Australian freshwaters have relatively low water hardness and different calcium to magnesium ratios compared with those in Europe. The hardness values of a substantial proportion of Australian freshwaters fall below the application boundary of the existing European nickel Biotic Ligand Models (NiBLMs) of 2 mg Ca/L. Toxicity testing was undertaken using Hydra viridissima to assess the predictive ability of the existing NiBLM for this species in extremely soft waters. This testing revealed a greater effect of calcium and magnesium in competing with nickel for binding to the biotic ligand in soft water (<10 mg CaCO3/L) than at higher water hardness. Modifications were made to the NiBLM to account for softer waters encountered in Australia and the more important competitive effect of calcium and magnesium on nickel toxicity. To validate the modified NiBLM, ecotoxicity testing was performed on five Australian test species in five different natural Australian waters. Overall, no single water chemistry parameter was able to indicate the trends in toxicity to all of the test species. The modified NiBLMs were able to predict the toxicity of nickel to the test species in the validation studies in natural waters better than the existing NiBLMs. This work suggests that the overarching mechanisms defining nickel bioavailability to freshwater species are globally similar, and that NiBLMs can be used in all freshwater systems with minor modifications.
This is the peer reviewed version of the following article: Peters, A, Merrington, G, Schlekat, C, De Schamphelaere, K, Stauber, J, Batley, G, Harford, A, Van Dam, R, Pease, C, Mooney, T, Warne, M, Hickey, C, Glazebrook, P, Chapman, J, Smith, R & Krassoi, R 2018, 'Validation of the nickel biotic ligand model for locally relevant species in Australian freshwaters' Environmental Toxicology and Chemistry, vol 37 no 10, 2566-2574, which has been published in final form at https://dx.doi.org/10.1002/etc.4213. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
- biotic ligand model
- tropical ecotoxicology