Navigation Links
Pesticides persist in ground water

Numerous studies over the past four decades have established that pesticides, which are typically applied at the land surface, can move downward through the unsaturated zone to reach the water table at detectable concentrations. The downward movement of pesticide degradation products, formed in situ, can also contribute to the contamination of ground water. Once in ground water, pesticides and their degradation products can persist for years, depending upon the chemical structure of the compounds and the environmental conditions.

Scientists at the U.S. Geological Survey (USGS) investigated the occurrence of selected pesticides and their degradation products in ground water during a study funded by the USGS National Water-Quality Assessment (NAWQA) Program. Specifically, the authors examined several of the factors that can influence the likelihood with which pesticides and their degradation products are detected in shallow ground waterincluding oxidation-reduction (redox) conditions and ground-water residence timesat four study sites across the United States. Results from the study were published in the May-June 2008 issue of the Journal of Environmental Quality.

The study revealed that the pesticides and degradation products detected most frequently in shallow ground-water samples from all four areas were predominantly from two classes of herbicidestriazines and chloroacetanilides. None of the insecticides or fungicides examined were detected in ground-water samples. In most samples, the concentrations of the pesticide degradation products greatly exceeded those of their parent compounds. Pesticides or their degradation products were detected most commonly in ground water that recharged between 1949 and 2004, and in monitoring wells spanning the full depth range (about 2 to 52 m) examinedfrom the shallowest to the deepest wellsin all four study areas. Comparisons of pesticide concentrations with a variety of environmental variables indicated that redox conditions, ground-water residence times, and the concentrations of dissolved oxygen and excess nitrogen gas from denitrification (the breaking down of nitrogen compounds such as nitrate) were all important factors affecting the concentrations of pesticides and their degradation products in all four ground-water systems.

The four sites selected for this study were located in agricultural landscapes in Maryland, Nebraska, California, and Washington. They were also selected for variability in overall land use, crops grown, climate, agricultural practices, irrigation, geohydrologic settings, and redox conditions. During the spring of 2004, water samples were collected from a network of 59 shallow single or clustered monitoring wells and analyzed for the occurrence of 45 pesticides and 40 pesticide degradation products, including herbicide, insecticides, and fungicides.

Greg Steele, senior author for this study, stated "Atrazine and its degradation product deethylatrazine both persisted in similar amounts at the Nebraska site, but in water samples from the other three study sites, there was little change with apparent age of water as the fraction as deethylatrazine generally exceeded 80% of the sum of atrazine and deethylatrazine. On the other hand, in three of the four areas studied (Washington excluded because it did not have any detections of metolachlor or its degradation products), the proportion of metolachlor in ground water was far less than that for its degradation products."


Contact: Sara Uttech
American Society of Agronomy

Related biology news :

1. Satellites help ensure efficient use of pesticides
2. Alternative methods proposed to detect pesticides and antibiotics in water and natural food
3. Persistent man-made chemical pollutants found in deep-sea octopods and squids
4. Using ground-penetrating radar to observe hidden underground water processes
5. Stakeholders use science to find common ground on wood supply from forests
6. Western Groundfish Conference to be held in Santa Cruz on Feb. 4-8
7. BGSU undergraduates to pilot groundbreaking genome project
8. Smart flower bulbs pull themselves to deeper ground
9. Local sources major cause of US near-ground aerosol pollution
10. Scientists from the UGR prove that rivers do not act as barriers for groundwater flow
11. Opium and marijuana research go underground
Post Your Comments:
(Date:11/18/2015)... , Nov. 18, 2015  As new scientific discoveries ... doctors and other healthcare providers face challenges in better ... and patients. In addition, as more children continue to ... patient,s adulthood and old age. John M. ... Children,s Hospital of Philadelphia (CHOP) . --> ...
(Date:11/17/2015)... Paris from 17 th until ... from 17 th until 19 th November ... has invented the first combined scanner in the world which scans ... Until now two different scanners were required: one for passports ... on the same surface. This innovation is an ideal solution ...
(Date:11/17/2015)... -- Vigilant Solutions announces today that Mr. Dick W. ... --> --> Mr. Boyce ... at TPG Capital, one of the largest global investment ... revenue.  He founded and led TPG,s Operating Group, which ... 1997 to 2013.  In his first role, he served ...
Breaking Biology News(10 mins):
(Date:12/1/2015)... Dec. 1, 2015 Oxford Finance LLC ("Oxford"), ... life sciences and healthcare services companies, today announced the ... with MDRejuvena, Inc. ("the Company"). Proceeds from the loan ... of the Company,s Rejuvaphyl™ and daily skincare products. ... the MDRejuvena brand of high potency skincare products that ...
(Date:12/1/2015)... ... December 01, 2015 , ... ... SICM Module, an add-on scanning ion conductance microscopy module to Park NX10 that ... an AFM. , Park SICM benefits virtually all materials characterization that require measurements ...
(Date:12/1/2015)... Cepheid (Nasdaq: CPHD ) today announced ... Jaffray Healthcare Conference in New York City ... its outlook for the fourth quarter of 2015 and ... longer term business model expectations. John Bishop ... to be the fastest growing company of the major ...
(Date:12/1/2015)... 2015 ) ... U.K. Virology and Bacteriology Testing Market: Sales ... Supplier Shares by Test, Innovative Technologies, Competitive ... --> ) has announced ... and Bacteriology Testing Market: Sales and Volume ...
Breaking Biology Technology: