Water Nitrate

AUS-TSR-URB-WNI General Moderate confidence

Benchmark Value

50 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 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

Significant Sub-lethal Harm (50 mg/L): A robust body of research on Australian native fish provides a clear threshold for significant physiological damage.

Metric Definition:

Nitrate concentration threshold causing significant sub-lethal harm to native fish species.

Benchmark Definition:

This benchmark represents the nitrate concentration threshold causing significant sub-lethal harm to native fish species in tropical and subtropical freshwater systems.

Justification:

Demonstrable physiological impacts observed in Australian native fish species at this concentration.

Sources (3)

Black ross (townsville) - water Quality improvement plan Journal

Black ross (townsville) - water Quality improvement plan

View Source

Land-use effects on water quality in an intensively managed catchment in the Australian humid tropics | Request PDF - ResearchGate, accessed July 30, 2025, Journal

Land-use effects on water quality in an intensively managed ...

View Source

Townsville basins - Queensland Environment Department, accessed August 2, 2025,

Environmental Protection (Water and Wetland Biodiversity) Policy 2019 - Schedule 1 (referencing WQOs for Black River Basin)

View Source

Context

Region Australia
Biome Tropical & Subtropical Rainforests
Land Use Urban & Developed Use
Assessment Not Stated
Evidence Type DegradationThreshold

Lifecycle

Status Rejected
Version 2
Effective From 3 Jun 2026
Effective To 3 Jun 2026

Notes

Includes reduced blood-oxygen carrying capacity, impaired swimming performance, and reduced tolerance to other stressors. AssessmentContext defaulted to 'Not Stated' because the source document did not state one. Pipeline correction 2026-06-03c: Rejected — erroneous BenchmarkForm (Point+UpperGuard for degradation threshold at 50 mg/L; correct form MaximumOnly+UpperGuard). MaximumOnly slot occupied by ID 1416 (0.015 mg/L eutrophication risk). Requires StratificationKey (e.g., 'sub-lethal-fish-harm-50mgL') to coexist. Requeue document with prompt v3.7.

Related Benchmarks

Other benchmarks in the AUS-TSR-URB-WNI family.