May 25, 2011 - Trace metals levels in slide and natural biofilms differed very markedly from those in water ... streams, algae-dominant autotrophic biofilms are.
Journal of Biodiversity and Environmental Sciences (JBES) ISSN: 2220-6663 (Print) 2222-3045 (Online) Vol. 1, No. 3, p. 19-26, 2011 http://www.innspub.net RESEARCH PAPER
OPEN ACCESS
Trace metals accumulation in biofilms of the upper and middle reaches of Otamiri river in Owerri, Nigeria Dike Henry Ogbuagu*, Chidiogo Grace Okoli, Enos Ihediohamma Emereibeole, Ikechukwu Chimezie Anyanwu, Osinachi Onuoha, Nkiruka Onyekachi Ubah, Chibueze Oscar Ndugbu, Obinna N. Okoroama, Arthur Okafor, Edu Ewa, Rex Ossai, Favour Ukah Department of Environmental Technology, Federal University of Technology, PMB 1526, Owerri, Nigeria. Received: 11 May 2011 Revised: 25 May 2011 Accepted: 26 May 2011
Key words: Biofilms, otamiri River, microcosm, exceedance times, water column. Abstract This study utilized biofilms as model in ecotoxicology to estimate pollutant loading of a natural water body. Water samples were collected from six sampling locations sited between the upper and middle courses of the Otamiri River in the southeastern city of Owerri, Nigeria and fixed with conc. HNO3. Biofilms were grown in microcosms housing serially arranged sterile glass slides at the sampling locations, harvested after 1, 2 and 3 weeks, minced in sterile sample bottles with distilled water and fixed with conc. HNO 3. Natural biofilms were also collected from submerged surfaces and fixed. Pb, Cu and Cd contents were determined in samples with atomic absorption spectrophotometer. The studentized t-test was used to compare trace metals levels in water column and biofilms, while single factor ANOVA was used to determine spatial homogeneity in mean variance. Mean Pb concentrations ranged from 1.5950-3.2900 (2.4303 ± 0.0835) mg/kg, Cu from 4.2934-7.5020 (5.6212 ± 0.1938) mg/kg and Cd from 0.0308-1.0559 (0.2082 ± 0.0005) mg/kg in the slide biofilms. However, they ranged from 0.0017-0.0267 (0.0150 ± 0.0003), 0.0333-0.6067 (0.2047 ± 0.0929) mg/L and totally undetected, respectively in water columns. Trace metals levels in slide and natural biofilms differed very markedly from those in water column (sig. t-values = 0.000, each), even as levels in slide and natural biofilms did not (sig. t-value = 0.747) at P
