Wadi estuary sediments on the Moroccan Mediterranean coast: an assessment of the impact of heavy metals using phytotoxicity and genotoxicity

Abstract

To evaluate the genotoxicity in the Loukkos River estuary, chemical and toxicological analyses were performed on water and sediments collected from six wadis. Heavy metal contents (Cr, Cu, Ni, Zn, Cd, Fe, and Pb), germination tests in lettuce, turnip, and alfalfa as well as micronucleus assay of Vicia faba were performed to assess phytotoxicity and genotoxicity. This study revealed that the Souani wadi had the highest concentration of Pb and Fe, and the highest concentrations of Zn, Cu, and Cd were recorded at the Aliane wadi. The heavy metal content in surface sediments is characterised by a high abundance of Fe followed by Zn and a low abundance of Cd in all river sediments studied. The germination index in water and sediment samples overreaches 80% in some cases. The highest mitotic index reaches 8.29% in the Souani wadi with a minimal value noted in the Oued el Maleh wadi (3.47%). The lowest micronucleus frequency is observed in the Martil wadi (1‰) and the highest value was noted in the Oued el Maleh (16.86‰), which reveals the genotoxic effect related to high levels of metals and salinity. These results support the use of micronucleus in V. faba as a tool in effectively monitoring genotoxicity in estuary.