Caption title. At head of title: Project summary. Distributed to depository libraries in microfiche. "Apr. 1987." "EPA/600-S2-87-003."

"Modern agricultural practices rely heavily on the use of pesticides to sustain high productivity. When pesticide containers and application equipment are rinsed after use, the contaminated water requires proper disposal. At Iowa State University in Ames, Iowa, dilute pesticide rinsates have been placed in a concrete-lined pit for more than ten years. The pit contains alternating layers of gravel and soil. Water evaporates from the pit surface while pesticide chemicals are adsorbed on soil particles, destroyed by microorganisms or broken down chemically. Monitoring for atmospheric and ground-water contamination at the pit site has indicated no detectable release of pesticides to the surrounding air or water. This type of disposal facility may be appropriate for pesticide users generating 10,000 gallons or less of dilute pesticide waste annually. This report includes a review of the design criteria for lined pesticide pits and descriptions of pits currently in use around the nation. These facilities are all similar with variations in use of soil and gravel within the pit and the addition of high density polyethylene liners to protect ground water from possible leakage of pit contents. Guidelines for proper siting and operation of the pit are also given."