Emerging Environmental Contaminants and the Metabolic Effects of Exposure Investigated by Mass Spectrometry
Stewart, David Taylor Rogers
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Contaminants released into the environment at very low concentrations pose special analytical and toxicological challenges. Low concentrations require long exposures or very sensitive tests to assess the potential toxic effects. Furthermore, accurate measurements of the concentration become difficult at very low concentrations and in the presence of complex matrices. Mass spectrometry can be used a sensitive technique for the measurement of contaminants and the biochemical changes that may indicate a biological response to exposure. Pharmaceuticals released by human activity are a significant area of current research. Pharmaceuticals are used because they affect biological systems at low doses but many of these compounds are not removed during wastewater treatment. Accurate measurements of pharmaceutical concentrations in surface water and other matrices will facilitate the study of the effect of pharmaceuticals on wildlife and the development of antibiotic resistance in bacteria. A comparison study has shown that there is still high variability in the quality of pharmaceutical measurements by mass spectrometry. Recommendations for improved methodology are given following a discussion of the performance of our laboratory in comparison to other laboratories analyzing the same samples. Nanomaterials, including quantum dots, are currently being developed and used in consumer products. Quantum dots are typically made from cadmium, a toxic metal. Quantum dots are shown to be a source of cadmium for earthworms to accumulate, but no traditional toxic effects were observed at the low concentration used. A potentially more sensitive method, using mass spectrometry to measure glucose metabolites, is presented and evaluated. Recommendations are proposed to improve the method performance.