Timothy Williams (University of Birmingham) - Addressing Pollution of the Aquatic Environment: How can ‘Omics Help?

Aquatic environments contain complex mixtures of organic and inorganic chemicals, many of which are derived from anthropogenic activity. Aquatic organisms are exposed chronically and their responses are modified by additional stressors, such as climate change. Typically ‘bottom up’ chemical monitoring quantifies only a very small proportion of the different chemicals present in the environment. Ecology and whole-organism biological effects ‘top down’ monitoring, such as acute toxicity and chronic reproduction tests, can reveal the risks of environmental mixtures to organisms but provides little information on the causative agents. Omics techniques such as genomics, transcriptomics, epigenomics, proteomics and metabolomics allow profiling of the molecular changes induced by exposure of organisms to complex mixtures, the exposome. Can they bridge the gap between ‘top down’ and ‘bottom up’ monitoring? We, and others, have demonstrated that it is possible to link biological effects to chemical contamination by interrogation of molecular response profiles with prior knowledge of the mechanistic adverse outcome pathways of single chemicals. Molecular profiling of biota can classify and rank environmental samples in terms of mechanistic responses detected and increasing efforts in profiling effects of individual chemicals is assisting further chemical classification by identifying shared key events of adverse outcome pathways. While there are significant data gaps that currently limit the application of these approaches, chemical and environmental risk assessment can already benefit from them and there is potential to revolutionise management of the environment.