Abstract
This chapter presents an overview of the knowledge on the impacts and toxicity of particulate plastics to a range of marine functional groups, including both acute and sub-lethal endpoints. A laboratory study on plastic leachates showed differential toxicity to the harpacticoid copepod Nitocra spinipes depending on the plastic product and the simulated weathering conditions applied. The potential toxicity of plastic additives, therefore, depends on the concentration of the additive, the residence time in the ingesting organism, and external factors, such as prey and background concentrations of the target contaminant. Plastic particles undergo a number of transformations after they enter the marine environment, which influence their pathways and behavior within food webs. Plastic exposed to marine conditions starts degrading, and, although this process is generally slow, the surface structure of the material changes, becomes more brittle and cracked, and provides a habitat for microbes and rafting organisms.