Abstract

In this report a method is proposed for the derivation of standards for the concentrations of organic contaminants in organic fertilizers which are used on agricultural land. The method is based on the premises that the long-term accumulation level of contaminants in soil, may not cause a risk for the terrestrial ecosystem. Therefore, the estimated long-term accumulation level in soil of these compounds, determined by the annual addition and the half-life in soil, may not exceed the target values. As a first application of the above described method, standards for the concentrations of a number of organic micro contaminants in sewage sludge and compost are proposed. Besides that also standards for contaminants in very clean-compost and black soil are proposed. Because by the Dutch law very clean compost and black soil are considered as soils, which as any other soil have to meet the requirements of the target values in soil, the standards for very clean compost and black soil are considerably lower than those for sewage sludge and compost. The organic contaminants were selected because of their persistent character in soil.