Executive Summary
Human Health
Consumers are exposed to esterquats through their presence in fabric conditioners mainly via the dermal route, but to some minor extent also via the oral route. Skin exposure occurs mainly in hand-washed laundry and through esterquats being present on the fabric of laundry treated with fabric conditioner. Consumers are orally exposed to esterquats through residues in drinking water or eating foods that have taken up esterquats through their presence in surface waters. The maximum total aggregate exposure of consumers to esterquats has been estimated to be 36.9 µg/kg bw/day.
A substantial amount of toxicological studies demonstrate that esterquats are of low toxicity. Esterquats were found to be mildly to moderately irritating to rabbit skin and eyes. The degree of irritation was concentration dependant as dilutions in water resulted in proportionally lower level of irritation. Local dermal effects due to skin contact with esterquat containing handwasing solutions or esterquat residues on skin are not of concern because esterquats are neither considered skin sensitizer nor expected to be irritating under in-use conditions. Accidental eye contact with undiluted esterquat containing fabric conditioner formulation may cause mild irritation which is, however fully reversible shortly after exposure. As other components in the fabric conditioner formulation may contribute to these effects, immediate rinsing with plenty of water is recommended and will mitigate any potential eye irritation effects.
With regard to repeated dose toxicity, existing subacute and subchronic toxicity studies with esterquats coherently demonstrate a low level of systemic toxicity of all types of esterquats. No major clinical effects were observed in any of the studies, even at dose levels up to 1,000 mg/kg bw/day. There is further no information suggesting that esterquats are genotoxic, mutagenic or toxic to the foetus. Although no carcinogenicity study has been conducted with esterquats yet, the absence of genotoxicity and the overall low toxicity of esterquats do not raise any carcinogenicity concern. Likewise, although no multigeneration studies are available, the absence of any effects on gonads in well-conducted subacute and subchronic toxicity studies, does not raise an immediate concern for a possible effect of esterquats on fertility.
For assessing risks associated with human exposure to esterquats in context of their use in fabric conditioner, a conservative NOAEL of 300 mg/kg bw/day was established on the basis of 90-day oral toxicity study with a TEA-based esterquat. The comparison of the aggregate exposure of 36.9 µg/kg bw/day and the NOAEL results in an MOE of 8,100. Taking into account the conservatism in the exposure calculation and the assigned NOAEL for esterquats, this margin of exposure is considered to be large enough to account for the inherent uncertainty of the database and variability of the database.
In summary, the human health risk assessment has demonstrated that the use of esterquats in fabric conditioners is safe and does not cause concern with regard to consumer use.
Environment
A large environmental data set is available for esterquats. The ester quats under consideration are assessed according to a group approach, which is scientifically justified by close similarities with regard to physico-chemical properties, structural aspects, and a homogeneous ecotoxicity profile of relevant endpoints. On the environmental fate side this is based on standard biodegradation studies, advanced simulation studies of removal in treatment systems, and effluent monitoring data. On the environmental effects side acute as well as chronic single-species data are available tested with laboratory test water as well as natural river water.
To assess the Predicted Environmental Concentration (PEC), chemical removal in waste water treatment plants was determined from advanced simulation test data. Monitoring studies on sewage treatment plant effluents indicated that the exposure estimates in this assessment are in good agreement with each other.
The Predicted No-effect Concentration (PNEC) was based on chronic ecotoxicity.
Based on this higher tiers exposure and effects data, it could be shown that the use of esterquats in HERA applications (household detergents and cleaning products) results in risk characterization ratios less than one for the micro-organisms in a sewage treatment plant as well as aquatic,sediment and terrestrial organisms indicating no concern for any of these environmental compartments.