ABSTRACT:
Runoff potential of a subsurface soil-injected volatile compound, such as the soil fumigant 1,3-dichloropropene (1,3-D), that diffuses rapidly through the soil profile has not been studied for potential to contaminate surface water bodies through edge-of-field runoff. The objective of this study was to measure the runoff of 1,3-D, a soil fumigant and nematicide, under severe rainfall conditions at a field study site near Blacksburg, Virginia. 1,3-D was injected into the Groseclose clay loam (clayey, mixed mesic Typic Hapludults) at a 30 cm (12 inch) depth on three replicate 0.04 ha test plots. Special considerations for 1,3-D were required to make a uniform application to each plot and maintain worst-case conditions (rainfall timing and plot conditions). The measured application rate was 367-kg/ha (32.4 gallons/acre), which is greater than the typical maximum rate for Telone II® uses on crops grown in the Southeastern United States. The study was conducted on a hydrologic group C soil with a 5% slope. The 2-hour simulated rainfall water input was 9.4 cm (4.7 cm/h), which is about a 1-in-50-year storm for Blacksburg, Virginia. Concentrations of 1,3-D measured in soil and air prior to the simulated rainfall event suggested that 1,3-D was present at the soil surface and available for runoff. An average of 0.002% of the applied 1,3-D was observed in runoff. Maximum 1,3-D concentration (sum of both isomers) observed in runoff was 17.2 ppb, which is more than one order of magnitude below the lowest aqueous toxicological level of concern (280 ppb).
Footnotes
Lucas G. Heim, Nathan J. Snyder, and Ian J. van Wesenbeeck are with the Dow AgroSciences Global Environmental Chemistry Laboratory in Indianapolis, Indiana.
- Copyright 2002 by the Soil and Water Conservation Society
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