Water Nitrate — Benchmark Detail

Benchmark Value

21.6 mg/L

Thresholds: Lower: —, Upper: 21.6

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 4 benchmarks together — the Point form drives the primary score, while 3 guard(s) constrain the result.

Contributing Benchmarks

Point Primary MaximumOnly Guard MaximumOnly Guard MaximumOnly Guard

Evidence & Context

The corrected DGV for 99% protection is 21.6 mg/L of nitrate (as NO3−), which is equivalent to 4.9 mg/L of nitrate-nitrogen (NO3−-N).

Metric Definition:

Nitrate concentration threshold for 99% species protection in high ecological value systems

Benchmark Definition:

This benchmark defines the regulatory maximum nitrate concentration to protect 99% of species in aquatic ecosystems within tropical and subtropical rainforest aquaculture areas.

Justification:

This value represents a regulatory line for preventing direct, acute toxic effects on the vast majority of species in high ecological value systems.

Sources (1)

Preview of Water quality guidelines - Queensland Environment Department, accessed August 1, 2025,

Water quality guidelines - Queensland Environment Department, accessed August 1, 2025, Government

Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000)

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Supporting Sources (9)

Additional references from the underlying research that informed this benchmark.

Altered water flows and quality | Wet Tropics Management Authority, accessed July 18, 2025,

Contextual Support Government

Declining water quality - Reef Authority

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Declining water quality - Great Barrier Reef Marine Park Authority, accessed August 1, 2025

Contextual Support Government

Denitrification in intertidal sediments of a tropical estuary subject to increasing development pressures - Northern Territory Government

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Industry | Australia state of the environment 2021

Contextual Support Journal

Industry | Australia state of the environment 2021

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

Contextual Support 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.

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Queensland Aquaculture Strategy 2024–2034, accessed August 1, 2025,

Contextual Support Government

land and water | Queensland Government

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Review of Nutrient Release from Aquaculture ... - Griffith University, accessed August 1, 2025

Direct Evidence Journal

Review of Nutrient Release from Aquaculture Activities Final Report - Griffith University

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Toxicant default guideline values for aquatic ecosystem protection ...

Contextual Support

Default guideline values - Water Quality Australia

View Source

Water quality guidelines - Queensland Environment Department, accessed August 4, 2025,

Contextual Support Journal

Salinity | Murray–Darling Basin Authority, accessed August 8, 2025,

View Source

WQIP - Water Quality Improvement Plan - Wet Tropics Plan, accessed July 18, 2025,

Contextual Support Government

Queensland Aquaculture Strategy 2024–2034

View Source

Context

Region Australia
Biome Tropical & Subtropical Rainforests
Land Use Aquaculture
Assessment Pristine Reference
Evidence Type RegulatoryTrigger

Lifecycle

Status Active
Version 2
Effective From 19 Mar 2026

Notes

Ecosystem degradation via eutrophication occurs at much lower concentrations, making the <1 mg/L TN benchmark the relevant target for maintaining high environmental health.

Related Benchmarks

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