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0 hydrochemical facies is of Ca-Na/HCO3-SO4 type. Groundwater retrieved from the Granite 3 well has proportionally more sulfate and is of Ca-Na/SO4-HCO3 type. Nitrate(asmnitr. e) concen ations in shallow groundwater samples re zeved fro the Hall well increased from abort 15 �0 30 mg/L etween 1994 and 1996, decreased to ab� t 20 .. in 1999, and have 0 remained elat i ly stable ince then with concentrations typically belo m in the last few years (Figure 19). i l entrations shown for the Faulkner well are typical slightly lower than in the Hall well,however, ong-term trends are similar with the exception of high concentrations observed in the Faulkner well in first year of monitoring. The high(st—M14Fate concentrations have historically been observed at the South Trac' #1 ell, ranging from up o 50 g/L in 1994{i.e.,above the drinking water maximum contaminant 1 vel CL}of 45 mg/L)tor ximately 35 mg/L in recent years. Nitrate concentrations observed in the South Tracy#3 well are approximately 10 mg/L lower than in the South Tracy#1 well, but show similar seasonal fluctuations(its record extends from 2004 to the present)_ During its period of record(1994-2001},r itr to co�trations in samples retrieved from the Brown's New well were stable, fluctuating between 6 aril 11 g/L, and concentrations in the Granite#3 well are P/ �� similarly low (2006 record). V` The greatest long-term variability and seasonal variability is exhibited by the Brown's#1 well. Nitrate concentrations initially increased from 12 to 30 mg/L in 1994, decreased to 12-16 mg/L in 1997-98, and since then continue to c e. To date,the greatest nitrate concentration in this well has been measured Q in the May 2006 sam I e(48.5 g/L). Since nitrate concentrations began increasing in 1999, seasonal fluctuations also incr ed{fro about 10 to 20 mg/L). The presence of the observed nitrate concentrations is likely related to both the historical agricultural land O use in the area prior to the commencement of aggregate mining by Teichert Aggregates and also continuing farming practices. This includes the recent increase of nitrate concentrations in the Brown's #1 well. Copper, iron, and zinc concentrations in shallow groundwater samples are typically low and frequently below their respective reporting limits. For example,during the entire period of record, copper has been reported above its report my once(Hall well, 100 gg/L in May 1999 sample). Similarly, a detectable concentratio"has s quantified only once in a sample from the Hall well(80 gg/L, November 2003), and zn quantified between 30 and 130 gg/L in this well. In samples retrieved from the Faulkner well,copper concentrations have always been nondetect; iron and zinc concentrations have ranged from<10 to 160 gg/L and form<20 to 220 gg/L,respectively. Manganese T' has not been detected in any shallow groundwater samples to date. Ji As in shallow groundwater samples,copper concentrations in deep groundwater samples are rarely detected. In contrast,iron concentrations in deep groundwater samples are highly variable. For example, a concentrations have ranged from<50 to 4,580 gg/L in the South Tracy#1 well. Also,manganese has sporadically been detected in deep groundwater samples with concentrations ranging from<10 to 290 gg/L(and one reported concentration of 1,700 gg/L in the Brown's New well in 1998). Zinc concentrations in the Brown's#1 well are typically between<20 and 200 gg/L, and have been as high as 580 gg/L. To date, copper, iron,manganese, and zinc concentrations have been nondetect in samples from the South Tracy#3 well. Lastly,total coliform bacteria have been absent from the domestic wells with few exceptions. Most recently, total coliform bacteria were reported at 6.9 WN/100 mL in the November 2006 sample of the 6 ©LLJNDdRFF & SEALMANINI CONSULTING ENGINEERS