Water Electrical Conductivity (EC)

AUS-TMS-IND-WEC General High confidence

Benchmark Value

42 µS/cm
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 3 benchmarks together — the OptimalRange form drives the primary score, while 2 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard Point Guard

Evidence & Context

The resulting chronic exposure limit for magnesium was set at 3 mg/L. This scientifically derived limit corresponds directly to an Electrical Conductivity Investigation Trigger Value of 42 µS/cm.

Metric Definition:

Electrical Conductivity (EC) as a reliable and continuously measurable proxy for magnesium concentration in water.

Benchmark Definition:

This benchmark represents the best available condition for water electrical conductivity in a high ecological value tropical monsoonal savanna industrial site, derived from decades of site-specific ecotoxicological research to protect aquatic species.

Justification:

Derived from decades of site-specific ecotoxicological research at the Ranger Mine, NT, to protect 99% of aquatic species in a High Ecological Value system.

Sources (2)

Preview of Waste Discharge Licence 174-13 Monitoring Report - NTEPA
Waste Discharge Licence 174-13 Monitoring Report - NTEPA Journal

Waste Discharge Licence 174-13 Monitoring Report - NTEPA

View Source
Preview of Water Quality Guidelines Assessing discharges from a uranium ...
Water Quality Guidelines Assessing discharges from a uranium ... Journal

Water scarcity exacerbates feral ungulate use of ephemeral savanna waterholes in northern Australia - CSIRO Publishing

View Source

Supporting Sources (20)

Additional references from the underlying research that informed this benchmark.

Preview of A Compendium of Ecological Information on Australia's Northern Tropical Rivers - Report 5 - Water quality - DCCEEW, accessed August 1, 2025,
A Compendium of Ecological Information on Australia's Northern Tropical Rivers - Report 5 - Water quality - DCCEEW, accessed August 1, 2025,
Contextual Support Journal

Threshold Indicator Taxa ANalysis and change points (dots) for the ...

View Source
Preview of A GUIDE TO THE APPLICATION OF THE ANZECC ... - ResearchGate, accessed August 11, 2025,
A GUIDE TO THE APPLICATION OF THE ANZECC ... - ResearchGate, accessed August 11, 2025,
Contextual Support GreyLiterature

Namoi River Water Quality Objectives explained - NSW Government

View Source
Preview of A review of water quality studies relevant to northern Australia - CSIRO, accessed July 21, 2025,
A review of water quality studies relevant to northern Australia - CSIRO, accessed July 21, 2025,
Contextual Support Journal

Salinity and water quality

View Source
Preview of ANZECC & ARMCANZ (2000) guidelines - Water Quality Australia, accessed August 12, 2025
ANZECC & ARMCANZ (2000) guidelines - Water Quality Australia, accessed August 12, 2025
Contextual Support Government

ANZECC & ARMCANZ (2000) guidelines - Water Quality Australia

View Source
Preview of Australia's tropical savannas: vast, ancient and rich landscapes - CSIRO Research Publications Repository, accessed May 11, 2025,
Australia's tropical savannas: vast, ancient and rich landscapes - CSIRO Research Publications Repository, accessed May 11, 2025,
Contextual Support GreyLiterature

Williams RJ, Duff GA, Bowman DMJS, Cook GD. Australia's tropical savannas: vast, ancient and rich landscapes. In: David Keith, editor/s. Australian vegetation. Cambridge, UK: Cambridge University Press; 2017. 368-388.

View Source
Preview of CLEAN BILL OF HEALTH FOR McARTHUR RIVER - Territory Q
CLEAN BILL OF HEALTH FOR McARTHUR RIVER - Territory Q
Contextual Support Journal

CLEAN BILL OF HEALTH FOR McARTHUR RIVER - Territory Q

View Source
Preview of Deriving guideline values using reference-site data - Water Quality Australia, accessed August 12, 2025
Deriving guideline values using reference-site data - Water Quality Australia, accessed August 12, 2025
Contextual Support Government

Water Quality Guidelines Home - Water Quality Australia

View Source
Preview of Environmental impact of the Ranger uranium mine, Alligator Rivers Region, Northern Territory, Australia - OSTI, accessed July 24, 2025
Environmental impact of the Ranger uranium mine, Alligator Rivers Region, Northern Territory, Australia - OSTI, accessed July 24, 2025
Contextual Support Journal

Revised Ranger Mine Water Quality Objectives for Magela Creek and Gulungul Creek (DOCX 1 MB) - DCCEEW

View Source
Preview of INDEPENDENT MONITOR REPORT - Glencore Australia
INDEPENDENT MONITOR REPORT - Glencore Australia
Contextual Support Journal

INDEPENDENT MONITOR REPORT - Glencore Australia

View Source
Preview of McArthur River Mine Annual Report Card 2023 - Northern Territory Government
McArthur River Mine Annual Report Card 2023 - Northern Territory Government
Contextual Support GreyLiterature

McArthur River Mine Annual Report Card 2023 - Northern Territory Government

View Source
Preview of McArthur River Mine Independent Monitor - Water Technology
McArthur River Mine Independent Monitor - Water Technology
Contextual Support Journal

McArthur River Mine Independent Monitor - Water Technology

View Source
Preview of McArthur River Mining welcomes release of independent environmental report
McArthur River Mining welcomes release of independent environmental report
Contextual Support GreyLiterature

McArthur River Mining welcomes release of independent environmental report

View Source
Preview of Namoi River Water Quality Objectives explained - NSW Government, accessed August 11, 2025,
Namoi River Water Quality Objectives explained - NSW Government, accessed August 11, 2025,
Contextual Support Government

Percentage compliance with ANZECC water quality trigger values for aquatic ecosystems, primary contact recreation and secondary

View Source
Preview of Risk-based contaminant management: Ranger Mine case study - Australian Centre for Geomechanics
Risk-based contaminant management: Ranger Mine case study - Australian Centre for Geomechanics
Contextual Support GreyLiterature

Risk-based contaminant management: Ranger Mine case study - Australian Centre for Geomechanics

View Source
Preview of the revised australian and new zealand water quality guidelines for toxicants: approach to their derivation and application - leusch.info
the revised australian and new zealand water quality guidelines for toxicants: approach to their derivation and application - leusch.info
Contextual Support Journal

Deriving guideline values using reference-site data - Water Quality Australia

View Source
Preview of Threats to water quality - Government of Western Australia
Threats to water quality - Government of Western Australia
Contextual Support Journal

The State and Future of the Northern Territory's ... - NationBuilder

View Source
Preview of Using the ANZECC Guidelines and Water Quality Objectives in NSW, accessed August 11, 2025,
Using the ANZECC Guidelines and Water Quality Objectives in NSW, accessed August 11, 2025,
Contextual Support Journal

Reference-site data - Water Quality Australia

View Source
Preview of Water quality | Australia state of the environment 2021, accessed August 11, 2025,
Water quality | Australia state of the environment 2021, accessed August 11, 2025,
Contextual Support Government

Drivers of water quality in Afromontane-savanna rivers - Frontiers

View Source
Preview of Water quality guidelines - Queensland Environment Department, accessed August 1, 2025,
Water quality guidelines - Queensland Environment Department, accessed August 1, 2025,
Contextual Support Government

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

View Source
Preview of Water quality guidelines - Queensland Environment Department, accessed August 4, 2025,
Water quality guidelines - Queensland Environment Department, accessed August 4, 2025,
Contextual Support Journal

Seasonal changes in water quality and macrophytes and the ...

View Source

Context

  • Region Australia
  • Biome Tropical Monsoonal Savannas
  • Land Use Industrial & Infrastructure Use
  • Assessment Pristine Reference
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 9 Jun 2026

Notes

No lower critical threshold applicable; natural baseline near-zero during wet season flows. Upper detrimental threshold at 42 µS/cm for high ecological value systems. Represents a conservative upper threshold for maintaining high environmental health.

Related Benchmarks

Other benchmarks in the AUS-TMS-IND-WEC family.

1000 µS/cm Moderate
Industrial & Infrastructure Use · Not Stated
MaximumOnly Active v1
42 µS/cm Moderate
Industrial & Infrastructure Use · Pristine Reference
MaximumOnly Active v1
1000 µS/cm Moderate
Industrial & Infrastructure Use · Rehabilitation Target
MaximumOnly Active v1