Water Nitrate

AUS-AKW-URB-WNI General Low confidence

Benchmark Value

4.4 mg/L
Range: — to 4.4 mg/L
Thresholds: Lower: —, Upper: 4.4
Optimal Range: — to 4.4
Direction: Lower is desirable ↓
Form: MaximumOnly

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context. The scoring engine uses 13 benchmarks together — the OptimalRange form drives the primary score, while 12 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MaximumOnly Guard MaximumOnly Guard MaximumOnly Guard MinimumOnly Guard MaximumOnly Guard Point Guard OptimalRange Guard MinimumOnly Guard MaximumOnly Guard Point Guard Point Guard MaximumOnly Guard

Evidence & Context

The value of < 4.4 mg/L (equivalent to < 1.0 mg/L as NO3−​-N) represents the threshold at which human influence on groundwater typically becomes detectable.

Metric Definition:

Water nitrate concentration in groundwater representing the natural background level and threshold for anthropogenic impact in an arid karstic urban environment.

Benchmark Definition:

This benchmark defines the upper limit of natural background nitrate concentration in groundwater for the arid karstic urban environment, beyond which anthropogenic pollution is indicated and ecological risk increases.

Justification:

Derived from a weight-of-evidence approach using analogous minimally impacted groundwater systems and ecological principles due to lack of direct field data.

Sources (1)

Preview of "Reference conditions and threshold values for nitrate-nitrogen in New Zealand groundwaters"
"Reference conditions and threshold values for nitrate-nitrogen in New Zealand groundwaters" Journal

National-scale estimates of reference conditions for nitrate in Australian groundwater

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Supporting Sources (55)

Additional references from the underlying research that informed this benchmark.

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(PDF) Mineral Nutrition of Plants in Australia's Arid Zone - ResearchGate, accessed July 13, 2025
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Putting the P in Ptilotus: a phosphorus-accumulating herb native to Australia - PMC

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(PDF) Nutrient limitations to aquatic production along an alluvial groundwater connectivity gradient in semi-arid northwest Australia - ResearchGate, accessed July 26, 2025,
Contextual Support GreyLiterature

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(PDF) Water Sensitive Urban Design - Case Studies (Australia/Dubai) - ResearchGate, accessed July 13, 2025,
Methodology Source GreyLiterature

WATER- SENSITIVE URBAN DESIGN AND PLANNING - Centre for Science and Environment

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An environmental flow to an ephemeral creek increases the input of carbon and nutrients to a downstream receiving river - Frontiers, accessed July 20, 2025
Contextual Support Government

An environmental flow to an ephemeral creek increases the input of carbon and nutrients to a downstream receiving river - Frontiers, accessed July 20, 2025

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An environmental flow to an ephemeral creek increases the input of carbon and nutrients to a downstream receiving river, accessed July 27, 2025,
Contextual Support

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Analysing water sensitive urban design options - Australian Water Association, accessed July 26, 2025,
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Extensions to Exmouth Water Supply Borefield Consultative Environmental Review - EPA WA, accessed July 26, 2025,

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Preview of Full article: Reference conditions and threshold values for nitrate-nitrogen in New Zealand groundwaters - Taylor & Francis Online
Full article: Reference conditions and threshold values for nitrate-nitrogen in New Zealand groundwaters - Taylor & Francis Online
Direct Evidence

Environmental Condition Index (Econd) - Wentworth Group of Concerned Scientists, accessed July 23, 2025

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Geology of the Nullarbor Plain (Webb and James 2006; courtesy JA Webb). - ResearchGate, accessed July 26, 2025,
Contextual Support

Geology of the Nullarbor Plain (Webb and James 2006; courtesy JA Webb). - ResearchGate, accessed July 23, 2025

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Geomorphology: Geology, Karst & the Gnargoo Range - Gnaraloo Wilderness Foundation, accessed July 26, 2025,
Contextual Support GreyLiterature

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Groundwater Monitoring for Nitrates in the Rural Areas of Clallam County, Washington, accessed July 26, 2025,
Contextual Support Journal

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Regulatory Framework

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Irrelevant

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Karst wetlands - WetlandInfo, accessed July 26, 2025,
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management plan for Cape Range National Park and proposed public conservation land additions - DBCA Library, accessed July 26, 2025,
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Memorandum - Nitrate guideline values in ANZECC 2000, accessed August 8, 2025
Regulatory Framework Journal

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Nitrate and nitrite | Australian Drinking Water Guidelines - NHMRC, accessed August 8, 2025
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Nitrate in freshwater and marine water - Water Quality Australia, accessed August 2, 2025,
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Irrelevant

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Outline of the geology and hydrogeology of Cape Range, Carnarvon Basin, Western Australia - Adec Preview Generated PDF File, accessed July 26, 2025,

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Context

  • Region Australia
  • Biome Arid Karstic Woodlands & Shrublands
  • Land Use Urban & Developed Use
  • Assessment Not Stated
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 2 Jun 2026

Notes

No direct benchmark exists for this specific context. The optimal range is as low as possible, ideally below detection limits, with any sustained concentration above 4.4 mg/L indicating ecological degradation. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.