Agreement No. CE 4/2009 (EP)
Environmental Monitoring and Audit
for Contaminated Mud Pit at Sha Chau (2009-2013) - Investigation
9th
MONTHLY PROGRESS REPORT FOR CONTAMINATED MUD PITS AT SHA CHAU - March 2010
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 March 2010.
1.3
Details of Sampling and
Laboratory Testing Activities
No field sampling
activities were scheduled for CMP IVc in this monthly
period.
For CMP V, sampling for Impact
Monitoring during Dredging Operations was conducted on 15 March
2010. 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 |
|
|
|
Water Sampling
and Chemical Analysis |
Routine water
quality monitoring |
February’s sampling: 30 March 2010 |
|
Sediment
Sampling and Chemical Analysis |
Sediment Toxicity Monitoring |
December’s sampling: 9 March 2010 |
|
|
|
|
|
Demersal
Trawling and Tissue Analysis |
Demersal Trawling |
February’s Sampling: 30 March 2010 |
|
|
|
|
|
CMP V |
|
|
|
Water Sampling
and Chemical Analysis |
Impact Monitoring
during Dredging Operations |
March’s sampling: 23 March 2010 |
|
|
|
|
1.4
Details of Outstanding
Sampling and / or Analysis
No outstanding sampling and laboratory analysis remained from March 2010.
1.5
Brief Discussion of the Monitoring
Results
Results of Sediment Toxicity
Monitoring for December 2009 and Routine
Water Quality Monitoring for February 2010 are presented for CMP IV. Results of Impact Monitoring during Dredging Operations for March 2010 are
presented for CMP V. Detailed results
will be discussed in the relevant Quarterly
Reports.
1.5.1
CMP IV
Sediment Toxicity Testing in December 2009
Sediment ecotoxicology tests were done on three
international species (burrowing amphipod Leptocheirus
plumulosus, marine benthic polychaete Neanthes
arenaceodentata and marine bivalve Mytilus
galloprovincialis) and two local species (barnacle Balanus amphitrite and shrimp Penaeus
(Litopenaeus) vannamei).
The survival rates of the amphipod, polychaete,
bivalve, shrimp and barnacle were not significantly different between animals
exposed to Near-Pit and Reference sediments.
Other indicators i.e. individual & total dry weight and growth rate
of the benthic polychaete were also not significantly different between animals
exposed to Near-Pit and Reference sediments.
Routine Water Quality Monitoring in February
2010
Laboratory Analysis
Concentrations of copper,
zinc and nickel were lower at the Impact stations than at the Intermediate and
Reference stations. Lead concentrations
were similar across the sampling stations (Figure
1 of Annex B). All
other metals sampled were below the limits of detection. Mean Total Suspended Solids (TSS) level was the
lowest at the Impact Stations. Mean TSS
levels at the Intermediate and Reference stations exceeded the WQO (Figure 3 of Annex B). Nitrogenous nutrients (NH3 and
TIN) and BOD showed minor variation in concentrations between stations (Figures 2 & 4 of Annex B).
1.5.2
CMP V
Impact Monitoring during Dredging Operations of
CMP V – March 2010
Impact
Monitoring during Dredging Operations of CMP V was conducted on 15 March
2010. 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
Pit Specific Sediment
Chemistry Monitoring for CMP IV and Impact Monitoring during Dredging Operations for CMP V are scheduled in the next monthly period of April 2010. The sampling schedule is presented in Annex A.
1.7
Study Programme
A summary of the Study programme is presented in Annex C.