Laserfiche WebLink
<br /> OOi98Q <br />. Table 2. Chemical and bacterial data lor ground-water samples Irom St. Charles Mesa <br /> [mglL, milligrams per liter; DOC, dissolved organic carbon; ~glL, micrograms per liter; MBAS, methylene blue active substances; mL, milliliter; E. coli, <br /> Escherichia coli bacteria; <, less than; >, greater than; --, sample not analyzed for this constituent] <br /> Map Nitrate, Ammonia, Total E.coli <br /> coliform <br /> number Local Identifier as as DOC Caffeine MBAS (colonies (colonies <br /> (1Igs.3,4, nitrogen nitrogen (mg/L) (~g/L) (mg/L) per <br /> and 5) (mg/L) (mg/L) per 100mL) <br /> 100mL) <br /> 1 SC02106407DACCI 0.2 <0.01 0.8 <0.05 <1 <1 <br /> 2 SC02106405DAACI 2.0 .02 1.9 <.05 31 <1 <br /> 3 SC02106409BAAD 1 5.7 <.01 1.4 <0.04 <.05 >82 <1 <br /> 4 SC02I 06409CB 1 .2 .04 1.6 <.05 >2,700 <3 <br /> 5 SC02106409DBAAl .9 <.01 .9 <.05 <1 <1 <br /> 6 SC02106410BBCBI 3.7 .04 2.2 .10 9 <3 <br /> 7 SC02106404DDBB 1 3.1 .03 2.5 .28 <.05 10 <3 <br /> 8 SC021 06404DABB I 5.2 .04 1.8 <.04 .05 <1 <1 <br /> 9 SC02106404AABDl 5.2 .04 2.0 <.04 .1 130 2 <br /> 10 SC02106403CBAB 1 2.3 .06 1.9 .05 <3 <3 <br /> It SC02106403BABCI 3.2 .04 1.9 <.04 .05 12 <3 <br /> 12 Spring 3.7 .04 2.8 <.04 .1 7 <10 <br /> 13 SC02106403ABCC I 5.9 .05 2.3 <.04 .1 55 <3 <br /> 14 SC02106402CBBB 1 5.3 <.01 2.2 <.04 .05 <1 <I <br /> 15 SC02106403DBCDI .07 .08 9.5 <.04 .15 <3 <3 <br />. 16 SC02106403DDCCI 7.1 <.01 1.6 <.04 .1 <1 <1 <br />17 SC02106411BCBBl 8.3 <.01 2.0 <.04 .15 50 9 <br /> 18 SC02106410DBCDI 4.3 .03 1.3 .1 23 <3 <br /> 19 SC02106414BCCBl .4 .05 1.8 <.04 <.05 470 <3 <br /> 20 SC02106414AAABI 7.7 .04 <.04 .15 120 <10 <br /> 21 SC02106402DCDC 1 5.9 <.01 2.0 <.04 .1 <1 <1 <br /> 22 SC02106402DBCBl 2.7 .02 1.3 <.04 .05 <3 <3 <br /> 23 SC0210640 1 BCCC I 9.2 .02 1.8 <.04 .15 <3 <3 <br /> 24 SC021064I 2ACBC 1 4.2 .02 1.6 .05 100 <3 <br /> 25 SC02106306BCDl 4.7 .02 1.7 <.04 .1 300 <3 <br /> <br />I. <br /> <br />indicates a positive result when detergents and other <br />natural and synthetic substances are present in the <br />sample (Greenberg and others, 1985). Therefore, the <br />fact that 18 samples were positive for MBAS indicates <br />that human practices may have contributed to MBAS <br />in the ground water, but the source, whether septic- <br />system effluent or natural or synthetic chemical <br />compounds, cannot be identified. <br />Total coliform bacteria were detected in <br />IS samples, and E. coli bacteria were detected in <br />2 samples (fig. 5) (table 2). The USEPA rule for total <br />coliform bacteria in public drinking-water supplies <br />(U.S. Environmental Protection Agency, 1995) <br /> <br />(table I) does not apply directly to the private wells <br />that were sampled for this study. Nonetheless, the rule <br />can be generally used as a guideline for determining <br />the suitability of the water from these wells for human <br />consumption. The concentrations of total coliforms in <br />the ground water exceeded the USEPA maximum <br />contaminant level goal for bacteria in drinking water <br />of zero colonies per 100 milliliters. Eleven samples in <br />which bacteria were detected were obtained from <br />wells in areas of the Mesa where the water table is <br />more than 10 feet below land surface (fig. 5), whereas <br />four samples containing bacteria were in areas where <br />the water table is within 10 feet of land surface. The <br /> <br />5 <br />