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Expansion of Hong Kong International Airport into a Three-Runway System |
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Contamination Assessment Report for Terminal 2 Emergency Power Supply Systems No.4 |
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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 with 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.
Based on the latest construction programme, decommissioning/ demolition of the Emergency Power Supply Systems No.4 (hereafter referred as EPSS4) of T2 building is scheduled to commence in 2nd Quarter of 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 EPSS4, to fulfil part of the SCAP’s recommendation as this CAR only covers one concerned system. The updated Implementation Schedule of Land Contamination – Construction Phase is provided 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 a number of Emergency Generator Rooms and Fuel Tank Rooms.
The EPSS4 was located at southern section of T2 Building. The system comprises underground and above-ground section. The locations of the captioned emergency power supply systems are shown in Appendix B. The identified potential land contamination sources are listed in Table 1.1 below,
Table 1.1: Identified Potential Land Contamination Source of Emergency Power Supply System
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Emergency Power Supply System |
Potential Land Contamination Source Reference ID |
Descriptions |
Location |
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Southern Section |
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Please refer to Appendix C |
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Underground Section |
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HS3 |
44 m-in-length underground fuel pipelines connecting the 1,500 L above-ground fuel tank (i.e. BH10) and the emergency generator (i.e. HS2) |
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Above-ground Section |
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BH10 |
A 1,500 L above-ground fuel tank at Fuel Tank Room |
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HS2 |
An emergency generator at Emergency Generator Room, connected to 1,500 L above-ground fuel tank (BH10) |
Layout plans of respective emergency power supply systems included in this CAR are presented in Appendix C.
1.3
Objective
According to the approved SCAP, for the above-ground sections including BH10 and HS2, final inspection and record checking shall be conducted right before decommissioning/ demolition. While for the underground section including HS3, enhanced SI programme shall be conducted along with decommissioning/demolition to confirm no potential land contamination taken place.
For the above-ground sections, decommissioning/ demolition works were scheduled in the 2nd Quarter of 2020. Final site inspections and record checking were conducted for the Emergency Power Supply System. Photo records and findings have been included in this CAR. For underground sections, enhanced SI programme for HS3 was carried out in September 2020.
This CAR has been prepared to present the findings of final inspections and record checking of the above-ground sections (i.e. BH10 and HS2), as well as the sampling procedures and laboratory testing of enhanced SI for the underground sections (HS3) as described in Section 1.2. Testing results have been interpreted based on the Guidance Manual for Use of Risk Based Remediation Goals (RBRGs) for Contaminated Land Management (Guidance Manual) and detailed in Section 4.
2 Summary
of Sampling and Testing Strategy
2.1
Proposed Sampling Method in the SCAP
2.1.1
Proposed Sampling Method of HS3
According to the SCAP, grab sampling was proposed for the concerned underground facilities of T2 Building, including HS3. The proposed sampling and testing plan including the parameters to be tested, sampling locations and sampling depths are presented in Table 2.1. Sand and soil samples should be grabbed manually during the decommissioning/demolition process of concerned underground pipeline trench (i.e. HS3). The whole sampling process should be under the supervision of on-site contamination specialist.
Sampling Selection of Underground Fuel Pipeline (i.e. HS3)
Sand and soil samples should be collected as follows:
· Sand samples should be taken at every curvature of pipeline 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 HS3 extracted from the SCAP are presented in Table 2.2 and Appendix D .
Table 2.1: Enhanced Sampling and Testing Plan for HS3 of Emergency Power Supply System No.4 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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HS34 |
Sand5 |
At the level of fuel pipelines |
HS3-S1 to HS3-S7 |
Lead only |
ü |
BTEX7 and MTBE8 |
PAHs9 |
Confirm no diesel leakage from underground fuel pipelines |
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Soil |
Right underneath concrete/brick trench |
HS3-S1, HS3-S3, HS3-S4 and HS3-S7 |
Lead only |
ü |
BTEX7 and MTBE8 |
PAHs9 |
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 bgs = Below Ground Surface.
7 BTEX = Benzene, Toluene, Ethylbenzene, and Xylenes.
8 MTBE = Methyl Tert-Butyl Ether.
9 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 HS3
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Sampling Locations |
Sampling Point |
Type of Sampling Point (Curvature/ Additional) |
Figure No. |
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HS3
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HS3-S1 |
Curvature |
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HS3-S2 |
Additional |
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HS3-S3 |
Curvature |
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HS3-S4 |
Curvature |
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HS3-S5 |
Additional |
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HS3-S6 |
Additional |
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HS3-S7 |
Curvature |
2.2
Assessment Criteria
The chemicals of concern (COCs) listed in EPD’s Guidance Manual for Use of Risk-Based Remediation Goals 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 were adopted for evaluating the contamination level of T2 building.
3
Site Investigation
3.1
Soil Sampling
3.1.1
Underground Fuel
Pipeline HS3
Site investigation works of HS3 segments was carried out by land contamination specialist on 15 September 2020. Soil samples were collected at sampling points HS3-S1, HS3-S3 and HS3-S7. Deviation with the as-built drawings in underground fuel pipeline layout was observed, there was only one curvature (i.e. HS3-S3) between segment HS3-S1 and HS3-S7, hence sampling point HS3-S4 (as identified in SCAP) is not applicable. The actual sampling points and on-site length measurement of the segments of underground pipeline HS3 are illustrated in Appendix E.
Sampling Point HS3-S1, HS3-S3 and HS3-S7
Based on site observation, it was found that the concrete trench was filled with concrete rather than sand, which previously shown in the as-built drawings, and no sand samples could be collected inside the concrete trench. Therefore, soil samples were collected at the following sampling points at the depth right underneath the concrete trench, where the curvature of the pipelines located,
● HS3-S1 (Same sampling point proposed in SCAP);
● HS3-S3 (Same sampling point proposed in SCAP); and
● HS3-S7 (Same sampling point proposed in SCAP)
No ground water was observed during soil sampling of HS3-S1, HS3-S3 and HS3-S7.
HS3 segment between HS3-S1 and HS3-S3
For the segment between HS3-S1 and HS3-S3, as no sand samples could be collected at sampling point HS3-S2 at the level of fuel pipelines, the condition of the concrete trench was examined on-site and the observations are presented in Appendix E. No cracks on the concrete-trench nor oil stains were found in the vicinity of this sampling point. However, due to the safety concerns of excavation at the time of on-site inspection, site photos at the sides and bottom of HS3-S2 could not be taken on 15 September 2020. With the consideration of the site observations as presented in Appendix E and the laboratory testing results of HS3-S1 and HS3-S3, which are at the same segment and near in location, it is confirmed that no diesel leakage from the underground fuel pipelines laid in concrete trench.
To err on a conservative side, additional site photo records at HS3-S2 will be provided to EPD after the pipeline at HS3-S2 was removed.
HS3 segment between HS3-S3 and HS3-S7
For the segment between HS3-S3 and HS3-S7, as no sand samples could be collected at sampling points HS3-S5 and HS3-S6 at the level of fuel pipelines, the condition of the concrete trench was examined on-site and the observations are presented in Appendix E. No cracks on the concrete-trench nor oil stains were found in the vicinity of these sampling points. However, due to the safety concerns of excavation at the time of on-site inspection, site photos at the sides and bottom of HS3-S5 and HS3-S6 could not be taken on 15 September 2020. With the consideration of the site observations as presented in Appendix E and the laboratory testing results of HS3-S3 and HS3-S7, which are at the same segment and near in location, it is confirmed that no diesel leakage from the underground fuel pipelines laid in concrete trench.
To err on a conservative side, additional site photo records at HS3-S5 and HS3-S6 will be provided to EPD after the pipeline at HS3-S5 and HS3-S6 was removed.
The actual sampling points and on-site length measurement of the particular segment of underground pipeline HS3 are summarized in Table 3.1 and illustrated in Appendix E. All soil samples were analyzed in accordance with the analysis schedules detailed in Table 2.1.
Table 3.1: Summary of Sampling Point of HS3
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Sampling Point |
Type of Sampling Point (Curvature/ Additional) |
Sampling Date |
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HS3
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HS3-S1 |
Curvature |
15 September 2020 |
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HS3-S3 |
Curvature |
15 September 2020 |
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HS3-S7 |
Curvature |
15 September 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 HS3-S2, HS3-S5 and HS3-S6 will be submitted to EPD upon the demolition work at these locations to reaffirm the conclusion drawn in Section 3.1.1 that there was no diesel leakage from the underground fuel pipe.
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. A CAR should be submitted to EPD and if remediation is required, a 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. Collected samples were then 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 F.
3.3.2
QA/QC Analysis
In this enhanced SI programme, QA/QC samples were collected in accordance with 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’ –
· Heavy Metals: Lead only.
· PCRs: C6-C8; C9-C16; C17-C35.
· VOCs: Benzene, Toluene, Ethylbenzene, Xylenes and Methyl Tert-Butyl Ether.
· 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 were 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 15 September 2020 during the sampling for HS3.
The laboratory results for QA/QC samples are presented in Appendix G.
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 HS3
A total of 3 soil samples were collected at HS3 for laboratory testing. The testing results are summarised in Table 4.1 and the testing reports are presented in Appendix G. The testing results of all parameters indicated that all soil samples from HS3 were below the value of RBRGs for Industrial.
Table 4.1: Laboratory Testing Results of Soil Samples at HS3
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Compound |
Concentration (mg/kg) |
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HS3-S1 |
HS3-S3 |
HS3-S7 |
RBRGs for Industrial |
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Heavy Metals |
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Lead |
59 |
57 |
50 |
2290 |
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PCRs |
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C6 - C8 |
<5 |
<5 |
<5 |
C6 - C8: 10,000 C9 - C16: 10,000 C17 - C35: 10,000 |
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C9 - C16 |
<200 |
<200 |
<200 |
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C17 - C35 |
<500 |
<500 |
<500 |
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VOCs |
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Benzene |
<0.2 |
<0.2 |
<0.2 |
9.21 |
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Toluene |
<0.5 |
<0.5 |
<0.5 |
10,000 |
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Ethylbenzene |
<0.5 |
<0.5 |
<0.5 |
8,240 |
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Xylenes (Total) |
<2.0 |
<2.0 |
<2.0 |
1,230 |
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Methyl tert-Butyl Ether |
<0.2 |
<0.2 |
<0.2 |
70.1 |
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SVOCs |
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Naphthalene |
<0.500 |
<0.500 |
<0.500 |
453 |
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Acenaphthylene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
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Acenaphthene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
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Fluorene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
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Phenanthrene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
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Anthracene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
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Fluoranthene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
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Pyrene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
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Benz(a)anthracene |
<0.500 |
<0.500 |
<0.500 |
91.8 |
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Chrysene |
<0.500 |
<0.500 |
<0.500 |
1140 |
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Benzo(b)fluoranthene |
<0.500 |
<0.500 |
<0.500 |
17.8 |
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Benzo(k)fluoranthene |
<0.500 |
<0.500 |
<0.500 |
918 |
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Benzo(a)pyrene |
<0.500 |
<0.500 |
<0.500 |
9.18 |
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Indeno(1.2.3.cd)pyrene |
<0.500 |
<0.500 |
<0.500 |
91.8 |
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Dibenz(a.h)anthracene |
<0.500 |
<0.500 |
<0.500 |
9.18 |
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Benzo(g.h.i)perylene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
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5
Final Inspection and Record Checking
Findings
5.1
General
According to Section 3.2.5 of the SCAP, it is recommended that final inspection and record checking should be conducted right before decommissioning/ demolition of the concerned above-ground fuel tank and the above-ground emergency generator for respective Emergency Power Supply System to ensure no contaminative activities during the period from the time of preparation of SCAP till the decommissioning. Summary of final inspection and record checking are given in ensuing paragraphs. Photo records of final inspections are presented in Appendix H.
5.1.1
Final Inspection and Record Checking Findings
5.1.1.1
Emergency Power
Supply System No.4
Final Inspection
The above-ground fuel tank (i.e. BH10) and emergency generator (i.e. HS2) of EPSS4 were disconnected in late-May 2020, and the fuel inside the system was removed in mid-June. Final inspection of the BH10 and HS2 was conducted on 18 June 2020. During our final inspection, BH10 and HS2 were at the same locations as for the time of preparation of SCAP in 2018. Both facilities were mounted on intact concrete floor with no oil stain observed, and no oil stain was observed inside the drip tray of the above-ground fuel tank (BH10). In addition, curb by builder was provided in the fuel tank room. Photo records of final inspections are presented in Appendix H.
Record Checking
Available monthly maintenance records of the BH10 and HS2 from the time of SCAP preparation (i.e. March 2018) to February 2020 (month of last maintenance) were checked. No abnormality on fuel re-filling record was observed and no fuel tank leakage was recorded. It is concluded that there was no fuel leakage for the above-ground facilities BH10 and HS2 from the time of SCAP preparation till decommissioning/ demolition.
6
Conclusion
Enhanced SI programme have been conducted for the underground sections, HS3, in September 2020. During the enhanced SI programme, a total of 3 soil samples were collected and testing of CoCs was undertaken. The testing results indicated that all the samples at HS3 were below the RBRGs standard for industrial. Based on the sample testing results, it is considered that there are no land contamination issues at the HS3, including the segment running from HS3-S1 to HS3-S3 and from HS3-S3 to HS3-37, as per the site photo record taken at HS3-S2, HS3-S5 and HS3-S6. To sum up, it is considered that there are no land contamination issues at HS3, therefore remediation works are not required.
To err on a conservative side, additional site photo records at the sides and bottom of HS3-S2, HS3-S5 and HS3-S6 will be submitted to EPD upon the demolition at these three specific sampling points to reaffirm the conclusion drawn in Section 3.1.1 that there was 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. A CAR should be submitted for the subsequent SI work and if remediation is required, a Remediation Action Plan and Remediation Report will also be prepared for submission to EPD.
Final inspection and record checking were conducted right before decommissioning/ demolition of the above-ground section of EPSS4 (i.e. BH10 and HS2). According to the inspection and record checking results, it is concluded that there was no contaminative activities during the period from the preparation of SCAP till decommissioning/demolition of the above-ground facilities.