Stage of Clean-up: Study Underway
Stoker Co. operates at 3390 Dogwood Road in a sparsely populated agricultural area in Imperial, Imperial County, California. The company has been an aerial pesticide applicator and pest control supplier since 1966 and in 1990 employed 45 people. A canal that runs along the southern and eastern borders of the airstrip delivers water to a residence less than 80 feet from the site, wetlands, and a commercial fishery. The wetland is located along the entire length of the airstrip and provides habitat for four endangered or threatened species. The fishery produces catfish for human consumption and is located 0.25 mile from the site. Wash waters from the cleaning of pesticide application equipment are sprayed onto a 20-acre land treatment area on-site consisting of a dirt road and landing strip. Occasionally rinse waters from the rinsing of hoppers in the aircraft and pesticide containers were also sprayed on this area. The disposal of wash waters is permitted under Waste Discharge Requirements issued by the California Regional Water Quality Control Board (CRWQCB) in October 1974 and June 1988. Under this permit, Stoker is required to sample the unsaturated zone and ground water beneath the site. The requirements indicate that approximately 300 gallons of pesticide rinsewater per day were disposed of in the land treatment area in the 1970s, dropping to approximately 100 gallons per day sometime prior to 1988. More...