Gracilaria gracilis as a bioindicator of environmental pollution: Insights into organochlorine pesticide contamination in Marchica Lagoon

¹ Laboratoire de la Lagune Marchica de Nador pour les Sciences Bio-Géo-Physique et Environnement (LOLMAN-BGPE), Faculté Pluridisciplinaire de Nador, Université Mohamed Premier-, Maroc.
² Fishing laboratory regional center of INRH in Nador, Morocco
³ Coastal resource prospecting laboratory regional center of INRH in Casablanca, Morocco
⁴ National Laboratory for Pollution Studies and Monitoring (LNESP), Rabat, Morocco

^* Corresponding author: ouiamelmekki@gmail.com

Abstract

Morocco's Mediterranean shoreline, specifically the Marchica Lagoon, is becoming ever more susceptible to agricultural pressure and pesticide-laden pollution in their aquatic ecosystems. This study explores the bioindicator potential of Gracilaria gracilis to identify organochlorine pesticide (OCP) contaminants. Samples were gathered in summer 2023 from Bouarg, a zone of high-density agriculture. Using the advanced analytical techniques of LC-MS/MS and GC-MS/MS, 320 pesticide compounds were analyzed in G. gracilis. While residues of organochlorine pesticides were found in the surface waters of the lagoon, none of these residues surpassed the pre-established quantification levels. This result questions the degree to which Gracilaria gracilis is capable of absorbing or mirroring pesticide contamination. The physiological characteristics, metabolic pathways, or selective adsorption processes of the species may be involved in lessening their sensitivity to these pollutants. Its usefulness as a bioindicator in this regard, therefore, is doubtful. The received evidence does not uphold, but nor does it entirely rule out, the prospective involvement of G. gracilis to indicate pesticial presence. To ascertain its bioaccumulation potential, more investigation is required utilizing more sophisticated analytical methods and a larger temporal and spatial scope. In order to better protect the delicate ecosystems of the Mediterranean littoral, these findings highlight the necessity of strengthening laws governing agricultural runoff and promoting more sustainable land use practices.