This report is based on the rationale described in the HERA Risk Assessment on Subtilisins (Protease) http://www.heraproject.com and builds on the data presented there for protease enzymes to assess the use of other enzymes used in household detergents.
1. Substance Characterisation and Usage
Amylases, cellulases and lipases used in detergents are hydrolytic enzymes, used in detergents and other technical applications like textile or pulp and paper industry to remove deposits and stains. Amylase is acting versus starch containing stains, lipase against natural fats and oils. Cellulase is used to exhibit effects on cotton fibers like anti pilling, colour brightening, and antigreying. The enzymes are of bacterial or fungal origin, and are produced by a fermentation process. Each of the enzymes is characterised by its amino acid sequence and three-dimensional structure as well as by its biocatalytic activity in hydrolysing glycosidic bonds (amylase and cellulase) or ester bonds (lipase).
The total amount of these enzymes used in detergents in the European Union in 2002 is in a range of 150 tons for amylases, 15 tons for cellulases and 8 tons for lipases (pure active enzyme protein). The concentration of amylases, cellulases or lipases in household detergent and cleaning products is very low and depends on the type of product. According to a 2003 A.I.S.E. survey, the concentrations in products typically range between 0.002 and 0.09%.
2. Environmental Assessment
Amylases, cellulases and lipases are proteins which are readily and ultimately biodegradable in the environment. An important aspect in the environmental exposure assessment is the fact that these enzymes are inactivated (loss of enzymatic activity) to a large extent under washing or cleaning conditions. These enzymes do not show relevant ecotoxic properties.
This allows to conclude that the use of amylases, cellulases and lipases in detergents does not pose a risk for the environment.
The key health concern identified for all enzymes is respiratory (Type 1) allergy. Consumers can be exposed to enzymes via the respiratory route during the task of dispensing powder products in the washing machine and during hand wash of laundry, or by suddenly opening the dish washer during the cleaning step. The exposure has been determined for the detergent protease Subtilisin which is considered the most critical enzyme type. This is seen due to the higher frequency of use, the higher concentration in the products, and the intrinsic irritation hazard (HERA Subtilisin Risk Assessment). Subtilisin has irritation properties due to its catalytic activity (breakdown of proteins) while amylases, cellulases and lipases are not irritant. Since amylases, cellulases and lipases are used in lower concentrations the exposure can be expected to be at equal or lower levels compared to Subtilisin.
According to human experience data the allergic potency of amylases, cellulases and lipases is considered to be in the same range as Subtilisin.
Since there is no well defined threshold for the induction of sensitisation a benchmark approach was used to assess the risk of consumers for respiratory allergy. For Subtilisin an upper benchmark where allergic symptoms occur was established at 212 ng/m3. Allergic symptoms can be excluded when exposure does not exceed a range of 1 ng/m3. There appears to be a complex relationship among frequency, magnitude and duration of exposure to the generation of enzyme specific IgE antibody. Therefore a lower benchmark where occurence of sensitisation is clearly absent cannot be given with sufficient accuracy. Since enzyme exposure associated with laundry products is calculated to be not more than 0.16 ng/m3, adverse effects are not expected. Even under the worst-case situation (opening a dishwasher during the cleaning step) such effects are not to be expected as in reality the thresholds at which respiratory sensitisation and allergy occur are likely to be distinctly higher than mentioned above, thus making, the margin of safety proportionately greater.
In conclusion it can be said, that use of amylases, cellulases and lipases in laundry and cleaning products represents no safety concerns for consumers.