Particle sources and sinks in anthropogenic coastal areas. Sources of particles in coastal areas from urban regions, aquaculture, sewage treatment plants, farming and industry introduce a range of particles into the waters, including nanoparticles, contaminants and microplastics. Natural particle inputs to coastal waters include lithogenic particles via land weathering (wind, rain) and erosive processes as well as organic particles such as phytoplankton. Particles sink and accumulate, particularly in seagrass beds, sheltered areas and deep basins. Aggregation processes increase particle size and thus sinking rates; however, particles are also resuspended by hydrodynamics, river run-off and activities such as dredging and trawling. DOI: https://doi.org/10.1525/elementa.149.f2