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
50th MONTHLY PROGRESS REPORT FOR October
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-427/2011/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 ()
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 ESC CMPs and SB CMPs is shown in Figure 1.1. In October 2016, the following works were
· Dredging operation at ESC CMP Vb;
· 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
This 50th Monthly Progress
Report covers the EM&A activities for
the reporting month of October 2016.
Details of Sampling and Laboratory Testing
monitoring activities have been undertaken for ESC CMPs
in October 2016:
· Water Quality
Monitoring During Dredging of
ESC CMP Vb was
undertaken on 3, 5, 7, 11, 13,
15, 17, 19, 24, 26, 28 and 31 October 2016;
Water Quality Monitoring of ESC CMPs was
undertaken on 4 October 2016;
Specific Sediment Chemistry of ESC CMP Vd was
undertaken on 6 October 2016.
Column Profiling of ESC CMP Vd was
undertaken on 12 October 2016;
· Sediment Chemistry
after a Major Storm of ESC CMPs was undertaken on 27 October 2016; and
activities were scheduled to be undertaken for SB CMPs
in October 2016.
No outstanding sampling remained for October 2016.
The following laboratory analyses
are in progress during the preparation of this monthly report and will be
presented in the next monthly report once the data are available:
Laboratory analyses of water samples collected for Sediment Chemistry
after a Major Storm of ESC CMPs in October 2016.
Brief Discussion of the Monitoring Results
for ESC CMPs
Brief discussion of the monitoring results of the
following activities for ESC CMPs is presented in
this 50th Monthly Progress Report:
Water Quality Monitoring During Dredging of ESC CMP Vb in October 2016;
Water Column Profiling of ESC CMP Vd in October 2016;
Routine Water Quality Monitoring of ESC CMPs
in October 2016; and
· Pit Specific Sediment
Chemistry of ESC CMP Vd in October 2016.
Impact Water Quality Monitoring during Dredging
Operations of ESC CMP Vb – October 2016
activities were carried out on 7 - 31 October 2016 during this reporting period and monitoring was conducted three
times per week on 3, 5, 7, 11, 13, 15, 17, 19, 24, 26, 28 and 31 October 2016. During the 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 CMP Vb. 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.
results are presented in Table B1 of Annex B. Daily dredging volume in October 2016 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 (),
except for the following occasion of exceedances
discussed in Table 1.1 below.
indicated that the dredging operations at ESC CMP Vb 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.
Water Column Profiling of ESC CMP Vd – October 2016
Water Column Profiling was undertaken at a total of two sampling stations (Upstream
and Downstream stations) on 12 October 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 (). 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 B2 of Annex B for details).
results for October 2016 indicated that
levels of DO and pH complied with
the WQOs at both Downstream
and Upstream stations (Table B3 of Annex B). In addition, DO and
Turbidity at all stations complied with the Action and Limit Levels (Table
of Annex B).
Laboratory Measurements for Suspended Solids (SS)
results for October 2016 indicated that the SS levels at all stations complied
with the WQOs (Table B3 of Annex B).
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.
Routine Water Quality Monitoring of ESC CMPs
– October 2016
Routine Water Quality Monitoring of ESC CMPs
was undertaken on 4 October 2016. The monitoring results have been assessed for compliance with the WQOs (see Section 1.5.7 for
details) The monitoring
results are shown in Tables B4 and B5 of Annex B and Figures 1 - 10 of Annex D. A total of sixteen (16)
monitoring stations were sampled in October 2016 as shown in Figure 1.3.
presentation of the monitoring results (Temperature, DO, pH, Salinity and
Turbidity) is shown in Figures 1 - 6 of Annex D. Analyses of results for October 2016
indicated that the levels of pH, Salinity and DO complied with the WQOs at all
stations (Impact, Intermediate, Reference and Ma Wan stations) in October 2016 (Table B4 of Annex B; Figures 1, 3 and 5 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 3 and 6 of Annex D).
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 October 2016.
analysis of October 2016 results indicated that concentrations of Cadmium, Silver
and Mercury were below their limit of reporting at all stations. Arsenic, Lead, Chromium, Nickel, Copper and Zinc were detected in October 2016 samples and the concentrations of these
metals and metalloids were similar
amongst stations (Table B5 of Annex B; Figure 7 of Annex D).
concentrations of Total Inorganic Nitrogen (TIN) at all stations except
Intermediate station in October 2016 were
higher than the WQO (0.5 mg/L) (Table B5 of Annex B; Figure 8 of Annex D). It should
be noted that due to the effect of Pearl River, the North Western WCZ has
historically experienced higher levels of TIN (). Since TIN
concentrations were recorded to be similar amongst all stations, the exceedances of TIN WQO at all stations are unlikely to be
caused by the disposal operation at ESC CMP Vd. Concentrations of Ammonia Nitrogen (NH3-N) were
relatively similar amongst all stations (Table B5 of Annex B; Figure 8 of Annex D). Levels of
5-day Biochemical Oxygen Demand (BOD5) appear to be higher at Impact stations in October 2016 (Table B5 of Annex B; Figure 9 of Annex D).
results for October 2016 indicated that the SS levels
at all stations were higher than the WQO (11.0 mg/L for wet season),
however SS levels at all stations complied with the Action and Limit Levels (Table B5 of Annex B; Figure 10 of Annex D).
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 October 2016. Detailed statistical analysis will be
presented in the Quarterly Report to investigate any spatial and temporal
trends of potential concern.
Pit Specific Sediment Chemistry of ESC CMP Vd – October 2016
locations for Pit Specific Sediment Chemistry for ESC CMP Vd are shown in Figure 1.4. A total of
six (6) monitoring stations were sampled in October 2016.
concentrations of all inorganic contaminants were lower than the Lower Chemical Exceedance Level
(LCEL) at all stations in October
2016 (Figures 11 and 12 of Annex D).
For organic contaminants, the
concentrations of Total Organic Carbon (TOC) were similar amongst the stations in October 2016 (Figure 13 of Annex D). In October 2016, Tributyltin (TBT) concentrations were higher
at Active Pit station ESC-NPAB in October 2016 (Figure 14 of Annex D). 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 October 2016.
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 October 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.
Activities Scheduled for the Next Month
The following monitoring
activities will be conducted in the next monthly period of November 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.
activities will be scheduled in the next monthly period of November 2016 for SB CMPs.
schedule is presented in Annex A.
A summary of the
Study programme is presented in Annex E.