HR: 0830h
AN: OS11A-08    [Abstracts]
TI: Distribution and Mass Inventories of p,p'-DDE and o,p'-DDE in the Water Column of the Southern California Bight, California
AU: Zeng, E Y
EM: eddyzeng@gig.cas.cn
AF: State Key Laboratory of Organic Geochemistry, Chinese Academy of Sciences, PO Box 1131, Guangzhou, 510640 China
AU: * Peng, J
EM: eddyzeng@gig.cas.cn
AF: Southern California Coastal Water Research Project, 7171 Fenwick Lane, Westminster, CA 92683 United States
AU: Tsukada, D
EM: davidt@sccwrp.org
AF: Southern California Coastal Water Research Project, 7171 Fenwick Lane, Westminster, CA 92683 United States
AU: Diehl, D
AF: Southern California Coastal Water Research Project, 7171 Fenwick Lane, Westminster, CA 92683 United States
AU: Noblet, J
AF: California State University San Bernardino, 5500 University Parkway, San Bernardino, CA 92407 United States
AU: Schiff, K
AF: Southern California Coastal Water Research Project, 7171 Fenwick Lane, Westminster, CA 92683 United States
AB: As part of the Southern California Bight(SCB) 2003 Regional Marine Monitoring Survey (Bight' 03), we examined the concentrations and distribution patterns of p,p'-DDE and o,p'-DDE in the water columns at randomly-selected sites throughout SCB using solid phase microextraction (SPME) technique. The technique involves deployment of polydimethylsiloxane (PDMS)-coated fibers at certain depths of the water column for a prolonged time (3 weeks or longer). The fibers were then retrieved and analyzed by GC-MS, and water column concentrations of DDTs were calculated based on an equilibrium partitioning between water and PDMS coating. Our results showed that p,p'-DDE concentrations were in the range of 0.05-0.22ng/L, and 0.005-0.036 for o,p'-DDE. For p,p'-DDE, there is a general increasing trend toward the sediment-water interface. Santa Monica Bay contains the highest concentrations of both p,p'-DDE and o,p'-DDE, indicative of the influence of `hot spots' at Palos Verdes Shelf. Concentrations of DDTs were lower in San Pedro Shelf and Santa Barbara Basin, and were mostly under detection limit in other areas. The results showed that water column DDT concentrations have decreased significantly compared with previous investigations, but a constant source of DDTs from sediment to the overlying water column is still significant. The spatial distribution patterns of water column p,p'-DDE and o,p'-DDE suggest that the Palos Verdes Shelf remains a dominant source of DDT contamination to the SCB. Based on the spatial data, we estimated that the total mass of DDTs in the entire SCB is rather low ( under 1 kg). The annual loss of DDTs from SCB to the open ocean should be about tens of kg. Based on the historical trend of the DDT input into SCB since the 1970s, SCB should have contributed considerable amount of DDTs to the open ocean.
DE: 4251 Marine pollution
DE: 4850 Organic marine chemistry
DE: 4857 Pollution
SC: Ocean Sciences [OS]
MN: 2005 Joint Assembly