Environmental Metabolomics: A Powerful Tool to Investigate Biochemical Responses to Drugs in Nontarget Organisms

Metabolomics is the analysis of endogenous and exogenous low molecular mass metabolites within cells, tissues, or biofluids of an organism in response to an external stressor. In this chapter, we highlight the importance of the subdiscipline of environmental metabolomics, which investigates the interactions of organisms with environmental stressors such as biotic and abiotic factors, xenobiotics, temperature shifts, and chemical contaminants. Over the past decade, there has been increasing scientific interest in environmental metabolomics, most likely attributable to the comprehensive nature of nontargeted metabolomics. Hypotheses have therefore been developed on complex environmental stressor effects, especially those with unknown modes of action. The availability of a wide variety of model organisms such as freshwater organisms of the food chain has promoted the potential of metabolomics to detect stress from an extensive range of external factors. Furthermore, these dynamics may shift from individuals to populations, contemplating the traditional fields of the ecophysiology and ecology from instantaneous effects to those over evolutionary timescales. In this chapter, we provide an overview of analytical instrumentation, extraction methods, general experimental design, and the statistical methods generally used in environmental metabolomics. Despite the difficulty in understanding the consequences of environmental exposure due to interand intra-individual variability, we believe that environmental metabolomics may enrich our understanding of the responses of organisms to the numerous types of environmental stressors.