Short- and long-term temporal changes in soil concentrations of selected endocrine disrupting compounds (EDCs) following single or multiple applications of sewage sludge to pastures

- Sewage sludge or inorganic fertilizer was applied to pasture.
- Soil PAH and PCB concentrations were not altered by sludge treatment.
- Temporal changes in soil phthalate and PBDE differed with season.
- Some soil EDC levels were elevated for more than three weeks after application.

Temporal changes in soil burdens of selected endocrine disrupting compounds were determined following application to pasture of either sewage sludge or inorganic fertilizer. Soil polycyclic aromatic hydrocarbon and polychlorinated biphenyl concentrations were not altered. Changes in concentrations of diethylhexyl phthalate (DEHP) and PBDEs 47 and 99 differed with season but concentrations remained elevated for more than three weeks after application, when grazing animals are normally excluded from pasture. It is concluded that single applications of sewage sludge can increase soil concentrations of some, but not all classes of EDCs, possibly to concentrations sufficient to exert biological effects when different chemicals act in combination, but patterns of change depend on season and soil temperature. Analysis of soil from pasture subjected to repeated sludge applications, over 13 years, provided preliminary evidence of greater increases in soil burdens of all of the EDC groups measured, including all of the PBDE congeners measured.