Clean shirts adclean water Soap and detergents belong to the category of massproduced chemical substances. Worldwide, the 30 million tons produced each year poses a substantial potential for harm to the aquatic environment. In North America and Western Europe each person uses an average of 23 kg of household detergents each year. These products contain “wash active” substances, builders, and other additives such as bleach and optical brighteners; a few hundred grams of these substances is dispersed into every cubic meter of wastewater. The imposition of stringent requirements on the ecological compatibility of soap and detergents is justified to protect the processing operations at wastewater treatment plants and to safeguard aquatic ecosystems. First, all organic detergent components should be fully biodegradable and should contain no decomposition intermediates; second, detergents should not contain algal nutrients that contribute to the man-made eutrophication of lakes. These two requirements are not met by many of the detergent formulations in common use today. But manufacturers deserve credit for mitigating the foam problem that plagued sewage treatment plants and receiving waters in the early 1960s. The June ES&T editorial (“Phosphate here, phosphate there . . .” p. 467) stated that “natural variations in the complex interrelations among nutrient levels, light availability, and plant growth are so substantial that single control measures . . . are likely to have extremely variable results, if applied over large areas.” Here I disagree; for every pollutant the cause-effect relationship is complicated, but our power to predict the effect of phosphate loadings on lakes (of different morphology and hydraulic residence time) is remarkably quantitative and suited to generalization. The entire limnological research community is united in the opinion that reduction of the supply of phosphate to receiving waters is the only cure against man-made eutrophication. Even in Nrbid waters, such as those found in the southeastern U.S., 100 g of algae (dry weight), derived from about I g of soluble phosphorus, will upon decomposition cause an oxygen deW13936x185i09191013001.5010 0 1985 American Chemical Society
mand of 100-140 g. Phosphate removal in treatment plants is necessary but insufficient because some wastes unavoidably escape treatment; not all households are connected to treatment plants and storm water overflows. It is important to decide whether we should prevent pollutants at the source or rely on some “end of pipe” therapy in a treatment plant. Some states in the U.S. ban the use of phosphates in home laundry detergents. Canada has a federal limit of 2.2% phosphorus. Most European countries have set other limits. In Switzerland, a land of many lakes, the history of Lake Zurich became the first well-documented case of man-made eutrophication; it is a history that has since been repeated in tens of thousands of lakes throughout the world. The Swiss government recently banned phosphates from home laundry detergents. This legislation complements that already in existence requiring chemical phosphate removal in sewage treatment plants. In Japan, detergent makers decided on total re-formulations. As a result, within only two years more than 90% of the detergents produced and sold in Japan are phosphate-free; they contain zeolites instead. It is technologically feasible to manufacture phosphate-free detergents that contain fully biodegradable surfactants. We can have clean shirts and clean water.
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Werner Snimm is a professor at the Swiss Federal lnsfifufeof Technolngy in Zurich and head of ifsLnbnrafory of Wafer resource.^ and WaferPollufinn Confrol (ii&re/or Aqumic Sciences and Wafer Pollurion Conrrol, EAWAG, CH-8600 Dubendorf, Swifzerland). Environ. Sci. Technot.. Val. 19. No. 11. 1985 1013
