Rapid mineralization of the endocrine-disrupting chemical 4-nonylphenol insoil

The persistence of the xenoestrogenic compound 4-nonylphenol in agricultura l, noncultivated temperate, and Arctic soils was assessed in laboratory mic rocosm incubations. At 30 degrees C, [ring-U-C-14]4-nonylphenol was rapidly mineralized without a lag in six soils tested. A sandy loam agricultural s oil was chosen for more detailed study. The 4-nonylphenol mineralization di d not occur in autoclaved soil. The response of 4-nonylphenol mineralizatio n to variation in temperature and moisture content was consistent with an a erobic biological mechanism of degradation. Mineralization of [ring-U-C-14] 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 b iological oxygen demand. Gas chromatographic-mass spectrometric analyses of extracts prepared from soil incubated with commercial nonylphenol indicate d that all detectable isomers were degraded. In summary, these results indi cate that microorganisms that can metabolize 4-nonylphenol are found in a w ide 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.