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

54^th MONTHLY PROGRESS REPORT FOR February 2017

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-427/2011/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 ([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 ESC CMPs and SB CMPs is shown in Figure 1.1. In February 2017, the following works were being undertaken:

¡P Disposal of contaminated mud at ESC CMP Vd.

Figure 1.1 Works Schedule for ESC CMPs and SB CMPs

1.2 Reporting Period

1.2.1 This 54^th Monthly Progress Report covers the EM&A activities for the reporting month of February 2017.

1.3 Details of Sampling and Laboratory Testing Activities

1.3.1 The following monitoring activities have been undertaken for ESC CMPs in February 2017:

¡P Demersal Trawling of ESC CMPs was undertaken on 8 and 9 February 2017;

¡P Routine Water Quality Monitoring of ESC CMPs was undertaken on 20 February 2017;

¡P Cumulative Impact Sediment Chemistry of ESC CMPs was undertaken on 21 and 23 February 2017;

¡P Sediment Toxicity Test of ESC CMPs was undertaken on 21 and 23 February 2017;

¡P Pit Specific Sediment Chemistry of ESC CMP Vd was undertaken on 24 February 2017; and

¡P Water Column Profiling of ESC CMP Vd was undertaken on 25 February 2017.

1.3.2 No monitoring activities were scheduled to be undertaken for SB CMPs in February 2017.

1.4 Details of Outstanding Sampling and/or Analysis

1.4.1 No outstanding sampling remained for February 2017.

1.4.2 A summary of field activities conducted are presented in Annex A. The following analyses are in progress and will be presented in the corresponding quarterly report:

¡P Species identification of the biota samples collected from Demersal Trawling for ESC CMPs in February 2017; and

¡P Laboratory analyses for Sediment Toxicity Test of ESC CMPs in February 2017.

1.4.3 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:

¡P Laboratory analyses of sediment samples collected for Pit Specific Sediment Chemistry of ESC CMP Vd in February 2017; and

¡P Laboratory analyses of sediment samples collected for Cumulative Impact Sediment Chemistry of ESC CMPs in February 2017.

1.5 Brief Discussion of the Monitoring Results for ESC CMPs

1.5.1 Brief discussion of the monitoring results of the following activities for ESC CMPs is presented in this 54^th Monthly Progress Report:

¡P Water Column Profiling of ESC CMP Vd in February 2017; and

¡P Routine Water Quality Monitoring of ESC CMPs in February 2017.

1.5.2 Water Column Profiling of ESC CMP Vd ¡V February 2017

1.5.3 Water Column Profiling was undertaken at a total of two sampling stations (Upstream and Downstream stations) on 25 February 2017. 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 dry season period (November to March) of 2006 - 2015 from stations in the Northwestern Water Control Zone (WCZ), where the ESC CMPs are located ([7]). For Salinity, the averaged value obtained from the Reference (Upstream) station was used for the basis as the WQO. Levels of Dissolved Oxygen (DO) and Turbidity were also assessed for compliance with the Action and Limit Levels (see Table B1 of Annex B for details).

In-situ Measurements

1.5.4 Analyses of results for February 2017 indicated that levels of DO and pH complied with the WQOs at both Downstream and Upstream stations (Table B2 of Annex B). In addition, DO and Turbidity at all stations complied with the Action and Limit Levels (Tables B1 and B2 of Annex B).

Laboratory Measurements for Suspended Solids (SS)

1.5.5 Analyses of results for February 2017 indicated that the SS levels complied with the WQO and the Action and Limit Levels at both Upstream and Downstream stations (Tables B1 and B2 of Annex B).

1.5.6 Overall, the 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.

1.5.7 Routine Water Quality Monitoring of ESC CMPs ¡V February 2017

1.5.8 Routine Water Quality Monitoring of ESC CMPs was undertaken on 20 February 2017. The monitoring results have been assessed for compliance with the WQOs (see Section 1.5.3 for details). The monitoring results are shown in Tables B3 and B4 of Annex B and Figures 1 - 10 of Annex C. A total of ten (10) monitoring stations were sampled in February 2017 as shown in Figure 1.2[RC1] .

In-situ Measurements

1.5.9 Graphical presentation of the monitoring results (Temperature, DO, pH, Salinity and Turbidity) is shown in Figures 1 - 6 of Annex C. Analyses of results for February 2017 indicated that the levels of pH, Salinity and DO complied with the WQOs at all stations (Impact, Intermediate, Reference and Ma Wan stations) in February 2017 (Table B3 of Annex B; Figures 1, 3 and 5 of Annex C).

1.5.10 The levels of DO and Turbidity complied with the Action and Limit Levels at all stations (Table B3 of Annex B; Figures 3 and 6 of Annex C).

1.5.11 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 February 2017.

Laboratory Measurements

1.5.12 Laboratory analysis of February 2017 results indicated that concentrations of Cadmium, Chromium, Silver and Mercury were below their limit of reporting at all stations. Arsenic, Nickel, Lead, Copper and Zinc were detected in February 2017 samples and the concentrations of these metals and metalloids were similar amongst stations (Table B4 of Annex B; Figure 7 of Annex C).

1.5.13 For nutrients, concentrations of Total Inorganic Nitrogen (TIN) at all stations in February 2017 were higher than the WQO (0.5 mg/L) (Table B4 of Annex B; Figure 8 of Annex C). It should be noted that due to the effect of Pearl River, the North Western WCZ has historically experienced higher levels of TIN ([8]). Therefore, the exceedances of TIN WQO at these 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 B4 of Annex B; Figure 8 of Annex C). Levels of 5-day Biochemical Oxygen Demand (BOD₅) appear to be higher at Impact stations than at other stations in February 2017 (Table B4 of Annex B; Figure 9 of Annex C).

1.5.14 Analyses of results for February 2017 indicated that the SS levels complied with the WQO (13.2 mg/L for dry season) and the Action and Limit Levels at all stations (Tables B1 and B4 of Annex B; Figure 10 of Annex C).

1.5.15 Overall, 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 February 2017. Detailed statistical analysis will be presented in the Quarterly Report to investigate any spatial and temporal trends of potential concern.

1.6 Activities Scheduled for the Next Month

1.6.1 The following monitoring activities will be conducted in the next monthly period of March 2017 for ESC CMPs:

¡P Water Column Profiling of ESC CMP Vd; and

¡P Pit Specific Sediment Chemistry of ESC CMP Vd.

1.6.2 No monitoring activities are scheduled in the next monthly period of March 2017 for SB 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.

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([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 ¡V 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) ¡V 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) ¡V Investigation. Agreement No. CE 4/2009(EP). Submitted to EPD in November 2010.

([7]) http://epic.epd.gov.hk/EPICRIVER/marine/?lang=en

([8]) http://www.epd.gov.hk/epd/misc/marine_quality/1986-2005/textonly/eng/index.htm

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[RC1]Please update Figure 1.2 to reflect the latest monitoring station change.