Rapid mineralization of the endocrine-disrupting chemical 4-nonylphenol in soil

The persistence of the xenoestrogenic compound 4-nonylphenol in agricultural, noncultivated temperate, and Arctic soils was assessed in laboratory microcosm incubations. At 30°C, [ring-U-14C]4-nonylphenol was rapidly mineralized without a lag in six soils tested. A sandy loam agricultural soil was chosen for more detailed study. The 4-nonylphenol mineralization did not occur in autoclaved soil. The response of 4-nonylphenol mineralization to variation in temperature and moisture content was consistent with an aerobic biological mechanism of degradation. Mineralization of [ring-U-14C]4-nonylphenol was rapid in the concentration range of 1 to 250 mg/kg soil. Sludge solids did not inhibit 4-nonylphenol mineralization, although sewage sludge at high concentrations was inhibitory, apparently because of high biological oxygen demand. Gas chromatographic-mass spectrometric analyses of extracts prepared from soil incubated with commercial nonylphenol indicated that all detectable isomers were degraded. In summary, these results indicate that microorganisms that can metabolize 4-nonylphenol are found in a wide variety of soils, including two originating from the Canadian Far North, which presumably have not been exposed anthropogenically to this chemical. We conclude that 4-nonylphenol should be generally biodegradable in well-aerated arable soils.