N.C. STATE UNIVERSITY

College of Agriculture and Life Sciences
N.C. Agricultural Research Service
N.C. Cooperative Extension Service

Behavior and Fate of Pesticides in the Environment

Prepared by: Dr. Jerome B. Weber

Long-Term Objectives:

1. Measure the dissipation and movement of pesticides in soils of North Carolina and the U.S.

2. Determine the mass-balance distribution of pesticides and their metabolites in air, water, soil and biomass using soil column Iysimeters.

3. Develop predictive models for evaluating the mass-balance distribution of pesticides.


Short-term Objectives:

1. Develop methodology for determining parent and metabolite pesticide concentrations, sorption, mobility, vaporization, and degradation processes of selected pesticides in soil and water.

2. Identify mechanisms of pesticide sorption to soil constituents, mobility through soils, volatilization from soils, and degradation of pesticides.

3. Determine the factors that regulate pesticide movement in soil water and evaluate models for predicting their dissipation and movement.


Accomplishments:

1. Determined soil sorption, half-life, soil mobility, and volatilization indices for the registration of many newly developed herbicides.

2. Developed mathematical equations for optimizing herbicide effectiveness and environmental safety.

3. Developed a mathematical model for ranking the relative ground water contamination potential for all pesticides used in North Carolina.

4. Prepared and published more than a dozen chapters in text books and co-produced two video tapes on pesticide behavior and fate.

5. Directed the research of four graduate students who presently teach and research at U.S. Universities and twenty six who direct environmental pesticide studies for major chemical industries.

Significance of Accomplishments: Methodology developed for determining the environmental behavior and fate of pesticides is utilized in the U.S.E.P.A. guidelines for registering pesticides for use in the U.S. Environmental indices determined for selected pesticides aided in getting the chemicals registered for use in the U.S. Soil parameters discovered to regulate pesticide behavior are utilized on pesticide labels. The Pesticide Leaching Potential model is used in the Agricultural Chemicals Manual, and by the N.C. Dept. of Agriculture and other agencies to evaluate the leaching potential of pesticides. The publications are used to educate students and the public on the behavior, fate, and safe use of pesticides. The scientists that were trained are ensuring that pesticides will be properly used and that newly developed pesticides will be environmentally safe.


Future Plans:

1. Develop methodology for extracting pesticides from soil, water, and biological samples using a supercritical fluid extractor.

2. Measure the biological availability of selected soil-bound pesticides and relate it to their mechanism of retention by specific soil colloids.

3. Refine our self-contained soil column Iysimeter system for carrying out pesticide mobility and dissipation studies in the field.

4. Refine our decision aid computer model for selecting optimum rates of environmentally safe pesticides for each soil type.

5. Write a textbook on the Principles of Pesticide Behavior and Fate.

6. Write six papers for publication of thesis research canted out by my previous students.

7. Continue cooperative studies and initiate new studies with colleagues at NCSU and UNC.