The physico-chemical parameters, composition and abundance of
macrobenthic invertebrates were studied in River Ogbere, from November 2009 to May
2010. Water samples and macrobenthic invertebrates were collected from three selected
sampling sites and analysed using standard methods. The mean biochemical oxygen demand
(106.9 ± 58.25 mg/l), Nitrate (40 ± 30.8 mg/l), dissolved oxygen (4.2 ± 2.16 mg/l) and total
suspended solids (124.02 ± 16.09 mg/l) were not within permissible standard limits suitable
for aquatic life and domestic purposes. Higher concentration of metals was recorded in
sediments than surface water. A total number of 563 individuals of macrobenthic
invertebrates belonging to 27 genera and four phyla were recorded. The dominant
invertebrate in River Ogbere during sampling period was
Chironomus
sp (65.01%). Other
pollution tolerant species encountered were leeches (
Pisciola
, 0.36%) and earthworm
(
Eiseniella
, 1.95%). The River Ogbere could be regarded as polluted since the adverse water
quality has led to presence of mainly pollution tolerant taxa of macrobenthic invertebrates in
the waterbed.
