Abstract
Many types and large quantities of detergents and hair care products are used in homes. If they are directly discharged into rivers, they may lead to serious pollution of river water, and have hazardous effects on aquatic organisms. Their toxicity was determined by the acute immobilization test using Daphnia magna as 48h-EC50 (concentration required to immobilize 50% of the daphnids at 48h exposure). The most toxic products are fabric softeners and laundry detergents. Shampoos and conditioners are less toxic. A significant difference in the 48h-EC50 values was observed among shampoos, but for the hand dishwashing detergents, less difference in the 48h-EC50 values was observed. The toxicities of detergents and hair care products in home wastewater were evaluated by concentration-48h-EC50 ratio in home wastewater. The laundry detergents group showed the largest concentration-48h-EC50 ratio of 5.9, and the conditioners or shampoos showed the smallest of 0.14 to 0.22. The concentration-48h-EC50 ratio was changed significantly by the selection of household detergents and hair care products with the most or least toxicity. The development of low-toxicity laundry detergent will lead to the reduction of the concentration-48h-EC50 ratio of home wastewater. The effect of popularization of dishwashing machines and conditioning shampoos on wastewater toxicity is also discussed.
