SU0005084 SSNL - Laserfiche WebLink

Home Browse Search

a. ow January 4,2006 NOA Project Number: E05166B ///4.2 Potential Ground Water Contamination Issues I y Identifying potential ground-water contamination sources was not part of the scope of work for the soil suitability study. Potential ground-water contamination can occur from a number of sources which often include leaky underground storage tanks, agricultural activities, dairies, septic systems, and storm water infiltration. Agricultural activities and the use of septic systems in the area should be considered potential ground-water contamination sources. P4.3 Water Sample Location According to the tentative parcel map provided by Monte Seibel,Land Surveyor, two wells exist on the site. One well permit was found during file review at EHD on December 20,2005.A water 4 sample was taken from the well head of the domestic well to the immediate south of the residence by Ms. Nancy Rosulek on December 9,2005 (Site Map,Plate 1). .. �� //4.4 Water Sample Constituents qmgwater sa ple was analyzed for nitrate and DBCP. DBCP was detected in the water sample at ug/L;be w the maximum contaminant level (MCL) of 0.2 ug/L set by the United States EPA. ate w ound at 1.74 m L-NO3,well below the maximum contaminant level (MCL) of 45 - O, set by the United States EPA. The analytical reports prepared by Precision Enviro-Tech can be found in the appendix of this report. Well construction, seals, age and depth of the well screens may play significant part in assessing the levels of Nitrate and DBCP in various aquifers. Without knowing specific details regarding well construction and condition,it would be difficult to accurately comment of the condition of the aquifer. Essentially,the water sample concentration approximately indicates the contaminant concentration level of the aquifer from which the well is drawing. It is Neil O. Anderson and Associate's opinion that,in general,near surface aquifers are more likely to have elevated concentrations of Nitrate and DBCP than the deeper aquifers. However the contaminant concentration of one aquifer cannot give any indication as to the concentrations of any other aquifer regardless of proximity. _ The presence of nitrates is not uncommon in shallow ground water aquifers in San Joaquin County and other parts of the Central Valley. Nitrate in ground water occurs as a result of the application of fertilizers,livestock waste, and untreated septic tank waste. Nitrate is mobile and often accumulates in the shallow ground water zones. 5