Agreement No. CE 63/2016 (EP)

Environmental Monitoring and Audit
for Disposal Facility to the East of Sha Chau (2017-2020) - Investigation

MONTHLY EM&A REPORT FOR February 2018

1.1                         Background

1.1.1                     The Civil Engineering and Development Department (CEDD) is managing a number of marine disposal facilities in Hong Kong waters, including the Contaminated Mud Pits (CMPs) to the South of The Brothers (SB) and to the East of Sha Chau (ESC) for the disposal of contaminated sediment, and open-sea disposal grounds located to the South of Cheung Chau (SCC), East of Tung Lung Chau (ETLC) and East of Ninepins (ENP) for the disposal of uncontaminated sediment.  Two 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 and 23 December 2011 for the Dredging, Management and Capping of Contaminated Sediment Disposal Facilities at ESC CMP V and SB CMPs, respectively.

Under the requirements of the two EPs for ESC CMP V and SB CMPs, EM&A programmes which encompass water and sediment chemistry, fisheries assessment, tissue and whole body analysis, sediment toxicity and benthic recolonisation studies as set out in the EM&A Manuals are required to be implemented.  EM&A programmes have been continuously carried out during the operation of the CMPs at ESC and SB.  A review of the collection and analysis of such environmental data from the monitoring programme demonstrated that there had not been any adverse environmental impacts resulting from disposal activities ([1]) ([2]).  The current programme will assess the impacts resulting from dredging, disposal and capping operations of CMP V as well as capping operations of SB CMPs.

1.1.2                     The present EM&A programme under Agreement No. CE 63/2016 (EP) covers the dredging, disposal and capping operations of the ESC CMP V as well as the capping operations of the SB CMPs (see Annex A for the EM&A programme).  Detailed works schedule for ESC CMP V and SB CMPs is shown in Figure 1.1.  In February 2018, the following work was being undertaken:

·             Disposal of contaminated mud at ESC CMP Vd.

Figure 1.1       Works Schedule for ESC CMP V and SB CMPs

1.2                         Reporting Period

1.2.1                     This Monthly EM&A Report for February 2018 covers the EM&A activities for the reporting month of February 2018.

1.3                          Details of Sampling and Laboratory Testing Activities

1.3.1                     The following monitoring activities were undertaken for ESC CMP V in February 2018:

·             Pit Specific Sediment Chemistry of ESC CMP Vd was undertaken on 5 February 2018;

·             Cumulative Impact Sediment Chemistry of ESC CMP V was undertaken on 6 and 7 February 2018;

·             Sediment Toxicity Tests of ESC CMP V was undertaken on 6 and 7 February 2018;

·             Routine Water Quality Monitoring of ESC CMP V was undertaken on 8 February 2018;

·             Water Column Profiling of ESC CMP Vd was undertaken on 9 February 2018; and

·             Demersal Trawling for ESC CMP V was undertaken on 26 and 27 February 2018.

1.3.2                     No monitoring activities were undertaken for SB CMP in February 2018.

1.4                         Details of Outstanding Sampling and/or Analysis

1.4.1                     No outstanding sampling remained for February 2018. 

1.4.2                     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 for ESC CMP Vd in February 2018; and

·             Laboratory analyses of sediment samples collected for Cumulative Impact Sediment Chemistry for ESC CMP V in February 2018.

1.4.3                     The following analyses are in progress and will be presented in the corresponding quarterly report:

·             Species identification of the biota samples collected from Demersal Trawling for ESC CMP V in February 2018; and

·             Laboratory analyses for Sediment Toxicity Test of ESC CMP V in February 2018.

1.5                          Brief Discussion of the Monitoring Results for ESC CMP V

1.5.1                     Brief discussion of the monitoring results of the following activities for ESC CMP V is presented in this Monthly EM&A Report for February 2018:

·             Water Column Profiling of ESC CMP Vd in February 2018;

·             Routine Water Quality Monitoring of ESC V in February 2018;

1.5.2                     Water Column Profiling of ESC CMP Vd – February 2018

1.5.3                     Water Column Profiling was undertaken at a total of two sampling stations (Upstream and Downstream stations) on 9 February 2018.  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 2007 - 2016 from stations in the Northwestern Water Control Zone (WCZ), where the ESC CMPs are located ([3]).  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 2018 indicated that levels of DO, Salinity and pH complied with the WQOs at both Downstream and Upstream stations (Table B2 of Annex B).  In addition, levels of 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 2018 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 CMP V – February 2018

1.5.8                     Routine Water Quality Monitoring of ESC CMP V was undertaken on 8 February 2018.  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 2018 as shown in Figure 1.2.

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 2018 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 2018 (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 2018. 

Laboratory Measurements

1.5.12                   Laboratory analysis of February 2018 results indicated that concentrations of Cadmium, Silver and Mercury were below their limit of reporting at all stations.  Arsenic, Chromium, Nickel, Lead, Copper and Zinc were detected in February 2018 samples at most stations 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 Reference and Ma Wan stations in February 2018 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 the Pearl River, the North Western WCZ has historically experienced higher levels of TIN ([4]).  In addition, no exceedances were recorded at Impact and Intermediate stations.  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) and 5-day Biochemical Oxygen Demand (BOD5) were similar amongst all stations, except for slightly higher level of BOD5 recorded at Ma Wan station in February 2018 (Table B4 of Annex B; Figure 8 and 9 of Annex C). 

1.5.14                   Analyses of results for February 2018 indicated that the SS levels at all stations were lower than the WQO (12.8 mg/L for dry season) and SS levels compiled with 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 2018.  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 2018 for ESC CMP V (see Annex A for the sampling schedule):

·             Water Column Profiling of ESC CMP Vd; and

·             Pit Specific Sediment Chemistry of ESC CMP Vd.

1.6.2                     No monitoring activities are scheduled to be undertaken for SB CMPs in March 2018.

1.7                         Study Programme

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


 


(1)    ERM (2013)  Final Report.  Submitted under Agreement No. CE 4/2009 (EP) Environmental Monitoring and Audit for Contaminated Mud Pit at East Sha Chau.  For CEDD.

(2)     ERM (2017)  Final Report.  Submitted under 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).  For CEDD.

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

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