The objectives of this project were to identify and quantitate certain common, more abundant organic pollutants, especially halogenated compounds, in water, tissue and sediment from selected marine sites in Texas and thus to identify sites appropriate for studies of biochemical responses of marine organisms to pollutants. This study concentrated on selected sites in Galveston Bay and Corpus Christi Bay, Texas. The results will be compared with those from sites in Maine, Massachusetts and other locations. The concentrations of pentachlorophenol (PCP), hexachlorobenzene (HCB), pentachlorobenzene (PCBz), polychlorinated biphenyl (PCB), certain phthalates (diethyl, DEP; di(n-butyl), DnBP; di(i-butyl), DiBP; di(2-ethylhexyl), DEHP; benzylbutyl, BzBP) and various chlorinated pesticides (e. g. DDT, DDE, dieldrin, alpha - and gamma -hexachlorocyclohexane (HCH) and chlordane) were measured in samples of water, sediment and tissue form the sites mentioned