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Glossary

&#945 risk
The probability, expressed as a decimal, of making a false rejection decision error (Type I error) (ie, rejecting a result when it is actually true).
Accuracy
A term used to express the proximity to the true value.
Air rotary drilling
A drilling technique using air to push the soil out of the borehole.
APHA
American Public Health Association.
ASTM
American Society for Testing and Materials.
Auger
A soil-sampling device manually or mechanically driven into the soil.
AWWA
American Water Works Association.
β risk
The probability, expressed as a decimal, of making a false acceptance decision error (Type II error) (ie, accepting a result when it is actually false).
Background samples
Soil samples collected in the area local to the site that represents naturally occurring ambient concentrations.
Bias
Asystematic deviation (error) in data that affects accuracy.
Blank
A sample for quality control purposes - should not contain the analyte of interest.
Blind replicate sample
Also referred to as a field duplicate or replicate. Two separate samples (replicates) are collected from a single sample location, stored in separate containers and submitted for analysis to the laboratory as two separate samples for QC purposes.
Borehole
An excavation undertaken using a drilling rig. This can be used for soil sampling and for installing soil, gas and groundwater monitoring devices.
BTEX
Benzene, toluene, ethylbenzene and xylenes - a group of volatile aromatic hydrocarbons.
Certified reference materials
Sample material obtained from an independent source which has been analysed by different laboratories to determine consensus levels of the analyte concentration.
Chain of custody
Documentation that is prepared by the field staff to document the handling and transport procedures of samples from the field to the laboratory.
Clean-up criteria
Specific limits or concentrations that may be specified in remediation documents.
CLMG
Contaminated Land Management Guidelines (CLMG) series.
Composite sampling
A procedure that involves collecting individual soil samples from different locations, then bulking and mixing equal weights of the samples in the lab to make one (composite) sample.
Conceptual site model
A working hypothesis covering the potential nature and sources of contaminants, their likely spatial distribution in the soil (and other environmental media), and the potential effects of the contaminants on the site and on adjacent sites and other receptors.
Confidenceinterval (error)
Instead of a single estimate for the mean, a confidence interval generates a lower and upper limit for the mean. The confidence interval is dependent on the sample size, with the interval estimate providing an indication of how much uncertainty there is in the estimate of the true mean: the narrower the interval, the more precise the estimate.
Confidencelimit
The mean plus or minus the confidence interval. Confidence limits are usually shown as error bars on graphs or as six values. For contaminated sites, the upper confidence limit (UCL) is more commonly of interest, but it is worth noting that the UCL does not represent the worst case scenario for a site but the value above which the site average is unlikely to occur.
Contaminated land
A generic term used to describe parcels of land where hazardous substances are, have been, or are likely to be present in the environment.
Contaminated site
A site at which hazardous substances occur at concentrations above background concentrations and where assessment indicates it poses, or is likely to pose, an immediate or long-term risk to human health or the environment (after ANZECC, 1992).
Decontamination
The process of washing and rinsing to remove contaminated material; applies to all equipment that can or has come into contact with contaminants.
Detailed site investigation
This involves intrusive techniques to collect field data and soil samples for analytical testing.
Detection limit (DL)
See Method detection limit.
DQOs
Data quality objectives - qualitative and quantitative statements that specify the quality of the data required.
Duplicate
See Blind replicate sample.
Equipment rinsate blanks
QC samples used to identify cross-contamination from decontamination procedures. They are obtained by taking a sample of deionised water collected off/through the sampling equipment after decontamination has been undertaken on the equipment.
Extractable metals
The fraction of metals that is likely to be extracted or leached from the sample under normal environmental conditions.
Field blanks
QC samples, which are bottles filled with deionised water in the field and used to identify any volatile organic compounds that may have been introduced to the sample during sample collection.
Field screening techniques
Techniques used to define soil contamination cost-effectively, or used as a first stage to assist in targeting the intrusive investigation.
Fill material
Material that has been imported onto a site; also referred to as made ground.
Flame ionisation detector
A detector used in gas chromatography.
Geometric mean
A statistical term representing an 'average' defined as the nth root of the product of n numbers.
Geophysical surveys
Non-intrusive investigation techniques based on physical measurements to help identify irregularities or hidden features in the subsurface.
HAIL
Hazardous Activities and Industries List - a New Zealand list of activities and industries that are considered to have a high potential for land contamination.
Hot spot
A localised area where the concentration of contaminants is relatively high compared to the surrounding area.
HSEP
Health, safety and environment plan - documented assessment of the hazards and measures to eliminate, isolate or minimise these hazards for the tasks proposed.
IANZ
International Accreditation New Zealand.
Inter-laboratory comparison programmes
Analytical proficiency schemes for laboratory tests.
Job safety analysis
A tool used to identify and document any hazards for each task, identify appropriate mitigation measures and assign responsibilities.
Judgemental sampling
Also called targeted, selective, strategic or model-based sampling. A method in which sample locations are selected based on prior knowledge.
Leaching tests
Soil tests used to assess the likely mobility of parameters from the soil to the water phase (see Synthetic precipitation leaching procedure, and Toxicity characteristic leaching procedure).
Made ground
See Fill material.
Mean
A statistical term representing an 'average' defined as the sum of measurements divided by the number of measurements made.
Median
A statistical term representing an 'average', defined as the middle number if the data set are ranked in numerical order. (If there are an even number of measurements, the median is the average of the middle two).
Method detection limit (MDL)
The minimum concentration of a substance that can be measured and reported with 95% confidence that the value is greater than zero.
Mode
A statistical term representing an 'average', defined as the most frequently occurring value.
Monocyclic aromatic hydrocarbons
A group of organic chemicals comprising one fused aromatic ring (eg, benzene).
NATA
National Association of Testing Authorities, Australia.
NES
National environmental standard.
NZS/ISO/IEC
New Zealand Standard/International Organisation for Standardisation/International Electrotechnical Commission.
OSH
Occupational safety and health.
PCB
Polychlorinated biphenyls.
Photo-ionisation detector
A field screening instrument used for detection of volatiles.
Polycyclic aromatic hydrocarbons (PAH)
A group of organic chemicals comprising two or more fused aromatic rings.
PQL
Practical quantitation limits - the lowest level of quantitation that can be reliably achieved within specified limits of precision and accuracy.
Precision
A measure of random variation in data, which affects the reproducibility of a method.
Preliminary site inspection
A site visit to augment or confirm the findings of the preliminary site study, and to identify any information to assist with the design of the detailed site investigation.
Preliminary site investigation report
A report documenting the information gathered in the preliminary site study and preliminary site inspection as set out in Contaminated Land Management Guideline No. 1: Reporting on Contaminated Sites in New Zealand (Revised 2011) (Ministry for the Environment, 2001).
Preliminary site study
The initial investigation phase.
QA
Field quality assurance - a field programme to ensure uncertainty in sampling is minimised and managed.
QC
Field quality control - field procedures and samples collected and used for the QA programme.
Relative percent difference
The difference between two sample results divided by their mean and expressed as a percentage.
Repeatability
A statistical term to represent the within-run precision of a method.
Replicate
See Blind replicate sample.
Reproducibility
A statistical term to represent the between-run precision of a method.
Sample logging
A soil profile logged on field record sheets using a consistent methodology and format for soil descriptions.
Sampling and analysis plan
A working document issued to field staff undertaking the sampling, which sets out the sampling objective, strategy and QA/QC requirements.
Sampling objectives
Descriptions of why the samples are being collected.
Sampling patterns
Descriptions of the lateral location of soil samples collected.
Sampling strategy
A description of where and how to collect the samples.
Site validation
A process of investigation to verify remediation at a site.
Site validation report
A report that assesses the results of post-remediation testing against clean-up criteria for a contaminated site.
Spike
A QC sample in which a known concentration of material is added to the sample.
Split samples
QC samples used to check on the analytical proficiency of the laboratory. A primary laboratory sends a portion of a sample to a second independent laboratory for testing.
Standard deviation
A statistical term which expresses the extent of divergence from the mean.
Stratified sampling
A sampling pattern in which the site is divided into (usually) non-overlapping sub-areas. Different sampling densities and sampling patterns are used in the different sub-areas.
Surrogate
A compound added to every sample prior to analysis to check the validity of the analytical method.
SVOCs
Semi-volatile organic compounds.
Synthetic precipitation leaching procedure
An analytical method designed to determine the mobility of toxic organic and inorganic soil contaminants to groundwater tables below a contamination source.
Systematic sampling
A sampling pattern, also referred to as non-targeted or grid sampling, which is a statistically based sampling strategy whereby soil sampling points are located at regular intervals throughout the site area on a grid pattern.
Test pit
Also referred to as trial pit - an excavation undertaken by using a backhoe excavator and used for investigating subsurface materials to obtain soil samples.
Toxicity characteristic leaching procedure
An analytical method designed to simulate the leaching processes and other effects that occur when wastes are deposited into a landfill.
TPH
Total petroleum hydrocarbons - an analytical test for compounds that are soluble in an organic solvent, and include hydrocarbons and other organics (eg, solvents).
Trip blanks
QC samples used to identify cross-contamination from sample transport or storage, and used when sampling soils for volatiles.
UCL
Upper confidence limit.
US EPA
United States Environmental Protection Agency.
Variance
The standard deviation squared.
VOCs
Volatile organic compounds.
WEF
Water Environment Federation.
WES
Workplace exposure standards.
X-ray fluorescence
An analytical technique used for measuring total metals in soils.
Zero headspace sampler
Equipment used for collection of soil for volatile analyses.