Plastics not only have physical effects on organisms, but there is also a chemical burden associated with their presence in the environment. Plasticisers are one of the most widely used classes of chemical additive in plastic items, and thus there is widespread potential for the release of these compounds into the environment over the lifetime of the plastic, where they may pose a risk to organisms. Despite this, there have been very few studies of the occurrence and fate of plasticisers in the UK environment. To address this knowledge gap, field surveys were carried out to assess the occurrence of multiple classes of legacy and emerging plasticiser in UK terrestrial and estuarine environments. The occurrence of macroplastics, and microplastics in the UK terrestrial environment was also investigated. In addition to these field studies, laboratory experiments were also carried out to investigate plasticiser release rates from microplastics into soils, and the persistence and degradation kinetics of multiple classes of plasticiser. Laboratory and field studies in this project were designed to investigate differences and similarities in the occurrence and fate of legacy phthalate and emerging non-phthalate plasticisers, many of which are increasing in use in response to legislative pressure. The results from these studies suggest that plasticiser contamination of UK terrestrial and estuarine environments is widespread, with phthalates the most abundant class of plasticiser in both soils and sediments. Multiple classes of emerging plasticiser were also detected in these environments. In some instances, concentrations of emerging compounds were greater than or equal to restricted phthalate plasticisers, although levels were generally relatively low. The laboratory mechanistic studies indicated that plasticiser release from microplastics into soils can proceed rapidly, and that some emerging plasticisers are among the most persistent plasticisers in soils. Overall, the results from this project suggest that future monitoring of plasticisers, in addition to investigations of the impacts and fate of emerging and legacy plasticisers in organisms, would be warranted in order to assess and manage the risk of these compounds in the UK and wider environment.