1 Department of Agroecology - Soil Fertility, Department of Agroecology, Science and Technology, Aarhus University2 Department of Agroecology - Climate and Water, Department of Agroecology, Science and Technology, Aarhus University3 Department of Geochemistry, University of Copenhagen4 Sektion, Food Safety and Zoonoses5 Department of Pharmacy, University of Copenhagen,6 Department of Agroecology - Climate and Water, Department of Agroecology, Science and Technology, Aarhus University7 Department of Agroecology - Soil Fertility, Department of Agroecology, Science and Technology, Aarhus University
The redistribution and fate of contaminants in pig slurry after direct injectionwere investigated at two field sites, Silstrup (sandy clay loam) and Estrup (sandy loam), in Denmark. Intact soil samples were collected for up to seven weeks after slurry injection and concentrations of Salmonella Typhimurium Bacteriophage 28B (phage 28B), Escherichia coli, steroid hormones and other slurry components (water, volatile solids, chloride and mineral N) determined in and around the injection slit. The two experiments at Silstrup and Estrup differed with respect to slurry solid content (6.3 vs. 0.8%), as well as soil clay content (27 vs. 15%) and differed considerably with respect to the initial redistribution of slurry-borne contaminants in soil. The transport of microorganisms from the slurry injection slit to the surrounding soilwasmuch lower than that of mineralN and chloride due to attachment and entrapment. The redistribution of E. coli was more affected by site-specific conditions compared to phage 28B, possibly due to the larger cell size of E. coli. The overall recovery of phage 28B was 0.8–4%, and of E. coli 0.0–1.3% in different samples, by the end of the study. Nine different steroid hormones were detected in the slurry slit, and a slow redistribution to the surrounding soil was observed. Overall recovery of estrogens was 0.0 to 6.6% in different samples. The study showed that the combination of soil and slurry properties determined the initial spreading of contaminants, and hence the potential for subsequent leaching.
Science of the Total Environment, 2014, Vol 466-467, p. 1003-1010