Description: Pages from 0103262 Monthly Progress Nov 12_v0_Page_1

Description: Pages from 0103262 Monthly Progress Nov 12_v0_Page_2

 

 

 

 

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

 

41st MONTHLY PROGRESS REPORT FOR CONTAMINATED MUD PITS AT SHA CHAU November 2012

 

1.1                                      Background

1.1.1                                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 HKSARs dredging and reclamation projects.  In November 2012, the following works were being undertaken at the CMPs:

P       Capping was being undertaken at CMP IVc;

P       Disposal of contaminated mud was taking place at CMP Va; and

P       The dredging of CMP Vd was in progress.

1.1.2                                The Environmental Monitoring and Audit (EM&A) programme for the CMPs at the East of Sha Chau area (ESC) presently covers the above operations.

1.2                                      Reporting Period

This Monthly Progress Report covers the monitoring period of November 2012.

1.3                                      Details of Sampling and Laboratory Testing Activities

1.3.1                                The following monitoring activities have been undertaken for CMP V in November 2012:

P       Routine Water Quality Monitoring was conducted on 5 November 2012;

P       Water Column Profiling was conducted on 6 November 2012;

P       Impact Water Quality Monitoring during Dredging Operations was conducted on 7 November 2012; and

P       Pit Specific Sediment Chemistry was conducted on 8 November 2012.

 

1.3.2                                A summary of field activities are presented in Annex A.

1.4                                      Details of Outstanding Sampling and / or Analysis

1.4.1                                No outstanding sampling remained and laboratory analysis of Pit Specific Sediment Chemistry was yet to be completed during preparation of this monthly report. 

1.5                                      Brief Discussion of the Monitoring Results for CMP V

1.5.1                                Table 1.1 summarises the monitoring results that are presented in the current monthly report.

1.5.2                                Brief discussion of the monitoring results is presented in this section.  Detailed discussion will be presented in the corresponding Quarterly Report.

Table 1.1         Monitoring activities in November 2012

Monitoring activities

Date of Monitoring

Monitoring results presented in this report?

Routine Water Quality Monitoring for CMP Va

5 November 2012

Yes

Water Column Profiling for CMP Va

6 November 2012

Yes

Impact Water Quality Monitoring during Dredging Operations of CMP Vd

7 November 2012

Yes

Pit Specific Sediment Chemistry Monitoring for CMP Va

8 November 2012

No.  Laboratory analysis yet to be completed during preparation of this monthly report.

1.5.3                                Impact Water Quality Monitoring during Dredging Operations of CMP Vd V November 2012

1.5.4                                Impact Water Quality Monitoring during Dredging Operations of CMP Vd was conducted on 7 November 2012.  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 Vd (Figure 1.1).  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).

1.5.5                                Monitoring results are presented in Table B1 of Annex B.  Levels of Dissolved Oxygen (DO), Turbidity and Suspended Solids (SS) complied with the Action and Limit Levels set in the Baseline Monitoring Report ([1]). 

1.5.6                                Overall, there appears to be no unacceptable water quality impacts causing by the dredging operations at CMP Vd and no additional measures are thus considered required except for those stated in the Environmental Permit (EP-312/2008).

1.5.7                                Water Column Profiling for CMP Va V November 2012

In-situ Measurements

1.5.8                                Water Column Profiling was undertaken at a total of two sampling stations in November 2012.  The water quality monitoring results for November 2012 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 1999-2010 from stations in the Northwestern Water Control Zone, where CMPs are located.  For Salinity, the average value obtained from the Upstream station was used for the basis as the WQO.  Graphical presentation of the monitoring results is provided in Annex C.

1.5.9                                Analyses of results for November 2012 indicated that levels of Salinity, pH and DO all complied with the WQOs at both Upstream and Downstream stations (Figures 1 V 3 of Annex C).  DO and Turbidity complied with the Action and Limit Levels set in the EM&A Manual ([2]).


Laboratory Measurements for Suspended Solids (SS)

1.5.10                            Analyses of data obtained in November 2012 indicated that the SS levels at both Upstream and Downstream stations complied with the WQO (Figure 4 of Annex C).  Also, SS levels at all stations measured in November 2012 complied with the Action and Limit Levels set in the EM&A Manual.

1.5.11                            Overall, the results indicated that the mud disposal operation at CMP Va did not appear to cause any deterioration in water quality during this reporting period.

1.5.12                            Routine Water Quality Monitoring for CMP Va V November 2012

1.5.13                            The results for the Routine Water Quality Monitoring conducted during November 2012 in the dry season have been assessed for compliance with the WQOs set by EPD as presented in Section 1.5.8 above (please see Figure 1.2 for the monitoring locations).  In-situ monitoring and laboratory results are shown in Table 1.2 and 1.3, respectively, with graphical presentation provided in Annex C.  Monitoring was undertaken at a total of ten stations in the reporting month.

In-situ Measurements

1.5.14                            Analyses of results for November 2012 indicated that for all stations (Impact, Intermediate and Reference), levels of pH, DO and salinity complied with the WQOs (Figures 5-8 of Annex C).  Levels of DO and Turbidity within the reporting month complied with the Action and Limit Levels set in the EM&A Manual ([3]) (Figure

1.5.15                            s 6 and 9 of Annex C).  All in-situ water quality measurements showed relatively minor variations amongst Impact, Intermediate and Reference stations (Figures 5 to 9 of Annex C). 


Laboratory Measurements

1.5.16                            Analyses of November 2012 results indicate that concentrations of Cadmium, Mercury and Silver were below their limit of reporting at all stations.  Arsenic, Copper, Lead, Nickel and Zinc were detected in samples from all stations (Figures 10 and 11 of Annex C).  Concentrations of Arsenic, Chromium, Lead and Nickel appeared to be similar amongst all stations while concentration of Zinc was the highest at Reference stations.  Levels of 5-day Biochemical Oxygen Demand (BOD5), Total Inorganic Nitrogen (TIN) and NH3-N were similar amongst all stations (Figures 12 and 13 of Annex C).  Concentrations of SS exceed WQO (15.34 mg/L for dry season) at Impact and Intermediate Stations while all of them complied with the Action and Limit Levels at all stations within the reporting month (Figure 14 of Annex C).

Table 1.2     In-situ Monitoring Results for Routine Water Quality Monitoring during November 2012

Stations

Temp

Salinity

Turbidity

pH

Dissolved Oxygen

 

(XC)

 

(NTU)

 

(%)

(mg L-1)

RFE (Reference)

24.86

29.05

6.89

7.53

90.06

6.33

IPE (Impact)

24.96

29.84

9.57

7.67

88.10

6.15

INE (Intermediate)

25.04

29.78

9.02

7.48

86.54

6.03

Ma Wan Station

25.09

30.74

6.04

7.54

84.74

5.88

WQO

N/A

26.15-31.96

N/A

6.5-8.5

N/A

>4

Note: #   Not exceeding 10% of natural ambient level which is the result obtained from the Reference Station.

Table 1.3        Laboratory Results for Routine Water Quality Monitoring during November 2012

Stations

As

(µg/L)

Ag

(µg/L)

Cd

(µg/L)

Cr

(µg/L)

Cu

(µg/L)

Hg

(µg/L)

Pb

(µg/L)

Ni

(µg/L)

Zn

(µg/L)

NH3-N

(mg/L)

TIN

(mg/L)

BOD5

(mg/L)

SS

(mg/L)

RFE

1.96

<LOR

<LOR

0.67

10.58

<LOR

1.29

3.08

19.50

0.04

0.55

1.24

13.75

IPE

2.00

<LOR

<LOR

1.15

5.67

<LOR

0.88

2.25

7.38

0.04

0.46

0.91

16.38

INE

2.08

<LOR

<LOR

0.63

6.96

<LOR

0.90

2.04

11.50

0.05

0.49

1.00

15.46

Ma Wan Station

1.88

<LOR

<LOR

1.00

5.50

<LOR

1.19

2.25

15.50

0.06

0.39

1.51

13.50

WQO of SS

15.34

1.5.17                            Overall, the results indicated that the disposal operation at CMP Va did not appear to cause any deterioration in water quality during this reporting period.

1.6                                      Activities Scheduled for the Next Month

1.6.1                                The following monitoring programmes will be conducted in the next monthly period of December 2012:

CMP V

P          Pit Specific Sediment Chemistry for CMP Va;

P          Cumulative Impact Sediment Chemistry for CMP Va;

P          Water Column Profiling for CMP Va; and

P          Impact Water Quality Monitoring during Dredging Operations for CMP Vd.

1.6.2                                The sampling schedule is presented in Annex A.

1.7                                      Study Programme

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


 



([1])    ERM (2009)  Baseline Monitoring Report.  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 September 2009.

([2])    ERM (2009).  Draft Second Review of the EM&A Manual.  Prepared for CEDD for EM&A for Contaminated Mud Pit at Sha Chau (2009-2013) V Investigation Agreement No. CE 4/2009 (EP).

([3])   ERM (2009).  Draft Second Review of the EM&A Manual.  Prepared for CEDD for EM&A for Contaminated Mud Pit at Sha Chau (2009-2013) V Investigation Agreement No. CE 4/2009 (EP).