Organotins are chemical compounds that are organic derivatives of tin. A major source of organotins in the marine environment is the antifouling paints applied on ship hulls. Organotin compounds (chemically, they are characterized by the presence of at least one covalent carbon-tin bond) have been used as biocides in antifouling paints applied on hulls of ships and boats and, in general, on surfaces in prolonged contact with seawater to control the growth of fouling organisms.