Chemical and biological processes govern the transformation of molecular matter in the environment, controlling the cycling of essential elements including carbon, nitrogen and oxygen, as well as hazardous metals and pollutants. In water, strong biogeochemical gradients can powerfully alter chemical reactions and fluxes. In the atmosphere, solar radiation drives molecular transformation, sometimes mitigating the hazard and sometimes exacerbating it. All of these processes in the context of a changing climate increase the vulnerability of biodiversity, food security, human health and water quality. Faculty in this department are making important discoveries of the drivers of environmental biogeochemical processes enabling advanced novel technologies to treat contaminated waters. We run large labs designed for invention and development of novel sensing devices. We are involved in large field data campaigns for monitoring water quality, soil contamination, atmospheric pollution and greenhouses gases. We run molecular-scale simulations of pollutant reactions and mass transport in water, soils and sediments. We create novel technologies to harness energy and nutrient recovery from waste streams. We come up with novel strategies for sequestering greenhouse gases deep underground.