Abstract:
In this study the residual concentrations of sixteen organochlorine pesticides (OCPs) were
analyzed in soils, water, some vegetables (cabbage, tomato, potato, beetroot, and onions) and
wheat irrigated with water from the downstream catchment of the Akaki River in the Oromia
regional state of Ethiopia. Sample preparation and extraction were carried out using standard
procedures (quick easy cheap effective rugged and safe (QuEChERS) multi- residue extraction
and clean up techniques). For vegetables and wheat, a liquid-liquid microextraction procedure
was used for water and a Soxhlet extraction for soil samples and followed by gas
chromatography-mass spectrometry (GC-MS) analysis. From the studied OCPs eight of them
were detected in vegetables, wheat, and water and soil samples. The OCPs found in all studied
samples include alpha-linden (α-HCH), delta-linden (δ-HCH) gamma-linden (γ-HCH),
heptachlor (HC), heptachilorepoxide (HCE), paradichlorodiphenyldichloroethylene (p, p’DDE),
dieldrin,
Endrin,
Para
dichlorodiphenyldichloroethane
(p,
p’-DDD) and Para
dichlorodiphenyltrichloroethane (p, p’-DDT). The concentrations of these OCPs in vegetables
and wheat samples ranged from 0.11 ± 0.01µg/kg (for ES-I) 18.78 ± 0.17 µg/kg (α-HCH) in the
Hechu zone cabbage and Meteli zone samples, respectively. Whereas, in water and soil samples,
the detected concentrations ranged from highest at Dawaratino zone water sample gamma
linden (10.88µg/L), the lowest in meteli zone water sample delta-linden (0.61(0.01) µg/kg) &
highest at mekana zone soil sample endosulfansulphate (ESS) (44.73 (0.33) µg/kg), the lowest in
dawara Tino zone soil sample p, p’-DDE (4.74 (0.12) µg/kg). Indeed, the concentrations of the
OCPs detected in the vegetables and wheat samples analysed were observed to be at alarming
levels, exceeding the maximum residue limits (MRL) set by the EU. ESS was not detected in any
of beetroot and wheat samples. The presence of pesticides residues in the analyzed samples
poses a significant threat to human health. Therefore, continuous monitoring is recommended so
as to regulate the use of these pesticides in the study area.
