Agreement No. CE 63/2016 (EP)
Environmental Monitoring and Audit
for Disposal Facility to the East of Sha Chau
(2017-2020) - Investigation
MONTHLY EM&A REPORT FOR November 2018
1.1
Background
1.1.1
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 South of The Brothers (SB) and to the East of Sha
Chau (ESC) for the disposal of contaminated sediment, and 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. Two Environmental Permits (EPs),
EP-312/2008/A and EP-427/2011/A, were issued by the Environmental Protection
Department (EPD) to the CEDD, the Permit Holder, on 28 November 2008 and 23
December 2011 for the Dredging, Management and Capping of Contaminated Sediment
Disposal Facilities at ESC CMP V and SB CMPs, respectively.
1.1.2
Under the requirements
of the two EPs for ESC CMP V and SB CMPs, 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 and SB. 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 as well as capping operations of SB CMPs.
1.1.3
The present EM&A
programme under Agreement No. CE 63/2016 (EP)
covers the dredging, disposal and capping operations of the ESC CMP V as well
as the capping operations of the SB CMPs (see Annex A
for the EM&A programme). Detailed works schedule for ESC CMP V and SB
CMPs is shown in Figure
1.1. In November 2018, the
following work was being undertaken:
· Disposal of contaminated mud at ESC CMP Vd.
Figure 1.1 Works Schedule for ESC CMP
V and SB CMPs
1.2 Reporting Period
1.2.1
This Monthly EM&A Report
for November 2018 covers the EM&A
activities for the reporting month of November 2018.
1.3
Details of Sampling and
Laboratory Testing Activities
1.3.1
The following monitoring activities were
undertaken for ESC CMP V in November 2018:
· Water Column Profiling of ESC CMP Vd;
· Routine Water Quality Monitoring of ESC CMPs; and
· Pit Specific Sediment Chemistry of ESC CMP Vd.
1.3.2
No monitoring activities were
scheduled to be undertaken for SB CMP in November 2018.
1.4 Details of Outstanding Sampling and/or Analysis
1.4.1
No outstanding
sampling remained for November 2018.
1.5
Brief Discussion of the Monitoring Results for ESC CMP V
1.5.1 Brief discussion of the monitoring
results of the following activities for ESC CMP V is
presented in this Monthly EM&A Report for November 2018:
· Water Column Profiling of ESC CMP Vd in November 2018;
· Routine Water Quality Monitoring of ESC CMPs in November 2018; and
· Pit Specific Sediment Chemistry of ESC CMP Vd in October and November 2018.
1.5.2
Water Column Profiling of ESC CMP Vd – November 2018
1.5.3
Water Column Profiling was undertaken at a total of two
sampling stations (Upstream and Downstream stations) on 5 November 2018. 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 dry season period
(November to March) of 2007 - 2016 from stations in the Northwestern
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 Annex B for details).
In-situ Measurements
1.5.4
Analyses of results for
November 2018 indicated that levels of Salinity, pH and DO complied with the
WQOs at both Downstream and Upstream stations (Table B2 of Annex B). Levels of DO and Turbidity at all stations complied
with the Action and Limit Levels (Tables B1
and B2 of Annex B).
Laboratory Measurements for Suspended Solids (SS)
1.5.5
Analyses of results for
November 2018 indicated that the SS levels at both Downstream and Upstream stations were higher than the WQO. However,
the SS levels complied with the Action and Limit Level at both Downstream and
Upstream stations (Tables B1 and B2 of Annex B).
Overall, the monitoring results indicated that the mud
disposal operation at ESC CMP Vd did not appear to
cause any deterioration in water quality during this reporting period.
1.5.6
Routine Water Quality Monitoring of ESC CMPs –
November 2018
1.5.7
Routine Water Quality Monitoring of ESC CMPs was
undertaken on 7 November 2018. The monitoring results have been assessed
for compliance with the WQOs (see Section 1.5.3 for details). The monitoring results
are shown in Tables B3 and B4 of Annex B and Figures 1 - 10 of Annex C. A total of sixteen (16) monitoring
stations were sampled in November 2018 as shown in Figure 1.2.
In-situ Measurements
1.5.8
Graphical presentation
of the monitoring results (Temperature, DO, pH, Salinity and Turbidity) is shown in Figures 1 - 6 of Annex C.
Analyses of results for November 2018 indicated that
the levels of pH, Salinity and DO complied with the WQOs at all stations
(Impact, Intermediate, Reference and Ma Wan stations) in November 2018.
1.5.9
The levels of DO and Turbidity also
complied with the Action and Limit Levels at all stations (Table
B3 of Annex B; Figures 3 and 6 of Annex C).
1.5.10
Overall, in-situ measurement results of the Routine Water
Quality Monitoring indicated that the disposal
operation at ESC CMP Vd did not appear to cause any
unacceptable impacts in water quality in November 2018.
Laboratory Measurements
1.5.11
Laboratory analysis of
November 2018 results indicated that concentrations of Cadmium, Silver and
Mercury were below their limit of reporting at all stations. Arsenic,
Chromium, Nickel, Lead, Copper and Zinc were detected
in November 2018 samples at most stations and the concentrations of these
metals and metalloids were similar amongst the stations (Table
B4 of Annex B; Figure 7 of Annex C).
1.5.12
For
nutrients, concentrations of Total Inorganic Nitrogen (TIN) at all stations in
November 2018 complied with the WQO (Table B4
of Annex B; Figure 8 of Annex C).
Concentrations of Ammonia Nitrogen (NH3-N) and 5-day Biochemical
Oxygen Demand (BOD5) were generally similar amongst the stations in
November 2018 (Table B4 of Annex B;
Figure 8 and 9 of Annex C).
1.5.13
Analyses of results for
November 2018 indicated that the SS levels complied with the WQO (12.8 mg/L for dry season) and the
Action and Limit Levels at all stations
(Tables B1 and B4 of Annex B;
Figure 10 of Annex C).
Overall, results
of the Routine Water Quality Monitoring indicated that the disposal operation at ESC CMP Vd did not appear to cause any unacceptable deterioration
in water quality in November 2018. Detailed statistical analysis will be presented in the Quarterly Report to investigate any
spatial and temporal trends of potential concern.
1.5.14 Pit Specific
Sediment Chemistry of ESC CMP Vd
– October and November 2018
1.5.15 Monitoring locations for Pit Specific
Sediment Chemistry for ESC CMP Vd are shown in Figure 1.3. A total of six (6)
monitoring stations were sampled monthly on 4 October 2018 and 6 November
2018.
1.5.16 The concentrations of all inorganic
contaminants were lower than the Lower Chemical Exceedance Level (LCEL) at all
stations, except for Arsenic which was slightly higher than LCEL at
Active Pit stations ESC-NPAA and ESC-NPAB in both October and November 2018 (Figures 11, 12, 15 and 16 of Annex C).
1.5.17 For organic
contaminants, the concentrations of Total Organic Carbon (TOC) were generally
similar in October and November 2018 (Figures 13
and 17 of Annex C). The
concentration of Tributyltin (TBT) was generally similar amongst stations in
October and November 2018 (Figures 14 and 18 of Annex C). Low and High Molecular Weight Polycyclic Aromatic
Hydrocarbons (PAHs), Total Polychlorinated Biphenyls (PCBs), Total dichloro-diphenyl-trichloroethane
(DDT) and 4,4’-dichlorodiphenyldichloroethylene (DDE) concentrations were below
the limit of reporting at all stations in October and November 2018.
1.5.18 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 Vd in October and November 2018. Statistical analysis
will be undertaken and presented in the corresponding
quarterly report to investigate whether there are any unacceptable impacts in
the area caused by the contaminated mud disposal.
1.6 Activities Scheduled for the Next Month
1.6.1 The following monitoring
activities will be conducted in the next monthly
period of December 2018 for ESC CMP V (see Annex A
for the sampling schedule):
· Water Column Profiling of ESC CMP Vd;
· Pit Specific Sediment Chemistry of ESC CMP Vd; and
· Cumulative Impact Sediment Chemistry of ESC CMP Vd.
1.6.2 The following monitoring activities
will be conducted in the next monthly period of
December 2018 for SB CMPs (see Annex A for the sampling schedule):
· Benthic Recolonisation Studies of SB CMPs.
1.7
Study Programme
1.7.1
A summary of the Study Programme is
presented in Annex 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.