Zeolite A (sodium aluminium silicate) is used as a builder in detergent powders and tablets for water softening in the washing process.
Environmental risk assessments of Zeolite A were conducted with the default values of EUSES 1.0 and with the HERA detergent scenario as well. Based on the calculated PEC/PNEC ratios which are below 1 (RCR < 1) in both scenarios, no cause of concern was indicated for any of the environmental compartments, i.e. water, sediment, soil and and sewage treatment plant (STP). In contrast to the 1st version of the HERA Zeolite A risk assessment, a risk quotient < 1 has also been established for the local soil compartment due to recently generated plant toxicity data of a high reliability. The favourable outcome of the present environmental risk assessment and the knowledge about the long-term fate of zeolites which ultimately turn into natural constituents provide a sound basis for the conclusion that the use of zeolite A in detergent products does not pose a risk to the environment.
Scenarios relevant to the consumer exposure to Zeolite A (sodium aluminium silicate) have been identified and assessed using the margin of exposure or equivalent assessments. Due to the lack of irritant and sensitising effects the local effects of dermal exposure do not cause concerns. Developmental or carcinogenic effects were not observed in experimental studies. No studies have been identified that investigated the reproductive toxicity of sodium aluminium silicate. However, no indication of toxicity to reproductive organs have been observed in long term studies and no structure activity relationship is known that indicates a concern. Chronic oral studies demonstrate that sodium aluminium silicate causes adverse effects in the urogenital tract. The NOAEL for these effects in a two-year rat oral toxicity study is 60 mg/kg BW. The Margin of Exposure for the combined estimated systemic dose is 567. This Margin of Exposure is considered to provide sufficient protection of consumers exposed to sodium aluminium silicate. The same conclusion is reached in assessing the possible effects of inhaled sodium aluminium silicate dust. Accidental exposure scenarios such as ingestion or contact to eyes were also assessed. Due to the lack of acute toxic effects of sodium aluminium silicates, these scenarios also do not cause concern. In summary, the human risk assessment has demonstrated that the use of sodium aluminium silicate in household detergents does not cause concern with regard to consumer use.