- Research Projects
- About Us
- Videos and Maps
Attention: We would like to make you aware that there are significant delays/curtailments of operations/work conditions at this time in Oregon due to the coronavirus COVID-19 and there may be delays in responses to emails and deliverables. We are doing our best to keep everything on schedule, but may have to adjust to changing conditions.
|Title||Bioavailable organochlorine pesticides in a semi-arid region of eastern Oregon, USA, as determined by gas chromatography with electron-capture detection.|
|Publication Type||Journal Article|
|Year of Publication||2001|
|Authors||Anderson KA, Johnson ER|
|Journal||J AOAC Int|
|Biological Availability, Chromatography, Gas, Chromatography, Gel, Data Interpretation, Statistical, Hydrocarbons, Chlorinated, Insecticides, Oregon, Pesticide Residues, Quality Control, Time Factors, Water Pollutants, Chemical|
A group of dissolved-bioavailable organochlorine (OC) pesticides and inorganic anions in water and total OC pesticides in sediments were measured in the 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. After calculating the dissolved fraction from the 1990, study it seems that DDD 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 found in all water samples tested. All of the OC pesticides tested during the 2-year study are well below the criterion continuous concentration for aquatic community exposure as defined by the U.S. Environmental Protection Agency (EPA). OC pesticides appear to be decreasing, however, at lower Ontario there remains a human health risk (EPA Human Health Risk Water Quality Criteria) for DDT, because this criteria includes daily consumption of water and fish from the river. Overall, although the upper forest watershed sites have lower OC pesticide concentrations, they represent an important contribution to the total DDT load to this watershed, a source not previously acknowledged. The large increase in DDT and sigmaDDT between the Ontario sites may indicate a possible historical point source of contamination or historical preferential deposition of contamination. Normalized sediment (sigmaDDT/organic carbon) strongly correlates with dissolved water sigmaDDT.
|Alternate Journal||J AOAC Int|