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Udfasning af Linære Alkylbenzen Sulfonater (LAS) i rengøringsmidler

English Summary

Linear Alkylbenzene Sulphonates (LAS) are the most extensive used anionic detergents in cleansing agents. Despite the high separation efficiency in sewage treatment plants LAS outlet concentrations are in the range 0,02 – 0,9 mg LAS l^-1 (Berna et al. 1989; Berna et al. 1991). LAS are only slowly degradable in anoxic environments and may become concentrated in marine environment. In estuaries and near-shore marine waters, LAS has been found in concentrations that affect normal growth and development of marine organisms (Christensen et al. 1998; Hansen et al. 1997; Kimerle 1989s. LAS are now on the Danish Environmental Protection Agency’s list of undesirable substances in the group of non-anaerobic degradable substances.

The purpose of this study was to substitute LAS with alternative detergents with better environmental properties in ten cleansing agents without reducing the quality of these products. To select for detergents suitable as substitutes for LAS the environmental properties of various detergents were elucidated. Initially a number of anionic, nonionic and amphoteric detergents were considered with respects to their environmental properties. The ecological risk assessment of numerous detergents revealed that most detergents are readily degradable in aerobic environments and relatively toxic to aquatic organisms. Thus, when selecting detergents for substituting LAS it is important to concentrate on the anaerobic degradability and bioaccumulation potential of the detergents. Natriumlaurylethersulphate, natriumlaurylsulphate and fatty alcoholethoxylate revealed to be suitable as substitutes for LAS. These detergents possessed the desirable environmental and functional properties. In contrast, to LAS all three substitution detergents were anaerobic degradable.

From these three detergents Respekt Danmark ApS developed ten LAS-free products. Previous experiences with all three detergents turned out to be an advantage during development of the LAS-free products. The relationship between the amount of the detergent and the efficiency of the products were optimised to reduce the active content in the products. Subsequent laboratory and user reports demonstrated a satisfactory degree of efficiency of all new LAS-free products. Test were conducted either with original LAS-containing products as references or according to the standards of "Ecolabeling Denmark".

In conclusion, this study shows that it is possible to substitute LAS with anaerobic degradable detergents without reducing the efficiency of the products.