Water Quality and Plankton Assessment of Eme River, Umuahia, Southeast Nigeria

Abstract

Abstract Certain anthropogenic activities have negative impacts on the aquatic ecosystems. Plankton are sensitive to their environment and are used to monitor anthropogenic impacts. A South-eastern Nigeria River was studied from December 2017 to November 2018 in 6 stations; to assess the plankton community, water quality and anthropogenic impacts. The river was subjected to intense sand mining activities among other activities. The plankton was sampled with filtration method while water was collected and analysed using standard methods. A total of 36 phytoplankton species and 27 zooplankton species were recorded with Chlorophyceae and Rotifers being the most abundant groups. The most abundant species - Melosira granulata (phytoplankton) and Daphnia pulex (zooplankton) are pollution indicators. Some of the physicochemical parameters showed that the river was perturbed by the anthropogenic activities in the watershed. However, the plankton assemblage and community structure gave an indication of a stable environment; though the zooplankton fauna showed some level of stress. The impacts of sand mining activities on water quality and plankton were more in the downstream stations (4–6) where sand mining was intense while perturbation from swimming children and related activities were observed in station 1 especially during the dry season. The presence of eutrophic indicators and tolerant species showed that the river was tending towards eutrophication. Sand mining activities contributed to the nutrient enrichment of the river. CCA showed the major water quality parameters that influenced the plankton community structure. There is need to regulate illegal sand mining activities in the river.