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 June 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 June 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
June 2018 covers the EM&A
activities for the reporting month of June 2018.
1.3
Details of Sampling and
Laboratory Testing Activities
1.3.1
The following monitoring
activities were undertaken for ESC CMP V in June 2018:
·
Water Column Profiling of ESC CMP Vd;
·
Pit Specific Sediment Chemistry of ESC CMP Vd; and
·
Cumulative
Impact Sediment Chemistry of ESC CMP V.
1.3.2
No monitoring activities were
undertaken for SB CMP in June 2018.
1.4
Details of Outstanding Sampling and/or Analysis
1.4.1
No outstanding sampling remained for June 2018.
1.4.2
The following laboratory analysis was still in
progress during the preparation of this monthly report and hence is not
presented in this monthly report:
·
Laboratory analyses of sediment samples
collected for Pit Specific Sediment Chemistry
of ESC CMP Vd in June 2018; and
·
Laboratory
analyses of sediment samples collected for Cumulative Impact Sediment
Chemistry for ESC CMP Vd in
June 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 June 2018:
·
Water Column Profiling of ESC CMP Vd in June 2018; and
·
Pit Specific Sediment Chemistry of ESC CMP Vd in May 2018.
1.5.2
Water
Column Profiling of ESC CMP Vd – June 2018
1.5.3
Water Column Profiling was undertaken at a total of two sampling stations
(Upstream and Downstream stations) on 29 June 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
wet season period (April to October) 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 June 2018 indicated that levels of DO, Salinity and pH complied with the WQOs at both Downstream
and Upstream stations, except slightly lower salinity was recorded at the
Downstream station (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 June 2018 indicated that the SS levels slightly exceeded the WQO at
the Downstream station (Tables B1 and B2 of Annex B). However, both Upstream and Downstream
stations complied with the Action and Limit Level.
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
Pit
Specific Sediment Chemistry of ESC CMP Vd – May 2018
1.5.8
Monitoring
locations for Pit Specific Sediment Chemistry for ESC CMP Vd are shown in Figure 1.2. A total of six (6) monitoring stations
were sampled in May 2018.
1.5.9
The concentrations of all inorganic contaminants were lower than the Lower Chemical Exceedance Level (LCEL) at all stations in May 2018 (Figures 1 and 2 of Annex C).
1.5.10
For
organic contaminants, the concentrations of Total Organic Carbon (TOC) were
generally similar in May 2018 (Figures 3 of Annex C). The concentration of Tributyltin (TBT) was generally higher at Active-Pit stations ESC-NPAB and ESC-NPAA
in May 2018 (Figure 4 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 May
2018.
1.5.11
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 May 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 July 2018 for ESC CMP V (see Annex A
for the sampling schedule):
·
Water Column Profiling of ESC CMP Vd;
·
Routine Water Quality Monitoring of ESC CMP Vd;
·
Pit Specific Sediment Chemistry of ESC CMP Vd; and
·
Demersal Trawling for ESC
CMPs.