Influence of atmospheric exposure period on the concentrations of polychlorinated dibenzo‐p‐dioxins, dibenzofurans and coplanar polychlorinated biphenyls (dioxins) in forage

Abstract

AbstractThe correlation between the period of atmospheric exposure and dioxin concentration in forage was examined to confirm whether a dioxin accumulation effect could be found in forage. Because it was clear from a previous study that most of the dioxins in forage originated from the atmosphere, if there was a dioxin accumulation effect, there would be a correlation between the concentration of dioxins in the forage and the period of atmospheric exposure. Alfalfa and Sudangrass were grown in two separate areas. The forage in one area was not cut during cultivation, whereas the forage in the other area was cut and allowed to regrow several times. The concentrations of dioxins in samples of uncut forage were compared with the concentrations of dioxins in samples of regrowth forage. There was no tendency in dry samples for a higher dioxin concentration to be associated with longer exposure to the atmosphere. No correlation was found between the concentration of dioxins and forage growing period; in other words, the atmospheric exposure period and the dioxin concentrations were unrelated. These results show that the dioxin accumulation effect does not occur in forage. Furthermore, it would not be possible to decrease the level of dioxins in forage by adjusting the cultivation period.