Bioavailability and toxicity of nickel to freshwater organisms : a modeling approach

Water quality criteria setting for metals is hampered by the fact that the bioavailability and hence also the toxicity of many metals is largely influenced by physicochemical parameters such as water hardness, pH and dissolved organic matter. Consequently, a single water quality criterium may be too conservative for certain water bodies whereas it may not be protective enough for other water bodies. This metal-specific issue can be overcome with the development of mathematical models capable of predicting metal bioavailability and toxicity as a function of water chemistry. In the first part of this doctoral thesis it was investigated to what extent several physicochemical parameters (such as calcium, magnesium, pH, dissolved organic matter) affect the acute and chronic toxicity of nickel to freshwater organisms. For each testing organism (a unicellular green alga, an aquatic invertebrate and a fish) a bioavailability model was developed capable of accurately predicting nickel toxicity in both artificial and natural waters. An important point of concern was that bioavailability models such as those developed in the first part of this doctoral thesis may underestimate metal toxicity in waters with hardness far below the lower water hardness boundary for which these models were originally developed and validated using ‘standard’ test organisms. In the second part of this research it was therefore investigated whether this concern is scientifically justified for nickel. A series of toxicity tests with field-organisms (microalgae and water fleas) originating from soft and hard surface waters demonstrated that in most cases soft water organisms are equally sensitive to nickel as hard water organisms and that a single bioavailability model can be used to predict the water hardness-dependent toxicity of nickel to soft and hard water organisms. The data and models generated in this thesis were already used in the European risk assessment of nickel and nickel compounds. The pan-European water quality criterium for nickel will be based on the outcome of this risk assessment. Current developments at the international regulatory level feed the expectation that the application domain of this thesis will further expand.

Grantor dc:publisher

Ghent University

Year dc:date

2008

Author dc:creator

• Deleebeeck, Nele

Contributors dc:contributor

• Janssen, Colin
• De Schamphelaere, Karel

• Biology and Life Sciences
• Earth and Environmental Sciences

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Identifier

https://biblio.ugent.be/publication/530349
urn:isbn:9789059892330
https://biblio.ugent.be/publication/530349/file/1881337

OAI identifier oai:identifier

oai:archive.ugent.be:530349