Environmental Monitoring & Audit for Contaminated Mud Pit

Agreement No. CE 4/2009 (EP)
Environmental Monitoring and Audit
for Contaminated Mud Pit at Sha Chau (2009-2013) - Investigation

21^st MONTHLY PROGRESS REPORT FOR CONTAMINATED MUD PITS AT SHA CHAU (for MARCH 2011)

June 2011

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 2011. 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 were completed for the construction of CMP Va and are now taking place to construct CMP Vb. The environmental monitoring and audit (EM&A) programme for the CMPs at the East of Sha Chau area presently covers disposal and capping operations at CMP IV and dredging operations at CMP Vb.

1.2 Reporting Period

This Monthly Progress Report covers the monitoring period of March 2011.

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 8March 2011. 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
Demersal Trawling	Marine Biota	February 2011: 15 March 2011
CMP V
Impact Monitoring during Dredging Operations	Water Quality	March 2011: 15 March 2011

1.4 Details of Outstanding Sampling and / or Analysis

No outstanding sampling and laboratory analysis remained from March 2011.

1.5 Brief Discussion of the Monitoring Results

Results of Demersal Trawling for February 2011 are presented for CMP IV and results of Impact Monitoring during Dredging Operations for March 2011 are presented for CMP V. Detailed results will be discussed in the 7^th Quarterly Report.

1.5.1 CMP IV

Demersal Trawling in February 2011

The final Demersal Trawling samples for the 2011 dry season were collected at CMP IV on 16 and 17 February 2011. Mean number of faunal species was relatively consistent between Impact and Reference stations (Table 1.2) but Number of Individuals, Biomass, Catch-per-Uni-Effort (CPUE) and Yield-per-Unit-Effort (YPUE) were notable higher at Impact station INA (Table 1.3). These results will be analysed in greater depth together with results from Demersal Trawling carried out in December 2010 and January 2011 in the 8^th Quarterly Report.

Table 1.2 Mean Number of Faunal Species caught February 2011 Monitoring.

Date of Sampling	IMPACT STATIONS		REFERENCE STATIONS
	INA	INB	TNA	TNB	TSA	TSB
Feb 2011	42.2	33.8	38.8	39.0	42.7	37.6

Table 1.3 Summary of CPUE and YPUE during February 2011 Monitoring

Station	Impact / Reference Area	No. of Individuals	Total Biomass (g)	Mean CPUE^#1 per Tow	Mean YPUE^#2 per Tow (g)
INA	Impact	38,468	343,150	7,694	68,630
INB	Impact	10,839	93,246	2,168	18,649
TNA	Reference	3,560	26,635	712	5,327
TNB	Reference	8,442	53,418	1,688	10,684
TSA	Reference	13,498	202,931	2,700	40,586
TSB	Reference	23,759	197,487	4,752	39,497

^#1 CPUE is calculated by dividing the number of individuals with the trawling time and number of nets (in hour and number of nets)

^#2YPUE is calculated by dividing the weight (g) of fish with trawling effort (in hour and number of nets)

1.5.2 CMP V

Impact Water Quality Monitoring during Dredging Operations of CMP V – May 2011

Impact Water Quality Monitoring during Dredging Operations of CMP V was conducted on 24 May 2011. On the survey day, 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 as well as water samples were taken from three depths in the water column (ie surface: 1 m below sea surface, mid-depth and bottom: 1 m above the seabed).

Monitoring results are presented in Table B1 of Annex B. Levels of Dissolved Oxygen (DO), Turbidity and Total Suspended Solids (TSS) complied with the Action and Limit Levels set in the Baseline Monitoring Report ([1]). Therefore, there appears to be no evidence of any unacceptable adverse water quality impacts arising from the dredging operations of CMP V at ESC.

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 2011. The sampling schedule is presented in Annex A.

1.7 Study Programme

A summary of the Study programme is presented in Annex C.

([1]) ERM (2009) Baseline Monitoring Report. Environmental Monitoring and Audit for Contaminated Mud Pit at Sha Chau (2009-2013) – Investigation. Agreement No. CE 4/2009(EP). Submitted to EPD in September 2009.