Water Quality Standards

Summary information extracted from: Guidelines for drinking-water quality, 2nd ed. - Vol. 1. Recommendations. - Geneva, World Health Organization, 1993. pp. 72-73.

Epichlorohydrin (ECH) is used for the manufacture of glycerol, unmodified epoxy resins, and water-treatment resins. No quantitative data are available on its occurrence in food or drinking-water. ECH is hydrolysed in aqueous media.

ECH is rapidly and extensively absorbed following oral, inhalation or dermal exposure. It binds easily to cellular components.

Major toxic effects are local irritation and damage to the central nervous system. It induces squamous cell carcinomas in the nasal cavity by inhalation and forestomach tumours by the oral route. It has been shown to be genotoxic in vitro and in vivo. IARC has placed ECH in Group 2A.

Although ECH is a genotoxic carcinogen, the use of the linearized multistage model for estimating cancer risk was considered inappropriate because tumours are seen only at the site of administration, where ECH is highly irritating.

A TDI of 0.143 µg/kg of body weight was therefore calculated by applying an uncertainty factor of 10 000 (100 for inter- and intraspecies variation, 10 for the use of a LOAEL instead of a NOAEL, and 10 reflecting carcinogenicity) to a LOAEL of 2 mg/kg of body weight per day for forestomach hyperplasia in a 2-year study in rats by gavage (administration 5 days per week). This gives a provisional guideline value of 0.4 µg/litre (rounded figure) based on an allocation of 10% of the TDI to drinking-water. A practical quantification level for ECH is of the order of 30 µg/litre, but concentrations in drinking-water can be controlled by specifying the ECH content of products coming into contact with it.