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Expansion of Hong Kong International Airport into a Three-Runway System |
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Contamination Assessment Report for |
Contents
1
Introduction
1.1 Background
The Environmental Impact Assessment (EIA) Report (Register No.: AEIAR-185/2014) prepared for the “Expansion of Hong Kong International Airport into a Three-Runway System” (the project) has been approved by the Director of Environmental Protection, and an Environmental Permit (EP) (Permit No.: EP-489/2014) has been issued for the project under the Environmental Impact Assessment Ordinance. As part of the EIA study, a Contamination Assessment Plan (CAP) (hereafter referred to as the Approved CAP) was prepared and presented as Appendix 11.1 of the approved EIA Report. In accordance to Section 8.1.1.1 of the Updated Environmental Monitoring and Audit (EM&A) Manual, which was submitted under Condition 3.1 of the EP, and Section 11.10.1.2 of the EIA Report, six areas (i.e. fuel tank room within Terminal 2 (T2) building, fuel tank room to the west of Civil Aviation Department (CAD) antenna farm, seawater pump house, switching station, pumping station and fire training facility), were inaccessible for site reconnaissance at the time of preparing the EIA Report.
According to Sections 11.5.4.14 and 11.5.4.37 of the EIA Report, it is anticipated that any potential land contamination concern related to possible leakage/ spillage of fuel in the fuel tank room within T2 building and fuel tank room to the west of CAD antenna farm will not cause any insurmountable impact. Furthermore, as mentioned in Sections 11.5.4.38, 11.5.4.47 and 11.5.4.50 of the EIA Report, the seawater pump house, switching station, pumping station and fire training facility are not identified as potential contaminative land use types as given in Table 2.3 of the Practice Guide for Investigation and Remediation of Contaminated Land, hence no potential land contamination along these areas are anticipated.
As part of the ongoing detailed design of the project, relocation of the switching station is no longer required for the modification of existing North Runway. Hence site appraisal process for land contamination potential at the switching station is considered not necessary. Further site reconnaissance was conducted at the remaining five assessment areas (i.e. the fuel tank room within T2 building, fuel tank room to the west of CAD antenna farm, seawater pump house, pumping station and fire training facility) in third quarter of 2016 and May 2017.
Further review on the as-built drawings when taking into account the latest design details of T2 Expansion project and planned site investigation (SI), as well as follow-up site reconnaissance at T2 building have been undertaken in January 2018 and February 2018 (i.e. fuel tanks and generators within the building). Findings and consideration of assessment results after EIA stage have been summarized in the Supplementary Contamination Assessment Plan (SCAP) being approved in August 2018.
To match with the construction programme, decommissioning/ demolition of the Emergency Power Supply System No.1 (hereafter referred as EPSS1) at T2 northern section was scheduled in 2019 and 2020. Mott MacDonald Hong Kong Limited (MMHK), as the project’s Environmental Team, was appointed by Airport Authority Hong Kong (AAHK) to prepare the Contamination Assessment Report (CAR) for Terminal 2 Emergency Power Supply System No.1 (Volume 1 and Volume 2) to partially fulfil the SCAP’s recommendation.
Environmental Protection Department (EPD) expressed no further comments on 2 March 2020 for the CAR for Terminal 2 Emergency Power Supply System No.1 (Volume 1), covering BH1, BH3, BH4, partial segment of BH2. In early 2020, CAR for Terminal 2 Emergency Power Supply System No.1 (Volume 2) are prepared to include the remaining segment of BH2 under the EPSS1. The scope of this CAR is presented in Section 1.2. The recommendations for the EPSS1 as stipulated in the SCAP are fulfilled and documented in the CAR for Terminal 2 Emergency Power Supply System No.1 (Volume 1) (hereinafter known as “CAR T2 EPPS1 Vol.1”) and CAR for Terminal 2 Emergency Power Supply System No.1 (Volume 2) (hereinafter known as “CAR T2 EPPS1 Vol.2”).
CAR(s) for the remaining areas of the Project Site will be submitted to EPD for endorsement in accordance with the SCAP and the updated Implementation Schedule of Land Contamination – Construction Phase is given in Appendix A.
1.2
Scope of this CAR
T2 building of the Hong Kong International Airport comprises northern and southern sections, where each section consists of number of Emergency Generator Rooms and Fuel Tank Rooms.
The Emergency Power Supply System No.1 was located at northern section of T2 Building as shown in Appendix B. This set of emergency power supply system comprises underground and above-ground section, with the following identified potential land contamination sources listed in Table 1.1 below,
Table 1.1: Identified Potential Land Contamination Source of Emergency Power Supply System No.1
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Potential Land Contamination Source Reference ID |
Descriptions |
CAR Documentation Status |
Location |
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Underground Section |
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Please refer to Appendix C |
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BH1 |
A 2,500 L underground fuel tank |
● In CAR T2 EPPS1 Vol.1 |
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BH2 |
53 m-in-length underground fuel pipelines connecting the 2,500 L underground fuel tank (i.e. BH1) and the 450 L above-ground fuel tank (i.e. BH3) |
● Segment running from BH1 to sampling point BH2-S3, and segment at BH2-S6, were documented in CAR T2 EPPS1 Vol.1 ● Remaining segment to be documented in CAR T2 EPPS1 Vol.2 (This report) |
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Above-ground Section |
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BH4 |
An emergency generator at Emergency Generator Room, connected to 450 L above-ground fuel tank (i.e. BH3) |
● In CAR T2 EPPS1 Vol.1 |
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BH3 |
A 450 L above-ground fuel tank at Emergency Generator Room |
● In CAR T2 EPPS1 Vol.1 |
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The scope of the agreed CAR T2 EPPS1 Vol.1 included the above-ground section (i.e. BH3 and BH4), and also the underground section (i.e. BH1, segment of BH2 running from BH1 to BH2-S3, and segment at BH2-S6). Enhanced SI results for the underground section, with the record checking and final Inspection findings the above-ground section confirmed that no land contamination issues at the above-ground section (i.e. BH3 and BH4) and the underground section (i.e. BH1, segment of BH2 running from BH1 to BH2-S3 and segment at BH2-S6).
Hence, the scope of this CAR, for T2 EPPS1 Vol. 2, is as follows,
● Partial portion of BH2, which includes:
– Segment running from sampling point BH2-S3 to BH2-S6 (including. BH2-S4, BH2-S5);
– Segment running from sampling point BH2-S6 to BH3 (including BH2-S7); and
– BH2-S3 and BH2-S6 as reference points (which enhanced SI results were presented in CAR T2 EPPS1 Vol. 1).
The sampling points BH2-S4, BH2-S5 and BH2-S7 were planned in accordance with the approved SCAP.
Graphical illustration of the scope of this CAR is presented in Appendix C.
1.3
Objective
According to the approved SCAP, the Emergency Power Supply System No. 1 located in northern section of the T2 building have been identified as the potential land contamination source, which being proposed in EIA Report as sampling locations.
This Contamination Assessment Report for Terminal 2 Emergency Power Supply System No.1 (Volume 2) has been prepared to present the procedures and laboratory testing of enhanced SI for segment of BH2, which runs from sampling point BH2-S3 to BH3 (i.e. segments running from sampling point BH2-S3 to BH2-S6, BH2-S6 to BH3, while BH2-S3 and BH2-S6 as reference points), under the scope presented in Section 1.2. The testing results have been interpreted based on the Guidance Manual for Use of Risk Based Remediation Goals (RBRGs) for Contaminated Land Management (Guidance Manual).
2
Summary of Sampling and Testing Strategy
2.1
Proposed
Sampling Method in the SCAP
2.1.1
Proposed
Sampling Method of BH2
According to the approved SCAP, grab sampling was proposed for the concerned underground facilities of T2 Building (i.e. BH2 in this CAR). The proposed sampling and testing plan in the SCAP, including the parameters to be tested, sampling locations and sampling depths are extracted and presented in Table 2.1. Sand samples shall be grabbed manually during decommissioning/demolition process of concerned underground pipeline trench. The whole sampling process shall be under the supervision of on-site contamination specialist.
Sampling Selection of Underground Fuel Pipelines (i.e. BH2)
Sand and soil samples should be collected as follows:
· Sand samples should be taken at every curvature of pipelines inside the concrete trench;
· Additional sampling points inside the concrete trench are set depending on length of pipeline segment (from curvature/connection to curvature):
° If pipeline segment is ≤10 m, additional sample is considered not required;
° If pipeline segment is >10 m and ≤20 m, one sample shall be taken at segment mid-point;
° If pipeline segment is >20 m and ≤30 m, samples shall be collected at 2 points which are evenly spaced with each other and segment ends.
· Soil samples should be taken right underneath concrete trench at every curvature.
Sampling point annotation and indicative sampling point locations of BH2 extracted from the SCAP are presented in Table 2.2 and Appendix D.
Table 2.1: Enhanced Sampling and Testing Plan for BH2 of Emergency Power Supply System No.1 in T2 Building
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Proposed Sampling Locations |
Sample Matrix |
Sampling Point Annotation |
Parameters to be Tested1 & 2 |
Rationale of Sampling |
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Heavy Metals |
PCRs3 |
VOCs3 |
SVOCs3 |
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BH24 |
Sand5 |
At the level of fuel pipelines |
BH2S1 - BH2S7 |
Lead only |
ü |
BTEX6 and MTBE7 |
PAHs8 |
Confirm no diesel leakage from underground fuel pipelines |
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Soil |
Right underneath concrete/brick trench |
BH2S1, BH2S2, BH2S3, BH2S6 |
Lead only |
ü |
BTEX6 and MTBE7 |
PAHs8 |
Confirm no leaked diesel (if any) penetrate the concrete /brick trench |
Remarks:
1 ü = testing proposed.
2 Having reviewed the potentially polluting activities of the site (use of diesel fuel) and S2.4.3 of Practice Guide, it is recommended to analyse the key COCs (i.e. Lead, PCRs, BTEX, MTBE and PAHs) of “Petrol Filling Station” which is the most relevant land use type for the case of T2. The concerned diesel tanks and pipelines are used for storage and transfer of diesel fuel only and only diesel fuel is used for the generator. It is noted BTEX, MTBE and Lead present in gasoline but unlikely to be found in diesel fuel.
3 PCRs = Petroleum Carbon Ranges; VOCs = Volatile Organic Chemicals; SVOCs = Semi-volatile Organic Chemicals;
4 Exact sampling locations will be identified on site during the removal of sand/soil during fuel tank and pipelines decommissioning/ demolition.
5 All sand samples will be collected within the concrete chamber or concrete/brick trench.
6 BTEX = Benzene, Toluene, Ethylbenzene, and Xylenes.
7 MTBE = Methyl Tert-Butyl Ether.
8 Polyaromatic hydrocarbons (PAHs) in the RBRGs include, acenaphthene, acenaphthylene, anthracene, benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene, dibenzo(a,h)anthracene, fluoranthene, fluorene, indeno(1,2,3-cd)pyrene, naphthalene, phenanthrene and pyrene.
Table 2.2: Sampling Point Annotation of Underground Fuel Pipeline BH2
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Proposed Sampling Locations |
Annotation of Sampling Point |
Type of Sampling Point (Curvature / Additional) |
Figure No. |
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BH2 |
BH2-S11 |
Curvature |
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BH2-S21 |
Curvature |
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BH2-S32 |
Curvature |
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BH2-S4 |
Additional |
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BH2-S5 |
Additional |
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BH2-S62 |
Curvature |
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BH2-S7 |
Additional |
Remarks:
1 Not within the scope of this CAR. BH2-S1 and BH2-S2 enhanced SI results were presented in CAR T2 EPPS1 Vol.1.
2 BH2-S3 and BH2-S6 enhanced SI results were presented in CAR T2 EPPS1 Vol.1. The enhanced SI result of these 2 sampling points are taken as reference in the CAR T2 EPPS1 Vol.2 (this CAR).
2.2
Assessment
Criteria
The chemicals of concern (COCs) listed in EPD’s Guidance Manual for Use of Risk-Based Remediation Goals (RBRGs) for Contaminated Land Management were referred to when proposing the analytical parameters listed in Table 2.1. According to Section 5.3 of the SCAP, categories of Industrial has been adopted for evaluating the contamination level of T2 building.
3
Site Investigation
3.1
Soil Sampling
3.1.1
Underground Fuel
Pipeline BH2
Soil sampling of the following sampling points were scheduled and carried out by Mott MacDonald HK Limited on 16 March 2020,
● BH2-S4 and BH2-S5, which located at BH2 segment between sampling point BH2-S3 and BH2-S6;
● BH2-S7, which located at BH2 segment between sampling point BH2-S6 to BH3.
For the reference sampling points BH2-S3 and BH2-S6, the sampling were carried out by Mott MacDonald HK Limited on 4 November 2019 and 14 November 2019 respectively.
3.1.1.1
BH2 Segment
between Sampling Point BH2-S3 and BH2-S6
As per on-site inspection, it was observed that the concrete trench running from BH2-S3 to BH2-S6, including sampling points BH2-S4 and BH2-S5, were filled with concrete rather than sand, which differs from the as-built drawings. Hence no sand samples could be taken at the level of fuel pipelines within the concrete trench at the sampling points BH2-S4 and BH2-S5.
With reference to the on-site observations as presented in Appendix E, no cracks on the concrete-trench nor oil stains were identified at the vicinity of sampling points BH2-S4 and BH2-S5. Due to safety concerns of excavation during the time of on-site observation, site photos at the sides and bottom of BH2-S4 and BH2-S5 could not be taken on 16 March 2020. In addition, taking into consideration of the laboratory testing results of the 2 reference points, BH2-S3 and BH2-S6, which were presented in CAR T2 EPPSA Vol. 1 with all tested parameters below the value of Risk-Based Remediation Goals (RBRGs) for Industrial, it is confirmed that no diesel leakage from the underground fuel pipelines laid in concrete-trench running from BH2-S3 and BH2-S6.
To err on a conservative side, additional site photo records at BH2-S4 and BH2-S5 will be provided to EPD upon demolition works at BH2-S4 and BH2-S5 as detailed in Section 3.1.2.
3.1.1.2
BH2 Segment
between Sampling Point BH2-S6 and BH3
According to site observation, it was observed that most of the underground fuel pipelines running from BH2-S6 to BH3, including sampling points BH2-S7, was laid inside the concrete trench, except a segment of underground fuel pipelines with 1 meter in length running between BH2-S7 and BH2-S6 was not laid inside the concrete trench.
Underground Fuel Pipelines Segment with No-Concrete-Trench
For the no-concrete-trench segment of underground fuel pipelines with 1 meter in length running between BH2-S7 and BH2-S6, to confirm no diesel leakage from underground fuel pipelines, 1 soil sample was taken right underneath the particular segment (i.e. NCTS2). Based on the sampling point selection strategy in the SCAP (i.e. If pipeline segment is ≤10 m, additional sample is considered not required;), together with the site observations where no oil stains being identified in the vicinity of NCTS2, and reference to the laboratory testing result of soil sample BH2-S6 (which were presented in CAR T2 EPPSA Vol. 1 with all tested parameters below the value of RBRGs for Industrial), it is considered that 1 sample collected at the depth right underneath the pipeline is deemed to be sufficient to represent and confirm if any diesel leakage from the 1m no-concrete-trench segment.
No ground water was observed during soil sampling of NCTS2.
Underground Fuel Pipelines Segment Laid inside the Concrete Trench (including BH2-S7)
For the underground fuel pipelines segment laid inside the concrete trench (including BH2-S7), as revealed on-site, the concrete trench was filled with concrete instead of sand, which differs from the as-built drawings. Hence no sand samples could be taken at the level of fuel pipelines within the concrete trench at the sampling points BH2-S7. With reference to the on-site observations as presented in Appendix E, no cracks on the concrete-trench nor oil stains were identified at the vicinity of sampling points BH2-S7. Due to safety concerns of excavation during the time of on-site observation, site photos at the sides and bottom of BH2-S7 could not be taken on 16 March 2020. Also, through taking into account the laboratory testing results of NCTS2 (refer to Section 4.1.1) which is near to the location of BH2-S7, it is confirmed that no diesel leakage from the underground fuel pipelines laid in concrete-trench running from the underground fuel pipelines segment laid inside the concrete trench.
To err on a conservative side, additional site photo records at BH2-S7 will be provided to EPD upon demolition works at BH2-S7 as detailed in Section 3.1.2.
Site observations during sampling are illustrated in Appendix E. The actual sampling point of underground pipeline BH2 is presented in Table 3.1 and Appendix F. All soil sample was analyzed in accordance with the analysis schedules detailed in Table 2.1.
Table 3.1: Summary of Sampling Point of BH2 in This CAR
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Sampling Locations |
Sampling Point |
Type of Sampling Point (Curvature/ Additional/ No-concrete-trench Segment) |
Sampling Date |
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BH2
|
NCTS2 |
No-concrete-trench Segment |
16 March 2020 |
3.1.2
Additional Photo
Record Upon Demolition Works
To err on a conservative side, additional site photo records at the sides and bottom of BH2-S4, BH2-S5 and BH2-S7 will be submitted to EPD upon demolition at the 3 specific sampling points to reaffirm the conclusion drawn in Sections 3.1.1.1 and 3.1.1.2 that no diesel leakage from the underground fuel pipes.
In case that sign of diesel leakage is spotted during the demolition works, agreement from EPD shall be sought for sampling strategy and subsequent SI shall be arranged in accordance with the agreed sampling plan. CAR will be submitted for the subsequent SI and if remediation required, Remediation Action Plan and Remediation Report will also be prepared.
3.2
Decontamination
Procedures
Before excavation/ sampling, all equipment in contact with the ground were thoroughly decontaminated between each excavation and sampling event to minimise the potential for cross contamination. The equipment should be decontaminated by steam cleaning or high-pressure hot water jet, then washed by phosphate-free detergent and finally rinsed by distilled water. During decontamination procedures and sampling, disposable latex gloves were worn to prevent the transfer of contaminants from other sources.
3.3
Quality
Assurance (QA) / Quality Control (QC) Procedure
3.3.1
QA/QC Procedure
The soil samples taken were placed in sample containers provided by the HOKLAS laboratory. Sufficient sample size was collected for the laboratory analysis. Samples were marked with sampling date, sampling identification number and sampling depth with appropriate chain-of-custody form. Following sampling, samples were stored in a cool box at a temperature between 0oC and 4oC and transported to the laboratory immediately after completion of the sampling.
The chain-of-custody records are given in Appendix G.
3.3.2
QA/QC Analysis
In this enhanced SI programme, QA/QC samples were collected in accordance to the frequency proposed in the SCAP as follows, with a Chain of Custody protocol adopted:
● One equipment blank per 20 samples for full suite analysis*;
● One field blank per 20 samples for full suite analysis*;
● One duplicate sample per 20 samples for full suite analysis*; and
● One trip blank per trip for the analysis of volatile parameters#.
Note:
* For the purposes of this enhanced SI programme, the following parameters were tested in a ‘full suite analysis’ –
1) Heavy Metals: Lead only.
2) PCRs: C6-C8; C9-C16; C17-C35.
3) VOCs: Benzene, Toluene, Ethylbenzene, Xylenes and Methyl Tert-Butyl Ether.
4) SVOCs: acenaphthene, acenaphthylene, anthracene, benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene, dibenzo(a,h)anthracene, fluoranthene, fluorene, indeno(1,2,3-cd)pyrene, naphthalene, phenanthrene and pyrene.
# For the purposes of this Project, the following parameters would be tested in the analysis of ‘volatile parameters’ – Benzene, Toluene, Ethylbenzene, Xylenes, Methyl Tert-Butyl Ether and C6-C8.
The duplicate, equipment blank and field blank samples were collected on 16 Mar 2020 during the sampling for NCTS2.
The laboratory results for QA/QC samples are presented in Appendix H.
All testing parameters were not detected (below the limit of reporting) in all blank samples obtained. QA/QC procedures for sample collection and preparation are considered acceptable.
4
Interpretation of Laboratory Testing Results
4.1 Soil Contamination
4.1.1
Underground Fuel
Pipeline BH2
A total of 1 soil sample was collected within the scope of this CAR at BH2 for laboratory testing. The testing results are summarised in Table 4.1 and the testing reports are presented in Appendix H. The testing results of all parameters indicated that the soil sample from NCTS2 was below the value of Risk-Based Remediation Goals (RBRGs) for Industrial.
Table 4.1: Laboratory Testing Results of Soil Sample at BH2
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Compound |
Concentration (mg/kg) |
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NCTS2 |
RBRGs for Industrial |
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Heavy Metals |
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Lead |
26 |
2290 |
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PCRs |
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C6 - C8 |
<5 |
C6 - C8: 10,000 C9 - C16: 10,000 C17 - C35: 10,000 |
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C9 - C16 |
<200 |
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C17 - C35 |
<500 |
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VOCs |
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Benzene |
<0.2 |
9.21 |
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Toluene |
<0.5 |
10,000 |
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Ethylbenzene |
<0.5 |
8,240 |
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Xylenes (Total) |
<2.0 |
1,230 |
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Methyl tert-Butyl Ether |
<0.2 |
70.1 |
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SVOCs |
|
|
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Naphthalene |
<0.500 |
453 |
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Acenaphthylene |
<0.500 |
10,000 |
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Acenaphthene |
<0.500 |
10,000 |
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Fluorene |
<0.500 |
10,000 |
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Phenanthrene |
<0.500 |
10,000 |
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Anthracene |
<0.500 |
10,000 |
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Fluoranthene |
<0.500 |
10,000 |
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Pyrene |
<0.500 |
10,000 |
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Benz(a)anthracene |
<0.500 |
91.8 |
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Chrysene |
<0.500 |
1140 |
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Benzo(b)fluoranthene |
<0.500 |
17.8 |
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Benzo(k)fluoranthene |
<0.500 |
918 |
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Benzo(a)pyrene |
<0.500 |
9.18 |
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Indeno(1.2.3.cd)pyrene |
<0.500 |
91.8 |
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Dibenz(a.h)anthracene |
<0.500 |
9.18 |
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|
Benzo(g.h.i)perylene |
<0.500 |
10,000 |
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5
Conclusion
Enhanced SI programme was conducted for the segment of BH2 running from sampling point BH2-S3 to BH2-S6, and segment running from BH2-S6 to BH3 in March 2020. During the enhanced SI programme, it was observed that the concrete trench of the concerned BH2 segment is filled with concrete instead of sand, which was differ from the as-built drawing. Hence no sand samples could be taken at the level of fuel pipelines within the concrete trench at the planned sampling points as in the SCAP (i.e. BH2-S4, BH2-S5 and BH2-S7). A total of 1 soil sample at underground fuel pipelines segment with no-concrete-trench (i.e. NCTS2) was collected and testing of CoCs was undertaken. From the testing results, the sample collected at NCTS2 was below the RBRGs standard for industrial. In addition to the site photo record at BH2-S4, BH2-S5 and BH2-S7, it is considered that there are no land contamination issues at the segment BH2 running from BH2-S3 to BH3, and therefore remediation works are not required.
To err on a conservative side, additional site photo records at sides and bottom of BH2-S4, BH2-S5 and BH2-S7 will be submitted to EPD upon demolition works at the 3 specific sampling points to reaffirm the conclusion drawn in Sections 3.1.1.1 and 3.1.1.2 that no diesel leakage from the underground fuel pipes. In case that sign of diesel leakage is spotted during the demolition works, agreement from EPD shall be sought for sampling strategy and subsequent SI shall be arranged in accordance with the agreed sampling plan, and CAR will be submitted to investigate any remediation actions is required. Remediation Action Plan and Remediation Report will also be prepared if remediations is needed.