The influence of application form on the toxicity of nonylphenol to Folsomia fimetaria (Collembola: Isotomidae).

The Collembola Folsomia fimetaria L. was exposed in the laboratory to a range of elevated soil and sewage sludge nonylphenol concentrations under three different contamination scenarios. When F. fimetaria were exposed to nonylphenol-spiked soil in a standard test design, a 10% effect concentration (EC10) of approximately 23 mg NP/kg was observed for reproduction. One of the primary sources of nonylphenol to agricultural soils is sewage sludge. Upon addition of nonylphenol to sewage sludge prior to homogeneously mixing this into the soil a 10% effect concentration (EC10) of approximately 6 mg NP/kg soil was observed for reproduction. Within soil core sewage, sludge is often not homogeneously distributed, but rather patchily distributed, enabling organisms to avoid it. To mimic the patchy distribution of sewage sludge, NP-contaminated sewage sludge pellets were distributed in noncontaminated soil and F. fimetaria were exposed to it. Exposed to the contaminated sewage sludge pellet F. fimetaria were affected by nonylphenol concentrations above approximately 19 mg NP/kg soil for reproduction. In this case the dose-response curve was considerably less steep than those of the two above exposure regimes.