The eutrophication process of Nador’s lagoon (Morocco) evaluated by the Life Cycle Impact Assessment method

Abstract

The Nador lagoon system of northeastern Morocco represents the largest regional paralic hydro-system between the Mediterranean Sea and the African continent. Due to its importance, this lagoon is one of the five Sites of Biological and Ecological Interest (SIBE) and was classified in 2005 as a protected site by the international Ramsar treatise. The Nador lagoon is subjected to eutrophic impacts due to pollutant releases from a wastewater plant, three major cities, an agricultural site, and to varied inputs carried by rivers draining the lagoon watershed. The NO2-, NO3-, NH4+, and PO43- contents of nine water samples collected during summer and winter times at different places in the lagoon were measured and translated in terms of the Redfield ratio (N/P) and the Aquatic Eutrophication Potential. The analyses show that N/P is less than 16 in terms of the Redfield ratio, which designates N as the limiting factor for the algal growth over the entire lagoon. However, one of the higher N/P ratios was obtained next to the releases of the Beni-Ensar city and near the outlets of the wastewater plant and the nearby Bouaroug creek. The aquatic eutrophication potential of the phosphorus compounds (AEP (P)) is systematically greater than the aquatic eutrophication potential of the nitrogen compounds (AEP (N)), whether in winter or summer, which confirms that nitrogen is the limiting factor for the local algal growth.