Contaminated Land
Management Guidelines No. 5
Site Investigation and
Analysis of Soils
(2016 RevisedDraft)
Disclaimer
While every effort has been made to ensure that this guideline is as clear and accurate as possible, the Ministry for the Environment will not be held responsible for any action arising out of its use. This guideline should not be taken as providing a definitive statement for any particular user’s circumstances. All users of this guideline should satisfy themselves, and their client(s) concerning the application of this guideline to their situation and in cases where there is uncertainty seek expert advice.
This document may be cited as:
Ministry for the Environment. 2016. Contaminated Land Management Guidelines No. 5: Site Investigations and Analysis of Soils (2016 RevisedDraft). Wellington: Ministry for the Environment.
First published in February 2004 by the
Ministry for the Environment
ManatūMōTeTaiao
PO Box 10362, Wellington 6143, New Zealand
Revised October 2001
2016 Consultation Draft February 2016
2016 Revised Draft August 2016.
ISBN: 978-0-908339-57-0
Publication number: ME 1260
© Crown copyright New Zealand 2016
This document is available on the Ministry for the Environment website:
Acknowledgements
The 2016 version of this guideline was prepared with assistance from Erin Richards and Graeme Proffitt of Pattle Delamore Partners Ltd for the Ministry for the Environment, with input from representatives of regional councils, territorial and unitary authorities, the oil industry, and senior contaminated land practitioners.
We would also like to thank the various contributors to previous versions of this document, including environmental consultants, local authority staff, and industry representatives who provided comments during the consultation periods.
Contents
Acknowledgements
Abbreviations
Glossary
1Introduction
1.1Purpose
1.2Use of this guideline
1.3Scope
1.4 Workplace health and safety
1.5Document structure
2Site investigations
2.1 Investigation objectives
2.2Preliminary site investigation
2.3Detailed site investigation
2.4Site validation report
2.5Further reading
3Conceptual site model
3.1 Objective of a conceptual site model
3.2 Information requirements for PSIs, DSIs and CSMs
3.3 Further reading
4Soil investigation design
4.1Overview
4.2Sampling and analysis plan
4.3Quality assurance and quality control
4.4Preparing for fieldwork
5Undertaking detailed site investigations
5.1Geophysical surveys
5.2Sample collection and handling
5.3Decontamination
5.4Field-screening techniques
5.5Further reading
6Laboratory analysis
6.1Selecting a laboratory
6.2Planning laboratory analytical test requirements
6.3Documentation
6.4Sample handling
6.5Laboratory quality assurance and quality control
6.6Laboratory reporting
6.7Uncertainty of measurement
7Basics of data interpretation
7.1Data quality review
7.2Data assessment
7.3Using statistical methods for data assessment
7.4Comparison to soil guideline values
7.5Common mistakes made in data interpretation
7.6Further reading
Appendix A: Conceptual site model examples
Appendix B: Hotspot detection
Appendix C: Detection limits
Appendix D: Example of determining uncertainty using duplicate and replicatesamples
Bibliography
Tables
Table 1: Main investigation phases and common alternative descriptors
Table 2: Conceptual site model input into the source-pathway-receptor model
Table 3: Sampling pattern selection guide
Table 4: Soil sampling techniques
Table A1: Example summary of exposure pathways
Table B1:Calculated number of samples for varying grid and site sizes based on appendix B equation
Table D1:Summary of duplicated samples
Table D2:Extracted precision data from replicate samples
Figures
Figure 1: Recommended approach to site investigation for NES purposes
Figure 2: Pathways by which contaminants in soil can migrate to receptors
Figure 3: Sampling patterns
Figure 4:Multiple grid patterns on a single site
Figure 5: Illustration of normal distribution and 95 per cent upper confidence limit of the mean
Figure 6: Right-skewed distribution
Figure A1: Example Illustrative conceptual site model for exposure to hydrocarbon fuels at petroleum retail sites
Figure A4: Flow diagram example of a conceptual site model
Contaminated Land Management Guidelines No. 5: Site Investigation and Analysis of Soils1
Abbreviations
ASTMAmerican society for testing and materials
BTEX benzene, toluene, ethylbenzene and xylene
CLMGContaminated Land Management Guidelines
CSM conceptual site model
DQO data quality objective
DSI detailed site investigation
FIDflame ionisation detector
HAIL Hazardous Activity and Industry List
IQR inter-quartile range
LIM land information memorandum
LNAPLlight non-aqueous-phase liquid
MDLmethod detection limit
NESResource Management (National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health) Regulations 2011
PAHs polycyclic aromatic hydrocarbons
PID photo-ionisation detector
PQLpractical quantitation limit
PSI preliminary site investigation
QA/QCquality assurance / quality control
RMA Resource Management Act 1991
RPD relative percent difference
SCS soil contamination standard
SGVsoil guideline value
SQEsuitably qualified and experienced practitioner
UCLupper confidence level
UoMuncertainty of measurement
XRF X-ray fluorescence
Glossary
AnalyteAn element or chemical that is being analysed.
Chain of custodyThisis a legal term that refers to the ability to guarantee the identification and integrity of samples from collection through reporting of test results. For the purpose of litigation, it is necessary to prove the legal integrity of all samples and data as part of the chain of evidence. Therefore, it is necessary to have anaccurate written history for the sample. This history should include sample bottle preparation, bottle possession, handling, and location of samples and data from the time of collection through to reporting. This can be conducted by using chain-of-custody procedures.
Detection limitThe lowest concentration that can be reliably measured by an analytical procedure.A detection limit is also known as limit of reporting (LoR) limit of blank (LoB), limit of detection (LoD), and limit of quantitation (LoQ).
Exposure areaThe area over, or from which, a receptor may be exposed to the contaminants of concern.
HotspotA localised area of elevated contaminant concentrations relative to the remainder of the site.
Quality assurance Relates to the planned activities implemented so that quality requirements will be met.
Quality control Relates to the observation techniques and activities used to demonstrate that the quality requirements have been met.
Remedial action plan(RAP) is used to plan remedial and management works to mitigate the risk posed by contaminants.Also known as a remediation action plan.
Rinsate blankIscollected after equipment decontamination and is obtained by running deionised water through the sampling equipment and collecting the water.A rinsate blank is tested for any residual contamination, which provides an indication of the potential for cross-contamination between samples as a result of poor decontamination procedures.A rinsateblank is also referred to as an equipment blank.
Sample matrixThetype of sample (eg, water, soil, sediment).
Sample holding timeThe period of time that samples can be retained between the taking of the sample and the laboratory analysis for a specific material before the results are considered invalid. Sample holding times vary between analytes.Some types of analyses require that preservatives be added to the sample, and some require storage of samples at refrigerated temperatures.
Soil guideline valueIn this document ‘soil guideline value’ has been used when referring to the soil concentration against which analytical results are to be compared.Where the objective is to assess and manage contaminants in soil to protect human health, then the soil concentration against which analytical results are to be compared will be the appropriate soil contaminant concentrations protective of human health.
Soil logging Writtenrecord of information about the soil encountered during the soil investigation.A sample log is also referred to as the stratigraphic log, strat log, geology log, bore log, test pit log or well log.
Trip blankMeasures sample contamination by cross-contamination from other samples, field handling, storage and transport.A trip blank is generally a sample container, often filled with distilled water, which travels unopened to the site with the empty sample containers and returns unopened to the laboratory with the samples.
VolatilesChemicals that have a high vapour pressure at ordinary room temperature. Their high vapour pressure results from a low boiling point, which causes large numbers of molecules to evaporate or sublimate from the liquid or solid form of the compound and enter the surrounding air.
Contaminated Land Management Guidelines No. 5: Site Investigation and Analysis of Soils1
1Introduction
1.1Purpose
Contaminated Land Management Guidelines No. 5 – Site Investigation and Analysis of Soils(the guideline) is the fifthin a series of five documents on contaminated site management produced by the Ministry for the Environment.It is designed to be used in conjunction with other documents in the series, and promotes a nationally-consistent approach to the investigation and assessment of contaminated sites.
This guideline describes good practice for the:
- design of contaminated site investigations
- sampling and analysis of soils on sites where contaminants are present or suspected to be present
- interpretation of the data obtained.
This Guideline is incorporated by reference into the Resource Management (National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health) Regulations 2011 (referred to hereafter as the NES). Preliminary site investigations (PSIs), detailed site investigations (DSIs), and site validation reports that are conducted forNES purposes and submitted to territorial authorities must be conducted in accordance with this guideline.
1.2Use of this guideline
This guideline is primarily aimed at contaminated land practitioners and regulatory authorities that undertake and/or review contaminated site investigations, and in particular for NES purposes. Owners, occupiers and other stakeholders may also find the guideline useful for reviewing work undertaken, or for assessing tenders or proposals for work.
For practitioners, the guideline provides guidance on good practice for establishing investigation objectives and developing a conceptual site model, and then for designing and carrying out fieldwork, specifying laboratory analysis, and interpreting the data to fulfil the purpose of the investigation. If the good practice requirements set out in this guideline are not met, the reasons for doing so should be documented in the site investigation report.The implications of not meeting these guidelines should be clearly stated to enable a council to exercise its discretion in assessing the adequacy of the investigation and the appropriateness of the conclusions.
The practitioner undertaking this work should be appropriately trained and have relevant experience in the type of investigation being conducted, or should be working under the direction of such a person. If the investigation is being carried out to meet a regulatory requirement of the NES, a suitably qualified and experienced practitioner (SQEP) must certify the report that is produced.
The overall content of the guideline should help regulatory authorities and other stakeholders using or assessing contaminated land reports to:
- understand the stated outcomes of the reports in the context of the site investigation objectives
- understand the uncertainties associated with the collection and analysis of soil samples and the interpretation of the resulting data
- assess whether the site investigation and analysis of soils have been undertaken in line with the nationally consistent approach set out in the guideline.
For sites that have regulatory requirements, the council should be satisfied with the adequacy of an investigation, its conclusions and any recommendations for further investigation, remediation or management, and that the investigation has been done by a suitably experienced and qualified practitioner.If the council is uncertain about any of these aspects, further advice could be sought or an external peer review commissioned.
The guideline is not intended to provide practitioners and stakeholders with definitive guidance on contaminated land management.Other documents that provide more specific details on the many aspects of site investigations are available, including New Zealand guidelines on the investigation, assessment and monitoring of land potentially contaminated by gasworks residues, petroleum hydrocarbons, timber treatment chemicals, and sheep dips. New Zealand and overseas documents used in the preparation of this guideline are listed in the bibliography, and sources of additional information are provided throughout the document.
1.3Scope
This document provides guidance on how to design and carry out an investigation of land where contaminants are present, or are suspected to be present, in soil. This document does not include guidance on generating a remediation action plan (RAP) or completing remedial work. Guidance on generating a RAP is provided in Contaminated Land Management Guidelines No. 1 – Reporting on Contaminated Sites in New Zealand (Ministry for the Environment, 2016) (referred to hereafter as CLMG No. 1).Contaminated site investigations for NES purposes should be carried out in a series of phases, with each phase designed to achieve specific objectives. This phased approach is shown in figure 1.Investigations for purposes other than NES requirements generally follow the process outlined in figure 1.
The first step in any investigation is to set clear and appropriate investigation objectives (refer section 2.1), that focus on the reasons for undertaking the site investigation, taking into account the originator’s requirements, the future land use, and any relevant regulations.
Once the objectives are established, preliminary information should be gathered to develop a conceptual site model (refer section 3) that describes the environmental setting of the site, potential contaminant sources, pathways for contaminant migration, and receptors (human and/or environmental). It is this model that guides the subsequent decisions on whether further investigations and/or remedial actions are required.
If it is decided that soil sampling is required to meet the objectives of the investigation, a soilinvestigation design (refer section 4) should be developed before undertaking the soil investigation (refer section 5) and any laboratory analysis (refer section 6).Depending on thefindings of the sampling work, further supplementary detailed investigations may be required. Data and information obtained at each investigation phase should be reviewed (refersection 7), and the conceptual site model updated to assess whether the information issufficient to fulfil the investigation objectives.
Figure 1: Recommended approach to site investigation for NES purposes
This phased approach is consistent with international guidance, such as that contained in Australia’s National Environmental Protection (Assessment of Site Contamination) Measure (NEPC, 2013) and the British Code of Practice for the Investigation of Contaminated Land (BS10175:2013). It is also broadly consistent with the planning approach contained in the U.S.EPA seven-step data quality objective process (U.S. EPA, 2006b).
It is important to note that although this guideline is concerned solely with the investigation and analysis of soil, the same general principles apply to the design of investigations of other media such as air, groundwater or surface waters affected by contaminants. The collection and analysis of samples from these media may also be integral to a detailed site investigation.
Clear reporting of the findings is a key aspect of any site investigation. Guidelines and a checklist for reporting are contained in CLMG No. 1. These can be applied to all contaminated site investigations, but investigations conducted under the NES and submitted to territorial local authorities must be reported on in accordance with CLMG No. 1.
1.4 Workplace health and safety
This guideline is not for the purpose of addressing health and safety requirements. For guidance on workplace health and safety when working on potentially contaminated land contact WorkSafe New Zealand or visit their website
1.5Document structure
Section 2provides an overview of the scope of a preliminary site investigation, a detailed site investigation, and site validation reports.
Section 3contains information about conceptual site models.
Section 4provides guidance on the design of soil investigations, including the sampling and analysis plan.
Section 5provides guidance on implementing the field sampling component of the investigation, including quality assurance and control.
Section 6contains information on laboratory analysis, including quality assurance and control.
Section 7provides guidance on interpreting the data gathered during the soil investigation, particularly the comparison of analytical results with soil guideline values.
2Site investigations
The aim of a site investigation is to complete an assessment to support a decision-making process about a site. Decisions made in the context of the NES are associated with assessing and managing the actual or potential adverse effects of contaminants in soil on human health from regulated activities[1].Site investigations may also provide information which allows an assessment of the actual or potential adverse effects on the environment and ecological receptors, or of compliance with regulations or statutory requirements other than the NES.Typically this is achieved through developing and refining a conceptual site model (CSM) which describes the source-pathway-receptor linkages at a site (refer section 3).
The NES includes specific site investigationtypes to comply with NES-specific requirements.The NES-specific site investigationsrelevant to this guideline are:
- preliminary site investigations (refer section 2.2)
- detailed site investigations (refer section 2.3)
- sitevalidation reports (refer section 2.4).
The NES specific ‘investigation’ types and common alternative descriptors are summarised intable 1 (below).
Site investigationsfor purposes other than NES requirements (eg,site purchase due diligence or assess environmental risks), generally follow the processes outlined in this guidance, and commonly also consist of the site investigation types described in Table 1.
Table 1: Main investigation phases and common alternative descriptors
Preliminary site investigation (PSI)Alternative names: / Preliminary site study; phase 1 desk-top study; phase 1 background information study; phase 1 contaminated site audit; phase 1 environmental site assessment (ESA)
Purpose: / To provide information about the nature and historical use of a site to inform development of the CSM.
The PSI often involves a preliminary site inspection (a walk-over), but it does not usually involve soil sampling.
Under the NES, a PSI may be:
a.used to establish whether the NES applies to a site by showing whether, or how likely it is that, the site has had Hazardous Activity and Industry List (HAIL) activities undertaken on it, or
b.required to establish whether pursuant to the NES a proposed land use can be carried out as a permitted activity.
Detailed site investigation (DSI)
Alternative names: / Stage 2; phase 2 field investigation; phase 2 ESA; environmental benchmarking
Purpose: / To collect field data to identify the nature and concentration of the contamination present on a site and delineate its extent to meet the investigation objectives. This typically involves collecting samples of various media (eg,. soil, groundwater, vapour) for laboratory analysis and characterisation of the site contamination conditions. The results of a DSI are used to update and reduce uncertainty in the CSM.
A DSI may be undertaken in stages to provide supplementary information where the investigations identify the need for more information to fulfil the investigation objectives.
Under the NES, a DSI may be:
a.used to establish whether the NES applies to a site by demonstrating that any contaminants in or on a site are at, or below, background concentrations
b.required to support applications for resource consent where the activity to be undertaken is not permitted.
Site validation investigation
Purpose: / To confirm that remedial works have adequately removed/mitigated site contamination.
2.1 Investigation objectives
So the correct data is collected, it is important to understand at the outset the purpose of the investigation and how the results might be applied in subsequent decision-making. The first step in defining the objectives of the investigation should therefore be to understand: