Project Number: 3604-13000-009-17
Project Type: Trust

Start Date: Oct 01, 2005
End Date: Sep 30, 2010

Objective:
The overall objective of the research is to evaluate the ability of commercially available filter materials to absorb or bind nutrients (nitrogen and phosphorus) and a select list of pesticides (2,4-D, chlorothalonil, and metalaxyl) from tile drainage water on a golf course green. Hypothesis A: The ability of the sorbent to adsorb a pesticide is dependent on the pesticide and its concentration. Hypothesis B: The capacity of the sorbent is limited and dependent on the targeted pesticide to be adsorbed. Hypothesis C: The ability of an in-line filter system to sorb/bind contaminants will be significantly impacted by operating at or near flow capacity conditions. Hypothesis D: The installation of an in-line filter on a tile drainage line from a golf course green will significantly reduce the amount of nutrients and pesticides exiting the site through subsurface drainage under natural conditions

Approach:
Hypothesis A will be tested in a controlled laboratory experiment. Pesticide sorption isotherms will be generated by batch equilibration of sorbent with a range of pesticide concentration standards using reagent grade pesticide in deionized water on an end-on-end shaker (Basta and Olness, 1992). Pesticide remaining in batch solutions will be determined after batch equilibration using HPLC with UV detection. The amount of pesticide adsorbed will be determined by difference. Pesticide sorption parameters will be determined from pesticide adsorption isotherm plots including distribution coefficient values. For Hypothesis B a controlled laboratory experiment will be conducted to develop pesticide breakthrough curves. Pesticide breakthrough curves will be determined for sorbent materials as follows. Solute transport experiments with packed columns similar to methods described by McGowen and Basta (2001) will be used. Sorbent materials in packed columns will be saturated with type 1 reagent grade water with continuous upward flow using a piston pump (Fluid Metering, Inc., Syosset, New York) until saturation. Following saturation, an aqueous solution containing pesticide will be pumped upward through the packed sorbent column and solution fractions will be collected with a fraction collector through evident breakthrough or 60 pore volumes. Column effluent will be passed through Teflon tubing and an in-line 0.45'm filter before collection into glass test tubes. Pesticide concentration measured in eluted fractions will be determined by HPLC with UV detection as described by Basta and Olness (1992) and Baird et al. (2000). Elution curves for pesticide will be plotted for each column (sorbent) experiment. Numeric integration of metal mass eluted (through 60 pore volumes) per mass of sorbent will be calculated. Hypothesis C research will be conducted in a controlled hydraulics laboratory. Each filter will be subjected to flow at a rate approaching its maximum capacity. The flow will contain concentrations of nutrients and pesticides similar to those documented from drainage waters on golf courses. A 1000 gallon storage tank will be spiked with known concentrations of 2,4-D, chlorothalonil, metalaxyl, nitrogen, and phosphorus. The filters will be subjected to the spiked source for 10-minutes. The devices will be required to be recharged 2 more times (4 replicates) and the same test completed. Water samples will be collected at the outlet of the filter every 30 seconds. The samples will be analyzed and compared to the initial source concentrations. Hypothesis D will be tested using field scale measurements. The tile drainage outlet from a test green located at Ridgewood Country Club in Waco, TX will be instrumented with two different commercially marketed filter devices. The devices will be required to be charged a total of 4 times for replication purposes. Drainage from both natural and forced events will be collected. Hydrologic and water quality data will be collected and sent to the Soil Drainage Research Unit, Columbus, OH for analysis. Samples will be analyzed for 2,4-D, chlorothalonil, metalaxyl, nitrogen, and phosphorus.