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Contents

1                      Introduction                                                                          

1.1                   Purpose of the Manual                                                    

1.2                   Review of EM&A Manual                                                     

1.3                   Background to the EM&A Programme                      

1.4                   Objectives of the EM&A Programme                          

1.5                   The Scope of the EM&A Programme                            

1.6                   Organisation and Structure of the EM&A             

1.7                   Structure of the EM&A Manual                                    

2                      EM&A GENERAL REQUIREMENT                                            

2.1                   Introduction                                                                          

2.2                   EM&A                                                                                            

2.3                   Environmental Management Plan (EMP)                   

3                      Water Quality                                                                        

3.1                   Introduction                                                                          

3.2                   Monitoring Activities                                                         

3.3                   Monitoring for Dredging Activities of CMP V       

3.4                   Monitoring for Backfilling Activities                     

3.5                   Monitoring for Capping Activities                              

3.6                   Sampling Procedure for Water Quality monitoring      

3.7                   QA/QC                                                                                          

4                      Sediment Quality                                                                  

4.1                   Introduction                                                                          

4.2                   Objective                                                                                  

4.3                   Hypotheses                                                                             

4.4                   Sampling Design                                                                    

4.5                   Statistical Treatment of Data                                     

4.6                   Use of Data                                                                             

4.7                   Sampling Procedure and Equipment                         

4.8                   QA/QC                                                                                          

4.9                   Data Quality Objectives                                                  

5                      Sediment Toxicity                                                                 

5.1                   Introduction                                                                          

5.2                   Objective                                                                                  

5.3                   Hypothesis                                                                               

5.4                   Sampling Design                                                                    

5.5                   Statistical Treatment of Data                                     

5.6                   Use of Data                                                                             

5.7                   Data Collection Parameters                                        

5.8                   Sampling Procedure and Equipment                         

5.9                   QA/QC                                                                                          

6                      Marine Biota                                                                           

6.1                   Introduction                                                                          

6.2                   Objective                                                                                  

6.3                   Hypothesis                                                                               

6.4                   Sampling Design                                                                    

6.5                   Statistical Treatment of Data                                     

6.6                   Use of Data                                                                             

6.7                   Data Collection Parameters                                        

6.8                   Sampling Procedure and Equipment                         

7                      Human Health and Ecological Risk Assessment

7.1                   Introduction                                                                          

7.2                   Objective                                                                                  

7.3                   Hypothesis                                                                               

7.4                   Sampling Design                                                                    

7.5                   Use of Data                                                                             

8                      Benthic Recolonisation                                                   

8.1                   Introduction                                                                          

8.2                   Objective                                                                                  

8.3                   Hypothesis                                                                               

8.4                   Sampling Design                                                                    

8.5                   Statistical Treatment of Data                                     

8.6                   Use of Data                                                                             

8.7                   Laboratory Procedures                                                

8.8                   Benthic Macro-Infauna and Taxonomic Identification   

9                      Impacts of Major Storms                                                

9.1                   Introduction                                                                          

9.2                   Sampling Design                                                                    

10                    Reporting                                                                                

10.1                 General                                                                                    

10.2                 Reports                                                                                     

 

 

 

ANNEXES

 

Annex A         Implementation Schedule for CMP V

Annex B         Complaints Proforma

Annex C         Sampling Programme

 

 

1                                        Introduction

1.1                                    Purpose of the Manual

This Environmental Monitoring and Audit (EM&A) Manual (“the Manual”) has been prepared by ERM-Hong Kong, Limited (ERM) on behalf of the Civil Engineering and Development Department (CEDD) of the Hong Kong Special Administrative Region (HKSAR) Government. 

The purpose of the Manual is to provide information, guidance and instruction to personnel charged with environmental duties and those responsible for undertaking EM&A work during the construction and operation of Contaminated Mud Pit V (CMP V) at East of Sha Chau (ESC).  It provides systematic procedures for monitoring and auditing of potential environmental impacts that may arise from the works.

EM&A works relating to CMP V have been prepared in accordance with the Environmental Permit (EP) (EP-312/2008/A) (EP) for Disposal of Contaminated Sediment – Dredging, Management and Capping of Sediment Disposal Facility at Sha Chau (hereafter referred as “the Project”) and the Technical Memorandum of the Environmental Impact Assessment Process (EIAO TM).

1.2                                    Update of EM&A Manual

The EM&A Manual is an evolving document that should be updated to maintain its relevance as the Project progresses to ensure the impacts predicted and the recommended mitigation measures remain consistent and appropriate to the manner in which the works are to be carried out at CMP V of ESC.  This updated submission incorporates the alternative monitoring stations for water quality (in Section 3), sediment quality (in Sections 4 and 9) and sediment toxicity (in Section 5) due to the marine construction works of the Expansion of Hong Kong International Airport into a Three-runway System.  The alternative monitoring stations were reported in the Proposal of Alternative Monitoring Locations for the EM&A Activities ([1]) and were approved by the Environmental Protection Department (EPD) on 1 February 2017.  In addition, this Updated EM&A Manual describes the sampling design of benthic recolonisation study for CMP V to verify the recolonisation of marine biota on the capped pits at CMP V.  The latest EM&A programme for CMP V between April 2017 and March 2021 is also presented in Annex C of this Updated EM&A Manual. 

Further reviews and subsequent updates of the EM&A Manual will be undertaken whenever necessary to take into account the findings obtained during the Study as the works progress and will be presented in separate documents.

1.3                                    Background to the EM&A Programme

Since December 1992, the ESC area has been the site of a series of dredged CMPs designed to provide confined marine disposal capacity for contaminated mud arising from the HKSAR’s dredging and reclamation projects.  The EM&A programme has been carrying out for the construction and operation of ESC CMPs since 1992 and the monitoring results were generally satisfactory, demonstrating the CMPs were operating in an environmentally acceptable manner.  The latest group of pits, CMP Va, Vb, Vc & Vd (collectively known as CMP V) began receiving contaminated mud from construction projects since February 2012. 
The dredging, backfilling and capping of CMP V is classified as a Designated Project by virtue of Item C (Reclamation, Hydraulic and Marine Facilities, Dredging and Dumping), Item C.10 (A Marine Dumping Area) and C.12 (A Dredging Operation Exceeding 500,000 m3) of Part I of Schedule 2 under the Environmental Impact Assessment Ordinance (Cap. 499) (EIAO).  The key components of the construction and operation of CMP V include:

i.    Dredging of a series of seabed pits at CMP V within the proposed facility boundaries at ESC (Figure 1.1);

ii.   Backfilling each dredged pit at CMP V with contaminated mud that has been classified as requiring Type 2 disposal in accordance with ETWB TCW No. 34/2002 ([2]); and

iii.  Capping each backfilled pit at CMP V with uncontaminated mud effectively isolating the contaminated mud from the surrounding marine environment.

The construction and operational impacts resulting from the implementation of CMP V are specified in the EIA Report.  The EIA Report also specifies mitigation measures that need to be implemented to ensure compliance with the required environmental criteria.  These mitigation measures and their implementation requirements are presented in the Implementation Schedule (Annex A).  The EIA recommended that environmental monitoring will be necessary to assess the effectiveness of measures implemented to mitigate potential water quality, marine ecology and fisheries impacts during the construction and operation of CMP V.  Regular environmental auditing is also recommended to ensure that potential impacts from other sources are adequately addressed through the implementation of the mitigation measures defined in the EIA Report. 

An EP (EP-312/2008) was issued by the EPD to the CEDD, the Permit Holder, on 9 September 2008 and varied on 28 November 2008 (EP-312/2008/A) for CMP V.  Under the requirements of Condition 3 of the EP (EP-312/2008/A) for CMP V, an EM&A programme as set out in the EM&A Manual is required to be implemented.  The current programme will assess the impacts resulting from dredging, disposal and capping operations of CMP V. 

1.4                                    Objectives of the EM&A Programme

The objectives of the EM&A programme are as follows:

1.  To monitor and report on the environmental impacts of the dredging operations associated with the construction of the disposal pits at CMP V.

2.  To monitor and report on the environmental impacts due to capping operations of the exhausted pits at CMP V.

3.  To monitor and report on the environmental impacts of the disposal of contaminated marine sediments in the active pits at CMP V, specifically to determine:

·           changes/trends caused by disposal activities in the concentrations of contaminants in sediments adjacent to the pits;

·           changes/trends caused by disposal activities in the toxicity of sediment adjacent to the pits;

·           changes/trends caused by disposal activities in the concentrations of contaminants in tissues of demersal marine life adjacent to and remote from the pits;

·           impacts on water quality and benthic ecology caused by the disposal activities; and

·           the risks to human health and dolphin of eating seafood taken in the marine area around the active pits.

4.  To monitor and report on the environmental impacts of the disposal operation at CMP V and specifically to determine whether the methods of disposal are effective in minimising the risks of adverse environmental impacts.

5.  To monitor and report on the benthic recolonisation of the capped pits at CMP V and specifically to determine the difference in infauna between the capped pits and adjacent sites.

6.  To assess the impact of a major storm (Typhoon Signal No. 8 or above) on the containment of any uncapped or partially capped pits at CMP V.

7.  To design and continually review the operation and monitoring programme and:

·           to make recommendations for changes to the operation that will rectify any unacceptable environmental impacts; and

·           to make recommendations for changes to the monitoring programme that will improve the ability to cost effectively detect environmental changes caused by the disposal activities.

8.  To establish numerical decision criteria for defining impacts for each monitoring component.

9.  To provide supervision on the field works and laboratory works to be carried out by contractors/laboratories.

The specific objectives of each component are discussed in the relevant sections of this EM&A Manual.

1.5                                    The Scope of the EM&A Programme

The scope of this EM&A programme is to:

·           Establish baseline water quality levels at specified locations prior to dredging operations for the construction of CMP V at Sha Chau;

·           Implement monitoring and inspection requirements for water quality monitoring programme during dredging, backfilling and capping operations of CMP V;

·           Implement monitoring and inspection requirements for sediment quality monitoring programme during backfilling operations at CMP V;

·           Implement monitoring and inspection requirements for sediment toxicity monitoring programme during backfilling operations at CMP V;

·           Implement monitoring and inspection requirements for the body burden (marine biota) monitoring programme during backfilling operations at CMP V;

·           Liaise with, and provide environmental advice (as requested or when otherwise necessary) to site staff on the comprehension and consequences of the environmental monitoring data;

·           Identify and resolve environmental issues and other functions as they may arise from the works;

·           Check and quantify the Contractor's overall environmental performance, implementation of Event and Action Plans (EAPs), and remedial actions taken to mitigate adverse environmental effects as they may arise from the works;

·           Conduct monthly reviews of monitored impact data as the basis for assessing compliance with the defined criteria and to ensure that necessary mitigation measures are identified and implemented, and to undertake additional ad hoc monitoring and auditing as required by special circumstances;

·           Evaluate and interpret all environmental monitoring data to provide an early indication should any of the environmental control measures or practices fail to achieve the acceptable standards, and to verify the environmental impacts predicted in the EIA;

·           Manage and liaise with other individuals or parties concerning other environmental issues deemed to be relevant to the construction and operation process; and,

·           Conduct regular site inspections of a formal or informal nature to assess:

-           the level of the Contractor’s general environmental awareness;

-           the Contractor’s implementation of the recommendations in the EIA;

-           the Contractor’s performance as measured by the EM&A;

-              the need for specific mitigation measures to be implemented or the continued usage of those previously agreed;

-              to advise the site staff of any identified potential environmental issues; and

-              submit regular EM&A reports which summarise project monitoring and auditing data, with full interpretation illustrating the acceptability or otherwise of any environmental impacts and identification or assessment of the implementation status of agreed mitigation measures.

1.6                                    Organisation and Structure of the EM&A

1.6.1                              General

CEDD will appoint an Environmental Team (ET) to conduct the monitoring and auditing works and to provide specialist advice on the undertaking and implementation of environmental responsibilities. 

The ET will have previous relevant experience with managing similarly sized EM&A programmes and the Environmental Team Leader (ET Leader) will be a recognised environmental professional, preferably with a minimum of seven years relevant experience in impact assessments and impact monitoring programmes, particularly with reference to those to the marine environment and where possible related to marine dredging / disposal activities. 

To maintain strict control of the EM&A process, CEDD will also appoint an Independent Auditor (IA) to verify and validate the environmental performance of the Contractor and the ET.

1.6.2                              Roles & Responsibilities

The roles and responsibilities of the various parties involved in the EM&A process are further expanded in the following sections.  The ET Leader will be responsible for, and in charge of, the ET; and will be the person responsible for executing the EM&A requirements.

Contractor

Reporting to CEDD, the Contractor will:

·           Work within the scope of the construction contract and other tender conditions;

·           Provide assistance to the ET in conducting the required environmental monitoring;

·           Participate in the site inspections undertaken by the ET and / or IA, as required, and undertake any corrective actions instructed by CEDD;

·           Provide information/advice to the ET and IA regarding works activities which may contribute, or be contributing to the generation of adverse environmental conditions;

·           Implement measures to reduce impact where Action and Limit levels are exceeded; and

·           Take responsibility and strictly adhere to the guidelines of the EM&A programme and complementary protocols developed by their project staff.

Civil Engineering and Development Department (CEDD)

CEDD will:

·           Monitor the Contractor's compliance with contract specifications, including the effective implementation and operation of environmental mitigation measures and other aspects of the EM&A programme;

·           Employ Independent Auditor(s) to audit the results of the EM&A works carried out by the ET;

·           Comply with the agreed Event and Action Plan in the event of any exceedance; and

·           Instruct the Contractor to follow the agreed protocols or those in the Contract Specifications in the event of exceedances or complaints.

Environmental Team (ET)

The duties of the ET and ET Leader are to:

·           Monitor the various environmental parameters as required by this or subsequent revisions to the EM&A Manual;

·           Assess the EM&A data and review the success of the EM&A programme determining the adequacy of the mitigation measures implemented and the validity of the EIA predictions as well as identify any adverse environmental impacts before they arise;

·           Conduct regular site inspections and to investigate and inspect the Contractor's equipment and work methodologies with respect to pollution control and environmental mitigation, monitor compliance with the environmental protection specifications in the Contract, and to anticipate environmental issues that may require mitigation before the problem arises;

·           Audit the environmental monitoring data and report the status of the general site environmental conditions and the implementation of mitigation measures resulting from site inspections;

·           Review Contractor’s working programme and methodology, and comment as necessary;

·           Investigate and evaluate complaints, and identify corrective measures;

·           Advice to the Contractor on environmental improvement, awareness, enhancement matters, etc, on site;

·           Report on the environmental monitoring and audit results and the wider environmental issues and conditions to the Contractor, CEDD and the EPD; and

·           Adhere to the agreed protocols or those in the Contract Specifications in the event of exceedances or complaints.

The ET will be led and managed by the ET leader.  The ET leader will have relevant education, training, knowledge, experience and professional qualifications subject to the approval of the Director of Environmental Protection.  Suitably qualified staff will be included in the ET, and ET should not be in any way an associated body of the Contractor.

Independent Auditor

·      Review and audit the implementation of the EM&A programme and the overall level of environmental performance being achieved;

·      Validate and confirm the accuracy of monitoring results, monitoring equipment, monitoring stations, monitoring procedures and locations of sensitive receivers;

·      Audit the EIA recommendations and requirements against the status of implementation of environmental protection measures on site;

·      Adhere to the procedures for carrying out complaint investigation;

·      Review, when required, the effectiveness of environmental mitigation measures and project environmental performance including the proposed corrective measures; and

·      Report, when required, the findings of audits and other environmental performance reviews to CEDD, ET, EPD and the Contractor.

The Independent Auditor will have relevant education, training, knowledge, experience and professional qualifications subject to the approval of the Director of Environmental Protection.  IA should not be in any way an associated body of the Contractor or the ET.

1.7                                    Structure of the EM&A Manual

The remainder of the Manual is set out as follows:

·           Section 2 sets out the EM&A general requirements;

·           Section 3 details the methodologies, parameters to be tested and the requirements for the marine water quality monitoring for the dredging, backfilling and capping operations at the active pits;

·           Section 4 details the methodologies, parameters to be tested and the requirements for sediment quality monitoring for the backfilling activities at the active pits;

·           Section 5 details the methodologies, parameters to be tested and the requirements for sediment toxicity quality monitoring for the backfilling activities at the active pits;

·           Section 6 details the methodologies, parameters to be tested and the requirements for marine biota monitoring for the backfilling activities at the active pits;

·           Section 7 details the requirements for Human Health and Dolphin Risk Assessment;

·           Section 8 details the requirements for benthic re-colonisation assessment;

·           Section 9 details the methodologies, parameters to be tested and the requirements for the assessment of impacts due to major storms; and

·           Section 10 details the EM&A reporting requirements.

2                                          EM&A GENERAL REQUIREMENT

2.1                                    Introduction

In this section, the general requirements of the EM&A programme are presented with reference to the EIA Study findings that have formed the basis of the scope and content of the programme.

2.2                                    EM&A

Key environmental issues associated with the construction and operation of the Project will be addressed through monitoring and controls specified in the EM&A Manual.  Water and sediment quality, marine ecology and fisheries issues will be subjected to EM&A, the details of which are outlined in Sections 3 to 9. 

2.2.1                              Action and Limit Levels

Action and Limit (A/L) Levels are defined levels of impact recorded by the environmental monitoring activities which represent levels at which a prescribed response is required.  This process by which these levels should be quantitatively defined are presented in the relevant sections of this manual and described in principle below:

·         Action Levels: beyond which there is a clear indication of a deteriorating ambient environment for which appropriate remedial actions are likely to be necessary to prevent environmental quality from falling outside the Limit Levels, which would be unacceptable; and

·         Limit Levels: statutory and/or agreed contract limits stipulated in the relevant pollution control ordinances, Hong Kong Planning Standards and Guidelines (HKPSG) or Environmental Quality Objectives established by the EPD.  If these are exceeded, works should not proceed without appropriate remedial action, including a critical review of plant and working methods.

2.2.2                              Event and Action Plan

The purpose of an Event and Action Plan (EAP) is to provide, in association with the monitoring and audit activities, procedures for ensuring that if any significant environmental incident (either accidental or through inadequate implementation of mitigation measures on the part of the Contractor) does occur, the cause will be quickly identified and remediated, and the risk of a similar event recurring is reduced.  This also applies to the exceedances of A/L criteria to be identified in the EM&A programme. 

2.2.3                              Enquiries, Complaints and Requests for Information

Enquiries, complaints and requests for information can be expected from a wide range of individuals and organisations including members of the public, Government departments, the press and media and community groups. 

All enquiries concerning the environmental effects of the Project (CMP V), irrespective of how they are received, will be reported to CEDD and directed to the ET Leader who will set up procedures for handling, investigation and storage of such information.  The following steps will then be followed:

1)     The ET Leader will notify CEDD of the nature of the enquiry.

2)     An investigation will be initiated to determine the validity of the complaint and to identify the source of the problem.

3)     The ET Leader will undertake the following steps, as necessary:

·           investigate and identify source of the problem;

·           if considered necessary by CEDD undertake additional monitoring to verify the existence and severity of the alleged complaint;

·           liaise with EPD to identify remedial measures;

·           liaise with CEDD and the Contractor to identify remedial measures;

·           implement the agreed mitigation measures;

·           repeat the monitoring to verify effectiveness of mitigation measures; and

·           repeat review procedures to identify further possible areas of improvement if the repeat monitoring results continue to substantiate the complaint.

4)     The outcome of the investigation and the action taken will be documented on a complaint proforma (Annex B).  A formal response to each complaint received will be prepared by the ET Leader within a maximum of five working days and submitted to CEDD, in order to notify the concerned person(s) that action has been taken.

5)     All enquiries which trigger this process will be reported in the EM&A reports which will include results of inspections undertaken by the ET Leader, and details of the measures taken, and additional monitoring results (if deemed necessary).  It should be noted that the receipt of complaint or enquiry will not be, in itself, a sufficient reason to introduce additional mitigation measures. 

In all cases the complainant will be notified of the findings, and audit procedures will be put in place to ensure that the problem does not recur.

2.2.4                              Reporting

Monthly, Quarterly and Annual reports will be submitted to CEDD, EPD and AFCD and will be prepared by the ET.  The reports will be prepared and submitted within a specified period.  Additional details on reporting protocols are presented in Section 10.

2.3                                    Environmental Management Plan (EMP)

To ensure effective implementation and reporting on compliance with the stated mitigation measures, as well as the monitoring and auditing requirements and remedial actions defined in the EIA, an appropriate contractual and supervisory framework needs to be established.  The basis of the framework within which implementation should be managed overall is through the preparation of EMPs by the Contractor(s).

An EMP is similar in nature to a quality plan and provides details of the means by which the Contractor (and all subcontractors working to the Contractor) will implement the recommended mitigation measures and achieve the environmental performance standards defined in Hong Kong environmental legislation, the contract and in the EIA documentation.  The primary reason for adopting the EMP approach is to make the Contractor aware of his environmental responsibilities and to be pro-active about the commitment to achieve the standards specified, rather than relying on the EM&A programme.

The EMP also provides opportunities for the Contractor to draw upon the strength of other institutional processes such as ISO 9000/14000 to ensure that the achievement of the required standards and fulfilment of commitments are documented.

The contractual requirement for an EMP would generally comprise appropriate extracts from (and references to) the EIA Report and EM&A Manual, and include such typical elements as the relevant statutory environmental standards, general environmental control clauses and specific environmental management clauses, as well as an outline of the scope and content of the EMP.  In drafting the documentation, due consideration should be given to the predictive nature of the EIA process and the consequent need to manage and accommodate the actual impacts arising from the construction process.  In particular, the Contractor must be placed under a clear obligation to identify and control any implications arising from changes to the working methods assumed in the EIA, or to the progress rates and other estimates made during the preliminary design phase.

 

3                                        Water Quality

3.1                                    Introduction

This Section provides details of the water quality monitoring to be undertaken during the construction and operation of the active pits.   Water quality modelling carried out for the EIA indicates that the potential water quality impacts associated with the dredging, backfilling and capping works at CMP V will be within acceptable levels and no adverse water quality impacts are expected.  However, the monitoring programme is designed to verify the predictions of the EIA and ensure compliance with the WQOs. 

3.2                                    Monitoring Activities

Water quality monitoring for the Project can be divided into the following stages:

·      Dredging Activities for CMP V;

·      Backfilling Activities for CMP V; and

·      Capping Activities for CMP V.

Each of these is discussed in turn below.

3.3                                    Monitoring for Dredging Activities of CMP V

Dredging activities for CMP Va to Vd were completed in mid-2013.  Maintenance dredging may be conducted at CMP Vb and CMP Vc prior to the commencement of disposal at these two sub-pits as and when necessary.  Water quality monitoring will be conducted during dredging at these sub-pits for CMP V at Sha Chau.  Baseline water quality monitoring was conducted between 28 July and 23 August 2009 prior to the commencement of marine dredging works for CMP V.  The Baseline Monitoring Report ([3]) was submitted to EPD in September 2009 to present the baseline monitoring requirements, methodology and results.  Readers should refer to the Baseline Monitoring Report for details of the baseline water quality monitoring.

3.3.1                              Impact Monitoring for Dredging Activities of CMP V

Impact monitoring for the dredging activities to form CMP V will be conducted at mobile stations around the dredging area.  Currently the impact monitoring is conducted for three times per week and the monitoring frequency may be revised upon agreement with the EPD.  Monitoring will be carried out during both mid-flood and mid-ebb tides on each monitoring day.  The location of the mobile stations is dependent on the location of the dredging activities.  These mobile stations will be located at an appropriate distance between each other along the up-current and down-current transect for the dredging area.  The following methodology will be adopted to determine the precise location of the mobile stations on each sampling occasion:

·      Contact the CEDD barge one day before the survey day for every sampling occasion to determine the dredging schedule for that particular survey day and to determine the likely location of dredging at the proposed time of sampling;

·      Determine current direction at mid-depth at one station upstream and one station downstream of the new facility during both mid-flood and mid-ebb tide;

·      Determine a suitable location for the station transect (the first down-current station will be located on the down current edge, and first up-current station will be located on the up-current edge, of the CMP V according to the current direction and the position of dredging at the time of sampling); and,

·      Collect samples from the stations located on a transect running up-current and down-current of the dredging area.

There will be two stations located up-current and five stations down-current of CMP V on the transect.  A 500 m separation distance will be adopted between adjacent stations except between adjacent upstream and downstream stations which are located on the pit edge.  In addition, water samples will be collected from the station MW1 as shown in Figure 3.1.  Locations of upstream and downstream stations are illustrated in Figure 3.1 based on assumed current direction and dredging position during monitoring.

Each station will be sampled and measurements will be taken at three depths, 1 m below the sea surface, mid depth and 1 m above the seabed.  Duplicate water samples and measurements will be taken at each depth.  Where water depth is less than 6m the mid-depth station may be omitted.  If water depth is less than 3m, only the mid-depth station will be monitored.

The following suite of parameters should be measured as part of the impact monitoring for dredging:

·     Dissolved Oxygen (mg L-1) (in situ);

·     Salinity (ppt) (in situ);

·     pH (in situ);

·     Turbidity (NTU) (in situ);

·     Temperature (°C) (in situ)

·     Current Velocity and Direction (ms-1) (in situ); and,

·     Suspended Solids (mg L-1) (laboratory analysis).

In addition to the water quality parameters, other relevant data will also be measured and recorded in Water Quality Monitoring Logs, including the location of the sampling stations, water depth, time, weather conditions, sea conditions, tidal stage, special phenomena and work activities undertaken around the monitoring and works area that may influence the monitoring results.

3.3.2                              Water Quality Compliance and Event & Action Plan

Impact monitoring for dredging activities of CMP V will be evaluated against Action and Limit Levels.  The key assessment parameters are dissolved oxygen (DO) and suspended sediment (SS) and thus Action and Limit Levels based on the assessment criteria are identified for these parameters.  However, turbidity can also provide valuable instantaneous information on water quality and thus an Action Limit is measured for this parameter to facilitate quick responsive action in the event of any apparent unacceptable deterioration attributable to the works.

The Action and Limit Levels for DO, turbidity and SS were determined in the Baseline Monitoring Report (1) according to the criteria shown in Table 3.2.  The Action and Limit Levels of DO, turbidity and SS were derived from the baseline monitoring data ([4]) and they are presented in Table 3.3.

Action and Limit levels are used to determine whether modifications are necessary to mitigate impacts to water quality.  In the event that the levels are exceeded, appropriate actions in Event and Action Plan (Table 3.4) should be undertaken. 

 

Table 3.2        Determination of Action and Limit Level of Water Quality for Dredging, Capping and Backfilling Activities of CMP V

Parameter

Action Level

Limit Level

Dissolved Oxygen

 

 

Surface and Middle

Depth Averaged

The depth average of the impact station readings are <5%ile of baseline data

 

and

 

Significantly less than the reference stations mean DO (at the same tide of the same day)

The average of the impact station readings are <4mg/L

 

 

and

 

Significantly less than the reference stations mean DO (at the same tide of the same day)

 

Bottom

The average of the impact station readings are <5%ile of baseline data

 

and

 

Significantly less than the reference stations mean DO (at the same tide of the same day)

The average of the impact station readings are <2mg/L

 

 

and

 

Significantly less than the reference stations mean DO (at the same tide of the same day)

 

Suspended Solids

 

 

Depth Averaged

The depth average of the impact station readings are >95%ile of baseline data

 

and

 

120% or more of the reference stations SS (at the same tide of the same day)

The depth average of the impact station readings are >99%ile of baseline data

 

and

 

130% or more of the reference stations SS (at the same tide of the same day)

 

Turbidity

 

 

Depth Averaged

The depth average of the impact station readings are >95%ile of baseline data

 

and

 

120% or more of the reference stations turbidity (at the same tide of the same day)

The depth average of the impact station readings are >99% of baseline data

 

and

 

130% or more of the reference stations turbidity (at the same tide of the same day)

 

Table 3.3        Action and Limit Levels of Water Quality for Dredging, Capping and Backfilling Activities of CMP V

Parameter

Action Level

Limit Level

Dissolved Oxygen (DO) (1)

 

 

Surface and Middle

Depth Averaged (2)

5%-ile of baseline data for surface and middle layer = 3.76 mg L-1

 

and

 

Significantly less than the reference stations mean DO (at the same tide of the same day)

1%-ile of baseline data for surface and middle layer = 3.11 mg L-1 (3)

 

and

 

Significantly less than the reference stations mean DO (at the same tide of the same day)

 

 

 

Bottom

5%-ile of baseline data for bottom layers = 2.96 mg L-1

 

and

 

Significantly less than the reference stations mean DO (at the same tide of the same day)

The average of the impact station readings are <2 mg/L

 

and

 

Significantly less than the reference stations mean DO (at the same tide of the same day)

 

 

 

 

Depth-averaged Suspended Solids (SS) (4) (5)

95%-ile of baseline data for depth average = 37.88 mg L-1

 

and

 

99%-ile of baseline data for depth average = 61.92mg L-1

 

and

 

 

120% of control station's SS at the same tide of the same day

130% of control station's SS at the same tide of the same day

 

 

 

Depth-averaged Turbidity (Tby) (4) (5)

95%-ile of baseline data = 28.14 NTU

 

and

 

99%-ile of baseline data = 38.32 NTU

 

and

 

120% of control station's turbidity at the same tide of the same day

130% of control station's turbidity at the same tide of the same day

 

 

 

Notes:

(1)    For DO, non-compliance of the water quality limits occurs when monitoring result is lower than the limits.

(2)    The Action and Limit Levels for DO for Surface & Middle layers were calculated from the combined pool of baseline surface layer data and baseline middle layer data.

(3)    Given the Action Level for DO for Surface & Middle layers has already been lower than 4 mg L-1, it is proposed to set the Limit Level at 3.11 mg L-1 which is the first percentile of the baseline data.

(4)    “Depth-averaged” is calculated by taking the arithmetic means of reading of all three depths.

(5)    For turbidity and SS, non-compliance of the water quality limits occurs when monitoring result is higher than the limits.

 


Table 3.4        Water Quality Event and Action Plan during Dredging Operations

Event

Environmental Team (ET)

Contractor

Action Level

 

 

Exceedance for one sample

·         Repeat in-situ measurement to confirm findings;

·         Identify the source(s) of impact;

·         Inform contractor and contractor informs CEDD, EPD and AFCD and confirm notification of the non-compliance in writing;

·         Check monitoring data;

·         Discuss potential mitigation measures if exceedance is attributed to the works with contractor.

 

·         Discuss potential mitigation measures with ET and agree on mitigation measures to be implemented if exceedance is attributed to the works;

·         Ensure mitigation measures are implemented;

·         Assess the effectiveness of the implemented mitigation measures.

Limit Level

 

 

Limit level for one occasion

·         Repeat in-situ measurement to confirm findings;

·         Identify source(s) of impact;

·         Inform contractor and contractor informs CEDD, EPD and AFCD;

·         Discuss further mitigation measures if exceedance is attributed to the works with contractor;

·         Increase the monitoring frequency to daily if exceedance is attributed to the works until no exceedance of the Limit Level.

·         Critical review of working methods;

·         Check plant, equipment and working methods;

·         Discuss further mitigation measures with ET to be implemented if exceedance is attributed to the works;

·         Ensure mitigation measures are being implemented;

·         Assess the effectiveness of the implemented mitigation measures.

 

 

 

Limit Level exceeded on two or more occasions

·         Identify source(s) of impact;

·         Inform contractor and contractor informs, CEDD, EPD and AFCD.

 

·         If exceedance is attributed to the works consider and if necessary reduce works until no exceedance of Limit Level.

 

 

 

Impacts attributable to works

·         Inform contractor and contractor informs, CEDD, EPD and AFCD.

 

·         Comprehensive review of works;

·         Reduce works; and

·         Suspension of works.

3.4                                    Monitoring for Backfilling Activities

3.4.1                              Objective

The main objective of this component is to determine the impacts, if any, of backfilling activities at CMP V on water quality.  Two separate components of water quality monitoring are necessary during backfilling:  

·     Routine Water Quality Monitoring - Conducted to examine the impacts of disposal activities on the level of inorganic metal contaminants in marine waters; and,

·     Water Column Profiling - conducted to examine in situ the effects of backfilling operations on water quality parameters within the water column.

3.4.2                              Hypotheses

The impact hypothesis for this work component has been defined based on the predictions from the EIA regarding impacts from the contaminated mud disposal operations and the objectives for the study.

Backfilling operations do not result in any exceedances of Northwestern Water Quality Control Zone (NWQCZ) Water Quality Objectives (WQO).

As a consequence of performing two separate tasks for assessing the impacts of disposal operations on water quality, two null hypotheses will be tested:

Routine Water Quality Monitoring

H0          There are no differences in the levels of contaminants in water samples in the plume arising from the disposal works and background levels in the vicinity of the backfilling. 

Water Column Profiling

H0          There is no change in the level of compliance with the NWWCZ WQOs of samples taken from the plume arising from backfilling activities (EIA predicted location).

3.4.3                              Sampling Design

Routine Water Quality Monitoring

Routine water quality monitoring will be undertaken during backfilling activities at mid-ebb or mid-flood tide.  Water samples will be collected at specific stations at fixed location, which should be located in three areas at increasing distances from the active facility; Reference, Intermediate and Impact stations/areas.  The design for this component of the programme allows impacts, if any, to water quality as a result of the backfilling activities in the vicinity of CMP V to be assessed.

The number of monitoring stations sampled depends on the state of the tide.  During the ebb tide, water samples are collected from five up-current Reference Stations, five down-current Impact Stations and five down-current Intermediate Stations.  During the flood tide, water samples are collected from three up-current Reference Stations, three down-current Impact Stations and three down-current Intermediate Stations.  The approach will ensure that the impact of temporal changes on the hydrodynamic conditions in the area is considered in the sampling.


The following suite of parameters should be measured as part of routine water quality monitoring operations:

·     Dissolved Oxygen (mg L-1) (in situ);

·     Salinity (ppt) (in situ);

·     pH (in situ);

·     Turbidity (NTU) (in situ);

·     Temperature (°C) (in situ)

·     Current Velocity and Direction (ms-1) (in situ);

·     Suspended Solids (mg L-1) (laboratory analysis);

·      Ammonia (mg L-1) (laboratory analysis);

·     Total Inorganic Nitrogen (TIN mg L-1) (laboratory analysis);

·     5-Day Biochemical Oxygen Demand (BOD5) (mg L-1) (laboratory analysis)

·     Cadmium (mg L-1) (laboratory analysis);

·     Chromium (mg L-1) (laboratory analysis);

·     Copper (mg L-1) (laboratory analysis);

·     Lead (mg L-1) (laboratory analysis);

·     Mercury (mg L-1) (laboratory analysis);

·     Nickel (mg L-1) (laboratory analysis);

·     Silver (mg L-1) (laboratory analysis);

·     Zinc (mg L-1) (laboratory analysis); and

·     Arsenic (mg L-1) (laboratory analysis).

In addition to the water quality parameters, other relevant data will also be measured and recorded in Water Quality Monitoring Logs, including the location of the sampling stations, water depth, time, weather conditions, sea conditions, tidal stage, special phenomena and work activities undertaken around the monitoring and works area that may influence the monitoring results.

Sampling Locations

The locations of stations during ebb and flood tides are shown in Figures 3.2 and 3.3, respectively, and the coordinates are shown Table 3.5.  An additional monitoring station at Ma Wan will be sampled.  Eight replicate samples should be collected from each monitoring station for eight times per year, twice in the dry season, twice during the wet season and twice in each of the two transitional seasons.  For a given sampling event water samples and in situ measurements should be taken at mid-depth of all stations during the same tidal state (ie mid-ebb or mid-flood tide).  Sampling frequency and number of replicates will be reviewed and adjusted accordingly based on power analyses in each Annual Review Report. 

Details on the Sampling Programme are shown in Annex C.

 

Table 3.5       Coordinates of Water Quality Monitoring Stations for Capping and Routine Water Quality Monitoring

Monitoring Stations

Eastings

Northings

Ebb

 

 

Reference Stations

 

 

ESC-RFE1

808527

822762

ESC-RFE2

808736

823066

ESC-RFE3

808956

823390

ESC-RFE4

809176

823715

ESC-RFE5

809427

824008

Impact Stations

 

 

ESC-IPE1A

811791

822303

ESC-IPE2A

810946

822252

ESC-IPE3

811763

821931

ESC-IPE4

812430

821717

ESC-IPE5

812894

822050

Intermediate Stations

 

 

ESC-INE1A

814051

822440

ESC-INE2A

813971

821801

ESC-INE3A

814579

822626

ESC-INE4A

814548

822128

ESC-INE5A

814263

821209

Ma Wan Station

 

 

MW1

823604

823654

Flood

 

 

Reference Stations

 

 

ESC-RFF1A

815060

822367

ESC-RFF2A

814211

821746

ESC-RFF3

813233

821127

Impact Stations

 

 

ESC-IPF1

809862

823353

ESC-IPF2

809293

822799

ESC-IPF3

810432

823907

Intermediate Stations

 

 

ESC-INF1

808346

823213

ESC-INF2

809013

823843

ESC-INF3

809680

824473

Ma Wan Station

 

 

MW1

823603

823653

Note: Coordinates are based on Hong Kong 1980 GRID Coordinate System.

Water Column Profiling

Water column profiling will be undertaken during backfilling activities.  There are two monitoring stations for Water Column Profiling.  Their locations are mobile, and will be dependent on the position of the disposal barge at the time of monitoring.  The two mobile monitoring stations will be approximately 100 m upstream and downstream of the disposal area, respectively. 

The following suite of parameters should be measured as part of the water column profiling:

·     Salinity (ppt) (in situ);

·     Dissolved Oxygen (mg L-1) (in situ);

·     Turbidity (NTU) (in situ);

·     Temperature (°C) (in situ)

·     Current Velocity and Direction (ms-1) (in situ)

·     pH (in situ); and

·     Suspended Solids (mg L-1) (laboratory analysis).

In addition to the water quality parameters, other relevant data will also be measured and recorded in Water Quality Monitoring Logs, including the location of the sampling stations, water depth, time, weather conditions, sea conditions, tidal stage, special phenomena and work activities undertaken around the monitoring and works area that may influence the monitoring results.

Water Column Profiling will be conducted monthly.  Four replicate samples for SS will be collected at mid-depth from each of the monitoring stations during each sampling event.  During each sampling event in situ measurements should be taken at 1 m depth intervals through the water column for a period of one hour at each station.  All water samples and in situ measurements should be taken during the same tidal state (ie mid-ebb or mid-flood tide) of a given sampling event.  Sampling frequency and the number of replicates will be reviewed and adjusted accordingly based on power analyses in each Annual Report.  Details on the Sampling Programme are shown in Annex C. 

3.4.4                              Statistical Treatment of Data

Routine Water Quality Monitoring

The hierarchy of sampling design should allow for the application of nested analysis of variance to statistically test any changes or trends in the dataset.  Under the nested design, differences will be tested between stations in a particular area and between the three areas (ie Impact, Intermediate and Reference).  Once a time series of data has been gathered temporal changes in water quality parameters can be analysed for significant differences.  In addition, the data gathered will be examined against the water quality objectives for the NWWCZ to determine if the relevant water quality objectives have been exceeded.

Water Column Profiling

The data gathered will be examined graphically against the water quality objectives for the NWWCZ to determine if the relevant water quality objectives have been exceeded for any apparent impacts arising from the backfilling activities.

3.4.5                              Use of Data

Should increases be detected in the level of contaminants or exceedances of the NWWCZ WQOs be detected, a review of the other monitoring parameters will be undertaken.  This will focus on sampling stations in the vicinity of the water quality stations where increases are detected to see if these can be attributed to contaminant spread from the active pits.  If so, consideration will be given to revising the facility operations plan and backfilling activities to reduce the spread of contaminants in the plume and achieve compliance with WQOs.

3.5                                    Monitoring for Capping Activities

The design for this component of the programme allows impacts to water quality as a result of the overall capping activities of CMP V to be assessed.  Replicate water samples will be collected at specific stations, which should be located in three discrete areas: Impact, Intermediate and Reference.  The number of monitoring stations sampled depends on the state of the tide.  During the ebb tide, water samples will be collected from five up-current Reference Stations, five down-current Impact Stations and five down-current Intermediate Stations.  During the flood tide, water samples will be collected at three up-current Reference Stations, three down-current Impact Stations and three down-current Intermediate Stations. 

The following suite of parameters should be measured as part of the impact monitoring for capping:

·     Dissolved Oxygen (mg L-1) (in situ);

·     Salinity (ppt) (in situ);

·     pH (in situ);

·     Turbidity (NTU) (in situ);

·     Temperature (°C) (in situ)

·     Current Velocity and Direction (ms-1) (in situ); and,

·     Suspended Solids (mg L-1) (laboratory analysis).

In addition to the water quality parameters, other relevant data will also be measured and recorded in Water Quality Monitoring Logs, including the location of the sampling stations, water depth, time, weather conditions, sea conditions, tidal stage, special phenomena and work activities undertaken around the monitoring and works area that may influence the monitoring results.

The locations of stations during ebb and flood tides are the same as Routine Water Quality Monitoring which are shown in Figures 3.2 and 3.3, respectively, and the coordinates are shown Table 3.5.  Samples will also be collected from an additional station at Ma Wan, for both ebb and flood tides.  Samples should be collected four times per year, twice in the dry season and twice during the wet season.  Three replicate samples of SS will be collected from mid-depth at each monitoring station during each sampling event.  In addition, in situ measurements should be taken at 1 m depth intervals through the water column at each station during a sampling event.  All water samples and in situ measurements should be taken during the same tidal state (ie mid-ebb or mid-flood tide) of a given sampling event.  Sampling will be undertaken during capping activities for the CMP as detailed in Annex C.  Sampling frequency and number of replicates will be reviewed and adjusted accordingly based on power analyses in each Annual Report. 

3.6                                    Sampling Procedure for Water Quality monitoring

In situ water quality monitoring (salinity, temperature, current velocity and direction) will be conducted using the equipment listed in Section 3.6.1 and following the testing protocols detailed in Section 3.6.2.  In order to ensure the reliability and quality of the data, the measuring instrument will be calibrated regularly and the probe of the measuring instrument will be maintained at a suitable distance from the seabed to avoid re-suspension of bottom sediments from skewing the results. 

Water quality profiling will be conducted continuously for a one-hour period from a fixed point.  After deployment, the probe of the measuring equipment will be allowed to equilibrate with the surrounding seawater for approximately 30 seconds.  Subsequently, average readings will be taken every few seconds to minimise sampling noise arising from the sensitivity of the equipment.

In addition to in situ water quality monitoring, water samples will be collected in a water sampler.  Samples will be stored in sealed sampling bottles and chilled, and on completion of the survey will be transported to the laboratory for immediate analysis.  Samples not for immediate analysis will be stored at 4 ± 2°C.

3.6.1                              Equipment

The following equipment will be supplied and used by the contractor for the water quality monitoring:

·      Positioning Device - Horizontal positioning will be used and determined by a differential Global Positioning System (dGPS) with the differential signal being provided by a UHF differential transmitter.  The UHF system should provide an accuracy of better than 3m at the 95% confidence level to ensure the survey vessel is in the correct location before taking measurements.  The dGPS will be calibrated daily before each survey period or results reported.  And all data will be printed and logged on disc.

·      Electronic data logging device - A data logging device capable of storing measurement data will be used.  The device will be able to read and store the output from all electronic meters used for this project and will record time and location as measured by the GPS.

·      Dissolved Oxygen and Temperature Measuring Equipment - The instrument will be a portable, weatherproof dissolved oxygen measuring instrument complete with cable, sensor, comprehensive operation manuals, and will be operable from a DC power source.  It will be capable of measuring:  dissolved oxygen levels in the range of 0 - 20 mg L-1 and 0 - 200% saturation; and a temperature of 0 - 45 degrees Celsius.

It will have a membrane electrode with automatic temperature compensation complete with a cable of not less than 20 m in length.  Sufficient stocks of spare electrodes and cables will be available for replacement where necessary (for example, YSI model 59 metre, YSI 5739 probe, YSI 5795A submersible stirrer with reel and cable or an approved similar instrument).

·      Turbidity Measurement Equipment - Turbidity within the water will be measured in situ by the nephelometric method.  The instrument will be a portable, weatherproof turbidity-measuring unit complete with cable, sensor and comprehensive operation manuals.  The equipment will be operated from a DC power source, it will have a photoelectric sensor capable of measuring turbidity between 0 - 1000 NTU and will be complete with a cable with at least 20 m in length (Hach 2100P or an approved similar instrument).

·      Salinity Measurement Instrument - A portable salinometer capable of measuring salinity in the range of 0 - 40 ppt will be provided for measuring salinity of the water at each monitoring location.

·      pH meter – A portable pH meter capable of measuring a range between 0.0 and 14.0 will be provided to measure pH in marine waters.

·      Suspended Solid Measurement Equipment - A water sampler (eg Kahlsico Water Sampler), which is a PVC cylinder (capacity not less than 2 litres) which can be effectively sealed with latex cups at both ends, will be used for sampling.  The sampler will have a positive latching system to keep it open and prevent premature closure until released by a messenger when the sampler is at the selected water depth.  Water samples for suspended solids measurement will be collected in high density polythene bottles, packed in ice (cooled to 4oC without being frozen), and delivered to the laboratory in the same day as the samples were collected.

·      Water Depth Gauge - A portable, battery-operated echo sounder (Seafarer 700 or a similar approved instrument) will be used for the determination of water depth at each designated monitoring station.  This unit will either be hand-held or affixed to the bottom of the work boat if the same vessel is to be used throughout the monitoring programme.

·      Water Sampling Equipment - A water sampler, consisting of a transparent PVC or glass cylinder of not less than two litres which can be effectively sealed with cups at both ends, will be used (Kahlsico Water Sampler 13SWB203 or an approved similar instrument).  The water sampler will have a positive latching system to keep it open and prevent premature closure until released by a messenger when the sampler is at the selected water depth.

·      Current Velocity Measuring Equipment – An NE Sensortec A/S UCM-60 current meter or Valeport 108 MKIII current meter or a similar approved instrument will be used for measuring current direction.  Current velocity is measured by ADCP.  Calibration of ADCP is not likely to be necessary for these instruments as they are calibrated for the life of the instrument.

3.6.2                              Sampling / Testing Protocols

The position of the survey vessel will be positioned to within 3 m of the designated coordinates at each monitoring station using a differential Global Positional System (GPS). 

All in situ monitoring instruments will be checked, calibrated and certified by a laboratory accredited under HOKLAS or any other international accreditation scheme before use, and subsequently re-calibrated at three month intervals throughout the stages of the water quality monitoring.  Responses of sensors and electrodes will be checked with certified standard solutions before each use.

On-site calibration of field equipment will follow the “Guide to Field and On-Site Test Methods for the Analysis of Waters”, BS 1427: 1993.  Sufficient stocks of spare parts will be maintained for replacements when necessary.  Backup monitoring equipment will also be made available so that monitoring can proceed uninterrupted even when equipment is under maintenance, calibration etc.

Water samples for SS measurements will be collected in high density polythene bottles, packed in ice (cooled to 4° C without being frozen), and delivered to a HOKLAS laboratory as soon as possible after collection.

At least two replicate samples should be collected from each of the monitoring events for in situ measurement and lab analysis.

3.6.3                              Laboratory Procedures

Using chain of custody forms, collected water samples will be transferred directly to laboratory for immediate processing of suspended solids, ammonia, nutrients and BOD5.  Water samples will be analysed for pH and BOD within 4 hours of their arrival at the laboratory.  All other parameters will be analysed within 48 hours of arrival.  During this period samples will be held at 4 ± 2ºC.  Prior to subjecting the sample to metals analysis, samples will be filtered to remove solids and colloidal matter.  Filtration will be accomplished using acid washed, single-use 0.45 micron membrane filters within a maximum of 8 hours from sample collection.  Where necessary, samples will undergo further preparation involving preconcentration which allows lower method detection limits to be achieved and removes some of the possible sources of interference. 

3.7                                    QA/QC

3.7.1                              Field Logs

Field logs will be maintained for all survey work, noting the date of the survey, equipment used, survey manager and a record of all activities and observations.  Field logs will be retained for the duration of the Project and archived on completion.

In-situ measured data will be digitally recorded from the instruments and converted into Microsoft Excel format, or manually noted.  Both disc copy and hard copy will be retained for the file records.  Any deviation from the standard procedure will be noted in the log and the reason for the deviation recorded.  In addition, field logs will contain notes of events or activities in the vicinity of the monitoring location which might give rise to anomalous data being recorded.

3.7.2                              Sampling

The sampling, collection, storage and identification procedures are described in Section 3.6 of this Manual and the Contractor will record all data from in situ testing and from any analysis carried out on the boat in a Field Log.  All samples will be identified with a unique date/time/location/depth/sample-type code which will be attached to the sample container or written in indelible ink directly on the container.  In order to avoid contamination of the samples, all containers will be new and unused and of analytical grade quality.  Sources of contamination will be isolated from the working area (for example, vessel fuel and exhaust fames) and any sample contaminated by local material (such as printed circuit boards) will be discarded and the sampling repeated.  Low level metal analysis in seawater is easily contaminated through inappropriate handling and sampling techniques.  Site staff involved in seawater sample collection intended for dissolved metal analysis will ensure that they wear non-contaminating disposable gloves if they have previously been operating or have handled metallic equipment.

3.7.3                              Measurement Procedures

All in situ monitoring instruments will be checked, calibrated and certified and subsequently re-calibrated at three monthly intervals throughout all stages of the water quality monitoring, or as required by the manufactures specification.  Certificate(s) of Calibration specifying the instrument will be attached to the monitoring reports. 

3.7.4                              Transport of Samples

All samples transferred from one sub-contractor to another will be accompanied by Chain of Custody (COC) forms.  Any missing or damaged samples require notification to ET Leader following logging in the laboratory QA system.  The number of samples, the parameters to be tested and the time of delivery should be clearly stated on the COC forms to ensure that samples are analysed for the correct parameters and suitable time is provided to the analytical laboratory for provision of resources required in the analyses.

3.7.5                              Laboratory Procedures

For details of the contaminants to be tested, the methods to be used, the accreditation status of laboratory analytical methods, instruments and procedures to be used, sample preparation information, method detection limits (MDLs), QA/QC protocols and turnaround times, contractor should refer to the previous monitoring programme for the ESC CMPIV ([5]) ([6])([7]). 

The analytical techniques to be adopted for this Project must conform to HOKLAS (or similar overseas) accreditation.   

3.7.6                              Data Quality Objectives

Data Quality Objectives (DQOs) have been developed in the previous monitoring programme for ESC CMPIV ([8]) ([9]) to address precision, accuracy and analyte recovery.  The Contractor is recommended to follow the DQOs developed for data analysis. 

Inorganic Analyses

Details of quality control specifications for inorganic testing should be included in the updated EM&A Manual prior to commencement of disposal activities. 

Precision

Duplicates (1 in every 20 samples) will be used to monitoring the precision of the analysis.  Results should be flagged for reference when:

·     In water samples, for metals with a concentration >4x MDL, the duplicate results have more than a 15% RPD

·     For all analytes with concentration <4x MDL, the duplicate results will be reported as analysed and no bounds should be quoted

Accuracy

Standard and certified reference material (CRM) will be used to monitor accuracy and precision within and between batches:  Results should be flagged for reference if:

·     The variation of the standard from its true value is more than ± 15% (for mercury: ± 20%).

Recovery

Post digest spikes will be used to determine the recovery of determinants in complex sample matrices.  Results should be rejected if:

·     Spike recoveries are more than ± 25% from the theoretical recovery for water samples.  An exceptional case would be if the sample concentration is greater than four times the spike value, the spike may be disregarded. 

 

4                                          Sediment Quality

4.1                                    Introduction

In accordance with the recommendations of the EIA for the present Project, a monitoring programme examining sediment quality will be instituted to verify the EIA predictions and ensure that there is no build-up in contamination adjacent to the pits.  Sediment chemistry has long been an important component of monitoring programmes at the ESC mud disposal complex.  A comprehensive list of Contaminants of Concern (COCs) has been used since 1997, comprising eight heavy metals and one metalloid, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (eg DDT) and Tributyltin (TBT).  These contaminants (which correspond to the list of COCs in ETWB TC(W) 34/2002) in sediments should be measured in the present monitoring programme and changes over time and distance should also be examined.

4.2                                    Objective

The main objective of this task is to determine if there are any changes and/or trends in the concentrations of contaminants in sediments adjacent to the pits caused by disposal activities at CMP V.  This objective is most appropriately addressed through two separate but intrinsically linked sub-tasks:

·      Pit Specific Monitoring of Sediment Quality - conducted to examine near field impacts of backfilling operations at CMP V on the spread of contaminants from the pits and to allow for rapid detection of any adverse environmental impacts and, if necessary, changes to the operations plan.

·      Cumulative Impact Monitoring of Sediment Quality - conducted to analyse the ambient conditions in the North Lantau region and to investigate whether any impacts to marine sediments are occurring due to the dispersion of contaminants from the active pits at CMP V. 

4.3                                    Hypotheses

The impact hypothesis for this task is as follows:

There is no increase in sediment contaminant concentrations over time at individual stations or a trend of increasing concentrations with proximity to the active pit.

As a result of the separation of this programme into two sub-tasks, two sets of null hypotheses should be tested:


Pit Specific Monitoring of Sediment Quality

H0          There is no increase in sediment contaminant concentration in the area adjacent to the pits during contaminated mud disposal works. 

Cumulative Impact Monitoring of Sediment Quality

H0          There is no increase in sediment contaminant concentration over time in the area of contaminated mud disposal activity.

H0          There is no increase in sediment contaminant concentration with proximity to the active pits.

4.4                                    Sampling Design

The designs for assessing the impacts of disposal of contaminated mud in the active pits at CMP V on the sediment chemistry of remote and adjacent areas take into account the following factors:

·      The null hypotheses being tested;

·      Background levels of contaminants in the region;

·      Predictions on sediment plume locations;

·      Spatial variability in sediment chemistry;

·      Temporal variability in sediment chemistry; and,

·      Expected statistical treatment of the data.

As mentioned in Section 1.2, this EM&A Manual is an evolving document that should be updated to maintain its relevance as the Project progresses.  This includes the relocation of monitoring stations to best suit the requirements of the monitoring programme and to take into account other work that is occurring in the direct vicinity of the active facility.

4.4.1                              Data Collection Parameters

The parameters that should be measured in sediments collected during the two sub-tasks and the rationale for each are given below.  Some of the contaminants listed are the "Contaminants of Concern" for which Lower and Upper Chemical Exceedance Limits (LCEL/UCEL) exist. 

 (a)   Total Organic Carbon (TOC) - an indicator of organic load and the impact on bottom layer dissolved oxygen.  TOC is an important factor influencing the chemical partitioning and toxicity of hydrophobic organic compounds such as PAHs, PCBs and pesticides.  High TOC often infers that hydrophobic contaminants are less bioavailable;

(b)     Inorganic Contaminants - metals and metalloids present in the disposed sediments which may be bioaccumulated;

(c)     Polycyclic Aromatic Hydrocarbons (PAH) - a class of organic compounds some of which are persistent and carcinogenic.  These compounds may be bioaccumulated and stored in the fatty body tissues of mammals;

(d)     Total Polychlorinated Biphenyls (PCB) - a class of persistent man-made chemicals which tend to bioaccumulate through the food chain and can cause reproductive failure and cancer;

(e)     Organochlorine Pesticides (DDE & DDT) - contaminants which are persistent, highly lipophilic (can be accumulated and stored in fat), have high bioaccumulation and biomagnification potential, and high toxicity to aquatic organisms; and,

(f)      Tributyltin (TBT) (in sediment and interstitial water) - moderately persistent toxic compound found in marine sediments which may be bioaccumulated and cause growth abnormalities and reproductive failure.

(g)     Percentage of Silt/Clay (% < 63µm) – measured in Cumulative Impacts Monitoring only.  Organic contaminants and metals bind more readily to finer particles than coarser particles due to their larger surface area and consequent larger number of binding sites;

4.4.2                              Pit Specific Monitoring of Sediment Quality

Pit specific monitoring of sediment quality will be undertaken during backfilling activities.  Sediment samples will be collected from two stations in the active pit, two stations on the edge of the active pits and two stations in close proximity to the pits.  For pit specific monitoring, parameters (a) to (g) in Section 4.4.1 will be analysed.

Sediment samples will be collected on a monthly basis from any of the six stations shown in Figure 4.1 and Table 4.1.  Locations of the six sampling stations will be dependent on the location of the active pit and will be adjusted accordingly.  For example when CMP Va is active, stations ESC-NNDA-B, ESC-NEDA-B and ESC-NPDA-B will be monitored.  Twelve replicates of composite samples (i.e. 5 grab samples obtained using a cluster grab) will be collected from each of the stations.  Sampling frequency and the number of replicates will be reviewed and adjusted accordingly based on power analyses in each Annual Report.

 

Table 4.1       Coordinates of Pit Specific Sediment Monitoring Stations

Monitoring Stations

Eastings

Northings

CMP Va active

Near-Pit

 

 

ESC-NNDA

809547

822778

ESC-NNDB

810636

821839

Pit-Edge

 

 

ESC-NEDA

809748

822606

ESC-NEDB

810398

822031

Active-Pit

 

 

ESC-NPDA

809976

822414

ESC-NPDB

810203

822206

CMP Vb active

 

 

Near-Pit

 

 

ESC-NNCA

810110

822994

ESC-NNCB

811003

822185

Pit-Edge

 

 

ESC-NECA

810288

822825

ESC-NECB

810792

822364

Active-Pit

 

 

ESC-NPCA

810477

822665

ESC-NPCB

810652

822509

CMP Vc active

 

 

Near-Pit

 

 

ESC-NNBA

810831

823066

ESC-NNBB

811780

822183

Pit-Edge

 

 

ESC-NEBA

810965

822939

ESC-NEBB

811549

822378

Active-Pit

 

 

ESC-NPBA

811156

822726

ESC-NPBB

811367

822544

CMP Vd active

 

 

Near-Pit

 

 

ESC-NNAA

811851

822535

ESC-NNAB

812735

821751

Pit-Edge

 

 

ESC-NEAA

812046

822372

ESC-NEAB

812553

821917

Active-Pit

 

 

ESC-NPAA

812196

822239

ESC-NPAB

812371

822080

Note: Coordinates are based on Hong Kong 1980 GRID Coordinate System.

4.4.3                                            Cumulative Impacts Monitoring of Sediment Quality

Sediment samples should be collected from stations located in four discrete areas, with two stations in each area.  The areas should be located at increasing distances from the disposal operations (ie. Near Field, Mid Field, Capped Pits and Far Field).  Sediment samples should also be collected from the Ma Wan station MW1.  For cumulative impacts monitoring parameters (a) to (g) in Section 4.4.1 will be analysed.

Sediment samples should be collected four times per year, twice during the dry season and twice during the wet season at stations indicated on Figure 4.2 and the coordinates are shown in Table 4.2.  Twelve replicates of composite samples (i.e. 5 grab samples obtained using a cluster grab) will be collected from each station.  Sampling frequency and number of replicates will be reviewed and adjusted accordingly based on power analyses in each Annual Report.

 

Table 4.2       Coordinates of Cumulative Impact Sediment Monitoring Stations

Monitoring Stations

Eastings

Northings

Near-field

ESC-RNA

809547

822778

ESC-RNB1

812875

822069

Mid-field

ESC-RMA

807797

825010

ESC-RMB

813278

820968

Far-field

ESC-RFA

806207

827812

ESC-RFB

806307

817693

Capped Pits

ESC-RCA1

810050

822436

ESC-RCB1

811770

822104

Ma Wan Station

 

 

MW1

823603

823653

Note: Coordinates are based on Hong Kong 1980 GRID Coordinate System.

4.5                                    Statistical Treatment of Data

4.5.1                              Pit Specific Monitoring of Sediment Quality

Observed differences in the levels of contaminants should be tested using analysis of variance (ANOVA) with factors area and station, followed by Student Newman Keuls (SNK) multiple comparison procedures to isolate which treatments differ from others.   

For all of the analysis of variance techniques performed during the monitoring programme, initial analyses should be performed to ensure that the data complies with the specific assumptions of analysis of variance.  These assumptions state:

·     the data within and among samples must be independent of each other;

·     the variance within samples must be equal (tested through the use of tests such as Levene's median test); and,

·     the data among the samples must be normally distributed (tested through the use of tests such as the Kolgomorov-Smirnov test). 

Should the data not comply with these assumptions then the appropriate transformation should be applied to the data (eg, arc-sin for percentage data, log (x+1) for abundance data, or rank transformation if necessary).  If, after transformation, the data are still non-compliant then non-parametric equivalents to ANOVA such as Kruskal-Wallis tests should be used. 

4.5.2                              Cumulative Impacts of Sediment Quality

The design of the monitoring programme should allow nested analysis of variance techniques to be employed.  These techniques will be used to analyse the data at different spatial and temporal scales of replication.  Statistical differences should be tested at the following levels: between areas and between sampling times.  An advantage of this sampling design is that it removes the possibility of detecting differences simply due to inherent variation over spatial scales in the active area and thus facilitates clearer attribution to disposal operations.  By replicating within each area, ie by sampling two stations in one area, any statistically significant differences detected between areas are more likely to be due to factors other than spatial variation (eg disposal operations).  This approach is now an internationally recommended technique for use in monitoring programmes ([10]).Multidimensional scaling ordination techniques will also be applied to the data, if deemed necessary.