Evaluation of selected polychlorinated biphenyls (PCBs) congeners and dichlorodiphenyltrichloroethane (DDT) in fresh root and leafy vegetables using GC-MS

Olatunde S Olatunji

doi:10.1038/s41598-018-36996-8

Abstract

Persistent organic pollutants (POPs) are dangerous and toxic pollutants that may cause adverse effects on human and animal health, including death. POPs such as polychlorinated biphenyls (PCBs) and pesticides are subtly released into the environment from industrial and agricultural use. Global circulation is due to their trans-boundary transport capacity, contingent on aerodynamic and hydrological properties. Plants have capacity to take-up POPs, and these bio-magnify along heterotrophic transfer pathways. In this study, levels of selected 6-PCB congeners and 3- DDTs in some leaf and root vegetables were investigated. Leaf and root vegetables were collected from different horticultural farms areas in Cape Town. The 6-PCBs and 3-DDTs were recovered from the samples using solid phase extraction(SPE), followed by GC-MS analysis. The ΣPCBs and ΣDDT (on-whole basis), were ranged: 90.9–234 ng/g and 38.9–66.1 ng/g respectively. The 3-PCBs and 6-DDTs levels were slightly higher in leaf vegetables compared to root vegetables. The detection of PCBs and DDTs in the vegetables suggest the probable use of PCBs containing pesticides. Although the observed concentrations were below the WHO maximum residue limits, consumption of such contaminated leaf and root vegetables portend a health risk.

Highlights

Persistent organic pollutants (POPs) such as pesticides and polychlorinated biphenyls (PCBs), are synthetic substances produced for a wide range of sanitary health, agricultural and industrial uses[1]
Our findings showed that vegetables and crop planted in farmlands within locations near residences and urban centers, especially informal farms in homes, may be exposed to leaked pesticides from home use and arrays other contaminants; many of which are classified as endocrine disruptors and neuro-degenerative substances
Concentrations of the 3-DDTs i.e. DDT and its metabolites DDD and DDE and 6-PCBs congeners in the 7-varieties of leafy vegetable and the 7-varieties of root vegetables collected from different farms were variable

Summary

Introduction

Persistent organic pollutants (POPs) such as pesticides and polychlorinated biphenyls (PCBs), are synthetic substances produced for a wide range of sanitary health, agricultural and industrial uses[1]. Polychlorinated biphenyls (PCBs) consist of 209 low vapour pressure, heat resistant, non-flammable congeners with high dielectric constants, used as heat exchange fluids or as insulating medium in electrical transformers and capacitors. Of these number, 13 congener compounds exhibit dioxin-like properties, and are reported to show extremely high toxicity[5,13,14]. Persistent and bio-accumulative pesticides include many first generation organochlorine (OC) compounds such as 1, 1′-(2, 2, 2-Trichloroethane-1, 1-diyl)bis(4-chlorobenzene) (DDTs), dieldrin, toxaphene and chlordane These compounds were largely used in agriculture for pests and weeds control, in order to maximize produce yield and thereby increase economic gains on the long run. There is need to be concerned about the exposure and levels of PCBs and pesticides in vegetables, since they are a major diet and a transfer pathway

Methods

Results

Conclusion