Organic Pollutants in Sewage Sludge: 1. effect of toluene, naphthalene, 2-methylnaphthalene, 4-n-nonylphenol and di-2-ethylhexyl phthalate on soil biological processes and their decomposition in soil

Five organic compounds found in relatively high concentrations in Swedish sewage sludge were added to soil. Additions were made at concentrations both close to those expected from agricultural practices and 100 to 1 000 times higher. None of the compounds reduced soil microbial respiration, but a higher carbon dioxide evolution was measured from soil treated with 500 mg kg-1 nonylphenol. Net nitrogen mineralization was not influenced by any of the compounds added. A short-term inhibition (7 days) of nitrite oxidation to nitrate was found when adding nonylphenol at a concentration of 500 mg kg-1, Naphthalene, 2-methylnaphthalene and nonylphenol decomposed rapidly, more than 90 % was degraded within 10 to 20 days. Most of the toluene volatilized during addition and mixture with the soil. Di-2-ethylhexyl phthalate decomposed much slower with remaining amounts of 15 to 50 % after 80 days.