Maximum contaminant level in drinking water

Both atrazine and metolachlor are classified as potential human carcinogens by the USEPA, which has established a maximum contaminant level in drinking water of 3000 ng/L [78]. The maximum concentrations of atrazine and metolachlor measured in the 1994-2000 Great Lakes survey were 1039 ng/L and 736 ng/L, respectively. The effects of long-term, low-level concentrations of atrazine and metolachlor on aquatic ecosystems are largely unknown [79]. The Canadian guidelines for the protection of aquatic fife and drinking water (Table 8) were not exceeded for either of these herbicides [80-83]. 

The Occupational Safety and Health Administration permissible exposure limit time-weighted averages (TWAs) for chromium compounds are for, chromi-um(0) and salts - 1.0 mg m for chromium(II) and chromium(III) - 0.5mgm . The American Conference of Governmental Industrial Hygienists threshold limit value - TWA for chromium(VI) is 0.01 mgm. The US Environmental Protection Agency maximum contaminant level in drinking water is 0.1 mgH. ... 

Maximum contaminant level in drinking water Toxic criteria ... 

Regulatory Status Criterion to protect freshwater aquatic life 0.014 pg/L 24 h avg. criterion to protect saltwater aquatic life 0.030 tg/L 24 h avg. criterion to protect human health preferably 0.0 lifetime cancer risk of 1 in 100,000 0.00079 ng/L maximum contaminant level in drinking water 0.5pg/L (for PCBs as decachlorobiphenyl). 

Later amendments to the SDWA listed additional contaminants with standards on the maximum contaminant level in drinking water. The chemicals listed... 

MCL Maximum contaminant level. This value is generally given for contaminants dissolved in drinking water... 

Maximum Contaminant Level). In other samples plasticizers were not detected. Data show that some amounts of plasticizers are detected in drinking water plants, groundwater sources, and rivers worldwide, but these are usually in parts per billion concentrations... 

The goal of filtration in the modem municipal treatment plant is a maximum of 0.1 ntu (nephelometric turbidity unit), which ensures a sparkling, clear water (8). Freedom from disease organisms is associated with freedom from turbidity, and complete freedom from taste and odor requites no less than such clarity. The National Interim Primary Drinking Water Regulations (NIPDWR) requite that the maximum contaminant level for turbidity at the point of entry into the distribution system be 1.0 ntu unless it can be shown that levels up to 5 ntu do not interfere with disinfection, interfere with the maintenance of a chlorine residual in the distribution system, nor interfere with bacteriological analyses. 

A National Primary Drinking Water Regulation (NPDWR or primary standard) is a legally-enforceable standard that applies to public water systems. Primary standards protect drinking water quality by limiting the levels of specific contaminants that can adversely affect public health and are known or anticipated to occur in water. They take the form of Maximum Contaminant Levels (MCL) or Treatment Techniques (TT). 

Maximum Contaminant Level (MCL) - The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to MCLGs as feasible using the best available treatment technology and taking cost into consideration. MCLs are enforceable standards. 

Maximum Contaminant Level Goal (MCLG) - The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety and are non-enforceable public health goals. 

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