Marine biota can be classified broadly into those organisms living in either the pelagic environment (plankton and nekton) or the benthic environment (benthos). Single-celled or multi-celled plankton with photosynthetic pigments are the producers of the photic zone in the pelagic environment. This data collection activity covers baseline, geographical and temporal trend monitoring of heavy metals and chlorinated hydrocarbons in biota from the marine chemistry monitoring programme. Data for biota covers Irish estuarine and Irish coastal waters. Biota sample stations have been collected since 1987. Contaminants in biota monitoring has been undertaken by the Marine Chemistry team of the Marine Environment and Food Safety Services (MEFSS) section of the Marine Institute (Ireland). Data 100% complete for surveys since 1987.