Authors: Paul N Diagboya Bamidele I OluOwolabi Kayode O Adebowale
Publish Date: 2015/02/28
Volume: 22, Issue: 13, Pages: 10331-10339
Abstract
In order to predict the bioavailability of toxic metals in soils undergoing degradation of organic matter OM and iron oxides IOs it is vital to understand the roles of these soil components in relation to metal retention and redistribution with time In this present work batch competitive sorptions of PbII CuII and CdII were investigated between 1 and 90 days Results showed that competition affected CdII sorption more than CuII and PbII The sorption followed the trend PbII CuII CdII irrespective of aging and this high preference for PbII ions in soils reduced with time Removal of OM led to reduction in distribution coefficient K d values of ≈33 for all cations within the first day However K d increased nearly 100 after 7 days and over 1000 after 90day period The enhanced K d values indicated that sorptions occurred on the long run on surfaces which were masked by OM Removal of IO caused selective increases in the K d values but this was dependent on the dominant soil constituents in the absence of IO The K d values of the IOdegraded samples nearly remained constant irrespective of aging indicating that sorptions on soil components other than the IO are nearly instantaneous while iron oxides played greater role than other constituents with time Hence in the soils studied organic matter content determines the immediate relative metal retention while iron oxides determine the redistribution of metals with timeWe acknowledge the supports of the World Academy of Sciences TWAS Trieste Italy and the Chinese Academy of Sciences CAS China for the award of CASTWAS Postgraduate Fellowship FR number 3240255024 to PN Diagboya Chief SL Edu/Chevron Research grant Nigeria Conservation Foundation Nigeria late Rebecca A Okoh and VPO Okoh Department of Estate Management Yaba College of Technology Lagos Nigeria
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