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Table 2. Statistical summary of selected ground-water data for the Fraser River watershed, 1998-2001, with U.S. Environmental Protection Agency and State of Colorado water-
<br />quality standards and U.S. Geological Survey National Water Quality Laboratory reporting levels.-Continued
<br />[All water-quality constituents are in the dissolved form except for total coliform bacteria, methylene blue active substances, and radon-222. USEPA, U.S. Environmental Protection Agency;
<br /> USEPA water-quality
<br />standards and health advisory are from U.S. Environmental Protection Agency (2002b) unless otherwise noted; WY, water year; MRL, minimum reporting level; LT-MDL, long-term method detection
<br /> level; LRL,
<br />laboratory reporting level; °C, degrees Celsius; --, no standard determined; gS/cm, microsiemens per centimeter at 25 degrees Celsius; mg/L, milligrams per liter; SDWR, USEPA secondary
<br /> drinking-water regu-
<br />lation; NTU, nephelometric turbidity units; TT, treatment techniques; WQS, water-quality standard; <, less than; gg/L, micrograms per liter; E, estimated; N, nitrogen; HA, health advisory;
<br /> MCL, maximum
<br />contaminant level; nitrate is nitrate plus nitrite; P, phosphorus; C, carbon; col/100 mL, colonies per 100 milliliters; MCLG, maximum contaminant level goal; pCi/L, picocuries per liter;
<br /> AMCL, alternative
<br />maximum contaminant level]
<br />Field properties,
<br />constituents, and
<br />reporting units Number
<br />of
<br />samples
<br />Minimum
<br />Median Maximum USEPA
<br />water quality
<br />standard or health
<br />advisory WY 1998
<br />
<br />MRL WY 1999
<br />
<br />LT-MDL *LRL
<br />( =MRL) WY 2000
<br />
<br />LT-MDL *LRL
<br />( =MRL) WY 2001
<br />
<br />LTMDL * LRL
<br />(=MRL)
<br /> Total coliform ba cteria, methylene blue active substances, and radon-222
<br />Total coliform 68 <1 <1 E 140 55% (MCLG) 1 *1 *1 *1
<br />bacteria
<br />(col/100 rnQ
<br />Methylene blue active 69 <0.02 <0.02 3.82 0.5 (SDWR) 0.02 *0.02 *0.02 0.02
<br />substances (mg/L)
<br />Radon-222, total 30 365 760 6,380 6300 (proposed MCL) *26 *26 *26 *26
<br />(pCi/L.) 4,000 (proposed
<br />'Treatment techniques are U.S. Environmental Protection Agency required processes, from U.S. Environmental Protection Agency (2002b).
<br />2Maximum allowable dissolved-solids concentration in ground water is the value that is less restrictive; applies to "agricultural use--quality," "surface-water quality protection," and
<br /> "potentially usable quality"
<br />classes of ground water, from Colorado Department of Public Health and Environment (2001).
<br />3Dissolved solids (sum of constituents) is computed as the sum of calcium, magnesium, sodium, potassium, silica, chloride, sulfate, and carbon (as carbonate equivalent) plus any other
<br /> constituents, such as
<br />dissolved iron, if they are present in the water.
<br />4Un-ionized ammonia [NH3] plus ammonium [NH4+].
<br />5No more than 5 percent of samples can be total coliform-positive in a month. Every sample that has total coliforms must be analyzed for fecal coliforms; no fecal coliforms are allowed.
<br /> From
<br />U.S. Environmental Protection Agency (2002b).
<br />UUnder review, from U.S. Environmental Protection Agency (2000b).
<br />Applies to those States that create Multimedia Mitigation programs to address radon in indoor air. Under review, from U.S. Environmental Protection Agency (2000b).
<br />C
<br />d
<br />C
<br />p
<br />e
<br />d
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