Assessment of the Polychlorinated Biphenyl (PCB) Occurrence in Copper Sulfates and the Influential Role of PCB Levels on Grapes

Copper sulfates (CuSO 4 ) are widely used as the primary component of fungicides in the grape industry. The agricultural-grade CuSO 4 that we collected from Chinese nationwide markets were found to be contaminated by polychlorinated dibenzo- p -dioxins and dibenzofurans and high levels of polychlorinated biphenyls (Σ 19 PCBs: 0.32~9.51 ng/g). In the following research, we studied the impact of CuSO 4 application on PCB levels in grape products through a field experiment, and conducted a national survey to speculate the role that CuSO 4 played on the occurrence of PCB in grapes. In the field experiment, an obvious increase of PCBs in grape leaves (from 174 to 250 pg/g fw) was observed after Bordeaux mixture (the main component of which is CuSO 4 ) application. As to the main PCB congener in CuSO 4 , the most toxic CB 126 (toxic equivalency factor = 0.1) also increased in grape peels (from 1.66 to 2.93 pg/g fw) after pesticide spray. Both the correlation study and the principal component analysis indicated that environmental factors were dominant PCB contributors to grapes, and grapes from e-waste dismantling area containing the highest PCBs also proved the notion. It is worth noting that this report describes the first research examining PCBs in CuSO 4 and its influence on agricultural products to date.