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
27th MONTHLY PROGRESS REPORT FOR NOVEMBER 2014
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
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 2014, the following works were being undertaken at the CMPs:
was being undertaken at ESC CMPs ;
contaminated mud was taking place at SB CMP 1 until 25 November 2014 and at SB
CMP 2 starting from 26 November 2014; and
operations were taking place at SB CMP 2 until 25 November 2014.
Figure 1.1 Works Schedule for ESC CMPs and SB CMPs
This 27th Monthly Progress Report covers the EM&A activities for the reporting month of November 2014.
Details of Sampling and Laboratory Testing
activity was scheduled to be undertaken for ESC CMPs
in November 2014.
monitoring activities have been undertaken for SB CMPs
in November 2014:
Impact Water Quality Monitoring during Dredging
Operations was undertaken for CMP 2 three
times per week on 3, 5, 7, 10, 12, 14, 17, 19, 21 and 24 November 2014;
Routine Water Quality Monitoring for CMP 1 was undertaken on 4 November 2014;
Pit Specific Sediment Chemistry for CMP 1 was undertaken on 6 November 2014; and
Water Column Profiling for CMP 1 was undertaken on 13 November 2014.
Details of Outstanding Sampling and/or
No outstanding sampling remained for November 2014.
A summary of
field activities conducted are presented in Annex A.
Brief discussion of the monitoring results of the
following activities for SB CMPs is presented in this
27th Monthly Progress Report:
Pit Specific Sediment Chemistry of CMP 1 conducted in October
and November 2014;
Impact Water Quality Monitoring during Dredging
Operations of CMP 2 conducted from 31 October 2014 to
24 November 2014;
Routine Water Quality Monitoring of CMP 1 conducted in October and November 2014; and
Water Column Profiling of CMP 1 conducted on 13 November 2014.
Pit Specific Sediment Chemistry of CMP 1 – October and November 2014
locations for Pit Specific Sediment Chemistry for CMP 1 are shown in Figure 1.2. A total of
six (6) monitoring stations were sampled in October and November 2014.
The concentrations of all inorganic contaminants were lower than the Lower Chemical Exceedance Level (LCEL) at all stations in October 2014 (Figures 1 and 2 of Annex B) and November
2014 (Figures 6 and 7 of Annex B).
For organic contaminants, the
concentrations of Total Organic Carbon (TOC) were
similar amongst stations in October and November 2014 (Figures 3
and 8 of Annex
B). Tributyltin (TBTs) were observed to be higher at Near
Pit station SB-NNAB and at Active Pit station SB-NPAB in October and November
2014, respectively (Figures 4 and 9 of Annex B). High Molecular Weight
Polycyclic Aromatic Hydrocarbons (MW PAHs) were above
limit of reporting at Active Pit stations SB-NPAA and SB-NPAB in October and
November 2014 (Figures 5 and 10 of Annex B) Low MW PAHs,
Total Dichloro-Diphenyl-Trichloroethane (DDT), 4,4’-Dichloro-Diphenyl-Dichloroethylene
(4,4’-DDE) and Total Polychlorinated Biphenyls (PCBs) were recorded below the
limit of reporting at all stations in October and November 2014.
As higher TOC, TBTs
and High MW PAHs concentrations were generally recorded
within the Active Pit stations only which were receiving contaminated mud
during the reporting months, there is no evidence indicating any dispersal of
contaminants from the active pit to nearby sensitive receivers.
Overall, there is no evidence
indicating any unacceptable environmental impacts to sediment quality as a
result of the contaminated mud disposal operations at CMP 1 in October and
Impact Water Quality Monitoring during Dredging
Operations of CMP 2 – 31 October to 24 November 2014
Impact Water Quality Monitoring
during Dredging Operations of CMP 2 was
conducted three times per week from 31 October to 24 November 2014 during the
reporting period. 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 of the dredging operations at CMP 2. Monitoring was also conducted at five
Sensitive Receiver Stations situated in Ma Wan, Shum Shui
Kok, Tai Mo To and Tai Ho Bay. A total of twelve (12) stations were
monitored and locations of the sampling stations are shown in Figure 1.3.
results are presented in Table C1 of Annex C. Daily dredging volume in October and November
2014 is reported in Annex D. Levels of Dissolved Oxygen (DO), Turbidity
and Suspended Solids (SS) generally complied with the Action and Limit Levels
(see Table C2 of Annex C for details) set in the Baseline
Monitoring Report (), except for the following occasion of exceedances
discussed in Table 1.1 below.
As presented in Table
1.1, the results indicated that the dredging
operations at CMP 2 did not appear to cause any unacceptable deterioration
in water quality during this reporting period.
Therefore, no further mitigation measures, except for those recommended
in the Environmental Permit (EP-427/2011/A), are considered necessary for the dredging operations.
Table 1.1 Details
of Exceedances Recorded at CMP 2 between 31 October and 24 November 2014
These exceedances were not
considered as indicating any unacceptable impacts from the dredging
operations to Water Sensitive Receivers (WSRs)
outside the works area due to the following reason:
· Stations DS2, DS3 and DS4
are located further away from the works area of CMP 2 when compared to
station DS1 at which the levels of Turbidity and SS did not exceed the Action
and Limit Levels during the same tidal period.
Routine Water Quality Monitoring of CMP 1 – October and November 2014
Routine Water Quality Monitoring were undertaken on 14 October and 4 November 2014 at a total of fourteen (14) sampling stations as shown in Figure 1.4. The water quality monitoring results have been
assessed for compliance with the Water Quality Objectives (WQOs)
through a review of the Environmental Protection Department (EPD) routine water
quality monitoring data for the wet season period (April to October) and dry season period (November to March) of 2004-2013 from stations in the North Western Water
Control Zone (WCZ), where CMP is located. Levels of DO, Turbidity and SS were also
assessed for compliance with the Action and Limit Levels (see Table C2 of Annex C for details). The
monitoring results are shown in Figures 11-30 of Annex B and Tables C3-C4 of Annex C.
Analyses of results for October and November 2014 indicated that the levels of pH, DO and Salinity complied with the WQOs at all
stations (Impact, Intermediate, Reference and Water Sensitive Receiver
stations) (Figures 11-14
and 21-24 of Annex B; Table C3 of Annex C).
The levels of
DO and Turbidity complied with the Action and Limit Levels at all stations in October
and November 2014 (Figures
12, 15, 22 and 25 of Annex B; Table C3 of Annex C).
analysis of October
and November 2014 results indicated that
concentrations of Mercury and Silver were below their limit of reporting at all stations.
Arsenic, Cadmium, Chromium, Copper, Lead, Nickel and Zinc were detected in samples from most stations (Figures 16-17
26-27 of Annex B; Table C4 of Annex C). Detailed statistical analysis will be presented in the Quarterly Report to observe
any spatial and temporal trends.
For nutrients, concentrations of
Total Inorganic Nitrogen (TIN) at all stations in October and November 2014
monitoring complied with the WQO of 0.5mg/L (Figures 18 and 28 of Annex B). Ammonia Nitrogen (NH3-N)
concentration was relatively similar amongst all stations (Figures 18 and 28 of Annex B). Level of 5-day Biochemical Oxygen Demand (BOD5)
was similar amongst stations (Figures 19
and 29 of Annex B).
Concentrations of SS exceeded the
WQO (11.6 mg/L for
wet season; 13.8 mg/L for dry season) at
Reference, Tai Mo To and Tai
Ho Bay 1 stations in October and November 2014. However, SS at all stations complied with the Action and Limit Levels in October and
November 2014 (Figures 20 and 30 of Annex B; Table C4 of Annex C).
results of the Routine Water Quality Monitoring indicated that the disposal operation at CMP 1 did
not appear to cause any unacceptable deterioration in water quality in October and
Water Column Profiling of CMP 1 – November 2014
Water Column Profiling was undertaken at a total of two sampling stations (Upstream
and Downstream stations) on 13 November 2014.
The water quality monitoring
results have been assessed for compliance with the WQO as discussed in Section 1.5.13. The monitoring results were also compared with the Action and Limit Levels set
Monitoring Report (see Table C2 of Annex C for details).
results for November 2014 indicated that levels of Salinity, turbidity, DO and pH
complied with the WQOs at both Downstream and
Upstream stations (Table C5 of Annex C).
Measurements for SS
Analyses of results
for November 2014 indicated that the SS levels at both Upstream and Downstream stations complied
with the WQO. SS levels at all stations complied with the Action and Limit Levels (Table C5 of Annex C).
monitoring results indicated that the mud disposal operation at CMP 1 did not
appear to cause any deterioration in water quality during this reporting
Activities Scheduled for the Next Month
monitoring activities will be conducted in the next monthly period of December 2014
for SB CMPs:
Pit Specific Sediment Chemistry of CMP 2;
Cumulative Impact Sediment Chemistry of CMP 2;
Water Column Profiling of CMP 2;
Water Quality Monitoring during Capping Operations
of CMP 1.
The following monitoring activities
will be conducted in the next monthly period of December 2014 for ESC CMPs:
Water Quality Monitoring
during Capping Operations of ESC CMPs; and
Studies of ESC CMPs.
schedule is presented in Annex A.
A summary of the Study
programme is presented in Annex E.