Water Quality Standards

Summary information extracted from: Guidelines for drinking-water quality, 2nd ed. - Vol. 1. Recommendations. - Geneva, World Health Organization, 1993. p. 72.

Residual acrylamide monomer occurs in polyacrylamide coagulants used in the treatment of drinking-water. In general, the maximum authorized dose of polymer is 1 mg/litre. At a monomer content of 0.05%, this corresponds to a maximum theoretical concentration of 0.5 µg/litre of the monomer in water. Practical concentrations may be lower by a factor of two to three. This applies to the anionic and nonionic polyacrylamides, but residual levels from cationic polyacrylamides may be higher. Polyacrylamides are also used as grouting agents in the construction of drinking-water reservoirs and wells. Additional human exposure might result from food, owing to the use of polyacrylamide in food processing.

Following ingestion, acrylamide is readily absorbed from the gastrointestinal tract and widely distributed in body fluids. Acrylamide can cross the placenta. It is neurotoxic, affects germ cells, and impairs reproductive function.

In mutagenicity assays, acrylamide was negative in the Ames test but induced gene mutations in mammalian cells and chromosomal aberrations in vitro and in vivo. In a long-term carcinogenicity study in rats exposed via drinking-water, acrylamide induced scrotal, thyroid, and adrenal tumours in males, and mammary, thyroid, and uterine tumours in females. IARC has placed acrylamide in Group 2B.

On the basis of the available information, it was concluded that acrylamide is a genotoxic carcinogen. Therefore, the risk evaluation was carried out using a non-threshold approach.

On the basis of combined mammary, thyroid, and uterine tumours observed in female rats in a drinking-water study, and using the linearized multistage model, a guideline value associated with an excess lifetime cancer risk of 10-5 is estimated to be 0.5 µg/litre.

The most important source of drinking-water contamination by acrylamide is the use of polyacrylamide flocculants that contain residual acrylamide monomer. Although the practical quantification level for acrylamide is generally in the order of 1 µg/litre, concentrations in drinking-water can be controlled by product and dose specification.