Contamination of polychlorinated dibenzo-p-dioxin and dibenzofurans in Jatropha curcas cultivation areas and their transfer from soil to seed in the Ba Vi, Quang Tri, and Trang Bang regions of Vietnam

Abstract

In this study, we investigated the levels of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDF) in soils from Jatropha plantations in three areas that were devastated during the Vietnam War, Ba Vi, Quang Tri, and Trang Bang, and in the Jatropha seeds from Trang Bang. The total toxic equivalent quantity (TEQ) in the soil was 2.1, 4.7, and 4.1 pg-TEQ/g-dry at Ba Vi, Quang Tri, and Trang Bang, respectively. These compounds were mainly of natural origin and were not attributed to “Agent Orange” contamination. The total TEQ in Jatropha seeds from Trang Bang was 1.2 TEQ/g-dry. The negative correlation between the ratios of PCDD/PCDFs in the seeds to those in the soil and the log K_ow (octanol–water partition coefficient) were found to have correlation coefficients (r) of −0.96 and −0.82 (P<0.05), respectively. These results suggest that the main pathway for the transfer of dioxin was root uptake and translocation to the seeds. The Jatropha seeds, however, can be safely used to produce biodiesel fuel.