Organophosphate Esters in Marine Environments: Source, Transport and Distribution

Organophosphorus esters (OPEs), widely utilized as flame retardants and plasticizers, are physically incorporated into those products and exhibit semi-volatility, resulting in release throughout their lifecycle. The ocean serves as a significant sink and plays a pivotal role in the global distribution and environmental fate of OPEs. However, the OPEs’ behavior and ecological effects in marine systems are not well understood. This review systematically examines recent advances in the sources, transport pathways, transformation mechanisms, and distributions of OPEs in the marine environment, and it also addresses current research limitations and suggests directions for future work. It is found that OPEs predominantly enter the marine environment through terrestrial input and in situ release; the transportation means include river input, long-range atmospheric transport, air–sea exchange, and oceanic circulation; and the degradation processes of OPEs are recognized as hydrolysis, photodegradation, and biodegradation. The distributions of OPEs in marine environments vary in different media, with their concentrations observed to range from pg m−3 to ng m−3 in marine air, ng L−1 to hundreds of ng L−1 in seawater, and pg g−1 dw to ng g−1 dw in sediments. The distributions of different species of OPEs are affected by many factors, such as compound properties, environmental conditions, and policy regulations. Comparisons between different regions and different seasons need to be further studied, and predictive models should be developed to better assess ecological risks and exposure pathways of OPEs.