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The guideline technical document for trihalomethanes (THMs) also includes a specific guideline for bromodichloromethane (BDCM). The maximum acceptable concentration (MAC) for trihalomethanes (THMs) in drinking water is 0.100 mg/L (100 µg/L) based on a locational running annual average of a minimum of quarterly samples taken at the point in the distribution system with the highest potential THM levels. The maximum acceptable concentration (MAC) for bromodichloromethane (BDCM) in drinking water is 0.016 mg/L (16 µg/L) monitored at the point in the distribution system with the highest potential THM levels.

Because cyanide is toxic to humans, a maximum acceptable concentration of 0.2 mg/L (200 µg/L) for free cyanide in drinking water has been set.

Under the right environmental conditions, microcystins and other cyanobacterial toxins are naturally formed in water in the environment. They are produced and stored in the cells of cyanobacteria, and released when the cells rupture or die. Most scientific studies on cyanobacterial toxins focus on microcystins, which are generally regarded as the most important of the freshwater cyanotoxins. A seasonal maximum acceptable concentration (MAC) of 0.0015 mg/L (1.5 µg/L) is established for total microcystins in drinking water.

Chromium occurs naturally in small amounts in rocks and soils, some of which is released into the aquatic environment through weathering and erosion processes. This guideline technical document reviews and assesses all identified health risks associated with chromium in drinking water. It incorporates new studies and approaches and takes into consideration the availability of appropriate treatment technology. A maximum acceptable concentration (MAC) of 0.05 mg/L (50 µg/L) is established for total chromium in drinking water.

Nitrate and nitrite are widespread in the environment. They are naturally produced by the oxidation of nitrogen by microorganisms and, to a lesser extent, by lightning. The maximum acceptable concentration (MAC) for nitrate in drinking water is 45 mg/L. This is equivalent to 10 mg/L measured as nitrate-nitrogen.

Antimony may enter the aquatic environment by way of natural weathering of rocks, runoff from soils, effluents from mining and manufacturing operations, and industrial and municipal leachate discharges. Household piping and possibly non-leaded solders are sources of antimony in tap water, as soft water may leach antimony from the pipes. The maximum acceptable concentration (MAC) for antimony in drinking water is 0.006 mg/L (6 µg/L).

The maximum acceptable concentration (MAC) for chlorite in drinking water is 1 mg/L. The MAC for chlorate in drinking water is 1 mg/L. A guideline for chlorine dioxide is not required because of its rapid reduction to chlorite in drinking water. Utilities should make every effort to meet the guidelines, however, any method of control employed must not compromise the effectiveness of water disinfection.

Although hardness may have significant aesthetic effects, a maximum acceptable level has not been established because public acceptance of hardness may vary considerably according to the local conditions. Water supplies with a hardness greater than 200 mg/L are considered poor but have been tolerated by consumers; those in excess of 500 mg/L are unacceptable for most domestic purposes.

Trichloroethylene (TCE) is a volatile solvent that is used extensively in the automotive and metals industries for vapour degreasing and cold cleaning of metal parts. Canadians can be exposed to TCE through its presence in drinking water, air and food. Certain segments of the population could be exposed via contaminated soil or occupational settings.The maximum acceptable concentration (MAC) for trichloroethylene in drinking water is 0.005 mg/L (5 µg/L).

An aesthetic objective of ≤250 mg/L has been established for chloride in drinking water. At concentrations above the aesthetic objective, chloride imparts undesirable tastes to water and to beverages prepared from water and may cause corrosion in the distribution system.