“…Various studies have been published in which the carry-over of PCDD/Fs in dairy cows was studied, including studies with single doses of pure (radiolabelled) standards (Jensen and Hummel, 1982;Jones et al, 1987Jones et al, , 1989Olling et al, 1991), or repeated doses of contaminated chemicals like pentachlorophenol (Firestone et al, 1979;Fries, 1999), grass containing background levels (McLachlan et al, 1990;McLachlan and Richter, 1998), grass contaminated by sewage sludge (McLachlan and Richter, 1998), or contaminated feed materials like citrus pulp (Traag et al, 1998) or minerals (Huwe and Smith, 2005). Other studies followed up the depletion of PCDD/Fs on affected farms after removal of the source, like citrus pulp (Malisch, 2000), minerals (Brambilla et al, 2008) or potato peels with kaolinic clay .…”