Phosphate is used in a detergent to bind calcium and magnesium ions. These would otherwise bind to the surface-active agents that are intended to dissolve dirt and the surface-active agents thus lose their action. Phosphate also prevents dirt from getting stuck on the washing goods and to form lime deposits in the washing machine. It is what is called a softener or builder.
Phosphate is a nutritive for algae and other plants when washing water is released to lakes and streams. The growth can be so large that the natural degradation is insufficiently fast and therefore an oxygen defiency will arise, something that has an influence on all other lifes in the water. Phospahtes in detergents for consumers were banned in Sweden from 1 March 2008.
Detergent and dishwashing powder quantities
Source: Products Register, KemI.
125 companies have reported that they manufactured or imported detergents for washing textiles during 2008. The total amount used was about 50,000 tonnes of detergents of which 84 per cent was imported. There were 613 different detergents during this year out of which 270 were intended for consumers. The latter products account for 85 per cent of all detergents.
Dishwasher powder was imported or manufactured by 77 companies. There were 258 different dishwasher powders of which 78 were sold to households. About 50 per cent of the dishwasher powder amount, 7,000 tonnes, was intended for industrial use.
Sodium tripolyphosphate in detergents and dishwasher powders
Source: Products Register, KemI.
During the end of the 1980s the annual use of sodium tripolyphosphate by Swedish households was estimated to be over 12,000 tonnes. In many detergents phosphates have since then been substituted by other softeners, for example carboxylates like citrates and gluconates or by zeolites.
The chart above clearly shows how the amount of phosphates decreased when the ban came into force on 1 March 2008.
Number of detergents classified as dangerous to health
Source: Products Register, KemI.
Sodium tripolyphosphate is neither dangerous to health nor to the environment. However, other ingredients in a detergent can make the product irritating in contact with skin or eyes. Many more detergents than a few years ago are now labelled with a warning of this danger.
