The Impact of Makeshift Oil Refineries on the Macro-Invertebrates of the Nun River Estuary, Niger Delta, Nigeria

Sampling was done in six sampling stations for one year (August, 2014-July, 2015) to investigate the impacts of makeshift oil refineries on the macroinvertebrates of the Nun River estuary in the Niger Delta region of Nigeria after over 3 years of chronic pollution of this estuary by the makeshift refinery activities.There was also a massive destruction of the benthic and mangrove associated macrofauna of the Nun River estuary and its tributaries.18 species of benthic macro-invertebrates distributed among 15 genera and 9 families were recorded during the study.A total of 2, 942 individual organisms were collected in which 41 belonged to the Class Polycheata, 684 belonged to the Class Decapoda (subphylum crustacea), and 2, 217 belonged to the Class Gastropoda.The class Gastropoda, made up of 1 family and 2 species had the highest percentage composition (75.36%) and are the most dominant species of the area, followed by the class Decapoda (23.25%), and Class Polychaeta (1.39%), respectively.About 12 organisms (which were present during the baseline study) were absent during the current study.The biodiversity of the estuary is low.The alteration of the physico-chemical parameters as well as the direct contact with the spilled crude oils which resulted from the makeshift oil refinery activities is responsible for the massive destruction of the macro zoobenthos in the area.