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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 February 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.
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.
1.1.2
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 February 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 February 2018 covers the EM&A activities for the reporting month of February 2018.
1.3
Details of Sampling and
Laboratory Testing Activities
1.3.1
The following
monitoring activities were undertaken for ESC CMP V in February
2018:
·
Pit Specific Sediment Chemistry of ESC CMP Vd was undertaken on 5 February
2018;
·
Cumulative Impact
Sediment Chemistry of ESC CMP V was undertaken on 6 and 7 February 2018;
·
Sediment Toxicity Tests of
ESC CMP V was undertaken on 6 and 7 February 2018;
·
Routine Water Quality Monitoring of ESC CMP V was undertaken on 8 February 2018;
·
Water Column Profiling of ESC CMP Vd was undertaken on 9 February 2018; and
·
Demersal Trawling for ESC CMP V was undertaken on 26 and 27 February 2018.
1.3.2
No monitoring activities were undertaken
for SB CMP in February 2018.
1.4
Details
of Outstanding Sampling and/or Analysis
1.4.1
No outstanding sampling remained
for February 2018.
1.4.2
The following
laboratory analyses were still in progress during the preparation of this
monthly report and hence are not presented in this monthly report:
·
Laboratory analyses of sediment samples collected
for Pit Specific Sediment Chemistry for
ESC CMP Vd in February 2018; and
·
Laboratory analyses of sediment samples collected
for Cumulative Impact Sediment Chemistry for ESC CMP V in February 2018.
1.4.3
The following
analyses are in progress and will be presented in the corresponding quarterly
report:
·
Species identification of the biota samples
collected from Demersal Trawling for ESC
CMP V in February 2018; and
·
Laboratory
analyses for Sediment Toxicity Test of
ESC CMP V in February 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 February 2018:
·
Water Column Profiling of ESC CMP Vd in February 2018;
·
Routine Water Quality Monitoring of ESC V in February 2018;
1.5.2
Water Column Profiling of ESC CMP Vd – February 2018
1.5.3
Water Column Profiling was undertaken at a total of two
sampling stations (Upstream and Downstream stations) on 9 February 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 February
2018 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 February
2018 indicated that the SS levels complied
with the WQO and the Action and Limit Levels at both Upstream and Downstream
stations (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 – February 2018
1.5.8
Routine Water Quality Monitoring of
ESC CMP V was undertaken on
8 February 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 ten
(10) monitoring stations were sampled in February
2018 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 February 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 February 2018 (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 February 2018.
Laboratory
Measurements
1.5.12
Laboratory
analysis of February 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 February 2018 samples at most stations 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 Reference and Ma Wan
stations in February 2018 were higher than the WQO (0.5 mg/L) (Table B4 of Annex B; Figure 8 of Annex 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]). In addition, no exceedances were
recorded at Impact and Intermediate stations. Therefore, the exceedances of TIN WQO at
these stations are unlikely to be caused by the disposal operation at ESC CMP
Vd. Concentrations of Ammonia
Nitrogen (NH3-N) and 5-day Biochemical Oxygen Demand (BOD5)
were similar amongst all stations, except for slightly higher level of BOD5
recorded at Ma Wan station in February 2018 (Table B4 of Annex B; Figure 8 and 9 of Annex C).
1.5.14
Analyses of
results for February 2018 indicated that
the SS levels at all stations were
lower than the WQO (12.8 mg/L
for dry season) and 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 February 2018.
Detailed statistical analysis will be presented in the Quarterly Report
to investigate any spatial and temporal trends of potential concern.
1.6
Activities Scheduled for the
Next Month
1.6.1
The following monitoring activities will be conducted
in the next monthly period of March 2018 for ESC CMP V (see Annex A for the sampling
schedule):
·
Water Column Profiling of ESC CMP Vd; and
·
Pit Specific Sediment Chemistry of ESC CMP Vd.