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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.

Low levels of fluoride occur naturally in most sources of drinking water in Canada. Fluoride can occur naturally in surface waters from the deposition of particulates from the atmosphere and the weathering of fluoride-containing rocks and soils, and in groundwater from leaching from rock formations. The maximum acceptable concentration (MAC) for fluoride in drinking water is 1.5 mg/L.

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.

The aesthetic objective for zinc is ≤5.0 mg/L. Zinc is an essential element and is generally considered to be non-toxic. Intake of zinc from food is more than sufficient to satisfy the recommended daily requirements. Drinking water is not regarded as an important nutritional source of this element.

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).

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).

Canadians can be exposed to carbon tetrachloride through its presence in air and drinking water. In addition, certain segments of the population may be exposed through the use of specific consumer products or in occupational settings. The maximum acceptable concentration (MAC) for carbon tetrachloride in drinking water is 0.002 mg/L (2 µg/L).

Dicamba is a broad-spectrum chlorobenzoic acid herbicide used in large quantities for general weed control on grain crops, pastures and non-crop areas. The maximum acceptable concentration (MAC) for dicamba in drinking water is 0.12 mg/L (120 µg/L).

Boron is an essential element for plant growth and is applied directly to the soil as a plant fertilizer. Sodium borate and boric acid are used as fungistatic agents on vegetables, fruits and trees. The maximum acceptable concentration (MAC) for boron in drinking water is 5 mg/L (5000 µg/L).

Naturally occurring barium can be found in most types of rocks and can enter surface and groundwater by leaching and eroding from sedimentary rocks. A maximum acceptable concentration (MAC) for total barium in drinking water is 2.0 mg/L (2,000 µg/L).