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Monitoring and Sampling Manual 2009 (Version 2, published June 2010)

Monitoring and Sampling Manual 2009 Environmental Protection (Water) Policy 2009

Version 2 September 2010 (July 2013 format edits)

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Prepared by: Department of Environment and Heritage Protection State of Queensland, 2013. The Queensland Government supports and encourages the dissemination and exchange of its information. The copyright in this publication is licensed under a Creative Commons Attribution 3.0 Australia (CC BY) licence.

Under this licence you are free, without having to seek our permission, to use this publication in accordance with the licence terms. You must keep intact the copyright notice and attribute the State of Queensland as the source of the publication. For more information on this licence, visit http://creativecommons.org/licenses/by/3.0/au/deed.en ISBN 978-0-9806986-1-9 Disclaimer This document has been prepared with all due diligence and care, based on the best available information at the time of publication. The department holds no responsibility for any errors or omissions within this document. Any decisions made by other parties based on this document are solely the responsibility of those parties. If you need to access this document in a language other than English, please call the Translating and Interpreting Service (TIS National) on 131 450 and ask them to telephone Library Services on +61 7 3170 5470. This publication can be made available in an alternative format (e.g. large print or audiotape) on request for people with vision impairment; phone +61 7 3170 5470 or email . Citation Department of Environment and Heritage Protection (2009) Monitoring and Sampling Manual 2009, Version 2, July 2013 format edits. This document contains the common techniques, methods and standards for sample collection, handling and data management for use by Queensland Government agencies, relevant persons and other organisations for release and impact monitoring and to assess the condition and trend of Queensland waters. July 2013

Contents 1 Introduction............................................................................................................................................................2

1.1 Edition identification.........................................................................................................................................2 1.2 Purpose of the manual.....................................................................................................................................2 1.3 Status of the manual........................................................................................................................................3 1.4 Intended users .................................................................................................................................................3 1.5 Content of the manual .....................................................................................................................................3 1.6 Limitations........................................................................................................................................................4 1.7 Disclaimer ........................................................................................................................................................4

2 PART A Sampling design overview.......................................................................................................................5 2.1 Sound sampling design is essential ................................................................................................................5 2.2 Determining the scope of the sampling strategy .............................................................................................7

2.2.1 Defining the aims and objectives of sampling.........................................................................................7 2.2.2 Define the spatial boundaries of sampling..............................................................................................7 2.2.3 Define the temporal scale of sampling....................................................................................................8 2.2.4 Define the frequency of sampling ...........................................................................................................8

2.3 Sampling design ..............................................................................................................................................8 2.3.1 Importance of understanding the system being sampled .......................................................................8 2.3.2 What to sample .....................................................................................................................................11 2.3.3 Where to sample ...................................................................................................................................12 2.3.4 When to sample ....................................................................................................................................12 2.3.5 How to sample ......................................................................................................................................13 2.3.6 Quality control in sampling....................................................................................................................14 2.3.7 Cost effectiveness.................................................................................................................................14

2.4 Transport and security of samples ................................................................................................................14 2.5 Contact laboratories.......................................................................................................................................15 2.6 Sampling schedule ........................................................................................................................................15 2.7 Useful source documents for sampling design..............................................................................................15

3 PART B Sampling physico-chemical indicators of water quality and environmental health ...............................17 3.1 Sampling in the field ......................................................................................................................................17

3.1.1 Using intermediate containers and sampling rods................................................................................17 3.1.2 Automatic samplers...............................................................................................................................18 3.1.3 Field filtration equipment.......................................................................................................................20 3.1.4 Items for sample security ......................................................................................................................20 3.1.5 Sample carrier boxes ............................................................................................................................20 3.1.6 Marking pens.........................................................................................................................................21 3.1.7 Camera .................................................................................................................................................21 3.1.8 Voice recorder.......................................................................................................................................21 3.1.9 Global positioning system (GPS) ..........................................................................................................21

3.2 Labelling.........................................................................................................................................................21

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3.3 Sample containers and preservation methods ..............................................................................................22 3.3.1 Sample containers ................................................................................................................................22 3.3.2 Preservation and storage......................................................................................................................23

3.4 Preventing contamination ..............................................................................................................................24 3.5 Collecting samples.........................................................................................................................................24

3.5.1 Surface waters ......................................................................................................................................25 3.5.2 Groundwaters........................................................................................................................................27 3.5.3 Sediments .............................................................................................................................................27 3.5.4 Fish and other aquatic animals .............................................................................................................27 3.5.5 Vegetation and algae ............................................................................................................................28 3.5.6 Wipe sampling of surface contaminants (also known as swab sampling) ..........................................29

3.6 Instrument-based field tests...........................................................................................................................29 3.6.1 General guidance on taking field measurements .................................................................................30 3.6.2 Overview of field measurements...........................................................................................................32 3.6.3 Test kits.................................................................................................................................................35

3.7 Sample security and transport .......................................................................................................................36 3.7.1 Securing your samples..........................................................................................................................36 3.7.2 Transporting your samples ...................................................................................................................37

3.8 Laboratory analysis........................................................................................................................................40 3.8.1 Selection of analytical methods ............................................................................................................40

3.9 Data analysis and interpretation ....................................................................................................................41 3.9.1 Sources of reference values .................................................................................................................41

3.10 Data custodianship, management, and submission for regulatory purposes ...........................................42 Part C Appendixes......................................................................................................................................................43

Appendix C1 Forms ................................................................................................................................................44 Appendix C2 Methods for overcoming limit of detection problems: in situ extractions and the use of passive samplers..................................................................................................................................................................45

C2.1 In situ extraction ....................................................................................................................................45 C2.2 Passive sampling devices.....................................................................................................................46

Appendix C3 Flow measurement............................................................................................................................49 Appendix C4 Sampling water quality in temporary waters .....................................................................................49

C4.1 Sampling the receiving environment.....................................................................................................49 C4.2 Sampling release waters.......................................................................................................................50 C4.3 What to sample .....................................................................................................................................50

Appendix C5 Bulk natural water and sediment collection for direct toxicity assessment (DTA).............................52 Appendix C6 Contact details for laboratories..........................................................................................................53 Appendix C7 Units and concentrations...................................................................................................................54 Appendix C8 Sample containers and preservation methods..................................................................................58 Appendix C9 Fluvial sediment sampling using P 61 sediment samplers and HelleySmith bedload samplers.....69

C9.1 Skills/competency and experience........................................................................................................69 C9.2 Equipment .............................................................................................................................................69 C9.3 Method ..................................................................................................................................................71

C9.4 Equipment use ......................................................................................................................................75 C9.5 Equipment maintenance .......................................................................................................................82 C9.6 Sample handling ...................................................................................................................................82 C9.7 Quality assurance .................................................................................................................................82 C9.8 References............................................................................................................................................83

Appendix C10 Sampling procedures for suspended solids and nutrientsapplication of water sampling technique.................................................................................................................................................................84

C10.1 Background for sampling procedures .......................................................................................................84 C10.2 Manual sampling procedures....................................................................................................................84 C10.3 Automatic sampling procedures ...............................................................................................................85 C10.2 Sampling procedures for filtered nutrients ................................................................................................86

PART D Sampling bio-indicators of water quality and environmental health .............................................................88 4.1 Macro-invertebrate sampling and assessment..............................................................................................88

4.1.1 Introduction to AusRivAS ......................................................................................................................88 4.1.2 Sampling program.................................................................................................................................88 4.1.3 Site selection.........................................................................................................................................89 4.1.4 Sampling frequency ..............................................................................................................................90 4.1.5 Habitats sampled ..................................................................................................................................91 4.1.6 Preparing for a field trip.........................................................................................................................93 4.1.7 Field sheets...........................................................................................................................................93 4.1.8 Water quality sampling..........................................................................................................................94 4.1.9 Biological sampling ...............................................................................................................................94 4.1.10 Laboratory macroinvertebrate sample processing ..................................................................................96 4.1.11 Database entry and software support ...................................................................................................98

4.2 Blue-green algae (cyanobacteria) sampling and assessment.......................................................................99 4.2.1 Introduction to blue-green algae ...........................................................................................................99 4.2.2 Guidelines for assessing blue-green algae...........................................................................................99 4.2.3 Monitoring sites ...................................................................................................................................101 4.2.4 Equipment required for algae sampling ..............................................................................................102 4.2.5 Sample collection ................................................................................................................................102 4.2.6 Contingency plan framework for blue-green algae response .............................................................105

4.3 Sampling fish ...............................................................................................................................................107 4.3.1 General considerations .......................................................................................................................107 4.3.2 Sampling fish using drift nets ..............................................................................................................108 4.3.3 Sampling fish using tow nets ..............................................................................................................108 4.3.4 Sampling fish using short seine nets ..................................................................................................109 4.3.5 Sampling fish using long seine nets....................................................................................................110 4.3.6 Sampling fish using fyke nets .............................................................................................................111 4.3.7 Sampling fish using cast nets .............................................................................................................114 4.3.8 Sampling fish using gill nets................................................................................................................116 4.3.9 Baited trap fishing.....................................................................................................................................117 4.3.10 Sampling fish using electrofishing ..........................................................................................................117

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4.4 References...................................................................................................................................................123 Part E Preparation of aquatic animal tissues (fish and crustaceans) for veterinary laboratory examination ...........124

5.1 Reasons for sending aquatic animal tissues for veterinary laboratory examination ...................................124 5.2 Collecting finfish specimens for diagnostic laboratory examination........................................................125

5.2.1 Sampling live finfish ............................................................................................................................125 5.2.2 Sampling and preparing fixed finfish specimens ................................................................................125 5.2.3 Freshly killed finfish on ice ..................................................................................................................125 5.2.4 Frozen finfish.......................................................................................................................................126 5.2.5 Fixatives and anaesthetics..................................................................................................................126 5.2.6 Basic anatomy of finfish ......................................................................................................................127 5.2.7 Gill and skin smears and wet mounts .................................................................................................127 5.2.8 Finfish dissection.................................................................................................................................129

5.3 Collecting crustacean specimens for diagnostic laboratory examination................................................130 5.3.1 Sampling live crustacea ......................................................................................................................130 5.3.2 Sampling fixed specimens ..................................................................................................................130 5.3.3 Basic anatomy of crustacea................................................................................................................131 5.3.4 Sampling and preparing fixed crustacean specimens ........................................................................132 5.3.5 Gill, appendage and larval wet mount preparations ...........................................................................134 5.3.6 Sampling and preparing molluscs.......................................................................................................135

Part F Monitoring mangrove forest health ................................................................................................................139 6.1 Mangrove litter trapping...........................................................................................................................139

6.1.1 Introductionwhat is litter and how is it related to mangrove forest health? .....................................139 6.1.2 Why monitor litter productivity?...........................................................................................................139 6.1.3 Method summary ................................................................................................................................139 6.1.4 Site selection.......................................................................................................................................140 6.1.5 Installing litter traps .............................................................................................................................140 6.1.6 Emptying the traps ..............................................................................................................................140 6.1.7 Sorting trap contents ...........................................................................................................................140 6.1.8 Dry and weigh trap contents ...............................................................................................................141 6.1.9 Data interpretation...............................................................................................................................142 6.1.10 References and further reading..............................................................................................................142

6.2 Seedling regeneration .............................................................................................................................142 6.2.1 Introductionwhy monitor mangrove seedlings?...............................................................................142 6.2.2 Method summary ................................................................................................................................143 6.2.3 Site selection.......................................................................................................................................143 6.2.4 Establishing a belt transect .................................................................................................................143 6.2.5 Tag seedlings......................................................................................................................................143 6.2.6 Measure height ...................................................................................................................................144 6.2.7 Measure stem diameter and stem density ..........................................................................................144 6.2.8 Count the leaves .................................................................................................................................144 6.2.9 Record sediment type, pH and salinity ...............................................................................................144

6.2.10 Draw a mud map of the site ...................................................................................................................144 6.2.11 Measurements needed during re-survey................................................................................................144 6.2.12 Data interpretation ..................................................................................................................................145 6.2.13 References and further reading..............................................................................................................145

6.3 Canopy cover and leaf area index...........................................................................................................145 6.3.1 Introductionwhat is leaf area index and how is it related to mangrove forest health? ....................145 6.3.2 Method summary ................................................................................................................................146 6.3.3 Site selection.......................................................................................................................................146 6.3.4 Using the light meter ...........................................................................................................................146 6.3.5 Data interpretation...............................................................................................................................148 6.3.6 References and further reading ..........................................................................................................149

6.4 Mangrove forest structure .......................................................................................................................149 6.4.1 Introductionwhat is mangrove forest structure and how is it related to mangrove forest health?...149 6.4.2 Method summary ................................................................................................................................149 6.4.3 Site selection.......................................................................................................................................149 6.4.4 Lay out transect and set up quadrats..................................................................................................149 6.4.5 Estimate canopy cover........................................................................................................................151 6.4.6 Estimate canopy dominance...............................................................................................................152 6.4.7 Measure stem diameter ......................................................................................................................152 6.4.8 Count saplings and seedlings .............................................................................................................153 6.4.9 Estimate height ...................................................................................................................................153 6.4.10 Soils ........................................................................................................................................................154 6.4.11 Tag and record position of trees.............................................................................................................154 6.4.12 Measurements needed during re-survey................................................................................................154 6.4.13 Data interpretation ..................................................................................................................................154 6.4.14 References and further reading..............................................................................................................156

6.5 Crab burrow counts .................................................................................................................................156 6.5.1 Introductionwhy monitor crab hole density?....................................................................................156 6.5.2 Method summary ................................................................................................................................156 6.5.3 Site selection.......................................................................................................................................156 6.5.4 Establish transects ..............................................................................................................................157 6.5.5 Count the number of crab burrows .....................................................................................................157 6.5.6 Data interpretation...............................................................................................................................157 6.5.7 References and further reading ..........................................................................................................157

Part G Monitoring seagrass ......................................................................................................................................158 7.1 Intertidal percentage cover......................................................................................................................158

7.1.1 Introduction .........................................................................................................................................158 7.1.2 What is seagrass percentage cover?..................................................................................................158

7.2 Method for measuring seagrass percentage cover.................................................................................158 7.2.1 Method summary ................................................................................................................................158 7.2.2 Site selection.......................................................................................................................................159

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7.3 Data interpretation...................................................................................................................................161 7.4 References and further reading...............................................................................................................161

Appendixes ...............................................................................................................................................................162 Appendix H1 Checklist of equipment needed for macroinvertebrate field sampling ............................................162 Appendix H2 Queensland Site Information Sheet ................................................................................................163 Appendix H3 Water Quality Sampling Field Sheet ...............................................................................................168 Appendix H4 Field Sheets.....................................................................................................................................169 Appendix H5 Keys used for identification of Queensland Macroinvertebrate Fauna ...........................................170 Appendix H6 List of predictor variables used for the Mark I and Mark II models .................................................173 Appendix H7 National taxonomic codes for macroinvertebrate families collected in Queensland.......................174 Appendix H8 Transport of live aquatic animals.....................................................................................................176

Glossary....................................................................................................................................................................177 References................................................................................................................................................................185

Preface Water monitoring is undertaken by the Queensland Government for a variety of reasons, including the provision of information to government for policy and investment decision-making, to underpin natural resource management decisions by government and stakeholders, to assess impacts on the environment and to educate and inform stakeholders and the community generally.

Monitoring is also required to be conducted by persons under statutory approvals, and is additionally conducted by other organisations across Queensland, including local government, industry, regional natural resource management bodies and community groups. Many of these organisations collect valuable information on the condition of Queensland waters that complement Queensland Government monitoring.

The Monitoring and Sampling Manual 2009 provides the common techniques, methods and standards for sample collection, handling and data management for use by Queensland Government agencies, relevant persons and other organisations.

Where monitoring is required under legislation to be carried out under a protocol, the Monitoring and Sampling Manual 2009 is the principal document to decide the protocols. This manual is intended to be used by persons and organisations involved in the monitoring of the condition and trend of Queensland waters.

The Monitoring and Sampling Manual 2009 will facilitate consistency and increased scientific rigour of monitoring data available for interpretation by all stakeholders. It will allow them to assess the condition and trend of Queensland waters so that the aquatic environment can be managed for sustainable development and aquatic ecosystem health.

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1 Introduction

1.1 Edition identification This second edition of the Monitoring and Sampling Manual 2009 (the manual) supersedes the first edition of that manual, and sampling manuals published by the former Environmental Protection Agency, Department of Primary Industries, and Department of Natural Resources and Mines.

1.2 Purpose of the manual The purpose of the manual is to provide the common techniques, methods and standards for sample collection, handling, quality assurance and control, custodianship and data management, for use by Queensland Government agencies, relevant persons and other organisations.

The manual is a part of an integrated monitoring framework to decide the priorities, indicator selection, data storage, data analysis and reporting, as shown in Figure 1 below.

Where monitoring is required under legislation to be done under a protocol, including the Environmental Protection (Water) Policy 2009 (EPP (Water)) and the Environmental Protection Regulation 2008, the manual is the primary document to decide the protocols.

Figure 1.1 Integrated monitoring framework

1.3 Status of the manual This manual is the updated version of the primary document originally listed in the Environmental Protection (Water) Policy 1997 for use in deciding protocols. Accordingly, if there is any inconsistency between this manual and the other documents, this manual takes precedence to the extent of the inconsistency.

Some standards and other documents that have been used in preparing this manual will be revised from time to time. This could result in a procedure differing from that presented in the manual. The rules provided in Box 1.1 cater for such instances. In any situation where users of this manual use a revised document and/or adopt a protocol on the advice of an analyst, they should note the use of any revisions adopted and keep a record of the analysts advice.

Box 1.1 When a standard is revised

If this manual is found to differ from a revision of any of the other documents listed in the EPP (Water), amended after the date of this manual, a user may decide that the updated version of the document is more appropriate than the manual for deciding a protocol, either generally or in particular circumstances. This manual should not be interpreted as being inconsistent with the other document provided that:

the revision of the document is subsequent to the date of this manual the specific procedure in the document is revised in the updated document an analyst advises that use of the revision in deciding the protocol will lead to a determination of a quality as good as or better than that derived from using the manual.

1.4 Intended users This manual is intended to be used by:

those who hold instruments under the Environmental Protection Act 1994 such as Environmental Authorities and Development Approvals (that comprise licences and approvals to carry out environmentally relevant activities) and Environmental Protection Orders

employees and consultants of those who hold instruments under the Environmental Protection Act 1994 those who analyse the samples collected for water quality determinations other persons and organisations involved in the monitoring of the condition and trend of Queensland waters.

1.5 Content of the manual The manuals content has been prepared in consultation with other Australian environmental agencies and Queensland state and local government agencies. Australian and New Zealand and relevant international standards were considered during the preparation of this edition.

The manual is consistent with the nationally adopted framework presented in the Australian Guidelines for Water Quality Monitoring and Reporting (ANZECC/ARMCANZ 2000) and covers the sections of the framework indicated in Figure 1.2 below.

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Figure 1.2 Framework for a water quality monitoring programAustralian Guidelines for Water Quality Monitoring and Reporting (2000).

This manual presents procedures for:

sampling design sampling in the field:

o making in situ tests and water quality measurements o taking samples for water quality assessments, including samples of wastewaters, environmental waters,

sediments and biota

o preserving and storing samples for water quality assessments, including samples of wastewaters, environmental waters, sediments and biota

o security and transport of samples arranging laboratory analysis data analysis and interpretation.

1.6 Limitations The manual cannot cover every set of circumstances encountered when determining a protocol for sampling, and may not always provide sufficient or relevant directions. In situations where the user has little confidence that the samples might produce useful data, this should not stop them from being collected, particularly if there is no other opportunity to obtain the information they could provide.

1.7 Disclaimer Where particular brand names of equipment are mentioned, this has been done for illustration purposes only. Other makes or brands providing equivalent function are equally applicable.

2 PART A Sampling design overview

Sampling DesignSampling Design

Scope ofSamplingScope ofSampling

Why Sample?Why Sample?

SpatialBoundaries?

SpatialBoundaries?

Duration?Duration?

Frequency?Frequency?

Scope ofSamplingScope ofSampling


SpatialBoundaries?

SpatialBoundaries?

Duration?Duration?



SpatialBoundaries?

SpatialBoundaries?

Duration?Duration?


Sampling Design

Sampling Design

What to Sample?What to Sample?

Where to Sample?Where to Sample?

When to Sample?When to Sample?

How to Sample?How to Sample?

QCQC

CostEffectiveness

CostEffectiveness

What to Sample?What to Sample?

Where to Sample?Where to Sample?

When to Sample?When to Sample?

How to Sample?How to Sample?

QCQC

CostEffectiveness

CostEffectiveness

Transport & Security


Check Transport?Check Transport?

Securing SamplesSecuring Samples

DocumentationDocumentation









ContactLaboratories

ContactLaboratories

Double-checkRequirementsDouble-checkRequirements

Turn-around TimesTurn-around Times

Accreditation?Accreditation?

ContactLaboratories

ContactLaboratories







Figure 2.1 Essential components of a comprehensive sampling design

2.1 Sound sampling design is essential Before any sampling is carried out, the aim of the sampling exercise and how the results will be used need to be established. For example, a single result might be compared with a written specification or benchmark (such as release limits in an Environmental Authority or Development Approval or with relevant guidelines). Alternatively, several results might be used in calculations, and if so, it needs to be understood how the calculated quantities will be used. Prior to collecting samples, the need to assess the circumstances and the kinds of inferences that could be drawn from the results of sample analyses should be determined. That information will help identify where and when sampling should take place, and the quality characteristics that need to be determined for those samples.

The essential features of a sampling strategy are to ensure that the material sampled is genuinely representative of the body of material from which it was collected, that in situ measurements are reliable, and that the integrity of materials sent for laboratory analysis has not been compromised by contamination, degradation, transformation or losses.

The basic intent of environmental analysis is that analysis is carried out with selected portions (i.e. samples) from the location of interest, and the quality of the source material is then inferred from that of the samples. If the source material quality is temporally and spatially consistent then this inference would be uncomplicated. However, such constancy is rarely, if ever, observed in the real world. For example, virtually all waters show both temporal and spatial variations in quality (see Box 2.1 and Box 2.2), and consequently the timing and choice of location/s for taking water samples must be chosen with great care. Other materials such as sediments and biota typically also show such variations.

When designing monitoring programs it is important to ensure that the sampling regime is representative of the system and parameter/s of interest. For example, where a water body is well mixed and a parameter of interest is evenly distributed in the water column a grab sample may be appropriate. However, it is important to consider that parameters of interest may not be equally distributed. In such circumstances it may be necessary to assess the variability of the parameter of interest within the water column prior to sampling.

Such an evaluation would aim to determine whether sampling at a particular point is representative of a homogenous unit of water at a given point in time. Where the extent of variation is not known, the variation might need to be established by a pilot sampling program designed for that purpose, or a comprehensive range of

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samples taken to enable variability to be determined along with the primary aim of the sampling exercise.

In circumstances where undertaking an assessment of variability is not practical or possible it is recommended that information from relevant peer reviewed literature on the likely variability is used to provide guidance on an appropriate sampling strategy.

A similar approach to dealing with variability is recommended when designing sampling programs involving the collection of other materials such as sediments and biota.

When deciding the number of samples to collect and the frequency of sampling required, ideally, sufficient samples and replicates would be collected to represent the full range of variability present in space and time. Sampling designs should ultimately be defined by program objectives that can include the required statistical power required for discriminating between hypotheses or be based on the levels of acceptable sampling variability. Sampling designs should also be guided by the where to sample and when to sample sections in this manual (Sections 2.3.3 and 2.3.4).

Box 2.1 Variability of water quality over time

If the environment to be sampled shows changes over timefor example, river systems within minutes or hours, or lakes within days or weeksthe temporal pattern of sampling is of great importance. The schedule for the sampling program should take account of the expected temporal resolution of changes in the environment. In programs for monitoring wastewater treatment effluents, sampling around the clock may be required to determine whether control variables have been met or exceeded. A single sample can only be a snapshot at a single point in time and may not reliably represent typical conditions for a system that varies over time.

If many samples are taken over a period of time, it is often appropriate to match the sampling rate to the expected pattern of variation in the environment.

When it is necessary to quantify a contaminant load, multiple sampling periods may be needed. For example:

Time-proportional sampling: samples containing identical volumes are taken at constant time intervals. Discharge-proportional sampling: the time intervals are constant but the volume of each sample is proportional to the volume of discharge during the specific time interval.

Quantity-proportional sampling (or flow-weighted sampling): the volume of each sample is constant but the temporal resolution of sampling is proportional to the discharge.

Event-controlled sampling: depends on a trigger signal (e.g. a discharge threshold). For example, to detect peak concentrations during short-term changes of water quality, event-controlled samplers are useful.

Alternatively, passive samplers can be used to integrate variations in water quality over an extended period of time. For further information on the applicability and use of passive samplers see Appendix C2.

Box 2.2 Variability of water quality in space

It is important to understand how natural processes in environmental waters can affect water quality characteristics, and to be aware that water bodies are not homogeneous within a cross sectional area or depth profile.

Water bodies can be stratified (layered). This means the composition of the different layers is substantially different in respect of at least one characteristic. For example, in estuaries, water quality characteristics can vary because of ingress/egress of saline waters. Estuaries are commonly stratified when freshwater flow is much larger than tidal flow; the fresh flows seawards over the saline waters and a salt wedge develops. Stratification could also result from temperature effects in waters with low current velocities. Such stratification is usually most pronounced in summer months when surface waters are much warmer than bottom waters. After separation, the water layers often develop markedly different chemistry. Such layers also tend to prevent mixing of discharged contaminants.

When sampling environmental waters (typically, when investigating a pollution incident), it could be important to remember that stratification might have occurred, and to take measurements at different depths to show whether this is so. The reverse process (de-stratification) can occur when the seasons change. The resulting inversion (turnover) of the water can result in low oxygen water rising to the surface and causing adverse effects (such as odours from anaerobic decomposition at depth, and/or nutrient/metal enrichment). Other examples include the distribution of suspended solids within the water column from physical processes of re-suspension, deposition and flocculation. The concentration of suspended solids is dynamic in the water column and can fluctuate naturally according to flow conditions and water chemistry.

When the purpose of sampling is to assess compliance with a statutory provision such as a condition attached to an Environmental Authority or Development Approval, the sample should be taken to provide a reliable measure of the specific characteristic or parameter specified (e.g. the concentration of suspended solids at a defined sampling point). Where the statutory provision is not explicit, the sample should represent fairly the body of material from which it is taken during the period of the sampling.

Where the aim of the sampling is to measure compliance with conditions of an environmental authority or development approval, and the conditions include a statistical sampling regime, this should be followed so that the results can be of use. However, if there is reason to believe variability is a confounding factor, additional samples may be needed to check this out.

The Environmental Protection Act 1994 and its subordinate legislation, including the Environmental Protection Regulation 1998 and the Environmental Protection (Water) Policy 2009, must be taken into account when deciding where and when to sample for compliance in a pollution investigation, checking compliance with an environmental authority or development approval, or undertaking a receiving environment monitoring program.

Reference should be made to the current conditions of any relevant licence or permits, particularly when confirming compliance. The conditions may include specific sampling locations, times of release and quality characteristics that will assist with designing the sampling strategy.

2.2 Determining the scope of the sampling strategy

2.2.1 Defining the aims and objectives of sampling

2.2.1.1 Purpose of sampling

Monitoring and assessment that involves sampling can be undertaken for a range of reasons. Some of the primary reasons covered by this manual include:

investigating pollution incidentssampling at a site where pollution has been reported can be challenging as you might not be aware of the constituent pollutants, or often the source of the release. In such cases, the aim of sampling should be to obtain evidence that will:

o discover and prove the nature, the source, and the effects of the contaminants o be performed in such a way as to be legally admissible in court

confirming compliance to licence conditions of an environmental authority or development approvalsampling of wastewater that is stored or released by the holder of an environmental authority or development approval or similar legal instrument is often performed routinely to confirm compliance with the imposed conditions of release. To test for compliance with the conditions, samples must be collected in a manner that will ensure valid analysis results for those particular contaminants

undertaking a receiving environment monitoring program undertaking an environmental evaluation of an activity. 2.2.1.2 Specific sampling objectives

The objectives of the sampling program should be determined and documented. These should be as specific as possible. Common sampling objectives include:

determining if one or more contaminants found in a waste or in the environment have originated from a singular or multiple source

determining whether one or more contaminants in a release are in sufficient quantity to cause adverse environmental effects consistent with those observed at the time of the incident

determining whether the contaminants in a waste release are having a measurable impact on the receiving environment water quality and whether environmental values are being affected

determining whether the quality of waters have changed significantly, consistent with the definition of the term environmental harm in the Environmental Protection Act 1994, and confirm whether the observed environmental change(s) occurred as a result of the release.

2.2.2 Define the spatial boundaries of sampling The geographic boundaries of the sampling event should be based on the issue of concern and the ecosystem type rather than on convenience and/or budgets. For example, some important considerations would include:

the likely spatial uniformity of the parameter(s) of interest the size of the area to be assessed.

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2.2.3 Define the temporal scale of sampling Temporal scale refers to the length of time over which a system is to be observed; that is, the appropriate period of time over which the samples are to be collected.

Different processes operate at different temporal scales, and the sampling designer should incorporate all the important time-related considerations into the design. For example, the movement of sediment in a river system occurs over tens of years at the catchment scale, whereas toxicant effects may occur over days (transient) or be continuous in nature. The temporal scale and, similarly, the frequency of sampling (see below) need to be suited to the temporal characteristics and occurrence of the contaminant.

2.2.4 Define the frequency of sampling Consideration needs to be taken of the frequency of observations (sampling events) required to provide sufficient resolution of the issues of concern. Sampling may be required every hour, day, week, fortnight, month or possibly only once a year. The sampling designer needs to determine a frequency of sampling (level of resolution) that is sufficient to satisfy the requirements of the program objective, yet not sample too frequently and cost more than necessary.

2.3 Sampling design

2.3.1 Importance of understanding the system being sampled The achievement of good sampling design can be assisted if the designer has some understanding of the ecosystem for which the sampling program is being designed. This understanding is best formalised in a conceptual model (or process model) of the system being examined. The model can be a simple box diagram that illustrates the components and linkages in the system, or a graphical representation of the system. Whatever model is used, it should present the factors that are perceived to be driving the changes in the system and the consequences of changes to these factors.

During the formulation of a model, several decisions must be made or the model will be too complex. For example:

What are the major issues of concern (e.g. nutrients, metal loads, bioavailable metals)? What ecosystem (including subsystem type) should the model describe (e.g. freshwater, marine waters, estuarine waters, wetland, seagrass bed, mangroves)? Which state of flow should the model describe (e.g. base flow, flood event)? Once formulated, the process model can be used to help define:

important components of the system and the important linkages key processes causeeffect relationships important questions to be addressed spatial boundaries valid measurement parameters for the processes of concern; what to measure, and with what precision site selection time and seasonal considerations. Examples of graphical conceptual models that may assist sampling design are at Figures 2.2, 2.3 and 2.4.

The importance of having an understanding of the ecosystem for which the sampling program is being designed is demonstrated by the complexity of nutrient cycling processes in waterways.

Plants use light as a source of energy for everyday growth and repair. They also require elements such as carbon (which they derive from carbon dioxide in the atmosphere) and the nutrients nitrogen (N) and phosphorus (P). Nutrients stimulate the growth of aquatic plants and are required to maintain the productivity of ecosystems. However, the growth of aquatic plants can be limited, despite there being sufficient light available, when nutrients are present only at minimal concentrations. Nutrients can become an environmental problem when they occur at excessive concentrations. Negative effects of higher-than-normal nutrient concentrations include the eutrophication of waterways.

Figure 2.2 Conceptual diagram of a coastal system including anthropogenic activities, inputs to waterways and areas of value

Typical direct effects of eutrophication include increased frequency of algal blooms (including toxic algae) and hypoxia. Increased production of aquatic plants and algae may temporarily increase oxygen production within a water body, but when these decompose, this may cause a depletion of dissolved oxygen (DO). Low DO levels can lead to fish kills and the death of other aquatic fauna. Other effects of eutrophication may include increased turbidity and changes in community composition.

The nutrients N and P occur naturally in Australian surface water systems. They often occur in both particulate (i.e. organic and sediment-bound) and dissolved forms. The movement of nutrients from land may originate from both diffuse and point sources. Pathways for diffuse sources include riparian litter fall, soil erosion and sediment transport (see Figures 2.3 and 2.4). Fertilisers may be a source of N and P in agriculturally dominated catchments. The concentration and types of particulate and dissolved forms of N and P in waterways can indicate potential stresses from land uses and land management practices in the catchment.

An understanding of the relationship between flow and nutrient concentrations, coupled with N and P cycling (and the transformation from one form to another), is crucial when interpreting concentrations and loads and subsequently making any type of assumption or conclusion (e.g. is the nutrient a new contribution to the cycle or a transformation of a previously deposited load?). Without this understanding, changes in N and P concentrations and/or loads may be more attributable to variable flow regimes and biological factors rather than any imposed management action.

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Figure 2.3 Typical processes affecting nutrients within different parts of a catchment

Figure 2.4 Illustration depicting typical nutrient and sediment inputs into catchments

2.3.2 What to sample What material is relevant to collect samples of, and what measurements should be taken?

When checking compliance, environmental authority or development approval conditions typically specify the contaminants and the permitted ranges of concentrations allowed in the release. However, in cases of suspected environmental pollution incidents, you might not know what pollutants are present. Furthermore, when sampling the receiving environment, there are a range of related indicators that may need to be measured across different media such as surface water, sediments or biota. This section provides guidance on determining which characteristics should be sampled.

When choosing indicators, it is important to know whether there are defined benchmarks such as water quality objectives, guidelines, limits or other standards relevant to your situation to compare with your measured data. Indicators may be chosen because they have such benchmarks and may best indicate water condition or potential environmental harm. If no defined benchmarks exist, it is essential that your sampling design includes appropriate reference or control sites so that you are able to make a comparison against something.

2.3.2.1 Sampling media

The aim of sampling is to estimate quality characteristics of one or more of the following:

wastes released to a water body (or potentially released) the receiving environment via:

o a permanent or temporary water bodyusually surface waters, but occasionally groundwater o bottom sediments of a permanent or temporary water body

specimens of animal or plant life thought to have been affected by a release or by a change in natural conditions.

2.3.2.2 Sampling waste streams

Environmental authority or development approval conditions typically specify the contaminants and the permitted ranges of concentrations allowed in the release. Additional characteristics may provide greater information about the potential environmental harm that might be caused, for example, although only biochemical oxygen demand (BOD) might be specified in the environmental authority or development approval, chemical oxygen demand (COD) and total organic carbon (TOC) often provide more information, and could be worth assessing. It may also be important to measure other characteristics due to a change in an operating condition or a specific incident.

The characteristics being measured should relate to the potential contaminants used and/or generated in the process that produces the waste stream, in addition to their potential effects on the receiving environment.

In addition to measuring water quality characteristics, flow measurement of wastes/wastewater is often required for point source releases. This allows regulation and quantification of flow and loads of contaminants. Flow measurements of water bodies can be important for regulation as they can be used to assess initial mixing of point source discharges or as triggers to allow licensed discharges, particularly for event-based releases. Flow measurements of waterways may also be required for pollution incidents to assess or predict the extent of impact. Further information on flow measurement can be found in Appendix C3.

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2.3.2.3 Sampling the receiving environment

Your assessment should take into account:

potential sources of contamination likely contaminants type of waterway and flow rates; whether freshwater, estuarine or marine, and whether a flowing stream, lake,

or ephemeral (in which case it may be wet or dry, or evaporating and concentrating contaminants at the time of sampling)

licensed releases into the waters potential sources of releases recent weather such as heavy rain, showers or drought conditions historical occurrences of similar incidents.

2.3.3 Where to sample

2.3.3.1 Where should samples be collected and measurements taken?

Many environmental authorities have conditions which specify where samples are to be taken. Some have more than one sample point (two or more outlets, or an intake as well as an outlet). Where no sampling location is specified, you should take a sample from a site you judge to be representative of the release material (and the receiving waters, where relevant).

In more populated areas identification of a particular location can be assisted by a map of the area at a suitable scale (typically 1:25 000 or larger), or an aerial photograph showing individual buildings, preferably printed beforehand and taken with you. In more remote areas, use other points of reference, such as topographic features (hills, quarries, stream bends, etc.) or structures like fences or stone walls, and a global positioning system (GPS).

When investigating environmental pollution incidents, you should consider all possible sources of the pollutant, including licensed and unlicensed sources of release. You should aim to sample at the site of the pollution reported, at the point of any suspected contributing releases and also in an area upstream/distant from the suspected source.

It is important to identify with sufficient accuracy the location from which a sample has been collected to avoid raising a doubt about what the sample represents, particularly in cases where a location a few metres away might have given significantly different results. For example, in a river, was the location upstream or downstream of a tributary stream; or on the inside or outside of the bend? Or, where multiple discharge points exist, could it have been the one next to the one claimed? This last instance could be significant when investigating complaints in situations where you do not know what other discharges may have occurred.

2.3.4 When to sample

2.3.4.1 Timing of sampling

The timing of the sampling should address the pre-defined objectives of the program. When there is a suspected environmental incident, it is prudent to sample as soon as possible after the incident has occurred.

Some conditions on environmental authorities specify that release is to take place only at certain times of the day (for example, on an outgoing tide) or under certain weather conditions. This should be considered in your sampling design where applicable.

For impact assessments, sampling before and after is important (but not always possible), preferably with multiple before and after reference sites. In situations where there is no before information available at the impact location, data collected by sampling from reference sites may be indicative of conditions at the impact location prior to the incident. For example, a chemical spill may have contaminated the receiving environment, and caused impacts on local biota, but there are no pre-spill data available. However, concentrations of contaminants or macroinvertebrate population indices measured at unimpacted reference sites after a chemical spill can be indicative of what those parameters could have been at the incident location prior to the spill.

Water quality varies with stream flow conditions, so in considering the timing of sampling, it is important to establish whether sampling during baseflow or during flood event conditions (or both) is appropriate.

2.3.4.2 Sampling during baseflow and event conditions

As maximum and minimum values for water quality indicators may be reached either during high and or low flow events, it may be necessary to target either baseflow and or event conditions of rivers or streams. Fluctuations in water quality may also occur due to effluent discharge from a point source. Baseflow sampling is carried out when the flow is predominantly influenced by groundwater and has little overland flow component (i.e. no flow derived from runoff after rainfall). Baseflow sampling of streams should be undertaken with adequate lag time following an event. In general, a period of at least six weeks following a major flow event should be allowed to elapse to ensure samples are solely baseflow water and are not capturing the tail of an event. An event is classified as any significant rise in water level caused by rainfall. Sampling regimes for event sampling may be targeted at obtaining results from either smaller more frequent events, or larger but less frequent events. Episodic events are known to transport large quantities of some contaminants though, in some circumstances significantly higher concentration peaks can occur in much smaller but frequent flood events (see example in Figure 2.5). In some cases, these smaller more frequent events may also have a greater contribution to total or annual contaminant loads. Sampling of a flood event can include a series of discrete grab samples collected to represent the extent of the event. See Appendix C10 for more information on grab sampling procedures.

Figure 2.5 Example of contaminant fluctuations with stream flow

2.3.5 How to sample

2.3.5.1 How many samples should be collected?

Unless the material being sampled is known to be well mixed (well mixed water body or end-of-pipe discharge), it is unlikely for a single measure to be representative of the source body of material. Multiple measurements are needed to allow the calculation of a mean and confidence interval for the characteristic of interest, or to allow statistical testing for significant differences between locations or non-compliance with statutory provisions. This requires multiple readings for in situ measurements and multiple samples where laboratory analysis is involved. A minimum is three data points per site for basic statistical tests, but more may be required depending on the inherent variability in the measurement data. Just how many data points are needed may not be known until after chemical analysis of some samples. Accordingly, it is sometimes good practice to take additional samples and to store these for subsequent analysis if required. However, the requirements of maximum holding times for many contaminants may make this untenable.

2.3.5.2 Is grab sampling adequate or should composite samples be taken?

Most samples taken will be grab samplestaken by filling sample containers over a short period (seconds or minutes). A single grab sample may be used where a hazardous situation has arisen or is suspected and the sample is taken to confirm the presence of the hazardous substance.

A single grab sample may also be used where the body of water being tested is well mixed and its quality can be adequately described by a single sample. However, in many situations, a single grab sample in isolation is of limited use because it takes no account of variations in quality with time or space (see Box 2.1 and Box 2.2). In

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such a situation, the taking of a composite sample is a useful strategy. A composite sample may be temporal by combining contributions of material collected over a longer period (minutes, hours or days). Alternatively, a composite sample may be spatial, for example, comprising a series of equal contributions of material taken along a transect (e.g. across a channel). This gives a spatially more representative sample than a single grab sample at a single point. An example of the advantage of using composite sampling occurs in measuring concentrations of total nitrogen from a sewage treatment plant for the purpose of estimating loads. A single weekly grab sample will not capture the variations across a day or week. A suitable alternative would be to take a 24-hour composite sample.

Notes:

Composite sampling will not provide information on the maximum concentration reached (i.e. spikes in concentrations) which is often relevant when dealing with toxicants.

The use of automatic samplers to prepare composite samples over a period of time could be problematic due to delays in delivering samples to the laboratory for analysis. Under some circumstances this might not be significant, but you should check with the analyst before sampling with such equipment.

2.3.6 Quality control in sampling Quality control is an important part of any sampling exercise. The purpose of a quality control scheme is to check whether bias, sample contamination, or analyte loss could affect the results, and so invalidate the process.

Suitable techniques include:

reference sites: comparable (but unimpacted) locations where samples are taken for comparison with others (for example, upstream of a discharge point, or a tributary other than the one of interest). Unless the condition of the reference site/s is known, and because of variability, it is often wise not to rely on a single reference site

control samples, including: o field spikesan uncontaminated sample of the media (e.g. water) contained and preserved in an identical

fashion to the field samples is spiked with contaminants of interest and accompanies the field samples during the sampling. Analysis of the spiked sample quantifies analyte loss (if any) through comparison with the spiked concentration

o field, transport and container blanksuncontaminated samples of the media (e.g. water) contained, handled (for example filtered) and preserved in an identical fashion to the field samples are analysed and measures of introduced contaminant (if any) are used to quantify and trace contamination problems associated with the sampling methods and materials.

These techniques are discussed in AS/NZS 5667.1:1998.

It is recommended that you discuss this aspect with the analyst during planning of a sampling exercise, particularly if the results are liable to be used in making decisions which could have significant health related, financial or legal implications.

2.3.7 Cost effectiveness It is preferable for the cost of sampling programs to be as small as possible while still meeting the stated objectives of the monitoring study. Cost-effectiveness considerations involve trade-offs between loss of statistical power (i.e. the capacity of a program to discriminate between various hypotheses) and the cost of data acquisition. Costs of data acquisition taken into account for cost effectiveness include:

the number of sampling stations, sampling occasions and replicates the cost of collecting samples (staff, transport, consumables) the cost of analysis the cost of data handling and interpretation (cost of reporting). Cost-savings can result from collaborative monitoring, for example, when local councils pool resources with other water managers to comprehensively monitor a particular water body.

2.4 Transport and security of samples Samples collected in areas remote from the laboratory might need to be freighted by private companiesroad or air transportif the sampler cannot deliver them personally. The samples need to be delivered within the maximum holding times.

2.5 Contact laboratories When possible, contact the appropriate laboratories before going to the field to ensure that analysis can be performed before expiry of the maximum holding times. You should inform the laboratory of details concerning the samples you will be sending. One way is to send a completed copy of a form such as the Notice of Samples Expected shown in Appendix C1. Send this by mail when the sampling is planned some days ahead, or by facsimile or email if urgent. If this is impracticable, try to contact the analyst by telephone to give details of the samples.

You should also try to give the laboratory any information you can about the sample source, likely range of concentrations and purpose for which the results are to be used. This will help the analyst choose a suitable analytical method with appropriate limit of reporting (LOR). In some cases the LOR can be improved if the analyst knows these details beforehand.

If sampling from areas affected by a chemical spill, try to advise the laboratory to expect high concentrations in the samples. Providing the laboratory with such information may help avoid results such as out-of-range concentrations, and subsequent delays while your samples are diluted and re-analysed.

2.6 Sampling schedule Once the sampling design has been finalised a sampling schedule should be prepared that includes such information as:

where and when the samples are to be collected source of each samplewhether from wastes, waters or sediments the nature of the material to be sampled the quality characteristics being sampled the sampling containers (and associated paraphernalia) needed preservatives needed the maximum holding time for each sample. A blank copy of a sampling schedule form is located at Appendix C1. (Details of sample containers, preservatives and holding times are given in Appendix C8).

2.7 Useful source documents for sampling design Source documents for sampling design are shown in Table 2.1.

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Table 2.1 A selection of relevant Australian and New Zealand standards related to water and sediment sampling

AS/NZS 5667.1:1998 Water qualitySampling

Part 1: Guidance on the design of sampling programs, sampling techniques and the preservation and handling of samples


Part 4: Guidance on sampling from lakes, natural and man-made


Part 5: Guidance on sampling of drinking water and water used for food and beverage processing


Part 6: Guidance on sampling of rivers and streams


Part 9: Guidance on sampling from marine waters


Part 10: Guidance on sampling of wastewaters


Part 11: Guidance on sampling of groundwaters


Part 12: Guidance on sampling of bottom sediments

AS/NZS 2031:2001 Selection of containers and preservation of water samples for microbiological analysis

AS2360:1993 various parts

AS/NZS 3778: various parts

Measurement of fluid flow in closed conduits

Measurement of water flow in open channels

3 PART B Sampling physico-chemical indicators of water quality and environmental health

3.1 Sampling in the field This section details the equipment and materials to be used in sampling. Appendix C1 contains a checklist of equipment and materials. You can copy this checklist for each sampling trip, and modify it as needed.

Sampling in the FieldSampling in the Field

Sample collection methods & equipment

Water, Sediments and/or Biota

Sample collection methods & equipment

Water, Sediments and/or Biota

Sample containersSample containers

Sample preservation & storageSample preservation & storage

Field measurementsField measurements

ConsiderQA/QC

ConsiderQA/QC

ConsiderOH&S

ConsiderOH&S

Figure 3.1 Necessary materials and equipment considerations for sampling in the field

3.1.1 Using intermediate containers and sampling rods It is always best to collect samples directly into the appropriate bottle or jar. However, it is sometimes necessary to use an intermediate container in order to collect samples, using buckets, beakers, pumps, filters, syringes, sediment grabs, trowels and/or sampling rods.

In using intermediate containers, contamination of the intermediate containers from previous samples becomes a risk. Contamination of the sample can occur by leaching of previous substances from the walls of the intermediate container, or loss of analyte by adsorption on to the walls of that container.

For samples containing substances in trace concentrations, typically in the microgram-per-litre (g/L) range (such as trace metals and pesticides), use of an intermediate container should be avoided if possible. Sometimes the use of intermediate containers such as syringes and filtering equipment or components of automatic samplers is unavoidable, and so precautions to reduce the risk of contamination are critical.

If samples need to be collected using intermediate containers, it is important that intermediate containers be pre-washed (for example syringes and filters) or flushed (for example in the case of automatic sampler lines) with existing site water before being used for the final collection of samples. The use of field blanks (see section 2.3.6) can identify sample contamination issues.

A sampling pole with a large clamp (or other suitable device) to hold the sampling containers can be used to give greater reach when collecting samples (see Figure 3.2). If the rod becomes contaminated, wash it promptly, making sure the washings cannot contaminate any samples or any material about to be sampled (for example by disposing of washings downstream of the sampling site).

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Figure 3.2 Sampling pole and sample bottle

3.1.2 Automatic samplers In some circumstances it may be preferable to use an automated sampling device to collect samples (Figure 3.3). When sampling flood waters it is often unsafe to approach a stream bank to collect a sample manually due to the presence of high flows or in stormwater drains that can have flashy unpredictable flows. Also, in some instances it may be necessary to sample at regular intervals throughout a 24 hour time period or at times when it is not possible to collect them manually. In these situations it is appropriate that an automated sampler be used to collect grab samples. Automated sampling devices include refrigerated or non-refrigerated automatic pump samplers and rising/falling stage samplers.

Automatic pump samplers, both refrigerated and non-refrigerated are comprised of a number of bottles in a carousel, a sample intake line that is fixed in place within the stream and connected to a pump or pumps, and a computer controlled data logger that requires programming. The equipment is programmed to be triggered when a pre-entered set of conditions are met. For example: a certain stream height, time of day, change in temperature, the rate of rise or fall of the stream level, a particular turbidity reading or any number of possible programmable triggers. Once triggered, the automatic sampler starts sampling according to the program set. Installation of automatic samplers should be in accordance with manufacturer instructions. When using automatic samplers for taking water samples, it is important to adhere to the requirements for sample handling including sample holding times and sample containers for the parameter of interest (see Appendix C8). If using automatic samplers, the sampling lines (tubing or pipes) must be regarded as an intermediate container (see section 3.1.1), and the possibility of exchange between the sample and the walls of the lines must be considered. The time of contact between the sample and the wall material is important, and residues of previous samples must be properly flushed out before liquid is delivered into the sample container. More detail on this aspect is given in AS/NZS 5667.1: 1998.

Automatic samplers also include remote samplers, such as rising-stage and falling-stage samplers. In regards to sampling event-based flows in ephemeral or temporary waterways, only falling-stage samplers should be considered, as rising-stage samplers tend to sample first flush waters. If the data is to be used to determine locally-derived water quality objectives (as per ANZECC/ARMCANZ 2000) then it is recommended that in accord with the AusRivAS sampling protocols (see section 4.1) sampling takes place 46 weeks after a flood event and flow has been established.

Figure 3.3 Auto-sampler

With rising stage samplers, water samples are taken as the river level rises and samples can only be retrieved after the river level has receded (Figure 3.4). As the water rises it reaches the crown of the intake, flow starts over the crown and begins to fill the bottle. Sample bottles fill progressively from bottom to top. Sampling ceases when the level of the water in the bottle reaches the inner end of the air exhaust, which then prevents circulation through the sampler. An air lock forms in the intake and prevents enrichment of the sample from water flowing back and forward and transporting sediment into the sample container.

Figure 3.4 Rising stage sampler

Rising stage samplers do not involve refrigeration and because samples are exposed to light and ambient temperatures they are only valid for total nutrient and sediment analysis. Note however that samples must be retrieved within a few hours for total nutrient analysis to be valid (particularly for N). Rising stage samplers are useful for collection of samples from flashy, intermittent streams at remote or sites that are not easily accessed.

Sampling units must be securely mounted, one above the other, with adequate support provided to prevent dislodging by large logs and other debris. Samplers should be erected and installed so that they are pointing in a downstream direction (ensure bottles are facing upstream). Sampler location is recommended in the following areas:

on the inside of river bends (debris tend to be swept to the outside of bends) adjacent and mid stream of large trees (providing partial protection) downstream of small shrubs and trees (provide partial protection). Each visit to the site should also involve inspecting sampling units for evidence of insects in the intake and breathing tubes, a common reason for missed samples (and contamination).

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3.1.3 Field filtration equipment For some characteristics listed in Appendix C8, the samples must be filtered in the field before they are placed in the container used for transport to the laboratory. Depending on the characteristics being measured, either vacuum or pressure filtration equipment may be needed.

An important factor in field filtration is to note that the equipment used for the filtering task is an intermediate container and as such the equipment is a potential source of contamination of the sample (see section 3.1.1) so that pre-rinsing and the use of field blanks (see section 2.3.6) is advisable.

Vacuum filtration is recommended for chlorophyll samples; the pressure difference across the filter should not exceed 40 cm of mercury to prevent lysis (rupturing) of the cells. You need to filter a known volume of the water and send only the filter paper to the analyst (see Appendix C8).The equipment comprises a vacuum flask, vacuum pump, sintered glass filter funnel and a supply of the specified filters. It is not essential to filter the volume shown in Appendix C8; usually, only one filter paper needs to be submitted. It is essential to record the actual amount of water passed through the filter and report this to the analyst, so that the concentration can be calculated.

Pressure filtration is recommended for dissolved metals and some nutrient characteristics. The water passing through the filter is sent to the laboratory and the filter discarded. Typical equipment comprises a hand-operated syringe with a supply

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