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 January 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 January 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
January
2018 covers the
EM&A activities for the reporting month of January 2018.
1.3
Details of Sampling and
Laboratory Testing Activities
1.3.1
The following monitoring
activities were undertaken for ESC CMP V in January 2018:
·
Pit Specific Sediment Chemistry of ESC CMP Vd was undertaken on 2 January 2018;
·
Routine Water Quality Monitoring of ESC CMP V was undertaken on 3 January 2018;
·
Water Column Profiling of ESC CMP Vd was undertaken on 5 January 2018; and
·
Demersal Trawling for ESC CMP V was
undertaken on 10 and 11 January
2018.
1.3.2
No monitoring activities were scheduled to be undertaken for
SB CMP in January 2018.
1.4
Details of Outstanding Sampling and/or Analysis
1.4.1
No outstanding sampling and analysis remained for January 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 January 2018:
·
Water Column Profiling of ESC CMP Vd in January 2018;
·
Routine Water Quality Monitoring of ESC CMP V in January 2018; and
·
Pit Specific Sediment Chemistry of
ESC CMP Vd
in January 2018.
1.5.2
Water
Column Profiling of ESC CMP Vd – January
2018
1.5.3
Water Column Profiling
was undertaken at a total of two sampling stations (Upstream and Downstream
stations) on 5 January 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 January 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 January 2018 indicated that
the SS levels at Upstream and Downstream stations complied with the WQOs as
well as 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 – January 2018
1.5.8
Routine Water Quality Monitoring of ESC CMP V was undertaken on
3 January 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 January 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 January 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 January 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 CM
1.5.12
P Vd did not appear to cause any
unacceptable impacts in water quality in January 2018.
Laboratory
Measurements
1.5.13
Laboratory analysis of January
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 January 2018 samples and the concentrations of these metals and metalloids were similar amongst stations (Table B4 of Annex
B; Figure 7 of Annex C).
1.5.14
For nutrients, concentrations of
Total Inorganic Nitrogen (TIN) at all stations in January 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 similar amongst all stations in January 2018 (Table B4 of Annex
B; Figure 8 and
9 of Annex
C).
1.5.15
Analyses of results for January 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).
1.5.16
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 January 2018.
Detailed statistical analysis will be presented in the Quarterly Report
to investigate any spatial and temporal trends of potential concern.
1.5.17
Pit
Specific Sediment Chemistry of ESC CMP Vd – January
2018
1.5.18
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 January 2018.
1.5.19
The concentrations of all inorganic contaminants were
lower than the Lower Chemical Exceedance Level (LCEL) at all stations in January 2018 (Figures 11 and 12 of Annex
C).
1.5.20
For organic contaminants, the
concentrations of Total Organic Carbon (TOC) were generally similar in January
2018 (Figure 13 of Annex
C). The concentration of Tributyltin (TBT) was generally higher at Active-Pit station ESC-NPAB in January 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 most stations in January 2018, except for High Molecular Weight PAHs, DDT and DDE being detected at
Active-Pit station ESC-NPAB and Near-Pit station ESC-NNAA (Figures 15 and 16 of Annex C).
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 January
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 February
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 V;
·
Pit Specific Sediment Chemistry of ESC CMP Vd;
·
Cumulative
Impact Sediment Chemistry of ESC CMPs;
·
Sediment
Toxicity Tests of ESC CMPs; and
·
Demersal Trawling for ESC CMP V.