Water Nitrate

AUS-TMI-LVG-WNI General Moderate confidence

Benchmark Value

0.7 mg/L
Direction: Lower is desirable ↓
Form: Point

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 5 benchmarks together — the OptimalRange form drives the primary score, while 4 guard(s) constrain the result.

Evidence & Context

Therefore, the recommended benchmark is 0.7 mg/L. This value should be interpreted as a target for the event mean concentration in runoff from a best-practice grazing system, with the expectation that ambient baseflow concentrations would be significantly lower.

Metric Definition:

Event mean concentration of nitrate (NO3−N or NOx−N) in runoff from best-practice grazing systems.

Benchmark Definition:

This benchmark represents the target event mean concentration of nitrate in runoff from best-practice grazing systems in the Tropical & Subtropical Maritime Islands biome, indicating sustainable water quality management.

Justification:

The value is based on a proxy data approach due to lack of direct field measurements, adjusted downward from the Brigalow Catchment Study value of 1.7 mg/L to account for the high ecological sensitivity and connectivity of the target biome.

Sources (1)

Preview of Memorandum - Nitrate guideline values in ANZECC 2000, accessed August 8, 2025
Memorandum - Nitrate guideline values in ANZECC 2000, accessed August 8, 2025 Journal

Hickey, C. (2002). Nitrate guideline values in ANZECC 2000. Memorandum MFE02237 prepared for Ministry for the Environment (New Zealand). NIWA Client Report: HAM2002-126.

View Source

Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Preview of Paddock scale water quality monitoring of grazing management ...
Paddock scale water quality monitoring of grazing management ...
Direct Evidence

Paddock scale water quality monitoring of grazing management ...

Context

  • Region Australia
  • Biome Tropical & Subtropical Maritime Islands
  • Land Use Livestock Grazing & Pasture
  • Assessment Conservation Target
  • Evidence Type TargetCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 17 Mar 2026

Notes

The benchmark aligns with the original ANZECC 95% ecosystem protection guideline value, considered more relevant to preventing eutrophication than modern toxicity thresholds. The natural baseline is oligotrophic with near-zero nitrate, and the detrimental upper threshold is defined by eutrophication onset, well below toxicity guidelines (~7.2 mg/L).