backfill material is needed after excavation;
·
If proposed remediation methods employ chemical oxidation methods as the contaminant mass reduction technology, chemicals will be securely and separately stored away from sources of ignition or oxidisable items.
Handling will be undertaken by personnel with appropriate training and Personal Protective Equipment;
·
Vehicles containing
any excavated materials should be suitably covered to limit potential dust
emissions or contaminated wastewater run-off, and truck bodies and tailgates
should be sealed to prevent any discharge during transport or during wet
conditions;
·
Speed control for the
trucks carrying contaminated materials should be enforced;
·
Vehicle wheel and
body washing facilities at the site’s exit points should be established and
used; and
·
Pollution control
measures for air emissions e.g. from biopile blower,
noise emissions e.g. from blower, and water discharges e.g. runoff control should
be implemented and complied with relevant regulations and guidelines.
Summary of Proposed
Occupational Health and Safety Controls
10.36 In the event that remediation is required the Occupation Safety and Health Ordinance (OSHO) (Chapter 509) and its
subsidiary Regulations should be followed by all site personnel working on the
site at all times to minimise the potential adverse effects on the health and safety of construction workers during the course of site
remediation. In addition, basic health and safety measures should be
implemented, but not limited to the followings:
·
Set up a list of
safety measures for site workers;
·
Provide written
information and training on safety for site workers;
·
Keep a log-book and
plan showing the contaminated zones and clean zones;
·
Maintain a hygienic
working environment;
·
Avoid dust
generation;
·
Provide face and
respiratory protection gear to site workers if necessary;
·
Provide personal
protective clothing (e.g. chemical resistant jackboot, liquid tight gloves) to
site workers if necessary; and
·
Provide first aid
training and materials to site workers.
10.37 The corresponding responsible party for the above precautionary measures
are provided in the implementation schedule of this EIA.
Evaluation of Residual Environmental Impacts
10.38 No exceedances of the adopted standards were detected in soil and groundwater samples collected in the SI works. During the construction phase, precautionary
measures outlined in Sections 10.26 through
10.35 should be implemented.
10.39 This land contamination assessment evaluates potentially contaminative
land uses within the relevant Assessment Area and includes assessment of potentially contaminative impacts on future use. The assessment incorporates site appraisals,
site investigations, and assessments of the extent of contamination
impacts. Based on the findings from the
SI works, no adverse impacts have been identified within the Assessment Areas.
[1] “Area 1” in the approved CAP (Appendix 10.1)
has been slightly modified due to the adjustment in the alignment design. Details regarding the change can be referred
to in the relevant Supplementary CAP for Works Area in Area 1 (Appendix
10.3 of this EIA report).
[2] The supporting area
where potential hotspot was identified (i.e. Waste diesel storage area at DSD
site office) in the approved CAP will no longer be required, according to the
latest design. Sampling and testing for the proposed borehole were, therefore,
not conducted.