|
Agreement No. CE59/2020(EP) Environmental Monitoring and Audit for Disposal Facility to the East of Sha Chau (2021-2026) – Investigation |
|
Monthly EM&A Report for Contaminated Mud Pits to the East of Sha Chau – June 2021 |
|
July 2021 |
|
|
|
Civil Engineering and Development Department |
|
|
|
Mott MacDonald 3/F International Trade Tower 348 Kwun Tong Road Kwun Tong Kowloon Hong Kong T +852 2828 5757 F mottmac.hk |
|
|
|
|
Environmental
Certification Sheet
(Certification by Environmental Team Leader &Verification by
Independent Auditor)
Issue
and Revision Record
|
Revision |
Date |
Originator |
Checker |
Approver |
Description |
|
A |
July 2021 |
Various |
Thomas Chan |
Eric Ching |
Revision A of Submission |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Document reference: |
423134 | 06/05/03 | A |
|
Information class: |
Standard |
|
This document is issued for the party which commissioned it and for specific purposes connected with the above-captioned project only. It should not be relied upon by any other party or used for any other purpose. We accept no responsibility for the consequences of this document being relied upon by any other party, or being used for any other purpose, or containing any error or omission which is due to an error or omission in data supplied to us by other parties. This document contains confidential information and proprietary intellectual property. It should not be shown to other parties without consent from us and from the party which commissioned it. |
Contents
1.3 Details of Sampling and Laboratory
Testing Activities
2 Brief Discussion of Monitoring
Results for ESC CMP V
2.2 Water Column Profiling of ESC CMP
Vb – in June 2021
2.2.2 Laboratory Measurements for
Suspended Solids (SS)
2.3 Routine Water Quality Monitoring of
ESC CMPs – in June 2021
2.4 Pit Specific Sediment Chemistry of
ESC CMP Vb – in June 2021
2.5 Cumulative Impact Sediment
Chemistry of ESC CMPs – in June 2021
3.1 Activities Scheduled for the Next
Reporting Period
Figure 2.1 Routine & Capping Water Quality
Sampling Stations (Ebb-Tide) for ESC CMPs
Figure 2.2 Pit Specific Sediment Quality
Monitoring Stations for CMP V
Figure 2.3 Cumulative Impacts Sediment Quality
Monitoring Stations for ESC CMPs
Appendices
B. Water Quality
Monitoring Results
The Civil Engineering and Development
Department (CEDD) is managing a number of marine disposal facilities in Hong
Kong waters, including the Contaminated Mud Pits (CMPs) to the East of Sha Chau
(ESC) for the disposal of contaminated sediment, and various open-sea disposal
grounds located to the South of Cheung Chau (SCC), East of Tung Lung Chau
(ETLC) and East of Ninepins (ENP) for the disposal of uncontaminated sediment.
Environmental Permits (EPs) (Ref. No. EP-312/2008/A)
was issued by the Environmental Protection Department (EPD) to the CEDD, the
Permit Holder, on 28 November 2008 for the Project - Disposal of Contaminated
Sediment – Dredging, Management and Capping of Sediment Disposal Facility at
Sha Chau.
Under the requirements of the EP, EM&A
programmes which encompass water and sediment chemistry, fisheries assessment,
tissue and whole body analysis, sediment toxicity and benthic recolonisation
studies as set out in the EM&A Manuals are required to be implemented.
EM&A programmes have been continuously carried out during the operation of
the CMPs at ESC. A review of the collection and analysis of such environmental
data from the monitoring programme demonstrated that there had not been any
adverse environmental impacts resulting from disposal activities.[1],[2] The current
programme will assess the impacts resulting from dredging, disposal and capping
operations of CMP V.
A proposal on the change of number of sample
replication of water quality and sediment monitoring as well as combination of
routine water quality monitoring and water quality monitoring during capping
operation was submitted to EPD and agreed by EPD on 3 December 2020. The
proposed changes have been effective for the EM&A activities since December
2020. The latest sampling schedule is provided in Appendix A.
The present EM&A programme under Agreement
No. CE 59/2020 (EP) covers the dredging, disposal and capping operations of the
ESC CMP V (see Appendix A for the EM&A
programme.) Detailed works schedule for ESC CMP V is shown in Table 1.1. In June 2021, the following works
were undertaken:
●
Disposal
of contaminated mud at ESC CMP Vb; and
●
Capping
operations at ESC CMP Vd.
Table 1.1: Works Schedule for ESC CMP V
This Monthly EM&A Report for
Contaminated Mud Pits to the East of Sha Chau – June 2021 covers the
EM&A activities for the reporting period of June 2021 (from 1 to 30 June
2021).
The following monitoring activities were
undertaken for ESC CMP V during the reporting period:
●
Water
Column Profiling of ESC CMP Vb;
●
Routine
Water Quality Monitoring of ESC CMPs;
●
Pit
Specific Sediment Chemistry of ESC CMP Vb; and
●
Cumulative
Impact Sediment Chemistry of ESC CMPs.
This section presents a brief discussion of the
results obtained from the following monitoring activities for ESC CMP V during
the reporting period:
·
Water
Column Profiling of ESC CMP Vb;
·
Routine
Water Quality Monitoring of ESC CMPs;
·
Pit
Specific Sediment Chemistry of ESC CMP Vb; and
·
Cumulative
Impact Sediment Chemistry of ESC CMPs.
Water Column Profiling was undertaken at a
total of two sampling stations (Upstream and Downstream stations) on 10 June
2021. The monitoring results have been assessed for compliance with the Water
Quality Objectives (WQOs) set by Environmental Protection Department (EPD).
This consists of a review of the EPD routine water quality monitoring data for
the wet season period (April to October) of 2010 – 2019 from stations in the
North Western Water Control Zone (WCZ), where the ESC CMPs are located.[3] For Salinity, the averaged
value obtained from the Reference (Upstream) station was used for the basis as
the WQO. Levels of Dissolved Oxygen (DO) and Turbidity were also assessed for
compliance with the Action and Limit Levels (see Table B1 of Appendix B for details).
Analyses of results for June 2021 indicated
that levels of Salinity, pH and DO complied with the WQOs at both Downstream
and Upstream stations (Table B2 of Appendix B). Levels of DO and
Turbidity at all stations complied with the Action and Limit Levels (Tables
B1 and B2 of Appendix B).
Analyses of results for June 2021 indicated
that the SS level at the Downstream station was higher than the WQO while the
SS level at the Upstream station complied with the WQO, but levels complied
with the Action and Limit Levels (Tables B1 and B2 of Appendix B).
Overall, the monitoring results indicated that
the mud disposal operation at ESC CMP Vb did not
appear to cause any deterioration in water quality during this reporting
period.
Routine Water Quality Monitoring of ESC CMPs
was undertaken on 8 June 2021. The monitoring results have been assessed for
compliance with the WQOs (see Section 2.2 above for details). The monitoring
results are shown in Tables B3 and B4 of Appendix B and Figures 1 to
10 of Appendix
C. A total of sixteen (16) monitoring stations were sampled in June
2021 as shown in Figure 2.1.
Graphical presentation of the monitoring
results (Temperature, DO, pH, Salinity and Turbidity) is shown in Figures 1
to 6 of Appendix
C. Analyses of results indicated that the levels of pH, Salinity and DO
complied with the WQOs at most stations during the reporting period, except for
higher levels of Salinity were recorded at Ma Wan station. The higher
Salinities recorded at Ma Wan station are likely to be caused by the larger
separation distance to Pearl River Delta mouth, which releases a large amount
of freshwater runoff in the area during wet season, when compared to the
Reference stations.
The levels of DO and Turbidity complied with
the Action and Limit Levels at all stations (Table B3 of Appendix B; Figures 3 and 6
of Appendix
C).
Overall, in-situ measurement results of the
Routine Water Quality Monitoring indicated that the disposal and capping
operation at ESC CMPs did not appear to cause any unacceptable impacts in water
quality in June 2021.
Laboratory analysis of samples obtained during
the reporting period indicated that the concentrations of Arsenic, Chromium,
Copper, Lead, Nickel and Zinc were detected in the samples at most stations and
their concentrations of most metals and metalloids were generally similar
across stations, except some concentrations recorded at Impact (IPF) station
which were comparatively lower than at other stations (Table B4 of Appendix B; Figure 7 of
Appendix
C).
For nutrients, concentrations of Total
Inorganic Nitrogen (TIN) at the Reference (RFF), Impact (IPF) and Intermediate
(INF) stations were higher than the WQO (0.5 mg/L) (Table B4 of Appendix B; Figure 8 of
Appendix
C). It should be noted that due to the effect of the Pearl River, the
North Western WCZ has historically experienced higher levels of TIN.[4] Therefore, the exceedances
of TIN WQO at these stations are unlikely to be caused by the disposal
operation at ESC CMPs. The concentrations of Ammonia Nitrogen (NH3-N)
and Biochemical Oxygen Demand (BOD5) were slightly higher at Ma Wan station
in the reporting month (Table B4 of Appendix B; Figure 8 and 9
of Appendix
C).
Analyses of results for the reporting period
indicated that most of the SS levels at all stations complied with the wet
season WQO (11.8 mg/L) and the Action and Limit Levels, except the SS level at
Impact (IPF) station (Tables B1 and B4 of Appendix B; Figure 10
of Appendix
C).
Overall, results of the Routine Water Quality
Monitoring indicated that the disposal and capping operation at ESC CMPs did
not appear to cause any unacceptable deterioration in water quality during the
reporting period. Detailed statistical analysis will be presented in the
Quarterly EM&A Report to investigate any spatial and temporal trends of
potential concern.
Monitoring locations for Pit Specific Sediment
Chemistry for ESC CMP Vb are shown in Figure 2.2. A total of six (6)
monitoring stations were sampled on 1 June 2021.
The concentrations of all inorganic
contaminants were lower than the Lower Chemical Exceedance Levels (LCELs) at
all stations (Figures 11 and 12 of Appendix
C).
For organic contaminants, the concentrations of
Total Organic Carbon (TOC) were higher at Pit-Edge stations ESC-NECA and
ESC-NECB and Active-Pit stations ESC-NPCA and ESC-NPCB during the reporting
period (Figure 13 of Appendix
C). The concentrations of Low Molecular Weight and High Molecular
Weight Polycyclic Aromatic Hydrocarbons (PAHs) were lower than the LECLs at all
stations (Figure 14 of Appendix
C). The concentrations of Tributyltin (TBT) were higher at Near-Pit
station ESC-NNCA and Active-Pit station ESC-NPCB (Figure 15 of Appendix
C). The concentrations of Total Polychlorinated Biphenyls (PCBs), Total
dichloro-diphenyl-trichloroethane (DDT) and 4,4’-dichlorodiphenyldichloroethylene
(DDE) were below the limit of reporting at all stations during the reporting
period.
Overall, there is no evidence indicating any
unacceptable environmental impacts to sediment quality outside the pit area as
a result of the contaminated mud disposal operations at ESC CMP Vb during the reporting period.
Statistical analysis will be undertaken and
presented in the corresponding Quarterly EM&A Report to investigate whether
there are any unacceptable impacts in the area caused by the contaminated mud
disposal.
Monitoring locations for Cumulative Impact
Sediment Chemistry for ESC CMPs are shown in Figure 2.3. A total of nine
(9) monitoring stations were sampled on 3 June 2021.
Analyses of results for the Cumulative Impact Sediment
Chemistry Monitoring indicated that the concentrations of all inorganic
contaminants were below the LCEL at all stations during the reporting period (Figures
16 and 17 of Appendix
C).
For organic contaminants, the concentrations of
TOC varied between stations during the reporting period, with generally higher
concentrations of TOC recorded at Mid-field stations ESC-RMA and ESC-RMB, Capped
station ESC-RCA1 and Ma Wan station (Figure 18 of Appendix
C). The concentrations of Low and High Molecular Weight PAHs were below
the LCEL at all stations (Figure 19 of Appendix
C). The concentrations of TBT were below the limit of reporting at all
stations, except at Ma Wan station where higher concentrations were recorded (Figure
20 of Appendix
C). The concentrations of Total PCBs, Total DDT, 4,4’-DDE and Low
Molecular Weight PAHs were below the limit of reporting at all stations during
the reporting period.
Overall, there is no evidence indicating any
unacceptable environmental impacts to sediment quality as a result of the
contaminated mud disposal operations at ESC CMP Vb
during the reporting period. Statistical analysis will be undertaken and
presented in the corresponding Quarterly EM&A Report to investigate whether
there are any unacceptable impacts in the area caused by the contaminated mud
disposal.
The
following monitoring activities will be conducted in the next reporting period of July 2021 for ESC CMP V
(see Appendix
A for the sampling schedule):
·
Water
Column Profiling of ESC CMP Vb;
·
Routine
Water Quality Monitoring of ESC CMPs;
·
Pit
Specific Sediment Chemistry of ESC CMP Vb; and
·
Demersal
Trawling for ESC CMPs.
A summary
of the Study Programme is presented in Appendix
D.
[1] ERM (2013) Final Report. Submitted
under Agreement No. CE 4/2009 (EP) Environmental Monitoring and Audit for
Contaminated Mud Pit at East Sha Chau. For CEDD.
[2] ERM (2017) Final Report. Submitted
under Agreement No. CE 23/2012 (EP) Environmental Monitoring and Audit for
Contaminated Mud Pits to the South of The Brothers and at East Sha Chau (2012 -
2017). For CEDD.
%20Jun%202021_html_files/Environmental%20Certification%20Sheet.jpg){kind=link}
%20Jun%202021_html_files/Table1-1%20Works%20Schedule%20for%20ESC%20CMP%20V.jpg){kind=link}