ABSTRACT
Huge quantities of wastes which are indiscriminately disposed into uncontrolled
dumpsites and flowing waters around residential areas are generated from Ibadan,
metropolis. These may adversely affect soil, surface- and ground-water qualities and
the fauna. Limited information exists on toxic effects that wastes from these nondesignated
sites have on associated fauna. Earthworms are one of the dominant fauna
in soils and are pollution bioindicators. Therefore this study was designed to
investigate physico-chemical parameters, earthworm diversity and abundance, and
acute toxicity of contaminated-water on some fauna in selected dumpsites in Ibadan.
One-hundred and twenty water samples from streams (Irefin, Gege, Gbagi, Odinjo,
and Omi-Adio) receiving domestic wastes; 60-composite soil samples each from
dumpsites (Ojokondo, Olodo, Moniya, Idi-Ope and Oremeji) and stream banks; 12-
composite soil samples from a control site at University of Ibadan (UI); 72
groundwater samples from wells around the dumpsites and UI were purposively
collected once every two months from March 2008 to February 2010. Earthworms
from top-soil were sampled using 0.25x0.25 m2 quadrat, handpicked, identified and
density determined following standard procedures. Earthworm species’ diversity and
evenness were determined using Shannon-Wiener diversity index and Shannon’s
evenness, respectively. Water samples were analysed for physico-chemical
parameters [including Dissolved-Oxygen (DO), Biochemical-Oxygen-Demand
(BOD), and Chemical-Oxygen-Demand (COD)] and soil samples including lead and
zinc using standard methods and results were compared with NESREA standards.
The 48-hour-LC50 of stream-samples were determined for Cloeon perkinsi (mayfly)
larvae (CP); while 96-hour-LC50 for Rana temporaria tadpoles, Clarias gariepinus
frys (CG1) and fingerlings (CG2) were determined using Probit method. Data were
analysed using descriptive statistics and ANOVA at p=0.05.
Three earthworm species (Eudrilus euginiae, Dichogaster modigliani and
Hyperiodrilus africanus) were identified at UI, streams and dumpsites. Highest
density of Eudrilus euginiae (30.0±13.7/m2) was recorded at UI and this was
significantly different from other sites, while lowest (6.4±2.2/m2) was recorded at
Ojokondo. Highest densities of Hyperiodrilus africanus (32.7±14.6/m2) and
Dichogaster modigliani (40.0±0.0/m2) were recorded at UI and Gbagi, respectively;
while lowest value of 4.0±0.0/m2 was recorded at Irefin and Gege. Eudrilus euginiae
UNIVERSITY OF IBADAN LIBRARY
and Dichogaster modigliani were not found at Gege and Idi-Ope, respectively, while
Hyperiodrilus africanus was not found at Odinjo, Moniya and Olodo. Earthworm
diversity (0.5) was highest in UI and lowest (0.3) at Gege. Earthworms were most
evenly distributed at Odinjo (2.4) and least at Ojokondo (0.8). The DO (mg/L) for
streams ranged from (0.4±0.4) to (2.6±0.6) and were lower than permissible limit for
aquatic life. Lead (260.6±77.7mg/kg, 269.6±46.4mg/kg) and zinc (456.9±69.9mg/kg,
1685.1±420.3mg/kg) values in Gege and Ojokondo soils, respectively were
significantly higher than NESREA limits. In all groundwater samples, BOD
(46.7±21.0mg/L) and COD (154.0±7.0mg/L) exceeded NESREA limits. The 48-hour-
LC50 of stream-water to CP (Irefin, 12.7%; Gege, 8.6%), and 96-hour-LC50 to CGI
(Gege, 0.8%; Gbagi, 2.8%) and CG2 (Gege, 3.3%; Irefin, 0.6%) indicated high
toxicity of the sites.
The low earthworm abundance, poor physico-chemical qualities and high toxicity of
the study sites revealed that the soil, streams and groundwater were polluted in
Ibadan. Consequently, there is need for adequate management and disposal of solidwastes
to prevent further environmental contamination.
ADEWOYIN, O (2021). Earthworm Diversity And Abundance In Selected Dumpsites In Ibadan, And Toxicity Of Contaminated Water On Associated Fauna. Afribary. Retrieved from https://track.afribary.com/works/earthworm-diversity-and-abundance-in-selected-dumpsites-in-ibadan-and-toxicity-of-contaminated-water-on-associated-fauna
ADEWOYIN, OLUTOMI "Earthworm Diversity And Abundance In Selected Dumpsites In Ibadan, And Toxicity Of Contaminated Water On Associated Fauna" Afribary. Afribary, 22 Apr. 2021, https://track.afribary.com/works/earthworm-diversity-and-abundance-in-selected-dumpsites-in-ibadan-and-toxicity-of-contaminated-water-on-associated-fauna. Accessed 23 Nov. 2024.
ADEWOYIN, OLUTOMI . "Earthworm Diversity And Abundance In Selected Dumpsites In Ibadan, And Toxicity Of Contaminated Water On Associated Fauna". Afribary, Afribary, 22 Apr. 2021. Web. 23 Nov. 2024. < https://track.afribary.com/works/earthworm-diversity-and-abundance-in-selected-dumpsites-in-ibadan-and-toxicity-of-contaminated-water-on-associated-fauna >.
ADEWOYIN, OLUTOMI . "Earthworm Diversity And Abundance In Selected Dumpsites In Ibadan, And Toxicity Of Contaminated Water On Associated Fauna" Afribary (2021). Accessed November 23, 2024. https://track.afribary.com/works/earthworm-diversity-and-abundance-in-selected-dumpsites-in-ibadan-and-toxicity-of-contaminated-water-on-associated-fauna