Toxicity of Zinc to Aquatic Life in Tropical Freshwaters of Low Hardness

Abstract

AbstractZinc (Zn) is a metal of potential concern for a uranium mine whose receiving waters are in the World‐Heritage listed Kakadu National Park in northern Australia. The chronic toxicity of Zn was assessed using seven tropical species in extremely soft freshwater from a creek upstream of the mine. Sensitivity to Zn was as follows (most sensitive to least sensitive based on 10% effect concentrations [EC10s]): mussel Velesunio angasi > gastropod Amerianna cumingi > fish Mogurnda mogurnda > cladoceran Moinodaphnia macleayi > green hydra Hydra viridissima > green alga Chlorella sp. > duckweed Lemna aequinoctialis, with EC10s (<0.45 µm filtered fraction) ranging from 21 to 320 µg/L Zn and EC50s ranging from 52 to 1867 µg/L Zn. These data were used to inform the risk assessment for the rehabilitation of the mine‐site and contribute to the global Zn dataset. Environ Toxicol Chem 2023;42:679–683. © 2023 Commonwealth of Australia. Environmental Toxicology and Chemistry © 2023 SETAC.