Metal fluxes to the sediments of the Moulay Bousselham lagoon, Morocco

Abstract

The metal content in surface sediments (0-2 cm, 26 samples), in a sediment core (120, 1 cm slices), taken from Moulay Bousselham (Morocco) was investigated. Concentrations of Al, Fe, Mn, Pb, Zn, Cu, Ni, Cr, Cd, As, and Hg were evaluated in surface and cored sediments of Moulay Bousselham lagoon. Significantly high concentrations in lg g -1 dw of Pb (31.7-6.2), Zn (758.9-167), Cu (310.7-22), Ni (96-10.5), Cr (113-18.9), Cd (0.84-0.02), As (1-0.1), and Hg (0.61-0.02) were found in sediment samples from Moulay Bousselham lagoon. Calculated enrichment factors [EF Me = (Me/Al) sample /(Me/Al) background ], using Al as a normalizer, and correlation matrices showed that metal pollution in Merja Zerga of Moulay Bousselham lagoon was the product of anthropogenic sources, while the metal content in Merja Kehla was of natural origins. The results suggest that a major change in the sedimentary regime of the lagoon, associated with internal trapping and re-distribution of heavy metal, has been occurring in the past few decades. The cause would appear to be the construction of a Nador Canal at the lagoon. Probable effects concentrations (PEC) were often exceeded for heavy metals in the lagoon sediments, especially for Zn, Cu, Ni, and Cr, and four stations, stations MZ-11, MZ-12, MZ-13, MZ-14, MZ-16, and MZ-17, had multiple metals at presumptively toxic levels. These comparisons suggest that sediment metal levels in the river are clearly high and probably pose an environmental risk at some stations. The levels of most of the metals were not greatly enriched, a consideration that is of the utmost importance when contamination issues are at stake. Metal concentrations found in Moulay Bousselham lagoon were comparable to aquatic systems classified as contaminated from other regions of the world.

Taxonomic diversity and structure of the molluscan fauna in Oualidia lagoon (Moroccan Atlantic coast)

“…However, these ecosystems are naturally vulnerable and their ecological balance can rapidly change under the influence of natural or anthropogenic factors (Affian et al 2009;Mhamdi Alaoui et al 2010;Maanan et al 2013;Maanan et al 2015;Zidane et al 2008). Molluscan fauna communities are species of benthic macrofauna that are important food sources for economically important fish and shellfish species in most aquatic environments where they are the major secondary producers (Ajao and Fagade 2002).…”

Multivariate analysis of potentially toxic metals in sediments of a tropical coastal lagoon

“…Sediments in tropical lagoon and estuarine systems of developing countries are increasingly studied because they can act as both sinks for potentially toxic metals (PTM), allowing records of past inputs to be reconstructed where no contemporary monitoring data exists, and as sources, with potential impacts on ecosystems and human health (Acevedo-Figueroa et al 2006;Ahmad et al 2010;Alagarsamy 2006;Alaoui et al 2010;El Ati Hellal et al 2011;Fonesca et al 2011;Jara-Marini et al 2008;Li et al 2007;Pereira et al 2010;Vázquez-Sauceda et al 2011;Xu et al 2009;Zourarah et al 2007). Pollutant metals may affect the population directly through contact with contaminated sediment or water and via the food chain.…”

Accumulation of Copper, Lead, Chrome, Cadmium in Some Tissues of <i>Procambarus clarkii</i> in Rharb Region in Morocco

“…The activities identified in the drainage areas particularly the use of copper sulfate in rice agriculture may explain this [1]- [3] (Figures 3-6). Cu was higher than world average at every station along the Merja Zerga [37]. According to Spanish legislation, a maximum limit for heavy metal in edible wet mass of Cu is 20 µg/g (BOE 195, 15/8/1991) [26].…”