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field pH at AMW-1, AMW-18, and AMW-19, potassium at AMW-4, AMW-10, AMW-11,
<br /> AMW-18, and AMW-19BR, sodium at AMW-4, AMW-10, AMW-18, and AMW-19, field
<br /> specific conductance at AMW-4 and AMW-11, strontium at AMW-4 and AMW-10, sulfate at
<br /> AMW-1, AMW-18, AMW-19, and AMW-19BR, field temperature at AMW4 and AMW-11,
<br /> TDS at AMW4, AMW-10, AMW-11, and AMW-19, and field turbidity at AMW-1 and AMW-
<br /> 18. Carbonate at AMW-18 and hexavalent chromium at AMW-11 exhibited apparent decreasing
<br /> trends according to the Mann-Kendall/Sen's Slope analysis,but these trends are due to historical
<br /> decreases in the laboratory PQL.
<br /> The field pH value observed at AMW-I during the second quarter 2010 (6.83 s.u.) is comparable
<br /> to historical pH values observed at that well, and is within the National Secondary Drinking
<br /> Water Standard range(6.5 - 8.5 s.u.). The field pH value observed at AMW-18 during the second
<br /> quarter 2010 (7.19 s.u.) is comparable to historical pH values observed at that well, and is within
<br /> the National Secondary Drinking Water Standard range (6.5 - 8.5 s.u.). The field pH value
<br /> observed at AMW-19 during the second quarter 2010 (7.58 s.u.) is comparable to historical pH
<br /> values observed at that well,and is within the National Secondary Drinking Water Standard range
<br /> (6.5 -8.5 s.u.).
<br /> The following VOCs exhibited an increasing trend according to the Mann-Kendall / Sen's Slope
<br /> analysis: 1,1-dichloroethane at AMW-1, cis-1,2-dichloroethene at AMW-1 and AMW-10,
<br /> tetrachloroethene at AMW-19, trichloroethene at AMW-19,and vinyl chloride at AMW-1.
<br /> The second quarter 2010 concentration of 1,1-dichloroethane at AMW-I (1.7 ug/L) is comparable
<br /> to historical concentrations observed at that well, and is the lowest concentration observed at
<br /> AMW-1 since August 2006. The second quarter 2010 concentration of cis-1,2-dichloroethene at
<br /> AMW-1 (2.3 ug/L) is comparable to historical concentrations observed at that well, and is well
<br /> below the National Primary Drinking Water Standard(70 ug/L). cis-1,2-Dichloroethene was not
<br /> detected(<0.50 ug/L)at AMW-10 during the second quarter 2010.
<br /> The second quarter 2010 concentration of tetrachloroethene at AMW-19 (2.0 ug/L) is comparable
<br /> to historical concentrations observed at that well, and is below the National Primary Drinking
<br /> Water Standard (5 ug/L). The second quarter 2010 concentration of trichloroethene at AMW-19
<br /> (1.0 ug/L) is comparable to historical concentrations observed at that well, and is below the
<br /> National Primary Drinking Water Standard (5 ug/L). The second quarter 2010 concentration of
<br /> vinyl chloride at AMW-1 (0.46 ug/L) is above the method detection limit (MDL) but below the
<br /> PQL. The concentration is comparable to historical concentrations observed at the well, and is
<br /> below the National Primary Drinking Water Standard(2 ug/L).
<br /> Mann-Kendall / Sen's Slope analysis identified decreasing trends in the following VOCs: 1,1-
<br /> dichlorochloroethane at AMW-10 and AMW-11, cis-1,2-dichloroethene at AMW-4 and AMW-
<br /> 11, dichlorofluoromethane at AMW-1, AMW-10, and AMW-11, tetrachloroethene at AMW-4,
<br /> AMW-10, and AMW-11,trichloroethene at AMW-4,AMW-10 and AMW-11, and vinyl chloride
<br /> at AMW-4. The following organic constituents exhibited an apparent decreasing trend according
<br /> to the Mann-Kendall / Sen's Slope analysis, but this trend is due to a historical decrease in the
<br /> laboratory PQL: 1,1-dichloroethane at AMW-4, 1,2-dichlorobenzene at AMW-1, 1,3-
<br /> dichlorobenzene at AMW-1, 1,4-dichlorobenzene at AMW-1,AMW-4,and AMW-10,benzene at
<br /> AMW-1, AMW-4, and AMW-10, dichlorofluoromethane at AMW-4, tetrachloroethene at
<br /> AMW-5R,trichloroethene at AMW-5R.
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