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

29th MONTHLY PROGRESS REPORT FOR January 2015

1.1                                      Background

1.1.1                                Since early 1990s, contaminated sediment ([1]) 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) ([2]) facility at the South of The Brothers (SB CMPs) which had been under consideration for a number of years.

1.1.2                                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) ([3]). The Director of Environmental Protection (DEP) approved this EIA report under the Environmental Impact Assessment Ordinance (Cap. 499) (EIAO) in September 2005 (EIA Register No.: AEIAR-089/2005).

1.1.3                                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 ([4]). 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.

 

1.1.4                                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 Manuals ([5]) ([6]) is required to be implemented for the CMPs.

1.1.5                                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 January 2015, the following works were being undertaken at the CMPs:

       Capping operations at ESC CMP Va ;

       Disposal of contaminated mud at SB CMP 2; and

       Capping operations at SB CMP 1.

Figure 1.1 Works Schedule for ESC CMPs and SB CMPs

1.2                                      Reporting Period

1.2.1                                This 29th Monthly Progress Report covers the EM&A activities for the reporting month of January 2015.

1.3                                      Details of Sampling and Laboratory Testing Activities

1.3.1                                                                               No monitoring activities have been undertaken for ESC CMPs in January 2015.

1.3.2                                                                               The following monitoring activities have been undertaken for SB CMPs in January 2015:

       Water Column Profiling of CMP 2 was undertaken on 14 January 2015;

       Routine Water Quality Monitoring of CMP 2 was undertaken on 15 January 2015;

       Pit Specific Sediment Chemistry of CMP 2 was undertaken on 16 January 2015; and

       Demersal Trawling for SB CMP was undertaken on 15 and 16 January 2015.

1.4                                      Details of Outstanding Sampling and/or Analysis

1.4.1                                No outstanding sampling remained for January 2015. The following laboratory analyses were still in progress during the preparation of this monthly report and hence are not presented in this monthly report:

      Laboratory analyses of sediment samples collected for Pit Specific Sediment Chemistry in January 2015;

      Laboratory analyses of water samples collected for Routine Water Quality Monitoring in January 2015; and

      Taxonomic identification of fishery resources collected during Demersal Trawling for SB CMP in January 2015.

1.4.2                                    A summary of field activities conducted are presented in Annex A.

1.5                                      Brief Discussion of the Monitoring Results for SB CMPs

1.5.1                                                                               A brief discussion of the monitoring results of the following activities for SB CMPs is presented in this 29th Monthly Progress Report:

       Pit Specific Sediment Chemistry of CMP 2 conducted in December 2014;

       In-situ measurements of Routine Water Quality Monitoring conducted in January 2015;

       Water Column Profiling conducted in January 2015; and

       Laboratory analyses of samples collected for Water Quality Monitoring during Capping of CMP 1 conducted in December 2014.

1.5.2                                Pit Specific Sediment Chemistry of CMP 2 December 2014

1.5.3                                                                               Monitoring locations for Pit Specific Sediment Chemistry for CMP 2 are shown in Figure 1.2. A total of six (6) monitoring stations were sampled in December 2014.

1.5.4                                                                               The concentrations of all inorganic contaminants were lower than the Lower Chemical Exceedance Level (LCEL) at all stations in December 2014 (Figures 1 and 2 of Annex B).

1.5.5                                                                               For organic contaminants, the concentrations of Total Organic Carbon (TOC) were similar amongst stations in December 2014 (Figure 3 of Annex B). Tributyltins (TBTs) were observed to be higher at Active Pit station SB-NPBB in December 2014 (Figures 4 of Annex B). High Molecular Weight Polycyclic Aromatic Hydrocarbons (MW PAHs) and Low MW PAHs were below the limit of reporting at all stations in December 2014 (Figures 5 of Annex B). 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 December 2014 as well.

1.5.6                                                                               Higher TBTs concentrations were recorded within the Active Pit stations only which were receiving contaminated mud during the reporting month, as such, there is no evidence indicating any dispersal of contaminants from CMP 2 (Active Pit) to nearby sensitive receivers.

1.5.7                                                                               Overall, there is no evidence indicating any unacceptable environmental impacts to sediment quality as a result of the contaminated mud disposal operations at CMP 2 in December 2014.

1.5.8                                Routine Water Quality Monitoring of SB CMP 2 January 2015

1.5.9                                The monitoring results for the Routine Water Quality Monitoring conducted in January 2015 in the dry season have been assessed for compliance with the Water Quality Objectives (WQOs) set by EPD. This consists of a review of the EPD routine water quality monitoring data for the dry season period (November to March) of 2004 - 2013 from stations in the Northwestern Water Control Zone, where the CMPs are located. For Salinity, the averaged value obtained from the Reference stations was used for the basis as the WQO. Levels of DO, Turbidity and SS were also assessed for compliance with the Action and Limit Levels (see Table C1 of Annex C for details). The monitoring results are shown in Figures 6-10 of Annex B and Table C2 of Annex C. A total of fourteen (14) monitoring stations were sampled in January 2015 as shown in Figure 1.3.

In-situ Measurements

1.5.10                                                                           Analyses of results for January 2015 indicated that the levels of pH, DO and Salinity complied with the WQOs at all stations (Impact, Intermediate, Reference and Water Sensitive Receiver stations) in January 2015 (Figures 6-9 of Annex B).

1.5.11                                                                           The levels of DO and Turbidity complied with the Action and Limit Levels at all stations (Figures 8 and 10 of Annex B; Table C1 of Annex C).

1.5.12                            Overall, results of the Routine Water Quality Monitoring indicated that the disposal operation at CMP 1 did not appear to cause any unacceptable impacts in water quality in January 2015.

1.5.13                            Water Column Profiling of CMP 2 January 2015

1.5.14                                                                           Water Column Profiling was undertaken at a total of two sampling stations (Upstream and Downstream stations) on 14 January 2015. The water quality monitoring results have been assessed for compliance with the WQO (see Section 1.5.9 for details). The monitoring results were also compared with the Action and Limit Levels set in Baseline Monitoring Report (see Table C1 of Annex C for details).

In-situ Measurements

1.5.15                                                                           Analyses of results for January 2015 indicated that levels of Salinity, DO and pH complied with the WQOs at both Downstream and Upstream stations (Table C3 of Annex C). DO and Turbidity levels at all stations complied with the Action and Limit Levels (Tables C1 and C3 of Annex C).

Laboratory Measurements for SS

1.5.16                                                                           Analyses of results for January 2015 indicated that the SS levels at both Upstream and Downstream stations complied with the WQO. SS levels at all stations also complied with the Action and Limit Levels (Tables C1 and C3 of Annex C).

1.5.17                                                                           Overall, the monitoring results indicated that the mud disposal operation at CMP 2 did not appear to cause any unacceptable impacts in water quality during this reporting period.

 

1.5.18                            Water Quality Monitoring during Capping Operations of CMP 1 December 2014

1.5.19                            The monitoring results obtained during December 2014 sampling in the dry season have been assessed for compliance with the WQOs (see Section 1.5.9 for details). A total of fourteen (14) monitoring stations were sampled in December 2014 as shown in Figure 1.3. Graphical presentation of the monitoring results is provided in Annex B.

Laboratory Measurements

1.5.20                            Concentrations of SS complied with the WQO at all stations in December 2014 (Figure 11 of Annex B).

1.5.21                            For nutrients, concentrations of Ammonia (NH3) and 5-day Biochemical Oxygen Demand (BOD5) were similar amongst all stations (Figures 12 and 14 of Annex B). Total Inorganic Nitrogen (TIN) at all stations complied with the WQO of 0.5 mg/L in December 2014 (Figure 13 of Annex B).

1.5.22                            Statistical analysis will be undertaken in the quarterly report to investigate whether the capping operations at CMP 1 is causing any unacceptable impacts in water quality of the area.

1.6                                      Activities Scheduled for the Next Month

1.6.1                               The following monitoring activities will be conducted in the next monthly period of February 2015 for SB CMPs:

       Pit Specific Sediment Chemistry of CMP 2;

       Cumulative Impact Sediment Chemistry of SB CMP;

       Sediment Toxicity Tests of CMP 2;

       Tissue / Whole Body Analysis of Trawled Samples for SB CMP;

       Demersal Trawling for CMP 2;

       Routine Water Quality Monitoring for CMP 2;

       Water Column Profiling of CMP 2; and

       Water Quality Monitoring during Capping Operations of CMP 1.

1.6.2                                Water Quality Monitoring during Capping Operations of ESC CMPs will be conducted in the next monthly period of February 2015 for ESC CMPs.

1.6.3                                The sampling schedule is presented in Annex A.

 

1.7                                      Study Programme

1.7.1                                A summary of the Study programme is presented in Annex D.


 



([1]) According to the Management Framework of Dredged/ Excavated Sediment of ETWB TC(W) No. 34/2002, contaminated sediment in general shall mean those sediment requiring Type 2 Confined Marine Disposal as determined according to this TC(W).

([2]) CAD options may involve use of excavated borrow pits, or may involve purpose-built excavated pits. CAD sites are those which involve filling a seabed pit with contaminated mud and capping it with uncontaminated material such that the original seabed level is restored and the contaminated material is isolated from the surrounding marine environment.7

([3]) Detailed Site Selection Study for a Proposed Contaminated Mud Disposal Facility within the Airport East/ East of Sha Chau Area (Agreement No. CE 12/2002(EP))

([4]) Under the CEDD study Contaminated Sediment Disposal Facility to the South of The Brothers (Agreement No. FM 2/2009)

([5]) ERM (2012) Environmental Monitoring and Audit (EM&A) Manual.Final First Review. Environmental Monitoring and Audit for Contaminated Mud Pits to the South of the Brothers and at East Sha Chau (2012-2017) Investigation. Agreement No. CE 23/2012(EP). Submitted to EPD in November 2012.

([6]) ERM (2010) Environmental Monitoring and Audit (EM&A) Manual.Final Second Review. Environmental Monitoring and Audit for Contaminated Mud Pit at Sha Chau (2009-2013) Investigation. Agreement No. CE 4/2009(EP). Submitted to EPD in November 2010.