|
Expansion of Hong Kong International Airport into a Three-Runway System |
|
Contamination Assessment Report for |
%20v4_files/image005.gif)
%20v4_files/image004.gif)
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.
In addition, further review of
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 have been scheduled
in 2019. 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) to partially fulfil the SCAP’s recommendation.
CAR(s) for the other 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
|
Potential Land Contamination Source Reference ID |
Descriptions |
Location |
||
|
Underground Section |
|
Please refer to Appendix C |
||
|
BH1 |
A 2,500 L underground fuel tank |
|||
|
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) |
|||
|
Above-ground Section |
|
|||
|
BH4 |
An emergency generator at Emergency Generator Room, connected to 450 L above-ground fuel tank (i.e. BH3) |
|||
|
BH3 |
A 450 L above-ground fuel tank at Emergency Generator Room |
|||
To
match with the construction programme, scope of the CAR for Terminal 2
Emergency Power Supply System No.1 (Volume 1) is as follows,
● BH1
● Partial portion of BH2, which
includes:
–
Segment running from BH1 to sampling point BH2-S3, i.e. BH2-S1, BH2 S2,
BH2-S3; and
–
BH2-S6;
● BH3
● BH4
Soil
sampling for BH1, BH2-S1, BH2-S2, BH2-S3 and BH2-S6 were planned in accordance
with the approved SCAP, therefore, the laboratory testing results of BH2-S6 as
well as the duplicate, equipment blank and field blank conducted in the event
of BH2-S6 sampling are presented in this CAR as QA/QC. Construction works will
only be conducted at (i) areas around BH1 and BH2-S3 and (ii) above-ground
structures at BH3 and BH4 (see delineated areas by orange dotted-line for BH1,
BH3 and BH4 in Appendix
F). No works will be conducted in other areas within the Emergency
Power Supply System No. 1 prior to the agreement of Vol. 2 of the CAR for T2
EPPS1, or Remediation Report for T2 EPPS1 (if remediation is required). No
works will be conducted for BH2-S6 at current stage and the works for BH2-S6
will be conducted together with the system portion to be included in Vol. 2 of
the CAR for T2 EPPS1.
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. As per the approved SCAP, for
the above-ground section (i.e. BH3 and BH4), final inspection and record
checking shall be conducted right before decommissioning/
demolition. While for the underground section (i.e. BH1 and BH2), enhanced SI
programme shall be conducted along with decommissioning/demolition to confirm no potential land contamination taken place.
For the
above-ground section (i.e. BH3 and BH4), demolition works have been
scheduled in early April 2019. Final site inspection and record checking have
been conducted on 19 March 2019. Photo records and findings have been included
in this CAR. For underground section, enhanced SI programmes for BH1, segment
of BH2 running from BH1 to sampling point BH2-S3, and the segment at BH2-S6
were carried out on 4 October 2019, 4 and 14 November 2019 respectively.
This Contamination Assessment
Report for Terminal 2 Emergency Power Supply System No.1 (Volume 1) has been
prepared to present the findings of final inspection and record checking of the
above-ground section (i.e. BH3 and BH4), as well as the procedures and
laboratory testing of enhanced SI for the underground section (including BH1,
segment of BH2 running from BH1 to sampling point BH2-S3, and the segment at
BH2-S6) 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 BH1 and BH2
Grab sampling was proposed for
the concerned underground facilities of T2 Building, including BH1 and BH2. 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 and soil samples shall be grabbed manually during
decommissioning/demolition process of concerned fuel tanks (i.e. BH1)
and underground pipeline trench (i.e. BH2). The whole sampling process shall be
under the supervision of on-site contamination specialist.
Sampling Selection of
Underground Fuel Tank (i.e. BH1)
Sand and soil samples should be
collected as follows:
·
Sand samples should be collected at 0.5 m, 1.5 m and bottom level inside
the concrete chamber of underground fuel tank;
·
Soil sample should be collected right underneath concrete chamber of
underground fuel tank.
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 BH1 and BH2 extracted from the SCAP are
presented in Table 2.2 and Appendix D.
Table 2.1:
Enhanced Sampling and Testing Plan for BH1 and BH2 of Emergency Power Supply
System No.1 in T2 Building
|
Proposed Sampling Locations |
Sample Matrix |
Sampling Point Annotation |
Parameters to be Tested1 & 2 |
Rationale of Sampling |
||||
|
Heavy Metals |
PCRs3 |
VOCs3 |
SVOCs3 |
|||||
|
BH14 |
Sand5 |
0.5 m, 1.5 m bgs6and bottom level inside the concrete chamber |
/ |
Lead only |
ü |
BTEX7 and MTBE8 |
PAHs9 |
Confirm no diesel leakage from underground fuel tank |
|
|
Soil |
Right underneath concrete chamber |
/ |
Lead only |
ü |
BTEX7 and MTBE8 |
PAHs9 |
Confirm no leaked diesel (if any) penetrate the concrete chamber |
|
BH24 |
Sand5 |
At the level of fuel pipelines |
BH2S1 - BH2S7 |
Lead only |
ü |
BTEX7 and MTBE8 |
PAHs9 |
Confirm no diesel leakage from underground fuel pipelines |
|
|
Soil |
Right underneath concrete/brick trench |
BH2S1, BH2S2, BH2S3, BH2S6 |
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 BH2
|
Proposed Sampling Locations |
Annotation of Sampling Point |
Type of Sampling Point (Curvature / Additional) |
Figure No. |
|
BH2 |
BH2-S1 |
Curvature |
|
|
BH2-S2 |
Curvature |
||
|
BH2-S3 |
Curvature |
||
|
BH2-S41 |
Additional |
||
|
BH2-S51 |
Additional |
||
|
BH2-S6 |
Curvature |
||
|
BH2-S71 |
Additional |
Remarks:
1 Not under
the scope of this CAR. BH2-S4, BH2-S5 and BH2-S7 will be presented in Vol. 2 of
the CAR for T2 EPPS1.
2.2
Alternative Sampling Method Formulated after Pre-demolition
Survey
2.2.1
Alternative Sampling Method of BH1
Pre-demolition survey have been
undertaken by the Contractor, AAHK and the land contamination specialist in
early October 2019. Based on the site condition, it is observed that the
concrete chamber structure was deviated from the as-built drawing, the revealed
as illustrated in Appendix
E. The fuel tank is still fully encased in a at least 300 mm thick
concrete chamber, however, the top slab of the chamber located at around 2.4 m
below ground level (bgl) rather than at the level right beneath the surface
ground level. In such case, borehole sampling for BH1 is proposed by the
Contractor, instead of grab sampling as proposed in SCAP. Agreement on the
proposed alternative sampling method of BH1 has been sought between the
Contractor, AAHK and the land contamination specialist.
Borehole has been undertaken by
means of rotary drilling method, as agreed with the on-site contamination
specialist. To inspect for any underground utilities at the proposed borehole
location, an inspection pit has been excavated down to 2.0 m below ground
surface (bgs).
Details of sampling depths please
refer to Section 3.1.1.
2.3
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
Sand/Soil Sampling
3.1.1
Underground Fuel Tank BH1
Site
investigation works of BH1 was carried out by DrilTech Ground Engineering
Limited on 4 October 2019. As per on-site measurement, the revealed inner depth
of the concrete chamber (i.e. depth from the bottom side of top concrete slab
to upper side of the bottom concrete slab) is around 1.73 m.
Since
there is a reduction of inner depth of concrete chamber (i.e. from ~3.9m as
shown in the as-built drawing, to the on-site revealed depth 1.73m), as decided
by the on-site contamination specialist, it is considered that 2 undisturbed
sand samples collected at 0.7m and 1.6m below the top concrete slab of the
concrete chamber is adequate and representative to confirm no land
contamination issue at the underground fuel tank. Also, 1 undisturbed soil sample was collected at 0.5m right
underneath the bottom of the concrete chamber. The entire SI programme was
supervised by the on-site land contamination specialist. The actual sampling
depths are summarized in Table 3.1 and illustrated in Appendix E. All
soil/sand samples were analyzed in accordance with the testing schedules
detailed in Table 2.1.
Table 3.1:
Summary of Sampling Depth of BH1
|
Sampling Locations |
Sampling Depth |
Sampling Date |
|
BH1 |
0.7m below the top concrete slab of the concrete chamber |
4 October 2019 |
|
|
1.6m below the top concrete slab of the concrete chamber |
4 October 2019 |
|
|
0.5m below the bottom slab of the concrete chamber |
4 October 2019 |
3.1.2
Underground Fuel
Pipeline BH2
Soil
sampling of BH2 segment between BH1 and sampling point BH2-S3 was carried out
by Mott MacDonald HK Limited on 4 November 2019. Soil sampling at sampling
point BH2-S6 was carried out by Mott MacDonald HK Limited on 14 November 2019.
BH2
segment between BH1 and sampling point BH2-S3
Soil
sample was collected at sampling points BH2-S1, BH2-S2 and BH2-S3. According to
site observation, the segment of underground pipeline located between BH1 and
BH2-S1 are not laid inside the concrete trench, while the underground pipeline
running from BH2-S1 to BH2-S3 is laid inside the concrete trench.
To
confirm no diesel leakage from underground fuel pipelines from the
no-concrete-trench segment, 1 soil sample have been taken right underneath the
particular segment (i.e. NCTS1). 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 NCTS1, and with reference to the
laboratory testing result of soil sample taken at 0.5m below the bottom
slab of the concrete chamber at BH1 (refer to Section 4.1.1) which is near to
the location of NCTS1, therefore, 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 <2m
(as revealed on-site) no-concrete-trench segment.
While opening up the concrete
trench from BH2-S1 to BH2-S3, it is observed that the concrete trench is filled
with concrete rather than sand, which previously shown in the as-built
drawings. Based on site situation, no sand samples could be taken at the level
of fuel pipelines within the concrete trench.
No ground water was observed
during soil sampling of NCTS1, BH2-S1, BH2-S2 and BH2-S3.
Sampling Point BH2-S6
Soil
sample was collected at sampling point BH2-S6. With reference to on-site
observation, it is observed that the concrete trench is filled with concrete
rather than sand, which previously shown in the as-built drawings. Based on
site situation, no sand samples could be taken at the level of fuel pipelines
within the concrete trench.
No ground water was observed
during soil sampling of BH2-S6.
The
actual sampling points and on-site length measurement of the particular segment
of underground pipeline BH2 are summarized in Table
3.2 and illustrated in Appendix F. All
soil samples were analyzed in accordance with the analysis schedules detailed
in Table 2.1.
Table 3.2: Summary of Sampling Point of BH2
|
Sampling Locations |
Sampling Point |
Type of Sampling Point (Curvature/ Additional/ No-concrete-trench Segment) |
Sampling Date |
|
|
BH2
|
NCTS1 |
No-concrete-trench Segment |
4 November 2019 |
|
|
BH2-S1 |
Curvature |
4 November 2019 |
||
|
BH2-S2 |
Curvature |
4 November 2019 |
||
|
BH2-S3 |
Curvature |
4 November 2019 |
||
|
BH2-S6 |
Curvature |
14 November 2019 |
3.2
Decontamination
Procedures
Before drilling/ excavation/
sampling, all equipment in contact with the ground were thoroughly
decontaminated between each excavation, drilling 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 have been collected on 14 Nov 2019 during the sampling
for BH2-S6.
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
Sand/Soil Contamination
4.1.1
Underground Fuel Tank BH1
A total of 2 sand and 1
soil samples were collected at BH1 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 all sand/ soil
samples from BH1 were below the value of Risk-Based Remediation Goals (RBRGs)
for Industrial.
Table 4.1:
Laboratory Testing Results of Sand/ Soil Samples at BH1
|
Chemical |
Concentration (mg/kg) |
|||
|
BH1 (0.7 m below the top concrete slab of the concrete chamber) |
BH1 (1.6 m below the top concrete slab of the concrete chamber) |
BH1 (0.5m below the bottom concrete slab of the concrete chamber) |
RBRGs for Industrial |
|
|
Heavy Metals |
|
|
|
|
|
Lead |
9 |
8 |
38 |
2290 |
|
PCRs |
|
|
|
|
|
C6 - C8 |
<5 |
<5 |
<5 |
C6 - C8: 10,000 C9 - C16: 10,000 C17 - C35: 10,000 |
|
C9 - C16 |
<200 |
<200 |
<200 |
|
|
C17 - C35 |
<500 |
<500 |
<500 |
|
|
VOCs |
|
|
|
|
|
Benzene |
<0.2 |
<0.2 |
<0.2 |
9.21 |
|
Toluene |
<0.5 |
<0.5 |
<0.5 |
10,000 |
|
Ethylbenzene |
<0.5 |
<0.5 |
<0.5 |
8,240 |
|
Xylenes (Total) |
<2.0 |
<2.0 |
<2.0 |
1,230 |
|
Methyl tert-Butyl Ether |
<0.2 |
<0.2 |
<0.2 |
70.1 |
|
SVOCs |
|
|
|
|
|
Naphthalene |
<0.500 |
<0.500 |
<0.500 |
453 |
|
Acenaphthylene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
Acenaphthene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
Fluorene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
Phenanthrene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
Anthracene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
Fluoranthene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
Pyrene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
Benz(a)anthracene |
<0.500 |
<0.500 |
<0.500 |
91.8 |
|
Chrysene |
<0.500 |
<0.500 |
<0.500 |
1140 |
|
Benzo(b)fluoranthene |
<0.500 |
<0.500 |
<0.500 |
17.8 |
|
Benzo(k)fluoranthene |
<0.500 |
<0.500 |
<0.500 |
918 |
|
Benzo(a)pyrene |
<0.500 |
<0.500 |
<0.500 |
9.18 |
|
Indeno(1.2.3.cd)pyrene |
<0.500 |
<0.500 |
<0.500 |
91.8 |
|
Dibenz(a.h)anthracene |
<0.500 |
<0.500 |
<0.500 |
9.18 |
|
Benzo(g.h.i)perylene |
<0.500 |
<0.500 |
<0.500 |
10,000 |
4.1.2
Underground Fuel Pipeline BH2
A total of 5 soil samples were
collected within the scope of this CAR at BH2
for laboratory testing. The testing results are summarised in Table
4.2 and the testing reports are presented in Appendix H. The testing
results of all parameters indicated that all soil samples from BH2 were below
the value of Risk-Based Remediation Goals (RBRGs) for Industrial.
Table 4.2:
Laboratory Testing Results of Soil Samples at BH2
|
Compound |
|
Concentration (mg/kg) |
|||||
|
|
NCTS1 |
BH2-S1 |
BH2-S2 |
BH2-S3 |
BH2-S6 |
RBRGs for Industrial |
|
|
Heavy Metals |
|
|
|
|
|
|
|
|
Lead |
9 |
52 |
80 |
48 |
41 |
2290 |
|
|
PCRs |
|
|
|
|
|
|
|
|
C6 - C8 |
<5 |
<5 |
<5 |
<5 |
<5 |
C6 - C8: 10,000 C9 - C16: 10,000 C17 - C35: 10,000 |
|
|
C9 - C16 |
<200 |
<200 |
<200 |
<200 |
<200 |
||
|
C17 - C35 |
<500 |
<500 |
<500 |
<500 |
<500 |
||
|
VOCs |
|
|
|
|
|
|
|
|
Benzene |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
9.21 |
|
|
Toluene |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
10,000 |
|
|
Ethylbenzene |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
8,240 |
|
|
Xylenes (Total) |
<2.0 |
<2.0 |
<2.0 |
<2.0 |
<2.0 |
1,230 |
|
|
Methyl tert-Butyl Ether |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
70.1 |
|
|
SVOCs |
|
|
|
|
|
|
|
|
Naphthalene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
453 |
|
|
Acenaphthylene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
|
Acenaphthene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
|
Fluorene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
|
Phenanthrene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
|
Anthracene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
|
Fluoranthene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
|
Pyrene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
|
Benz(a)anthracene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
91.8 |
|
|
Chrysene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
1140 |
|
|
Benzo(b)fluoranthene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
17.8 |
|
|
Benzo(k)fluoranthene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
918 |
|
|
Benzo(a)pyrene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
9.18 |
|
|
Indeno(1.2.3.cd)pyrene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
91.8 |
|
|
Dibenz(a.h)anthracene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
9.18 |
|
|
Benzo(g.h.i)perylene |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
<0.500 |
10,000 |
|
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 450 L above-ground fuel tank equipped with drip tray (i.e.
BH 3) and the above-ground emergency generator (i.e. BH 4) to ensure no
contaminative activities during the period from the time of preparation of SCAP
till the decommissioning.
BH3 and BH4 have been decommissioned/ demolished in early April 2019. Summary
of final inspection and record checking are given in ensuing paragraphs.
5.1.1
Final Inspection Findings
Final inspection of the BH3 and
BH4 was conducted on 19 March 2019. The demolition of Emergency
Generator Room building structure was commenced in early April 2019
which leading to unsafe condition for further inspection of the facilities.
During our final inspection, BH 3 and BH 4 are at the same locations as for the time of
preparation of SCAP in 2018. Both facilities are
mounted on intact concrete floor with no oil stain. The above-ground fuel tank
was surrounded by concrete curb and no oil stain was observed on its drip tray.
The
fuel pipelines running through BH3 and BH4 are buried by sand inside a concrete
and brick trench at floor level. 2 sections of the pipelines were checked by
removing the chequer plate cover and no sign of leakage was observed.
Photo
record of final inspection is presented in Appendix I.
5.1.2
Record Checking Findings
Available monthly maintenance
records of BH3 and BH4 from the time of SCAP preparation (i.e. March 2018) to
23 February 2019 (date of last maintenance) has been checked in March 2019. No abnormality on fuel re-filling record have been observed
and no fuel tank leakage was recorded, it is considered that no fuel leakage
for the above-ground facilities BH3 and BH4 from the time of SCAP preparation
till decommissioning/ demolition.
6
Conclusion
Enhanced SI programme have been
conducted for the underground section, BH1, segment
of BH2 running from BH1 to sampling point BH2-S3, and segment at BH2-S6, in October and November 2019 respectively. During
the enhanced SI programme, a total of 2 sands and 6 soil samples were collected
at BH1, the segment of BH2 running from BH1 to
sampling point BH2-S3, and sampling point BH2-S6 and testing of CoCs was
undertaken. From the testing results, it is concluded that all the samples at
BH1 and the segment of BH2 were below the
RBRGs standard for industrial. It is considered that there are no land contamination
issues at BH1, the segment of BH2 running from
BH1 to sampling point BH2-S3, and segment at BH2-S6, and therefore remediation
works are not required.
Final inspection and record
checking have been conducted right before decommissioning/ demolition of the
above-ground section of EPSS1 (i.e. BH3 and BH4). According to the inspection
and record checking results, it is considered that no contaminative activities
during the period from the preparation of SCAP till decommissioning/demolition
of the above-ground facilities.
Construction
works will only be conducted at (i) areas around BH1 and BH2-S3 and (ii)
above-ground structures at BH3 and BH4 (see delineated areas by orange
dotted-line for BH1, BH3 and BH4 in Appendix F).
No works will be conducted in other areas within the Emergency Power Supply
System No. 1 prior to the agreement of Vol. 2 of the CAR for T2 EPPS1, or
Remediation Report for T2 EPPS1 (if remediation is required). No works will be
conducted for BH2-S6 at current stage and the works for BH2-S6 will be
conducted together with the system portion to be included in Vol. 2 of the CAR
for T2 EPPS1.