Agreement No. CE 23/2012 (EP)
Environmental Monitoring and Audit
for Contaminated Mud Pits to the South of The Brothers
and at
49th MONTHLY PROGRESS REPORT FOR September 2016
1.1
Background
1.1.1
Since early 1990s, contaminated sediment ([1]) arising from various construction works
(e.g. dredging and reclamation projects) in Hong Kong
has been disposed of at a series of seabed pits at East of Sha
Chau (ESC). In
late 2008, a review indicated that the existing and planned facilities at ESC
would not be able to meet the disposal demand after 2012. In order to meet this demand, the Hong Kong
Special Administrative Region Government (HKSARG) decided to implement a new
contained aquatic disposal (CAD) ([2]) facility at the South of The Brothers
(SB CMPs) which had been under consideration for a
number of years.
1.1.2
The environmental acceptability of the construction and
operation of the Project had been confirmed by findings of the associated
Environmental Impact Assessment (EIA) study completed in 2005 under Agreement No. CE 12/2002(EP) ([3]).
The Director of Environmental Protection (DEP) approved this EIA report
under the Environmental
Impact Assessment Ordinance (Cap. 499) (EIAO) in September 2005 (EIA Register No.: AEIAR-089/2005).
1.1.3
In accordance with the EIA recommendation, prior to
commencement of construction works for the SB CMPs,
the Civil Engineering and Development Department (CEDD) undertook a detailed
review and update of the EIA findings for the SB site ([4]). Findings of the EIA review undertaken in
2009/ 2010 confirmed that the construction and operation of the SB site had
been predicted to be environmentally acceptable.
1.1.4
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
for ESC CMP V and on 23 December 2011 for SB CMPs,
respectively. Under the requirements of
the EPs, an Environmental
Monitoring and Audit (EM&A) programme as set out in the EM&A Manuals ([5])
([6])
is required to be implemented for the CMPs.
1.1.5
The present EM&A programme under Agreement No. CE 23/2012 (EP) covers the dredging,
disposal and capping operations of the SB CMPs
as well as ESC CMPs. Detailed works schedule for ESC CMPs and SB CMPs is shown in Figure 1.1. In September 2016, the following works were
being undertaken:
· Disposal of contaminated mud at ESC CMP Vd; and
· Capping operation at SB CMP 2.
Figure 1.1 Works
Schedule for ESC CMPs and SB CMPs
1.2
Reporting
Period
1.2.1
This 49th Monthly Progress Report covers the EM&A activities for the reporting month of September 2016.
1.3
Details
of Sampling and Laboratory Testing Activities
1.3.1
The following monitoring activities have been undertaken for
ESC CMPs in September 2016:
· Pit Specific Sediment
Chemistry of ESC CMP Vd was
undertaken on 1 September 2016; and
·
Water Column Profiling of ESC CMP Vd was undertaken on 2 September 2016.
1.3.2
No monitoring activities were scheduled to be undertaken for
SB CMPs in September 2016.
1.4
Details of Outstanding Sampling and/or
Analysis
1.4.1
No outstanding sampling and analysis remained for September 2016.
1.5
Brief
Discussion of the Monitoring Results for ESC CMPs
1.5.1
Brief discussion of the
monitoring results of the following activities for ESC CMPs
is presented in this 49th Monthly Progress Report:
·
Water Column Profiling of ESC CMP Vd in September 2016;
· Pit Specific Sediment
Chemistry of ESC CMP Vd
in August and
September 2016; and
· Cumulative
Impact Sediment Chemistry of ESC CMPs in August 2016.
1.5.2
Water Column Profiling of ESC CMP Vd – September 2016
1.5.3
Water Column Profiling was undertaken at a total of two sampling stations
(Upstream and Downstream stations) on 1 September 2016. 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 2006 - 2015 from
stations in the Northwestern Water Control Zone
(WCZ), where the ESC CMPs are located ([7]). For Salinity, the averaged value obtained from
the Reference stations 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 September 2016 indicated that levels of Salinity, DO and pH
complied with the WQOs at both Downstream and
Upstream stations (Table B2 of Annex B). In addition, DO
and Turbidity at all stations complied with the Action and Limit Levels (Table B1 of Annex B).
Laboratory Measurements for Suspended Solids (SS)
1.5.5
Analyses
of results for September 2016 indicated that the SS levels were higher than the
WQO at both Upstream and Downstream stations.
However, both Upstream and Downstream stations complied with the Action
and Limit Levels (Table B1 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
Pit Specific Sediment Chemistry of ESC CMP
Vd – August and September 2016
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 August and September 2016.
1.5.9
The concentrations of all inorganic contaminants
were lower than the Lower Chemical Exceedance
Level (LCEL) at all stations in
August and September 2016 (Figures 1, 2, 5 and 6 of Annex C).
1.5.10
For organic contaminants,
the concentrations of Total Organic Carbon (TOC) were similar amongst the stations in August and
September 2016 (Figures 3 and
7 of Annex C). In August 2016, Tributyltin
(TBT) concentrations were higher at Active Pit station ESC-NPAB and Pit Edge
station ESC-NEAA whilst TBT concentrations were higher at Active Pit ESC-NPAA
station in September 2016 (Figures 4 and
8 of Annex C). Low and High Molecular Weight Polycyclic
Aromatic Hydrocarbons (PAHs), Total Polychlorinated Biphenyls
(PCBs), Total dichlorodiphenyltrichloroethane (DDT) and
4,4’-dichlorodiphenyldichloroethylene (DDE) concentrations were below the limit
of reporting at all stations in August
and September 2016.
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 August and September 2016. Statistical
analysis will be undertaken and presented in the quarterly report to
investigate whether there are any unacceptable impacts in the area caused by
the contaminated mud disposal.
1.5.12
Cumulative Impact Sediment Chemistry of
ESC CMPs – August 2016
1.5.13
Monitoring locations for Cumulative Impact Sediment Chemistry for ESC CMPs are shown in Figure 1.3.
A total of nine (9) monitoring stations were sampled in
August 2016.
1.5.14
Analyses
of results for the Cumulative Impact Sediment Chemistry
Monitoring indicated that the
concentrations of all inorganic contaminants were below the LCEL in
August 2016 (Figures 9 and 10 of Annex C).
1.5.15
For organic contaminants, concentrations of TOC were observed to be similar among all stations (Figure 11 of Annex C). Concentrations of TBTs were recorded to be higher at Ma Wan
station and Capped Pit station ESC-RCA (Figure
12 of Annex C).
Total DDT, 4,4’-DDE, Total PCBs as well as Low and High Molecular Weight PAHs were recorded below the limit of
reporting at all stations.
1.5.16
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 August 2016. Statistical
analysis will be undertaken and presented in the 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 October 2016 for ESC CMPs:
·
Water Column Profiling of ESC CMP Vd;
·
Routine Water Quality Monitoring of ESC CMP Vd;
·
Water Quality Monitoring During Dredging of ESC CMP Vb; and
·
Pit Specific Sediment Chemistry of ESC CMP Vd.