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above the Method Detection Limit (MDL) / the number of exceedances <br />between the MDL and the Practical Quantitation Level (PQL) / censored, <br />that is, the number of sample values below the MDL but the MDL was <br />higher than the standard / the total number of samples. Below is a <br />summary of standards that were exceeded in the 2015 water year. Given in <br />parenthesis is the source and use of each standard. <br />Parameter <br />Boron (CDPHE, select plant species) <br />Cadmium (CDPHE, irrigation) <br />pH (CDPHE, irrigation) <br />Iron (CDPHE, irrigation) <br />Lead (CDPHE, livestock) <br />Manganese (CDPHE, irrigation) <br /># of Wells / # of Excursions <br />1/2 <br />2/2 <br />2/3 <br />3/5 <br />2/2 <br />6/11 <br />The boron standard (750 ug/1) was exceeded twice at one site WW14 with <br />values of 920 ug/1 and 990 ug/l in the spring and fall respectively. <br />According to the CDPHE, the 750 ug/l standard is set for sensitive crops <br />(CDOH, Reg. 41, 2008), and that the limit otherwise is 5000 ug/l. None <br />of these sensitive plant species are grown commercially in this area. <br />This is also not an irrigation or livestock standard. <br />A total of two samples from two sites had cadmium values that were less <br />than an elevated detection limit (30 ug/l vs. a normal detection limit <br />of 3 ug/1), which was higher than the CDPHE standard of 10 ug/l. <br />Likewise, the same samples had lead values that were less than an <br />elevated detection limit (200 ug/l vs. a normal detection limit of 20 <br />ug/1), which was higher than the CDPHE standard of 100 ug/l. The cause <br />of these elevated detection limits was a decision by the laboratory to <br />dilute the samples prior to analyses in order to reduce the effects of <br />interferences (primarily high salinity). <br />Elevated levels of iron (i.e., greater than 5 mg/1) may be attributed to <br />natural (i.e., not mining related) conditions. The one bedrock well <br />(WW14) that often exhibits high levels (20.80 mg/l this year) may have <br />higher than usual concentrations of iron pyrite in the rock. The high <br />8 <br />