Agreement No. CE 4/2009 (EP)
Environmental Monitoring and Audit
for Contaminated Mud Pit at Sha Chau
(2009-2013) - Investigation
6th MONTHLY PROGRESS REPORT FOR CONTAMINATED MUD PITS AT SHA
CHAU - December 2009
1.1
Background
Since 1992, the East of Sha Chau area has been the site of a series of dredged
contaminated mud pits (CMPs) designed to provide
confined marine disposal capacity for contaminated mud arising from the HKSAR’s dredging and reclamation projects. CMP IVc is
presently in operation for backfilling by contaminated mud and is anticipated
to reach its capacity in 2010. A
series of four newly constructed seabed pits at the East of Sha
Chau area, CMP Va-d, will
be provided for the disposal of contaminated mud after CMP IVc
is full. Dredging operations are
now taking place to construct CMP Va.
The environmental monitoring and audit (EM&A) programme for the CMPs at the East of Sha Chau area presently covers disposal operations at CMP IVc and dredging operations at CMP V.
1.2
Reporting Period
This Monthly Progress Report
covers the monitoring period of December 2009.
1.3
Details of Sampling and
Laboratory Testing Activities
Field sampling activities conducted in this monthly period for CMP IVc are listed below:
· Benthic Macro In-fauna Monitoring was conducted on
7 December 2009;
· Cumulative Impact Sediment Chemistry and Sediment Toxicity Monitoring were
conducted on 8 December 2009; and,
· Pit Specific Sediment Chemistry Monitoring and Water Column Profiling were conducted on
9 December 2009.
For CMP V, samplings for Impact
Monitoring during Dredging Operations and Water Column Profiling were conducted on 10 and 11 December 2009,
respectively. A summary of field
activities are presented in Annex A.
A summary of laboratory analysis results submitted by the Contractor in
this reporting month is presented on Table
1.1.
Table 1.1 Summary
of laboratory analysis results submitted by the Contractor during the reporting
month
|
Key Task |
Monitoring Component |
Results Received from the Contractor |
|
CMP IV |
|
|
|
Sediment Sampling and Chemical Analysis |
Sediment Chemistry after a Major Storm Event |
September’s sampling: 15 December 2009 |
|
Sediment Toxicity Testing |
|
August’s sampling: 15 December 2009 |
|
CMP V |
|
|
|
Water Sampling
and Chemical Analysis |
a) Water Column
Profiling |
September’s sampling: 15 December 2009 |
|
|
|
November’s sampling: 15 December 2009 |
|
|
b) Impact Monitoring during Dredging
Operations |
September’s sampling: 15 December 2009 |
|
|
|
October’s sampling: 15 December 2009 |
|
|
|
November’s sampling: 15 December 2009 |
1.4
Details of Outstanding
Sampling and / or Analysis
No outstanding sampling remained from December 2009,
however, Water Quality Monitoring during
Capping of CMP IV was not conducted as capping activities were not
scheduled in this monthly period. Data for Tissue/Whole Body Contaminant Testing remained outstanding from the
Contractor.
1.5
Brief Discussion of the
Monitoring Results
Results of Sediment Toxicity
Testing for August 2009 are presented for CMP IVc. For CMP V, monitoring results are
presented for Water Column Profiling
and Impact Monitoring during Dredging
Operations for December 2009.
Detailed results will be discussed in the relevant Quarterly Reports.
1.5.1
CMP IV
Sediment Toxicity Testing
in August 2009
Sediment ecotoxicology tests
were done on three international species (burrowing amphipod Leptocheirus plumulosus,
marine benthic polychaete Neanthes arenaceodentata and marine bivalve Crassostrea gigas) and
two local species (barnacle Balanus amphitrite and shrimp Penaeus (Litopenaeus) vannamei).
The survival rates of the burrowing amphipod, bivalve,
shrimp and barnacle were not significantly different between animals exposed to
Near-Pit and Reference sediments.
The total dry weight of the benthic polychaete
was also not significantly different between Near-Pit and Reference
sediments.
1.5.2
CMP V
Water Column Profiling for
CMP V during December 2009
Results of Water Column Profiling
for December 2009 show that levels of salinity, pH and DO compiled with the WQOs at both Upstream and Downstream stations (Figures 2 to 4 of Annex B). Levels of TSS exceeded the WQO at both Upstream and Downstream stations (Figure 1 of Annex B).
Impact Monitoring during
Dredging Operations of CMP V – December 2009
Impact Monitoring during Dredging Operations of CMP
V was conducted on 10 December
2009. Sampling was conducted during
both mid-ebb and mid-flood tides at two Reference (Upstream) stations upstream
and five Impact (Downstream) stations downstream of the dredging operations at
CMP V. Monitoring was also
conducted at the Ma Wan station. At
each station, in-situ measurements of
water quality parameters and water samples were taken from three water depth
levels of the water column which were surface (1m below sea surface), mid-depth
and bottom (1m above the seabed).
Monitoring results are presented in Figures
5 to 8 of Annex B. Levels of DO, depth-average Turbidity
and TSS complied with the Action and Limit Levels set in the Baseline Monitoring Report ([1]) (Tables B1 and B2 of Annex B).
1.6
Activities Scheduled for the
Next Month
The following monitoring activities will be conducted in the next monthly period of January
2010:
·
Demersal Trawling for CMP IV;
·
Impact Monitoring during Dredging Operations for CMP V; and,
·
Water Column Profiling for both CMP IV and CMP V.
The sampling schedule is presented in Annex A.
1.7
Study Programme
A summary of Study programme is presented in Annex C.