Health risks associated with pesticides residues in vegetables and soils

Abstract

Applications of pesticides help to increase agricultural productivity. However, their applications on vegetables can be detrimental to the health of consumers. In view of this, the study was conducted to investigate pesticides residues in soils and vegetables and their associated health risks. Cabbage heads, carrot roots, green pepper fruits and lettuce leaves and soils from the vegetable farms were analysed for organophosphates (OPP), organochlorines (OCP) and synthetic pyrethroids (SPP) pesticides. The Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) mini multi-residue method for extracting multi pesticides residues was used and pesticides levels determined using Gas Chromatography-Mass Spectrometry (GC-MS). Correlation between physicochemical properties of soils and pesticide residues levels were determined. OPPs, OCPs and SPPs occurred in all samples. OPPs levels in soils ranged from 0.016 ± 0.01 to 0.059 ± 0.007 mg/kg. OCPs levels in soils ranged from 0.013 ± 0.006 to 0.052 ± 0.002 mg/kg whilst that of SPPs ranged from 0.022 ± 0.005 to 0.074 ± 0.039 mg/kg. Pesticides levels in vegetables ranged from 0.002 ± 0.001 to 0.042 ± 0.004 mg/kg (OPPs), 0.002 ± 0.001 to 0.059 ± 0.002 mg/kg (OCPs) and 0.003±0.001 to 0.064 ± 0.008 mg/kg (SPPs). However, levels of some of the OPPs (Diazinon, Pirimiphos, and Dimethoate), OCPs (Aldrin, Beta Endosulfan, and Dieldrin) were above MRLs sanctioned by USEPA and European Union. The high levels of the pesticides detected indicate that vegetables were contaminated based on the USEPA and EU acceptable maximum residue limits. OPPs (Diazinon, Pirimiphos, Malathion and Dimethoate) and OCPs (Aldrin, Beta Endosulfan, Dieldrin, P‘P‘ DDE and Methoxychlor) detected in soils and the vegetables are banned for use or not registered for use by USEPA and European Union or Ghana EPA. Positive correlations existed between pH, H+, exchangeable cations, clay, moisture contents, organic carbon, bulk density, and total nitrogen, available phosphorus of soils and pesticides levels in vegetables. Thus, soil properties influenced the distributions and levels of pesticides in vegetables. The HQs and HIs of pesticides were below 1. However, continuous consumption of the vegetables could lead to development of certain health risks in consumers due to bioaccumulation in tissues. It is recommended that farmers should be educated on prpper handling and use of approved pesticides and should be educated on negative health issues linked to pesticides application.