Bioavailable organochlorine pesticides in a semi-arid region of Eastern Oregon, USA, as determined by gas chromatography with electron-capture detection

Citation
Ka. Anderson et E. Johnson, Bioavailable organochlorine pesticides in a semi-arid region of Eastern Oregon, USA, as determined by gas chromatography with electron-capture detection, J AOAC INT, 84(5), 2001, pp. 1371-1382
Citations number
30
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Agricultural Chemistry
Journal title
JOURNAL OF AOAC INTERNATIONAL
ISSN journal
1060-3271 → ACNP
Volume
84
Issue
5
Year of publication
2001
Pages
1371 - 1382
Database
ISI
SICI code
1060-3271(200109/10)84:5<1371:BOPIAS>2.0.ZU;2-3
Abstract
A group of dissolved-bioavailable organochlorine (OC) pesticides and inorga nic anions in water and total OC pesticides in sediments were measured in t he Malheur Watershed, a semi-arid region in the western United States, over a 2-year period. OC pesticide levels were compared with those from a 1990 study of the lower section of the river, the most recent data available. Af ter calculating the dissolved fraction from the 1990, study it seems that D DD and dieldrin levels have decreased in the water by 50-70%, while DDE and DDT have changed little. Although banned nearly 30 years ago, DDT is still persistent throughout the Malheur River basin/watershed because it was fou nd in all water samples tested. All of the OC pesticides tested during the 2-year study are well below the criterion continuous concentration for aqua tic community exposure as defined by the U.S. Environmental Protection Agen cy (EPA). OC pesticides appear to be decreasing, however, at lower Ontario there remains a human health risk (EPA Human Health Risk Water Quality Crit eria) for DDT, because this criteria includes daily consumption of water an d fish from the river. Overall, although the upper forest watershed sites h ave lower OC pesticide concentrations, they represent an important contribu tion to the total DDT load to this watershed, a source not previously ackno wledged. The large increase in DDT and Sigma DDT between the Ontario sites may indicate a possible historical point source of contamination or histori cal preferential deposition of contamination. Normalized sediment (Sigma DD T/organic carbon) strongly correlates with dissolved water Sigma DDT.