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

Xiaomin Li,Xiaoou Su

doi:10.1371/journal.pone.0144896

Abstract

Copper sulfates (CuSO4) are widely used as the primary component of fungicides in the grape industry. The agricultural-grade CuSO4 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 (Σ19PCBs: 0.32~9.51 ng/g). In the following research, we studied the impact of CuSO4 application on PCB levels in grape products through a field experiment, and conducted a national survey to speculate the role that CuSO4 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 CuSO4) application. As to the main PCB congener in CuSO4, 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 CuSO4 and its influence on agricultural products to date.

Highlights

Both polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are known as notorious persistent organic pollutants (POPs) and were listed into the Stockholm Convention [1]
Wang et al reported that levels of PCDD/Fs in CuSO4 were in the range of 8.58~41.2 pg/g, and toxic equivalent (TEQ) values were 0.35~3.92 pg WHO-TEQ g-1, and those compounds came from polluted hydrochloric acid [10]
The results showed that S19PCB levels slightly decreased from 102 to 86.3 pg/g

Summary

Introduction

Both polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are known as notorious persistent organic pollutants (POPs) and were listed into the Stockholm Convention [1]. The concise structure of these chemicals, two benzene rings modified with chlorine and linked directly or with an ether bond, makes them highly stable and likely to be generated during organochlorine-related chemical industry [2,3]. The toxicity of PCBs, especially dioxin-like PCBs (dl-PCBs), is similar to PCDD/Fs. The PCBs are collectively referred to as dioxin-like compounds, and toxic equivalent (TEQ) has been adopted to assess the health risk aroused by PCDD/Fs and dl-PCBs [4]. It has been determined that the levels of PCBs are generally orders of magnitude higher in the environment than PCDD/Fs due to their high-volume production [5,6,7].

Methods

Results

Conclusion