Agreement No. CE 23/2012 (EP)
Environmental Monitoring and Audit
for Contaminated Mud Pits to the South of The Brothers
and at East Sha Chau (2012-2017) - Investigation
39th MONTHLY PROGRESS REPORT FOR November 2015
Since early 1990s, contaminated sediment ()
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) ()
facility at the South of The Brothers (SB CMPs) which
had been under consideration for a number of years.
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) (). The Director of Environmental Protection
(DEP) approved this EIA report under the Environmental Impact Assessment
Ordinance (Cap. 499) (EIAO) in September
Register No.: AEIAR-089/2005).
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 (). 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.
Environmental Permits (EPs) (EP-312/2008/A and EP-427/2011A) 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 ()
is required to be implemented for the CMPs.
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 both CMPs is shown in Figure 1.1. In November 2015,
the following works were being undertaken at the CMPs:
· Dredging operation at ESC CMP Vd;
· Capping operations at ESC CMP Va; and
· Disposal of contaminated mud at SB CMP 2.
Figure 1.1 Works
Schedule for ESC CMPs and SB CMPs
This 39th Monthly Progress
Report covers the EM&A activities for
the reporting month of November 2015.
Sampling and Laboratory Testing Activities
The following monitoring activities have
been undertaken for ESC CMPs in November 2015:
Impact Water Quality Monitoring during Dredging Operations of ESC CMPs
was undertaken on 13, 16, 18 and 20 November 2015.
The following monitoring activities have
been undertaken for SB CMPs in November 2015:
Specific Sediment Chemistry of CMP 2 was undertaken on 3 November 2015;
Column Profiling of CMP 2 was undertaken on 5 November 2015; and
Water Quality Monitoring of CMP 2 was
undertaken on 12 November 2015.
Outstanding Sampling and/or Analysis
No outstanding sampling remained for November 2015.
A summary of field activities conducted are presented in Annex
A. 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 of SB CMP 2 in November 2015.
of the Monitoring Results for ESC CMPs
Brief discussion of the monitoring results of the
Impact Water Quality Monitoring
during Dredging Operations of ESC
CMP Vd conducted in November 2015 is
Impact Water Quality
Monitoring during Dredging Operations of ESC CMP Vd – November
Dredging activities were carried out on 13 and 14 November 2015 during this reporting
period. As such, Impact Water Quality Monitoring during Dredging
Operations of ESC CMP Vd was conducted three times per week from
13 to 20 November 2015 to monitor water quality around
the CMP during dredging activities. On
each survey day, monitoring was conducted during both mid-ebb and mid-flood
tides at two Reference (Upstream) stations and five Impact (Downstream)
stations around the dredging operations at ESC
Monitoring was also conducted at one Sensitive Receiver station situated in Ma Wan. A total of eight (8) stations were monitored
and locations of the sampling stations are shown in Figure 1.2.
Monitoring results are presented in Table B1 of Annex B. Daily dredging volume in November 2015 is
reported in Annex C. Levels of Dissolved Oxygen (DO), Turbidity and
Suspended Solid (SS) complied with the Action and Limit Levels (see Table B2 of
Annex B for details) set in
the Baseline Monitoring Report ().
The results indicated that the dredging operations at ESC
CMP Vd did not appear to cause any unacceptable
deterioration in water quality during this reporting period. Therefore, no further action, except for
those recommended in the Environmental Permit (EP-312/2008/A), are considered
necessary for the dredging operations.
of the Monitoring Results for SB CMPs
Brief discussion of the monitoring results of
the following activities for SB CMPs is presented in
Monthly Progress Report:
· Pit Specific Sediment Chemistry of CMP 2 in October
Water Quality Monitoring of CMP 2 in November 2015; and
Column Profiling of CMP 2 in November 2015.
Pit Specific Sediment
Chemistry of CMP 2 – October 2015
Monitoring locations for Pit Specific Sediment
Chemistry for CMP 2 are shown in Figure 1.3.
A total of six (6) monitoring stations were sampled in October 2015.
The concentrations of most inorganic
contaminants (Arsenic, Cadmium, Chromium, Lead, Nickel and Zinc) were lower than the Lower Chemical Exceedance
Level (LCEL) at all
stations, except Copper, Mercury and Silver (Figures 1 and 2 of Annex D).
the LCEL at Active
Pit stations SB-NPBA (Figure
1 of Annex D) while Silver exceeded the LCEL at both Active Pit stations SB-NPBA and SB-NPBB (Figure
2 of Annex D). In addition, mercury exceeds LCEL at Near Pit
Stations SB-NNBA and SB-NNBB and Pit-edge Station SB-NEBA (Figure 2
of Annex D).
and Silver concentrations were recorded within the Active Pit stations only
which were receiving contaminated mud during the reporting month whilst
higher Mercury concentrations were only recorded at Near Pit stations and
Pit-edge Station. Therefore, there is no evidence indicating any
dispersal of contaminants from the Active Pit due to the disposal activities.
organic contaminants, the concentrations of Total Organic Carbon (TOC) were
similar at all stations (Figure 3 of Annex D). Tributyltin (TBT) concentrations were observed to be
higher at Active Pit station SB-NPBA (Figure 4
of Annex D).
Low and High Molecular Weight Polycyclic Aromatic Hydrocarbons (PAHs), Total Polychlorinated Biphenyls (PCBs),
4,4’-dichlorodiphenyldichloroethylene (DDE) and Total dichlorodiphenyltrichloroethane
(DDT) concentrations were below the limit of reporting at most stations, except
High Molecular Weight PAHs at Active Pit stations
SB-NPBA and SB-NPBB (Figure 5 of Annex D).
there is no evidence indicating any unacceptable environmental impacts to
sediment quality as a result of the contaminated mud disposal operations at CMP
2 in October 2015.
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.
Water Quality Monitoring of SB CMP 2 – November 2015
results for the
Routine Water Quality Monitoring conducted in November 2015 in the dry season
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 2005
- 2014 from stations in the Northwestern Water
Control Zone (WCZ), where the CMPs are located (). For Salinity, the averaged value obtained
from the Reference stations was used for the basis as the WQO. Levels of DO and Turbidity were also assessed
for compliance with the Action and Limit Levels (see Table B3 of Annex B for details). The monitoring results are shown in Figures 6-16
of Annex D and Tables B4 and B5
of Annex B. A total of fourteen (14) monitoring stations
were sampled in November 2015 as shown in Figure 1.4.
Graphical presentation of the monitoring results (Temperature,
DO, pH, Salinity and Turbidity) is shown in Figures 6 -11 of Annex D. Analyses of results for November 2015
indicated that the levels of pH, DO and Salinity complied with the WQOs at all stations (Impact, Intermediate, Reference and
Water Sensitive Receiver stations) in November 2015 (Figures 6 – 8, 10 of Annex D).
The levels of DO and Turbidity complied with
the Action and Limit Levels at all stations (Table B4 of Annex B; Figures 8 and 11 of Annex D).
Overall, in-situ measurement results
of the Routine
Water Quality Monitoring indicated that the disposal operation at
CMP 2 did not appear to cause any unacceptable impacts in water quality in November 2015.
analysis of November 2015 results indicated that
concentrations of Cadmium, Silver and Mercury were below their limit of reporting at all stations. Arsenic, Chromium, Copper, Lead, Nickel and
Zinc were detected in November 2015 samples and the concentrations were
similar amongst stations (Figures 12 & 13 of Annex D). Results of laboratory analysis were shown in Table B5 of Annex B.
nutrients, concentrations of Total Inorganic Nitrogen (TIN) at Intermediate
stations in November 2015 exceeded the WQO (0.5 mg/L) (Figure 14 of Annex D). Ammonia Nitrogen (NH3-N) concentration was
relatively similar amongst all stations (Figure 14 of Annex D). Levels of
5-day Biochemical Oxygen Demand (BOD5) appear to be higher at Shum Shui Kok and Tai Mo To stations in November 2015 (Figure 15 of Annex D).
of SS exceeded the WQO (13.5 mg/L for dry season)
at Reference and Sham Shui Kok stations in November 2015.
Concentrations of SS also
exceeded the Action Levels at Sham Shui Kok while it complied with the Action and Limit
Levels at all other stations in November 2015 (Figure 16 of Annex D; Table B5 of Annex B). Since Sham Shui
Kok station is located further away from Impact
stations where exceedances of Action and Limit Levels
did not occur, the exceedance of SS level was
unlikely to be caused by mud disposal works at CMP 2 and it is considered to be
sporadic events and characteristic of water quality in this area of Hong Kong.
Overall, results of the Routine Water Quality
Monitoring indicated that the disposal operation at CMP 2 did not
appear to cause any unacceptable deterioration in water quality in November 2015. Detailed statistical analysis will be
presented in the Quarterly Report to investigate any spatial and temporal
trends of potential concern.
Column Profiling of CMP 2 – November 2015
Column Profiling was undertaken at a total of two sampling stations
(Upstream and Downstream stations) on 5 November 2015. The monitoring results have been assessed for
compliance with the WQOs (see Section 1.6.9 for
Analyses of results for November 2015
indicated that levels of Salinity, DO and pH complied with the WQOs at both Downstream and Upstream stations (Table B6 of Annex B). In addition, DO and Turbidity at all stations
complied with the Action and Limit Levels (Tables B3 and B6 of Annex B).
Laboratory Measurements for SS
Analyses of results for November 2015 indicated
that the SS levels complied with the WQO at Downstream stations. Both Upstream and Downstream stations complied
with the Action and Limit Levels (Tables B3 and B6 of Annex B).
Overall, the monitoring results indicated
that the mud disposal operation at CMP 2 did not appear to cause any
deterioration in water quality during this reporting period.
Scheduled for the Next Month
The following monitoring activities will be conducted in the
next monthly period of December 2015 for SB CMPs:
Pit Specific Sediment Chemistry of CMP 2;
Cumulative Impact Sediment Chemistry of SB CMPs;
Water Column Profiling of CMP 2;
Water Quality Monitoring During Capping of CMP 1;
Studies of CMP 1.
The following monitoring activities will be
conducted in the next monthly period of December 2015 for ESC CMPs:
Impact Water Quality Monitoring during Dredging Operations of CMP Vd
Studies of CMP IV; and
Water Quality Monitoring During Capping of ESC CMPs.
The sampling schedule is presented in Annex
A summary of the Study programme is
presented in Annex E.