According to its high production and value, Akkar is considered as the second agricultural region in Lebanon. Groundwater constitutes the principal source of water in Akkar including drinking water of local inhabitants in Akkar. As such, the contamination of groundwater by organic pollutants can impact directly the population health. In this study, we evaluated the contamination status of groundwater in this region. Three classes of pesticides including 19 organochlorine (OC) pesticides, 8 organophosphorus (OP) pesticides, and 6 organonitrogen (ON) pesticides were monitored in 15 groundwater samples collected from different villages on the Akkar plain. Samples were extracted by using solid phase extraction (SPE) and analyzed by gas chromatography coupled with mass spectrometry (GC-MS). The results showed high contamination of Akkar groundwater by OCs with levels that can reach 58.9 μg/L. They were detected in the majority of the sample and represent 95-100% of ∑pesticides. Our results showed the recent use of these molecules with an average level of 0.3 and 0.39 μg/L for ∑HCHs and DDTs, respectively. Their concentrations were higher than those observed in the same region in 2014 and other regions elsewhere. OPs were also detected at high levels and among them, methylparathion was the predominant OP detected (44.6 μg/L). For ONs, lower levels were measured in all samples with a mean value of 5.6 μg/L. As a conclusion of this work, groundwater on the plain of Akkar was remarkably contaminated by the studied pesticides; indefinitely, more efforts should be taken to manage the pesticide use in this region, assess, and reduce their effects on human health. In the future, the application of organic farming can be a great solution to the groundwater contamination problem.
Keywords: GC-MS; Groundwater; Organochlorine pesticides; Organonitrogen pesticides; Organophosphorus pesticides; SPE.