Effect of physico-chemical parameters on distribution of macrobenthic invertebrates at Rosetta branch the heaviest polluted area of Nile River

Abstract

Rosetta branch considered the most polluted area of Nile River especially the region from Kanater city to kafr Elzayat city. Six stations selected longitudinally at this region for collection of water and macrobenthic invertebrates. Samples were collected during the period from August, 2019 to April, 2020. Some heavy metals were measured to evaluate the degree of pollution in the studied sites. Macrobenthic invertebrates (MBI) comprised 18 species belong to three phyla; phylum Annelida (5 species), phylum Mollusca (10 species), phylum Arthropoda (2 species). Annelida was the abundant group, where it represented 98 % of the total MBI with an annual average of 28887 Org./m 2 .The highest number of MBI was observed at site 4 (Tamalay) with a value of (8514 Org./m 2 ), while the lowest one (45 Org./m 2 ) was recorded at site 2 due to the effect of El-Rahawy drain. The correlation depending on Principlal Component Analysis and biological indices showed that, water temperature, nitrie, nitrate, pH, transparency and DO had a significant positive correlation with MBI. Cadmium showed a significant positive correlation with the most dominant macrobenthic invertebrates groups and species. The study recommended that, the water discharged from El-Hahawy drain should treated.