N.C. STATE UNIVERSITY

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

Herrings Marsh Run Demonstration Area

Prepared by: Richard A. McLaughlin, Gregory D. Jennings, Frank Humenik, and Maurice Cook

Long-Term Objectives

1. Determine the most effective way to achieve Best Management Plan adoption.

2. Measure or predict water quality trends as a result of grower adoption of Best Management Plans.

3. Evaluate and modify simulation models and Geographic Information Systems for predicting water quality impacts of agricultural production systems.


Short-Term Objectives

1. Use established monitoring and domestic wells to target subwatersheds for intensive sampling and modeling efforts.

2. Determine the priority data needs for simulation models to most accurately reflect the water quality data collected.

3. Determine the chemical structure of cross-contaminants in well samples screened using immunoassay.


Accomplishments

1. Domestic well water surveys for pesticides and nitrate have been conducted annually to establish trends. Data was also used a part of the educational efforts for growers and residents of the watershed.

2. Pesticide detections were confirmed by gas chromatography/mass spectrometry in 1995.

3. Sensitivity analyses indicated that local soil physical and chemical properties can be very important data to collect for simulation models.

Duplin County is one of the top agricultural counties in the state and is representative of many areas of the Coastal Plain. Ground water is the source of drinking water for most residents and it is relatively shallow and vulnerable to contamination. Approximately 50% of the land is in production, which creates additional risks to drinking water. Annual screening of domestic wells has found 20% to 50% contamination with a pesticide residue, mostly at very low concentrations (0.1 - 0.5 ppb), and confirmed detections of pesticides and metabolites were 26% in 1995 with none over health limits. Our efforts are directed at determining the most important factors in the movement of pesticides to ground water and using that information to help target preventative BMPs.


Future Plans

1. Test models in similar watersheds with significant monitoring data for comparison.

2. Establish a pesticide fate database for the Coastal Plain for use in simulation modeling.