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 JuLy 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 July 2018, the following work was
being undertaken:
¡P 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 July 2018 covers the EM&A
activities for the reporting month of July 2018.
1.3
Details of Sampling and
Laboratory Testing Activities
1.3.1
The following monitoring activities were
undertaken for ESC CMP V in July 2018:
¡P
Water Column Profiling of ESC CMP Vd;
¡P
Routine Water Quality Monitoring of ESC CMPs;
¡P
Pit Specific Sediment Chemistry of ESC CMP Vd; and
¡P
Demersal
Trawling for ESC CMPs.
1.3.2
No monitoring activities were
scheduled to be undertaken for SB CMP in July 2018.
1.4
Details of Outstanding Sampling and/or Analysis
1.4.1
No outstanding sampling remained for July 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:
¡P
Laboratory analyses of sediment samples collected for Pit Specific
Sediment Chemistry of ESC CMP Vd in July 2018.
1.4.3
The
following analyses are in progress and will be presented in the corresponding
quarterly report:
¡P Species identification of
the biota samples collected from Demersal Trawling for ESC CMPs in July 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 July 2018:
¡P
Water Column Profiling of ESC CMP Vd in July 2018;
¡P
Routine Water Quality Monitoring of ESC CMPs in July 2018;
¡P
Pit Specific Sediment Chemistry of ESC CMP Vd in June 2018; and
¡P
Cumulative
Impact Sediment Chemistry of ESC CMP V in June 2018.
1.5.2
Water
Column Profiling of ESC CMP Vd ¡V July 2018
1.5.3
Water Column
Profiling was undertaken at a total of two
sampling stations (Upstream and Downstream stations) on 28 July 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 July 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 July 2018
indicated that the SS levels complied with the WQO at
both Downstream and Upstream stations (Tables B1 and B2 of Annex
B). 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
Routine
Water Quality Monitoring of ESC CMP V ¡V July 2018
1.5.8
Routine Water
Quality Monitoring of ESC CMP V was undertaken on 27 July 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 July 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 July 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 July 2018.
1.5.10
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).
1.5.11
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 July 2018.
Laboratory Measurements
1.5.12
Laboratory
analysis of July 2018 results indicated that concentrations of Cadmium,
Chromium, Silver and Mercury were below their limit of reporting at all stations. Arsenic, Nickel, Lead, Copper and Zinc were detected in July 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).
1.5.13
For
nutrients, concentrations of Total Inorganic Nitrogen (TIN) at all stations in July 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]). 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 generally similar amongst the stations in July 2018 (Table
B4 of Annex
B; Figure 8 and
9 of Annex
C), except higher BOD5 was detected at Ma Wan station.
1.5.14
Analyses
of results for July 2018 indicated that the
SS levels at most stations were lower than the WQO (10.8 mg/L for wet season), except the slight exceedance of SS
recorded at the Impact station.
However, the 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 July 2018. 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 ¡V June 2018
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 June 2018.
1.5.18
The concentrations of most inorganic contaminants were lower
than the Lower Chemical Exceedance Level (LCEL) at all stations in June 2018, except the concentration of Arsenic slightly
exceeded the LCEL at the Active-Pit stations ESC-NPAA and ESC-NPAB
(Figures 11 and 12 of Annex C). Whilst the average concentration of Arsenic in the Earth¡¦s crust is
generally ~2mg/kg, significantly higher Arsenic concentrations (median = 14 mg/kg)
have been recorded in Hong Kong¡¦s onshore sediments ([5]). It is presumed
that the natural concentrations of Arsenic are similar in onshore and offshore
sediments ([6]), and relatively high Arsenic levels may thus occur
throughout Hong Kong. Therefore,
the LECL exceedances of Arsenic are unlikely to be caused by the disposal
operations at ESC CMP Vd but rather as a result of naturally occurring
deposits.
1.5.19
For
organic contaminants, the concentrations of Total Organic Carbon (TOC) were
generally similar in June 2018 (Figure 13 of Annex C).
The concentration of Tributyltin
(TBT) was generally similar amongst stations in June 2018 (Figure
14 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 June 2018.
1.5.20
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 June 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.
1.5.21
Cumulative
Impact Sediment Chemistry of ESC CMP V ¡V June 2018
1.5.22
Monitoring locations for Cumulative
Impact Sediment Chemistry for ESC CMP V are shown in Figure 1.4. A total of nine (9) monitoring stations
were sampled in
June 2018.
1.5.23
Analyses of results for the Cumulative
Impact Sediment Chemistry Monitoring indicated that
the concentrations of most inorganic contaminants were below
the LCEL at all stations in June 2018, except Arsenic
exceeded the LCEL at Mid-field stations ESC-RMA and ESC-RMB as well as the Far-field
stations ESC-RFA and ESC-RFB (Figures 15 and 16 of Annex C).
1.5.24
As discussed in Section 1.5.18, the
natural concentrations of Arsenic are relatively high in Hong Kong. Therefore, the LCEL exceedances of
Arsenic are unlikely to be caused by the disposal
operations at ESC CMP Vd but rather as a result of naturally occurring deposits.
1.5.25
For organic
contaminants, the concentrations of TOC were generally similar in June 2018, except
higher concentration of TOC recorded at Ma Wan station (Figure 17 of Annex C). The
concentrations of TBT recorded were
generally similar amongst stations except lower concentrations of TBT were recorded
at the Capped-Pit stations ESC-RCA and ESC-RCB (Figure
18 of Annex C). Low and High Molecular Weight PAHs, PCBs, DDT and DDE concentrations were
generally recorded below the limit of reporting at all stations, except
concentrations of High Molecular Weight PAHs was higher than the limit of
reporting at Capped Pit station ESC-RCA (Figure 19 of Annex C).
1.5.26
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 June 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 August 2018 for ESC CMP V (see Annex A for the sampling schedule):
¡P
Water Column Profiling of ESC CMP Vd;
¡P
Routine Water Quality Monitoring of ESC CMPs;
¡P
Pit Specific Sediment Chemistry of ESC CMP Vd;
¡P
Cumulative Impact Sediment Chemistry
of ESC CMP V;
¡P
Sediment Toxicity Tests of
ESC CMP V; and
¡P
Demersal Trawling for ESC
CMPs.
1.6.2
The following monitoring activities will be
conducted in the next monthly period of August 2018 for SB CMPs (see Annex A for the sampling schedule):
¡P
Benthic Recolonisation Studies of SB CMPs.