Water Nitrate

AUS-TMS-LVG-WNI General Moderate confidence

Benchmark Value

No specific value — see range
Range: 0.005 to 0.01 mg/L
Thresholds: Lower: 0.005, Upper: —
Optimal Range: 0.005 to 0.01
Direction: Lower is desirable ↓
Form: OptimalRange

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 10 benchmarks together — the OptimalRange form drives the primary score, while 9 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

The practical lower end of the natural range for healthy, unpolluted tropical savanna aquatic ecosystems can be considered to be approximately 0.005 - 0.010 mg/L NO3-N (or NOx-N).

Metric Definition:

Nitrate-N (NO3-N) or Oxidised Nitrogen (NOx-N) concentration in water.

Benchmark Definition:

This benchmark defines the lower natural concentration range of nitrate or oxidised nitrogen in water for healthy tropical savanna aquatic ecosystems.

Justification:

This range is based on the lowest median water quality objectives and observed data in reference streams, indicating natural background levels.

Sources (1)

Preview of www.rrrc.org.au, accessed May 15, 2025,
www.rrrc.org.au, accessed May 15, 2025, Journal

Sediments and nutrients in north Queensland tropical streams: changes with agricultural development and pristine condition status (Technical Report No. 62, Australian Rainforest CRC, 2006)

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Preview of environment.nt.gov.au, accessed May 11, 2025,
environment.nt.gov.au, accessed May 11, 2025,
Direct Evidence Journal

Water Quality objectives for the region - Department of Lands, Planning and Environment

View Source
Preview of The impact of nitrate pollution in waterways on freshwater species, accessed August 8, 2025
The impact of nitrate pollution in waterways on freshwater species, accessed August 8, 2025
Direct Evidence Journal

Toxicant default guideline values for aquatic ecosystem protection ...

View Source
Preview of Water Quality objectives for the region - Department of Lands, Planning and Environment
Water Quality objectives for the region - Department of Lands, Planning and Environment
Direct Evidence Journal

Water Quality objectives for the region - Department of Lands, Planning and Environment

View Source

Context

  • Region Australia
  • Biome Tropical Monsoonal Savannas
  • Land Use Livestock Grazing & Pasture
  • Assessment Pristine Reference
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 25 Mar 2026

Notes

No evidence suggests these low levels are detrimental; they characterize healthy, oligotrophic systems.

Related Benchmarks

Other benchmarks in the AUS-TMS-LVG-WNI family.

11.3 mg/L Moderate
Livestock Grazing & Pasture · Pristine Reference
MaximumOnly Active v3
0.019 mg/L Moderate
Livestock Grazing & Pasture · Pristine Reference
Point Active v1
— mg/L Moderate
Livestock Grazing & Pasture · Conservation Target
OptimalRange Active v1
2.4 mg/L Moderate
Livestock Grazing & Pasture · Pristine Reference
MaximumOnly Superseded v2
0.05 mg/L Moderate
Livestock Grazing & Pasture · Pristine Reference
MaximumOnly Superseded v1