CORRESPONDENCE_1992-1999 - Laserfiche WebLink

Home Browse Search

EMCOn Issociates 1433 North Market Boulevard • Sacramento,California 95834-1943 • (916)928-3300 • Fax(916)928-3341 July 26, 1993 Project 0939-002.61 cf, n � � o M Mr. Wes Johnson CD rn San Joaquin County � - : Department of Public Works a 1810 East Hazelton Avenue � o Stockton, California 95201 C Re: May 20, 1993, Letter from the California Regional Water Quality Control Board (RWQCB), Central Valley Region Dear Mr. Johnson: The purpose of this letter is to respond to the RWQCB's May 20, 1993; letter to you regarding surface water quality monitoring results for North County Sanitary Landfill. In the letter,the RWQCB suggested that the concentrations of chloride,total dissolved solids (TDS), and electrical conductivity (EC) detected in samples collected from surface water monitoring point S-1 during the first quarter 1992 monitoring event were not representative of the general conditions at the time. The RWQCB states that because of this, the analytical results should be treated as outlier data and excluded from any statistical analysis for the landfill monitoring program. EMCON Associates believes that these data should not be excluded from the database for the following reasons: • A review of the water sample field data shows no indication of procedural deviations which may have affected the integrity of the samples collected. • The laboratory quality assurance/quality control data show the results to be valid. • Field data sheets indicate low flow conditions which may have resulted in higher concentrations for chloride, TDS, and EC. • Higher than average concentrations of chloride, TDS, and EC were observed in samples collected from monitoring point S-1 in February 1991, indicating that natural seasonal variations may occur in the stream. SACIpj0,093M390026.1dI-93 Val