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Journal of Applied Sciences and Environmental Management
World Bank assisted National Agricultural Research Project (NARP) - University of Port Harcourt
ISSN: 1119-8362
Vol. 22, No. 9, 2018, pp. 1511-1517
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Bioline Code: ja18253
Full paper language: English
Document type: Research Article
Document available free of charge
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Journal of Applied Sciences and Environmental Management, Vol. 22, No. 9, 2018, pp. 1511-1517
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Effect of Oxidation-Reduction Fluctuations on Metal Mobility of Speciated Metals and Arsenic in Bottom Sediments of Middleton River, Bayelsa State, Nigeria
AIGBERUA, AO; TARAWOU, JT & ABASI, CY
Abstract
Speciation and chemical mobility of heavy metals were assessed with a view to provide information on
bioavailability of metals in a sediment matrix in order to account for the vulnerability of sediment dwelling fauna within the
Middleton river ecosystem. Sediment was collected in triplicate from seven locations (five reflecting activities of oil
installations in the study area and two controls). Sediments were collected in the months of March and August 2017 to reflect
the dry and wet seasons respectively. Concentration of metals in each fraction was determined using a GBC Avanta Atomic
Absorption Spectrophotometer. The residual fraction was the most important for Cr with average levels of (49.4%) and
(41.1%) for the dry and wet seasons respectively. Also, the most prevalent fractions of Zn were the residual fractions which
revealed (31.7%) and (42.6%) during the dry and wet seasons respectively. The metalloid (As) had (14.7%) and (13.8%) of
its total concentration bound to the residual and crystalline Fe-oxide fractions during the dry and wet seasons respectively.
The oxidation-reduction potential (ORP) was measured electrometrically using a redox potential meter; ORP ranged from
(+288.67 to +351.33 mV) and (+331.00 to +465.67 mV) for the dry and wet seasons respectively, hence, depicting a fairly
oxidizing sediment environment. Mobility factor of metals depicted (As > Cu > Cr) and (As > Cr > Cu) for the dry and wet
seasons respectively. The effect of oxidation-reduction potential on metal mobility revealed the transportability of chromium
with increasing redox potential while arsenic was barely mobile with increasing oxidation level. Also, zinc mobility
diminished strongly with increasing oxidation-reduction potential.
Keywords
Speciation; chemical mobility; bioavailability; Middleton River
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© Copyright 2018 - Aigberua et al.
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