The use of brown mussel as bioindicator of pesticides pollution in Agadir Bay (Southern Morocco)

The rapid expansion of agriculture in the Souss Massa region has been accompanied by a significant increase in pesticide usage to protect and increase crop yields. Unfortunately, these pesticides leave behind residues that can have detrimental effects on both human health and the environment. To investigate the impact of pesticide contamination on the coasts of Agadir Bay, our study focuses on the bivalve Perna perna (Linnaeus, 1758) as a biomonitoring sentinel species. Between autumn 2009 and summer 2010, we conducted measurements of pesticide residue concentrations and assessed two biomarkers of pollution the Glutathion-S-transferase (GST) and acetylcholinesterase (AChE) in the soft tissues of P. perna. These bivalves were seasonally collected from two different locations along the Agadir Bay coast. The results revealed that Glutathion-S-transferase and acetylcholinesterase showed seasonal variations, likely influenced by the species' reproductive cycle. In terms of pesticide concentrations, the levels of organochlorines were found to range from 13.40 to 109.76 ng g⁻¹ of dry weight (dw) for Dichlofluanide, not-detected (ND) to 38.66 ng g⁻¹ dw for Endosulfan S, ND to 15.76 ng g⁻¹ dw for Lindane, ND to 33.66 ng g⁻¹ dw for Fenarimol, and 0.26–35.02 ng g⁻¹ dw for Buperimate. It should be noted that these levels of pesticide contamination are relatively low compared to values reported in similar studies conducted in other regions of the world. The contamination of Agadir Bay by pesticides can be attributed to their extensive use in agricultural practices in the Souss Massa region.