Water FAQ 5

Table 2: Metals

Aluminum (Al)
no numerical guideline
Aluminum is a naturally occurring abundant metal. The Guidelines for Canadian Drinking Water Quality have set an operational guideline for treatment systems that use aluminum-based coagulants (for example, municipal drinking water supplies). No guideline applies to other systems (for example, private wells).

Antimony (Sb)
MAC of 0.006 milligrams per litre (mg/L)
Antimony is naturally occurring, but the most common source of antimony in drinking water is the corrosion of antimony-containing plumbing materials. Exposure to very high levels of antimony (above 30 mg/L) in drinking water can cause nausea, vomiting, and diarrhea.

Arsenic (As)
MAC of 0.01 milligrams per litre (mg/L)
Arsenic is a naturally occurring element present in soil and rock. Exposure to high levels of arsenic in drinking water can cause nausea, diarrhea, and muscle pain. Over the long term, exposure to low levels of arsenic can cause certain types of cancer.

Barium (Ba)
MAC of 1 milligrams per litre (mg/L)
Barium is a common element in the earth’s crust. Exposure to high levels of barium in drinking water can cause gastrointestinal discomfort, muscular weakness, high blood pressure, or cardiovascular disease.

Beryllium (Be)
no numerical guideline
Beryllium is a metal found naturally in rocks, and in some precious stones such as emeralds and aquamarine. It is also found in certain industrial and municipal effluent. It is very rare for beryllium to be present in water above detectable levels.

Bismuth (Bi)
no numerical guideline
Bismuth is a metal found as crystals in nickel, cobalt, silver, and tin ores. It is usually recovered as a byproduct of lead and copper smelting.

Boron (B)
MAC of 5 milligrams per litre (mg/L)
Boron is a naturally occurring element found in rock and soil. Some boron found in groundwater is naturally occurring. It may also be present in groundwater due to industrial effluent, leaching of fertilizer, sewage, or leaching of landfill materials. Exposure to very high concentrations of boron in drinking water can cause reproductive malfunction in men and developmental abnormalities.

Cadmium (Cd)
MAC of 0.005 milligrams per litre (mg/L)
Cadmium is found in very low concentrations in most rocks, as well as in coal and petroleum. It can be present in groundwater through erosion and weathering of certain minerals and rock types. There are many synthetic sources of cadmium in drinking water, the most common being the corrosion of galvanized pipe. Exposure to high levels of cadmium in drinking water can cause gastrointestinal discomforts and kidney damage.

Chromium (Cr)
MAC of 0.05 milligrams per litre (mg/L)
Chromium is a metal found naturally in rocks, soils, and plants. It is an essential element required in small amounts by all living organisms. Chromium compounds from natural sources are usually found in groundwater in trace amounts only. The most common man-made sources of chromium in groundwater are the burning of fossil fuels, as well as mining and industrial effluent. Chromium can be present as chromium 3 or chromium 6 in water. Chromium 3 is non-toxic, but exposure to high levels of chromium 6 in drinking water can cause kidney and liver damage.

Cobalt (Co)
no numerical guideline
Cobalt is an element that is relatively rare in groundwater. It may be released into the environment through the emissions of coal burning industries. Cobalt is not considered a health risk, because it is generally not often freely available in the environment.

Lead (Pb)
MAC of 0.01 milligrams per litre (mg/L)
The main source of lead in drinking water is through corrosion of plumbing materials with lead components, such as pipes, solder, faucets, fittings, and older galvanized well liners. Exposure to lead in drinking water can cause damage to the brain and nervous system, behaviour problems and learning disabilities, developmental delays, and hearing disorders.

Molybdenum (Mo)
no numerical guideline
Molybdenum is a metal found naturally in small quantities in rocks and soils. It is an essential element required in small amounts by all living organisms. Sources of molybdenum in groundwater include fossil fuel combustion, sewage sludge, certain fertilizers, and mining waste.

Nickel (Ni)
no numerical guideline
Nickel is a metal found naturally in rocks, soils, and plants. In groundwater, nickel can be present through the weathering of rocks and as a result of human activities, such as the burning of fossil fuels, smelting, and the electroplating industry. Although nickel may be toxic in high concentrations, the concentrations in water are not usually high enough to cause health concerns.

Phosphorous (P)
no numerical guideline
Phosphorus is an element commonly found in soil, rocks, and plants. It is an essential nutrient for all forms of life. Phosphorus is used in agricultural fertilizers and is also present in detergents, as well as in human and animal wastes. It is much more common in surface water than in groundwater, since it is immobile and is very unlikely to reach groundwater in significant concentrations. A more general concern of phosphorus is its environmental effects. Elevated levels of phosphorus may cause blue-green algal blooms in surface water. The algal blooms can affect human health through contact or consumption.

Selenium (Se)
MAC of 0.01 milligrams per litre (mg/L)
Selenium is found naturally in small quantities in rocks and soils. It is an essential element required in small amounts by all living organisms. Selenium may be present naturally in dissolved form in groundwater through weathering and erosion of certain rock and soil types. Other sources of selenium in groundwater include contamination from industrial effluent, municipal wastewater, and hazardous waste sites. Exposure to very high levels of selenium (above 9 mg/L) in drinking water can cause fatigue and irritability, as well as damage to hair, fingernails, and liver tissue.

Silver (Ag)
no numerical guideline
Silver is a relatively rare metal. The major commercial uses of silver are in photography, electronic components, and in the manufacturing of metal alloys. Silver may be adsorbed by soils, but is very immobile and is unlikely to be present above detection limits in groundwater.

Strontium (Sr)
no numerical guideline
Strontium is an element abundant in rocks and soil. The presence of strontium in well water is more prevalent in certain rock and soil types.

Thallium (Tl)
no numerical guideline
Thallium is naturally present in rocks. The most common source of thallium in groundwater is through the leaching of thallium from ore processing operations.

Tin (Sn)
no numerical guideline
Tin is a metal found in many rocks and minerals. It is rare for tin to be naturally present in soils and water. Most tin present in groundwater is due to manufacturing and industrial effluent.

Titanium (Ti)
no numerical guideline
Titanium is an element found naturally in many igneous and sedimentary rocks. Titanium compounds are stable in soil, so only small amounts of titanium end up in water from the weathering of rocks. Titanium may also be present in groundwater due to manufacturing effluent. Titanium is relatively non-toxic. It does not accumulate in the human body.

Uranium (U)
MAC of 0.02 milligrams per litre (mg/L)
Uranium is a naturally occurring radioactive element that exists in soil and rock throughout the world. Exposure to uranium in drinking water can result in kidney damage.

Vanadium (V)
no numerical guideline
Vanadium is found naturally in small quantities in rocks and soils. The presence of vanadium in well water depends on the rock and soil type in the area. Other human-related sources of vanadium are from emissions from the production of oil, gas, and metal alloys.