Spatio-temporal evaluation of the surface water quality in the middle Nile Delta using Palmer’s algal pollution index

Abstract

This work aims to evaluate the spatio-temporal change in the surface water pollution in the middle Nile Delta using algal pollution index (Palmer Index). Water was sampled during winter and summer seasons from 18 stations distributed along the water pathways from south to north for two main irrigation canals (Qudaba and Mit-yazed canals) and two drains (El-Gharbia main drain and Janag drain). An algal analysis was carried out based on the species and genera that mentioned in Palmer Index (PI). High Palmer Index scores were noticed in most of the stations especially during summer, which might be related to various pollution supplies. Limited number of stations showed low palmer index scores indicating relatively clean water. In winter, the two irrigation canals showed similar spatial distribution patterns where PI values increased reaching its maximum at the middle of water pathways and then decreased. In summer, PI had no definite trend in Qudaba canal and decreasing trend in Mit-yazed canals along the water pathway to the northern direction. PI of El-Gharbia main drain showed increasing and decreasing trends in winter and summer, respectively. Janag drain had opposite patterns compared to that of El-Gharbia main.One of the major differences between irrigation canals and drainage water was the algal community structure where the drainage water was characterized by the abundance of Euglenophyta and Chlamydomonas spp. and rare occurrences of Bacillariophyta except the last station of El-Gharbia main drain, which was of estuary nature.