Aluminum salts: Aluminum chloride, Aluminum nitrate, Aluminum sulphate
What are they?
- Some aluminum compounds, including aluminum chloride, aluminum nitrate and aluminum sulphate, are manufactured for a wide range of industrial and commercial uses, including use in some consumer products.
How are they used?
- Aluminum sulphate (or "alum") and aluminum chloride are primarily used in municipal drinking water and wastewater treatment facilities to help remove suspended particles and bacteria from the water. The other major uses of these two salts are in industrial water and wastewater treatment and in the pulp and paper industry.
- Aluminum sulphate and aluminum chloride are also used as ingredients in drugs, natural health products and cosmetics, such as antiperspirants and topical creams.
- Aluminum sulphate is permitted as a food additive in a limited number of products.
- Aluminum nitrate, used in far lower quantities than the sulphate and chloride salts, may be used in some fertilizers and as a chemical reagent in various industries.
- Aluminum chloride and aluminum sulphate are manufactured in Canada, primarily for use within Canada. Aluminum nitrate is imported into Canada in very small quantities.
Why did the Government of Canada assess them?
- Aluminum chloride, aluminum nitrate and aluminum sulphate were included on the Priority Substances List (PSL) in order to assess the potential environmental and human health risks posed by exposure to aluminum derived from these three salts in Canada.
- When these salts were added to the PSL, some studies indicated that there may be a link between exposure to aluminum in the environment and effects in humans (e.g., Alzheimer's disease), as well as possible adverse ecological effects, especially in acidic environments (e.g. acidic lakes and rivers) where the solubility of aluminum increases.
- Aluminum chloride, aluminum nitrate and aluminum sulphate were assessed because of their potential widespread use in municipal drinking water treatment and their release to the environment through water and wastewater treatment or through other industrial uses.
How are Canadians exposed to these salts?
- Canadians may be exposed to low levels of aluminum sulphate or aluminum chloride through their consumption of drinking water.
- Canadians are exposed to low levels of aluminum sulphate as a result of its presence as a food additive in a small number of food products.
- Exposure to the general population of Canada to aluminum nitrate is expected to be very low as it is used in limited quantities.
How are these salts being released into the Canadian environment?
- Aluminum sulphate minerals occur naturally in small quantities in restricted geological environments and can be released into the Canadian environment from these natural sources. However, aluminum chloride and aluminum nitrate do not occur naturally in the environment.
- The amount of aluminum released due to human activity involving aluminum salts is small compared with natural releases but can dominate in certain areas.
- Most direct releases into surface waters of aluminum derived from the use of aluminum salts in water treatment processes originate from drinking water treatment plants. However, these direct releases are regulated by provincial and territorial authorities.
- Disposal of sludge produced by municipal and industrial water treatment facilities on land through farming practices is a source of aluminum to soil.
What are the results of the assessment?
- The Government of Canada has conducted an evaluation of aluminum chloride, aluminum nitrate, and aluminum sulphate, and published the results in a final assessment report.
- As a result of this final assessment, the Government of Canada has concluded that aluminum chloride, aluminum nitrate and aluminum sulphate are not entering the environment in a quantity or under conditions that constitute a danger to the environment or human health.
- The final assessment report was published on January 23, 2010.
What is the Government of Canada doing?
- Based on the conclusion of the final assessment, no further action will be taken at this time under the Canadian Environmental Protection Act, 1999 (CEPA 1999) on aluminum chloride, aluminum nitrate, or aluminum sulphate.
- In 1998, Health Canada published its recommendation that water treatment plants using aluminum salts optimize their operations to reduce residual aluminum levels in treated water to the lowest extent possible. For conventional treatment plants using aluminum-based coagulants, an operational guidance value of less than 0.1 mg/L (100 µg/L) total aluminum is recommended. Health Canada continues to support this approach to controlling the levels of aluminum in drinking water.
- Health Canada is currently re-evaluating dietary exposure to aluminum (which includes many other forms of aluminum) and reviewing current uses of aluminum-containing food additives, to identify whether further controls are needed. Health Canada Review of Dietary Exposure to Aluminum
What can Canadians do?
- The health risks associated with a chemical depend on the hazard (its potential to cause health effects) and the dose (the amount of chemical to which you are exposed).
- Because exposure to aluminum sulphate, aluminum chloride and aluminum nitrate among the general population is very low, the Government of Canada is not currently recommending any specific actions by Canadians to reduce their exposure.
- As a general precaution, Canadians who handle these aluminum salts in an industrial or manufacturing setting are reminded to carefully follow safety warnings and directions when using products containing these substances.
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