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 2017
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 2017, 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
2017 covers the EM&A
activities for the reporting month of November 2017.
1.3
Details of Sampling and
Laboratory Testing Activities
1.3.1
The following monitoring activities were
undertaken for ESC CMP V in November 2017:
·
Pit Specific Sediment Chemistry of ESC CMP Vd was
undertaken on 6 November 2017;
·
Water Column Profiling of ESC CMP Vd was
undertaken on 7 November 2017; and
·
Routine Water Quality Monitoring of ESC CMP V was undertaken on 8 November 2017.
1.3.2
No monitoring
activities were scheduled to be undertaken for SB CMPs in November 2017.
1.4
Details
of Outstanding Sampling and/or Analysis
1.4.1
No outstanding sampling and analysis remained for November 2017.
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 2017:
·
Water Column Profiling of ESC CMP Vd in November 2017;
·
Routine Water Quality Monitoring of ESC CMP V in November 2017; and
·
Pit Specific
Sediment Chemistry of ESC CMP Vd in November 2017.
1.5.2
Water Column Profiling of ESC CMP Vd – November 2017
1.5.3
Water Column Profiling was undertaken at a total of two sampling stations (Upstream
and Downstream stations) on 7 November 2017. 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 2017
indicated that levels of DO,
Salinity and pH complied with
the WQOs at both Downstream and Upstream stations (Table B2 of Annex B).
In
addition, 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 2017
indicated that the SS levels were higher than the WQO at Downstream
station. However, both Upstream and
Downstream stations complied with the Action and Limit Levels (Tables B1 and B2 of Annex B).
1.5.6
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.
1.5.7
Routine Water Quality Monitoring of ESC CMP V
– November 2017
1.5.8
Routine Water Quality Monitoring of ESC CMP V was undertaken on 8 November 2017. 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 ten (10) monitoring stations were sampled in November 2017 as shown in Figure 1.2.
In-situ Measurements
1.5.9
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 2017 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 2017 (Table B3 of Annex B; Figures 1, 3 and 5 of Annex C).
1.5.10
The levels of
DO and Turbidity complied with the Action and Limit Levels at all stations (Table B3 of Annex B; Figures 3 and 6 of Annex C).
1.5.11
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 2017.
Laboratory Measurements
1.5.12
Laboratory analysis of November 2017
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 2017 samples and the concentrations of these metals and metalloids were similar amongst stations (Table B4 of Annex B; Figure 7 of Annex C).
1.5.13
For nutrients, concentrations of Total
Inorganic Nitrogen (TIN) at all stations in November 2017 were lower than the WQO (0.5 mg/L) (Table B4 of Annex B; Figure 8 of Annex C).
Concentrations of Ammonia Nitrogen (NH3-N) were similar
amongst all stations in November 2017 (Table B4 of Annex B; Figure 8 of Annex C).
Levels of 5-day Biochemical Oxygen Demand (BOD5) were relatively
similar amongst all stations in November 2017 (Table B4 of Annex B; Figure 9 of Annex C).
1.5.14
Analyses of results for November
2017 indicated that the SS levels at all stations were higher than the WQO (12.8 mg/L for dry season), however SS levels compiled with
the Action and Limit Levels at all stations (Tables B1 and B4 of Annex B; Figure 10 of Annex C).
1.5.15
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 2017. Detailed statistical analysis will be presented
in the Quarterly Report to investigate any spatial and temporal trends of
potential concern.
1.5.16
Pit Specific Sediment Chemistry of ESC CMP Vd – November 2017
1.5.17
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 in November 2017.
1.5.18
The concentrations of most inorganic
contaminants were lower than the Lower Chemical Exceedance Level (LCEL) at all stations in November 2017, except Copper and Silver (Figures 15 and 16 of Annex C).
In November 2017, concentrations of Copper and Silver exceeded the LCEL
at Active Pit stations ESC-NPAA and ESC-NPAB (Figures 15 and 16 of Annex C).
1.5.19
Since the Active Pit stations are located
within ESC CMP Vd which were
receiving contaminated mud during the reporting period, the exceedances of LCEL
for Copper and Silver recorded at the Action Pit stations only are not
considered as indicating any dispersal of contaminated mud from ESC CMP Vd.
1.5.20
For organic contaminants, the
concentrations of Total Organic Carbon (TOC) were similar in November 2017 (Figure 17 of Annex C). The
concentrations of Tributyltin (TBT)
were higher at Active Pit stations ESC-NPAA and ESC-NPAB and Near Pit station
ESC-NNAA in November 2017 (Figure 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 November 2017.
1.5.21
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
November 2017.
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 2017 for ESC CMP V (see Annex A for the sampling schedule):
·
Water Column Profiling of ESC CMP Vd;
·
Cumulative Impact Sediment
Chemistry of ESC CMPs; and
·
Pit Specific Sediment Chemistry of ESC CMP Vd.
1.6.2
The following monitoring
activities will be conducted in the next monthly period of December 2017 for SB CMPs (see Annex A for the sampling schedule):
·
Benthic Recolonisation Studies of
SB CMPs.