Organic contaminants in sewage sludge and their ecotoxicological significance in the agricultural utilization of sewage sludge

The screening of sewage-sludge for organic pollutants was carried out in the state of Brandenburg, Germany. Samples were taken both in summer and winter. The waste water treatment plants were classified in three groups depending on the types of sewage treated (domestic, municipal and industrial waste water). The content of polychlorinated terphenyls, naphthalenes, chloropesticides, halogenated hydrocarbon solvents, aromatic hydrocarbon solvents (BTEX), chlorobenzenes, polyaromatic hydrocarbons, phenols, chlorophenols, phthalates, petroleum hydrocarbons, surfactants, organotin compounds and 2,4-dichloroaniline was estimated. Data from terrestrial ecotoxicology were used to estimate tolerable levels of soil contamination. This yields the so-called “standard values” for concentrations of organic pollutants in sewage sludge. The concentrations of most pollutants in sewage sludge were found to be below the standard value. However, surfactant and toluene concentrations exceeded the standard value.