SU0006799_SSCRPT - Laserfiche WebLink

Home Browse Search

10� 'tri nkl e and Eloy, Ash Flying ng Service. San Joaquin County E h.i s facility has 4:eE>rr utilized b.y three aerial applicator, businesses over the Fast 40 years.. The current operators acquired the facility from their parents and implemented changes in rinse water disposal practices. One chanoe, made a few months before our inspection, was to install a sump. a suturiersible" pump.: anti. an above-around tank for rinse water. Prior disposal wa:_- onto a paved area (part of which had numerous cracks) or into a small pit, f raw where it probanly infiltrated. 'Fhc--- first sarrij inl site selected was a gravel area adjacent to the runway .� at the end where t"tie wash area is located. The sampling site was approxi- mately 5D "Feet- from the old pit in the wash area; the separating area is oaved with asphalt- At approximately 8 inches depth, an underlying fill of large gravel was encountered. The large gravel was discolored and had a ;pesticide/hydrocarbon odor. Free water was encountered at 18 inches. >amples of the discolored gravel and of the water were collected. soil composite samples were taken from areas adjacent to other portions Or the runway. tone composite was from 1"-6" at five sites (surface debris was removed prior to sampling) , and the other sample was from 18-24" at two it.es . A water sample was collected from a faucet supplied by an on-site well . Analyses re;�r��,' � -i t.ha.t: the gravel contained several pesticides at fairly ` hiq_ h levels, including UDE at 22 ppm, DDD at 15 ppm, disulfoton (Di-Syston) at ?_50 ppm, and c�arbofuran at 38 ppm. The tree-water sample also contained rUmercus pesticides, but generally at low levels. Carbofuran, however, was •• a'. 16 pprrn. s,i l composite contained seven pesticides includ#ng eth i on at. IDD D 1-orn and ethyl parathion at 48 ppm- The 18"-24" soil com- posite snowed only one pesticide, 2,4-D at 0.16 ppm. No pesticides were detected in the well water sample. it is pos:c�ible t..hai:. the discolored gravel 'is part of an old leach field to disperse water from the pit in the wash area. In any event, some miti- csation will be necessary to prevent the off-site movement of pesticides in the shallow ground water. Some mitigation may also be necessary in areas where surface soils have significant. 'pesticide residues, but additional ampling is necessary to define the areas, and a review of site soils and hydrogeology is nec..essary to determine the degree of protection afforded by site specific conditions. Y