Pentachlorophenol and tetrachlorophenols in wadden sediment and clams Mya arenaria of the Jadebusen after a 14-year period of wastewater discharge containing pentachlorophenol

Pentachlorophenol (PCP) and tetrachlorophenol (TCP) concentrations in anaerobic Wadden sediments and clams of the Jadebusen were determined two years after the end of a long-lasting discharge of PCP into the region. Concentrations of PCP were of the same order of magnitude as those determined in sediments and organisms of the Weser estuary; concentrations after acid hydrolysis were 2–5 times higher than those of free PCP. 2,3,4,5-TCP contents exceeded those of PCP eight times in sediments and fifteen times in clams. PCP and 2,3,4,5-TCP were accumulated in clams 100- to 1000-fold compared with sediments. It is assumed that, under anaerobic conditions, a reductive dechlorination of PCP occurs, resulting in 2,3,4,5-TCP, which is more persistent than PCP in the environment under study.