Biolog Ecoplate® as a supplementary tool for evaluating ecotoxicity in a freshwater microplanton community

Abstract

Due to the production and release of chemicals into the environment, is happening at a pace that is outrunning the capacity of assessment and monitoring, it is important to consider alternative methods for evaluating the ecotoxicity of chemicals. The aim of this project is to evaluate Biolog Ecoplates® as a community level method for assessment of toxicity and VUV-facilitated toxicity mitigation. Laboratory scale microcosms with a freshwater microplankton community were contaminated with one of the three selected biocides (benzalkonium chloride, chlorhexidine, and didecyldimethylammonium chloride) or 1 herbicide (glyphosate), as well as a set of microcosms each contaminated with one of the selected chemicals, that had undergone VUV-treatment. After 9 days microcosm incubation, a sample from each microcosm was then incubated in a Biolog Ecoplate. To accommodate the evaluation of Biolog Ecoplates® as a method for toxicity assessment, measurements of ATP concentration and colony-forming-units in the microcosms were also included. Biolog Ecoplates did not succeed in identifying a toxic effect of the examined biocides on the activity in the Biolog Ecoplates, as was otherwise expected. The Biolog Ecoplates were however to some degree able to differentiate the substrate utilisation patterns of the contaminated microplankton communities, from the communities of the control microcosms. These results indicate a change in functional diversity and therefore a possible shift in community structure, which was especially found in the microcosms contaminated with either didecyldimethylammonium chloride or glyphosate as well as the microcosms contaminated with either VUV-treated didecyldimethylammonium chloride or glyphosate. The Biolog Ecoplates identified the toxicity mitigation of VUV-treatment by preventing a decrease in functional diversity, that was otherwise observed for the microcosms contaminated with the examined biocides. The overall findings in this project therefore indicate that Biolog Ecoplates® have potential as a community level method for assessment of chemical toxicity on a freshwater microplankton community.

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A master thesis from Aalborg University

Biolog Ecoplate® as a supplementary tool for evaluating ecotoxicity in a freshwater microplanton community