The Influence of Abattoir Wastes on Macroinvertebrate Distribution in River Idemili, Obosi, South-Eastern Nigeria

Abstract

The influence of abattoir wastes on macroinvertebrates distribution in River Idemili, South-Eastern Nigeria, was studied. Three sampling stations 1, 2 and 3 representing upstream of the impacted site, impacted site and downstream of the impacted site respectively were selected. The water quality characteristics, which were significantly different (p<0.05) among the study stations, include water temperature, conductivity, dissolved oxygen and biochemical oxygen demand and phosphatephosphorus. There was no significant difference (p>0.05) in the levels of pH and nitrate-nitrogen among the study stations. Thirteen taxa composed of 201 individuals were encountered. Station 1 had the highest taxa (13) species, as well as the number of individuals (92, 45.8%), followed by station 3 with 12 species and 64 (31.8%) individuals. Station 2 had the least diversity and abundance of 6 species composed of 45 (22.4%) individuals. Macroinvertebrate abundance in the study stations were significantly different (p<0.05). Arthropoda (54.7%) was the dominant phylum. Chironomids (Family: Chironomidae) dominated the samples at all the study stations. Coleoptera was completely absent at the impacted site due to organic pollution. Margalef’s species richness and Shannon Wiener index for general diversity were the highest in stations 1 and 3. The low macroinvertebrate abundance, species richness and Shannon diversity index in station 2 may be attributed to the decimating impacts of abattoir wastes entering the water in this station. Renkonen’s number calculated for pairs of stations revealed that stations 1 and 3 were significantly similar, while stations 1 and 2, 2 and 3 were dissimilar. Conclusively, abattoir wastes distort water quality and affect the community structure, composition, distribution and abundance of macroinvertebrates inhabiting aquatic ecosystems.