DEVELOPING HUMAN HEALTH-RELATED CHEMICAL GUIDELINES FOR RECLAIMED WASTE-WATER IRRIGATION

We examined the methodology of developing globally applicable human he alth-related chemical guidelines of using wastewater for crop irrigati on. Two approaches may be used to develop pollutant loading guidelines : (a) preventing pollutant accumulation in waste receiving soil and (b ) maximizing soil's capacity to assimilate, attenuate, and detoxify ha rmful chemicals. Pollutant loading rates based on the first approach a re in agreement with the fundamental principle of maintaining ecologic al balances in soil. But numerical limits usually are very stringent a nd it is difficult for communities to meet these requirements. Recomme ndations derived with the second approach represent the maximum permis sible loadings beyond which pollutant levels in the soil may be harmfu l to the exposed population. A method employing the second approach wa s evaluated. Preliminary pollutant loading limits for land application of wastewater are derived by considering the food chain transfer of p ollutants via intake of grain, vegetable, root/tuber, and fruit grown on wastewater-affected soils. Copyright (C) 1996 IAWQ Published by Els evier Science Ltd.