Evaluation of anthropic activities impact through the monitoring of aquatic fauna on Oued Lârbaa in Taza City of Morocco

Abstract

The accelerated development of industrial activities in Taza City implies the appearance of new sources of pollution that directly affect the quality of surface water. This is reflected in the structure and biodiversity of the city’s Oueds, particularly Oued Lârbaa, which receives the majority of the pollution load produced. Therefore, the study of the benthic fauna can be an effective tool to characterize the state of the waters of Oued Lârbaa. The objective of our study is to assess the impact of anthropogenic activities on Oued Lârbaa, through the monitoring of physicochemical parameters (hydrogen potential (pH), salinity, conductivity, total dissolved solids (TDS), and oxidation–reduction potential) and biological biodiversity represented by benthic macroinvertebrates at 10 stations, during two periods of the year: a wet period (December 2018) and a dry period (June 2019). The spatial variations of recorded physicochemical parameters, as well as the effect of anthropogenic activities, control the diversity of macroinvertebrates at Oued Lârbaa. In relation to these data, the first stations of our study (S1-S2-S3) are moderately polluted, characterized by an important biodiversity, which includes sensitive species (Crustacea, Trichoptera, Ephemeroptera), and other resistant species (Diptera). The stations S4-S5-S6-S7-S8-S9 and S10 are characterized by a low biodiversity represented mainly by macroinvertebrates that colonize waters of critical quality (Diptera). The statistical study by principal component analysis consisting of a projection of the biological (benthic macroinvertebrates) and physicochemical variables obtained from each of the two study periods on a two-dimensional factorial plane shows the existing correlations between these variables.