Influence of irrigation on the occurrence of organic and inorganic pollutants in soil, water and sediments of a Spanish agrarian basin (Lerma)

Abstract

In order to understand the several possible environmental impacts caused by irrigation, the existence of a study area under transition from unirrigated to irrigated land is a great advantage. This work investigates the presence of 44 pesticides and metabolites, 11 organochlorinated compounds, 17 polycyclic aromatic hydrocarbons (PAHs), 13 polychlorinated biphenyls (PCBs), and several metals and metalloids such as Cd, Cr, Cu, Ni, Pb, Zn, As, Se and Hg, in the soil, water and sediments of an agrarian basin in Northeast Spain. The study area was unirrigated until 2006, when irrigation began. The objective of this work was to verify if the first irrigation years influenced the concentrations of the substances and elements analyzed. The main contaminants detected were organochlorinated compounds, PAHs and metals in the soil; atrazine, desethylatrazine, terbuthylazine, dicofol and pp’-DDT in the water; and PAHs, 1,2,4 trichlorobenzene and metals in the sediments. Until the conclusion of this study, no serious contamination issues existed related to the analyzed substances, and for the moment, irrigation has not signif icantly influenced the concentrations of such substances in the basin. Nevertheless, slightly elevated punctual values were observed for endrin in the soil, pp’-DDT in the water, and Ni and Zn in the sediments.