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<br /> TCN Proper-ties, L.P. 6793.4.001.01
<br /> North Lathrop Properties August 28, 2006
<br /> QUARTERLY GROUNDWATER SAMPLING RESULTS Page 2
<br /> On July 12 and 13, 2005, ENGEO drilled and installed five shallow groundwater monitoring wells
<br /> (NMW-1, NMW-2, NMW-3, NMW-4 and NMW-5) at the site, as summarized in Reference 3.
<br /> The approximate locations of these wells are shown on Figure 2. On September 15, 2005, we
<br /> installed one HOBO U20 automated groundwater level logger within each monitoring well.
<br /> GROUNDWATER SAMPLING PROCEDURES
<br /> Monitoring well groundwater samples were collected from Wells NMW-1 through NMW-5 on
<br /> July 19, 2006. The following sampling protocol was used to collect the water samples:
<br /> a The groundwater depth in the monitoring well was measured and used to calculate the number
<br /> of well volumes required for purging.
<br /> a The wells were purged using a 12-volt pump while monitoring stabilization of groundwater
<br /> parameters (temperature, pH and electrical conductivity). A minimum of three well casing
<br /> volumes were evacuated prior to the collection of samples. The pump was decontaminated
<br /> between each well sampling and new,pre-cleaned tubing was attached.
<br /> 0 Water samples were obtained from all locations using a 12-volt pump and clean plastic tubing.
<br /> 0 Samples were filtered in the field as needed. A list of filtered and unfiltered samples is
<br /> provided in the summary table attached.
<br /> 9 All samples were placed in an ice-cooled chest for transport to an accredited analytical
<br /> laboratory.
<br /> SAMPLE ANALYSIS
<br /> Samples were delivered under documented chain of custody to California Laboratory Services in
<br /> Rancho Cordova, California. Samples were analyzed for alkalinity (carbonate, bicarbonate,
<br /> hydroxide, and total), metals (As, Ba; Cr, Pb, Zn, Ca, Mg, Fe, Al, Mn, Ni, Na, K), pH,
<br /> miscellaneous ions (fluoride, chloride, bromide, sulfate), specific conductance, total dissolved
<br /> solids, ammonia as N, nitrate as N, Nitrate +Nitrite as N, Orthophosphate, total kjeldahl nitrogen
<br /> (TKN), boron, thallium, bromoform, bromodichloromethane, dibromochloroform, chloroform,
<br /> total trihalomethanes, and total coliforms.
<br /> The results of the laboratory analysis are summarized in Table I and the laboratory data sheets are
<br /> attached.
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