Environmental impacts of phenol pollution on phytoplankton biodiversity at Assiut region, Egypt

Abstract

Phenol is a common organic pollutant in the aquatic habitats. However, its adverse effects on the composition and diversity of phytoplankton are still poorly understood. Phenol can cause toxic effects to different living organisms even at low concentrations. The present study investigated the effect of phenol on phytoplankton diversity and community structure in samples collected from ten polluted sites. The concentration of phenol in the investigated sites were generally higher than 0.05 mg L −1 which is over the allowable limit. The spatial complexity of the microalgal community was investigated using different alpha (α) diversity measures for the largest microalgal groups (Cyanobacteria, The current investigation revealed the spatial variability in phytoplankton assemblage in relation to phenol pollution in different study sites at Assiut region, Egypt. In general, increasing phenol and organic pollution showed to have distinct adverse effects on richness, diversity, evenness, taxonomic diversity, and functional groups of the phytoplankton community as indicated by the dbRDA analysis. The algal pollution index (API) was fluctuated between 1.75 and 3.16, which indicated moderate to high organic pollution as well as it exhibited strong positive correlations with phenol pollution. In vitro phenol toxicity experiment showed that microalgal assemblage was altered as a consequence of short-term exposure to phenol stress. A distinct reduction in richness and biodiversity was mainly correlated to the disappearance of the most sensitive algal taxa. The results of the present study indicated that phenol is a toxic organic pollutant, which can adversely affect ecosystem functioning. Therefore, it is fundamental to monitor phenol pollution using phytoplankton as a bioindicator. Furthermore, proper water treatments are required to remediate phenol and reduce its toxic effects on the environment.