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
2.1 Introduction
2.2 EM&A
2.3 Environmental Management Plan
(EMP)
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
4.1 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
5.1 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
6.1 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
8.1 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
9.1 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.
4.6
Use
of Data
Should
significant increases be detected in the level of contaminants in sediment
samples, a review of the other monitoring parameters should be undertaken. This review will focus on sampling
stations in the vicinity of the sediment quality monitoring stations where
increases are detected to see if these can be attributed to contaminant migration
from the active pits. Assessment of the statistical
significance of the data, confidence in the data and the presence of supporting
data from other components of the monitoring programme should be jointly
assessed. If appropriate, changes
to the operations plan should be considered.
4.7
Sampling
Procedure and Equipment
All
samples should be collected by an experienced sampling team, deployed on a
survey boat equipped with fully calibrated sampling equipment and precision
navigational instruments. All
vessel positioning should be accomplished with a calibrated Differential Global
Positioning System (DGPS), ensuring station location accuracy to < ± 1 m (95% confidence), with
sample position automatically logged and mapped by the navigation
computer. Where sample stations are
located in close proximity to the pit area, positioning should be further
validated by use of an echo sounder to detect whether the vessel is within the
boundaries of the pit.
At
each sampling station the top 5 cm of seabed sediment should be collected using
a 5-component cluster grab sampler which collects surface sediments with a
minimal disruption to the surface layer and is designed to work effectively in
soft sediment such as those found in the area. The cluster grab should be deployed once
at each of the stations located within each sampling area (eg
Pit-Edge). The grabs can be
customised and a fine mesh lid added, which ensures that the fine fluid
sediments on the surface of the seabed are retained in the sample. Utilisation of this cluster sampler
allows a large volume of sediment to be collected in a single deployment. Other similar samplers (eg Petit-ponar) collect less
sediment in each deployment may have difficulty in collecting adequate samples
in soft sediments, such as those within the study area, thereby reducing
efficiency and increasing collection time.
The five-cluster grab should be collected and combined, and the sample,
labelled, double-bagged and stored in an ice chest cooled to a temperature of 4oC
with ice packs. The sediment
sampler and all other utensils should be rinsed with seawater after each sample
has been collected to avoid cross contamination between samples. On completion of the survey, all samples
should be promptly transported, in chilled containers, to the testing
laboratory for analysis.
4.8
QA/QC
A
broad range of contaminants should be analysed in sediment samples including
metals, metalloids, PAHs, PCBs, pesticides and Tributyltin in both sediment and
interstitial water. The method
detection limits should be consistent with previous monitoring programmes at
ESC. Other QA/QC procedures to be
implemented for marine sediment analyses include:
·
Laboratory blanks - an analyte
free matrix to which all reagents will be added in the same volumes or
proportions as used in the standard sample preparation to monitor contamination
introduced in the laboratory (organics and inorganics);
·
Batch duplicates - an intralaboratory
split sample randomly selected from the sample batch to monitor method
precision (intrabatch) in a given sample matrix
(inorganics only);
·
Certified Reference
Materials
- analysis of a material with a known concentration of contamination to
determine the accuracy of results in a given matrix (inorganics only);
·
Single Control Samples - a known,
interference-free matrix spiked with target analytes
used to monitor laboratory preparation techniques (organics only);
·
Duplicate Control Samples - multiple single control
samples designed to monitor preparation technique reproducibility
(organics).
4.9
Data
Quality Objectives
Data Quality Objectives
(DQOs) have been developed to address precision, accuracy and analyte recovery.