SU0007710_SSCRPT - Laserfiche WebLink

Home Browse Search

1 O1 May 2007 AGE-NC Project No. 07-1516 ? Page 14 of 39 Soil samples were analyzed for organochlorine, organophosphorous and carbamate pesticides; the results of the analyses inferred that all but one sample (BC-5) contained detectible concentrations of one or more constituents. The only compounds found above current regulatory criteria were from the dichlorodiphenyltrichloroethane (DDT) family of chemicals (DDT, DDE and DDD), but at relatively low levels. Water samples were analyzed for organochlorine, organophosphorous, and carbamate pesticides and chlorinated phenoxy acid and triazine herbicides; the results of the analyses inferred that only MW-3 (located in the airplane parking strip) contained detectible concentrations of bromacil,carbaryl and diuron;no concentrations exceeded the Primary or Secondary Drinking Water Standards. The recommendations from the 1989 Weston report noted that since soils were predominately fine textured and laterally contiguous and that the ground water yield was very limited, the soil had low permeability and transmissivity. These hydraulic conditions, coupled with the known low mobility of organochlorine pesticides found in soil suggested that the migration of compounds through the soil was unlikely. It was recommended that an annual ground water monitoring program be initiated utilizing the three existing monitoring wells and that the wells should be sampled for organochlorine and carbamate pesticides.The monitoring program would ensure that no significant chemical migration occurred and would serve as a routine assessment of site conditions. No further remedial actions were recommended, noting that remediation costs would over-weigh any benefit gained by the removal of the low-residue soil. • 09 October 1990: Based on the results of the 1989 Weston investigation, Monitoring and Reporting Program(M&RP)Order 490-810 was issued by the CVRWQCB for the property. The M&RP Order required that the three monitoring wells should be sampled in January and June and that samples should be analyzed for organochlorine and carbamate pesticides and phenoxy acid herbicides and in January, April, June and October for temperature, pH, electrical conductivity and ground water elevation. • 09 October 1990:A letter from the CVRWQCB,dated 09 October 1990,notes that with the issuance of Monitoring and Reporting Program (M&RP) Order #90-810, Cleanup and Abatement Orders#87-734 and 89-705 were rescinded. The letter notes that no soil cleanup was required at that time. • 26 February 1991:Initiation of the ground water monitoring events.Analysis of ground water from the first (26 February 1991) and third (19 September 1991) quarters of 1991 inferred the presence of bromacil at 5.5 micrograms per liter(µG/Q),carbaryl at 0.4µg/Q,diuron at 6.0 µg4, methiocarb at 1.0 µg/Q and carbofuran at 2.0 pg/Q. Based on the results of the 1991 monitoring events,the CVRWQCB indicated that the monitoring program was complete as Advanced GeoEnvironmentsl,Inc.