Laundry detergents as a source of heavy metals in Irish domestic wastewater.

Concentrations of Cd, Cu and Zn in 175 detergent samples representing twenty-one brands of washing powders were analysed. Mean concentrations of 3.03 (+/- 0.50) microg Cd/g, 2.61 (+/- 1.22) microg Cu/g and 15.23 (+/- 7.26) microg Zn/g were recorded. The concentration of cadmium was much lower than previously reported. The daily contribution of metals from laundry washing are in the order of 54.5 microg Cd/ca/d, 47.0 microg Cu/ca/d and 274.1 microg Zn/ca/d. In Irish municipal wastewater the contribution from detergents of these metals are 31.9% for Cd, 0.24% Cu and 0.30% for Zn. This has important implications for sewage sludge disposal.