Assessment of the environmental impact of discharges from fishmeal factories located in Levrier Bay, Nouadhibou-Mauritania

Abstract

Levrier Bay, located in the western part of Mauritanian Cost, has a strategic position in Mauritania’s fish economy and reproduction environment. Recently, fishmeal factories have multiplied in the bay. This study was carried out in Levrier Bay. It is the first one in this area which is interested in assessing the environmental impact of fishmeal factory discharges by measuring several parameters such as suspended matter, chemical oxygen demand (COD), biological oxygen demand (BOD), conductivity, turbidity, and salinity. A total of 27 samples were collected at 9 sites distributed on the link between effluents from factories and the Atlantic Ocean (discharge site). Results show that some parameters are over permissible values, like suspended matter content (SS), which reached 2020 mg. L.-1 level. The turbidity measure shows excessively high values (50 to 961 mg.L.-1); impacted by effluents at the reject point, the seawater conductivity and salinity are particularly low (4.53 to 188.2 and 13 to 56.4, respectively). The total organic carbon (TOC) values ranged from 200 to 780 mg/L, whereas the highest measured level of chemical oxygen demand was 4010 mg.L.-1 Biochemical oxygen demand content ranged from 685 to 961 mg/L. The biodegradability index (COD/BOD) shows that these effluents are not easily biodegradable because the index > 3.