PCDDs and PCDFs in municipal sewage sludge and effluent from potw in the state of Mississippi, USA

During the summer 1995, we collected sewage sludge and effluent samples from 17 publicly- owned treatment works (POTW) in the State of Mississippi, USA. Most PCDDs and PCDFs were detected in the sludge, and the hepta- and octaCDD congeners typically were dominant. One plant had an octaCDD value in sludge exceeding 400 000 pg/g d.m. The primary source probably is pentachlorophenol. An earlier US EPA finding of 116 pg/g d.m. 2,3,7,8-tetraCDD in sludge from the Corinth POTW was not confirmed in this study, where only 0.3 pg/g d.m. was measured. Most effluent samples were below the detection limit of approximately 10 pg/L for the tetra- through hexachlorinated congeners. The New Augusta POTW had the higbest octaCDD value in effluent (2 500 pg/L). This plant is a point source to the Leaf River.