Umwelt- und analytische Toxikologie

Phytoplankton Determination of the Trophic Status and Portability of Aiakhuakhuari River, Benin City, Edo State, Nigeria

Abstract

Raymond Sunday Ezenweani, Mabel Amen Akhere, Catherine Olamiposi Ikudaisi

A limnological study of phytoplankton composition of Aiakhuakhuari river in Oredo local government area was carried out for six months to assess the water quality using phytoplankton composition of the river. Three sampling stations were chosen and phytoplankton samples were collected (using 55 μm plankton net) and values for air temperature, water temperature, pH and total dissolved solids were estimated in situ. A total of 135 phytoplankton species were identified comprising 4 divisions namely; bacillariophyta, Chlorophyta, euglenophyta and cyanophyta. Bacillariophyta, which was represented by two orders (centrales and pennales), dominated the phytoplankton taxa, of which they accounted for 45.92% of the total phytoplankton composition. The division Chlorophyta made the second highest contribution (38.52%), with bulk belonging to the order Zygnematales. The euglenophyta was represented by one order (Euglenales) and three genera (Euglena, Trachelomonas and Strombomonas) contributed 8.89%, while cyanophyta made the least contribution (6.67%) and had 4 genera (Dactylococcus, Oscillatoria, Phormidium and Anabaena). The high and low relative abundance of bacillariophyta and cyanophyta respectively, indicate that Aiakhuakhuari river is not polluted, oligotrophic and low in productivity. The physic chemical parameters also showed that the river was not polluted when compared with WGO and SON standard for portable water. It recommended that there should be routine check on the portability of all sources of portable water for safety and health sustainability.