Drinking water maximum containment levels

The drinking water maximum contaminant level (MCL) set by the USEPA for altrazine is 0.003 mg/L and its Reference Dose (RfD) is 3.5 ingAcg-d. How many liters of water containing atrazine at its MCL would a person have to drink each day to e.xceed the RfD for this triazine herbicide ... 

Safe Drinking Water Act. (1974, 1986, 1996). Specifically applied to water supplied for humans consumption, this act requires the EPA to set maximum levels for contaminants in water delivered to users of public water systems. Two criteria are established for a particular contaminant the maximum containment level goal (MCGL) and the maximum contaminant level (MCL). The former, the MCLG, is the level at which no... 

U.S. Primary Drinking Water Standards Maximum Containment Levels. . 4-13... 

There is uncertainty as to what levels of MTBE in drinking water cause a risk to public health.9 U.S. EPA has issued an advisory suggesting that drinking water should not contain MTBE in concentrations >20-40 pg/L, based on taste and odor concerns, but has not issued a federal maximum contaminant level (MCL) for MTBE, which will be based on the ongoing U.S. EPA studies.1... 

For maximum protection of human health from the potential carcinogenic effects of exposure to arsenic through drinking water or contaminated aquatic organisms, the ambient water concentration should be zero, based on the nonthreshold assumption for arsenic. But a zero level may not be attainable. Accordingly, the levels established are those that are estimated to increase cancer risk over a lifetime to only one additional case per 100,000 population. These values are estimated at 0.022 pg As/L for drinking water and 0.175 pg As/L for water containing edible aquatic resources (USEPA 1980 Table 28.7). 

The 1993 Environmental Protection Agency (EPA) regulation contains standards for 84 chemicals and minerals in drinking water. According to the EPA one of the most prevalent of the listed contaminants is naturally occuring antimony. The maximum contaminant level for antimony and nickel has been set at 0.006 mg/L and 0.1 mg/L respectively. 

Finished water supplies obtained from groundwater sources were tested by ERA for contaminants. It was reported that up to 10.8% of 158 nonrandom sample sites from across the United States contained detectable levels of 1,1-dichloroethane. The maximum concentration was 4.2 ppb (Westrick et al. 1984). 1,1-Dichloroethane was detected at a maximum concentration of 220 ppb in samples from 193 private wells in Rhode Island analyzed over a period of nine years (RIDH 1989). A maximum concentration of 40 ppb 1,1-dichloroethane was detected in 6 public drinking water systems in Rhode Island between April 1982, and April 1989 (RIDH 1989). 

The concentration of calcium ion in a town s supply of drinking water is 0.0020 M. (This water is referred to as hard water because it contains such a large concentration of Ca. ) Suppose the water is to be fluoridated by the addition of NaF for the purpose of reducing tooth decay. What is the maximum concentration of fluoride ion that can be achieved in the water before precipitation of CaF2 begins Will the water supply attain the level of fluoride ion recommended by the U.S. Public Health Service, about 5 X 10 M (1 mg fluorine per liter) ... 

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