title: Accumulation, distribution and metabolism of 14C-1,1,1-trichloro-2, 2-, bis-(p-chlorophenyl)ethane (p,p'-DDT) residues in a model tropical marine ecosystem.
abstract: Accumulation, distribution and metabolism of ring labelled, 14C-1,1,1,-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) in a model marine aquatic ecosystem consisting of seawater, sediment, oysters (Isognomonon alatus) and Humbug fish (Dascillus aruanus) were studied in the laboratory. 14C-p,p'-DDT distributes rapidly in the ecosystem immediately after application on the water surface with reduction of its concentration in the water phase from 1.18 ng g(-1) to 0.71 ng g(-1) after 2 hours and an increase in its content in the sediment and oysters. The bioconcentration factor reached a maximum of 19 x 10(3) in oysters, and 1657 in Humbug fish after 24 hours. The sediment concentration reached 117 ng g(-1) after 168 hours from start of application. A peak bioconcentration factor of 111 x 10(3) was calculated after 120 hours when 0.24 mg kg(-1) of 14C-p,p'-DDT was maintained through dosing every 24 hours with 0.002 mg kg(-1) of a mixture of labelled and non-labelled pesticide. The rate of depuration of accumulated 14C-p,p'-DDT sediment residues was up to 78.3% after 24 hours while oysters lost only 14.0% during the same period. The loss in Humbug fish was only 22.2% in three days. Volatilisation and sorption losses from seawater alone (without sediment/biota) were found to be very high in the range of 73.8 - 91.5% over 24 h for p,p'-DDT in aerated and nonaerated ecosystem. Gas chromatograph and TLC analysis of water, sediment and oyster samples revealed presence of p,p'-DDT and substantial amounts of p,p'-DDE and p,p'-DDD three days after pesticide dosage.
authors.forename: S O
authors.initials: SO
authors.lastname: Wandiga
authors.forename: D M K
authors.initials: DM
authors.lastname: Ongeri
authors.forename: L
authors.initials: L
authors.lastname: Mbuvi
authors.forename: J O
authors.initials: JO
authors.lastname: Lalah
authors.forename: I O
authors.initials: IO
authors.lastname: Jumba
mesh_terms: D000818:Animals; D002250:Carbon Radioisotopes / Q000032:analysis; D003634:DDT / Q000378:metabolism* / Q000493:pharmacokinetics*; D017753:Ecosystem; D005399:Fishes; D020387:Food Chain; D019015:Geologic Sediments / Q000737:chemistry; D008962:Models, Theoretical; D010125:Ostreidae; D014018:Tissue Distribution; D014329:Tropical Climate; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000493:pharmacokinetics*
chemical_list: D002250:Carbon Radioisotopes; D014874:Water Pollutants, Chemical; D003634:DDT