Effect of Sewage Sludge on Accumulation of Persistent Organic Pollutants in Soils

A pot experiment was carried out of Trifolium pretense and different soils treated with different types of sewage sludge.Three kinds of organic pollutants,including 19 compounds,such as polychlorinated biphenyls(PCBs),organochlorine pesticides(OCPs)and polycyclic aromatic hydrocarbons(PAHs),in the soils were systematically analyzed with the GC and HPLC techniques to investigate effects of the sludges on accumulation of organic pollutants in the tested soils.OCPs dominated in the soils and PCBs,PA,and B[a]P followed.Strongly carcinogenic B[a]P was detected in all the soils,but far below the criteria in the soil standards of Canada(0.1 mg/kg)and the Netherlands(0.025 mg/kg).The contents of PA in the soils were much higher than B[a]P,but still below the criteria of the soil standards of Canadian(0.1 mg/kg)and onty the contents of some individuals were high than criteria in the soil standards of the Netherlands(0.045 mg/kg).Application of sewage sludge in farmland will lead to soil pollution with organic pollutants to a varying degree.Pollution degree is closely related to properties of sewage sludges,chemical compounds and soils.