Copper mobilization

Iron-reducing bacteria from a copper-contaminated sediment were more tolerant of copper adsorbed to hydrous ferric oxide (HFO) than were pristine-sediment bacteria (Markwiese et al. 1998). Copper-tolerant bacteria were more efficient in reducing contaminated HFO, with greater potential for copper mobilization in aquatic sediments (Markwiese et al. 1998). 

Markwiese, J.T., J.S. Meyer, and PJ.S. Colberg. 1998. Copper tolerance in iron-reducing bacteria implications for copper mobilization in sediments. Environ. Toxicol. Chem. 17 675-678. 

Temminghof, E., van der Zee, S., De Haan, F. (1997). Copper mobility in a copper-contaminated sandy soil as affected by pH and solid and dissolved organic matter. Environmental Science Technology, 31, 1109-1115. 

This can be rationalized by noting that the sulfate head groups have some affinity for Cu(II) and may be decreasing the copper mobility through complexation. In any case the affect is not large. When HTAC or HTAB are added it is clear from the rate Increases that a mechanism which relys only on a random encounter in the Interphase is no longer applicable. Insight into the rate enhancement process can be obtained if we compare the stability for the formation of CuBr and CuCl. Log 64 for the reaction ... 

With PIXE (particle-induced X-ray emission analysis) or SYXEA (synchrotron radiation X-ray emission analysis) it is possible to study copper in the amniotic fluid (Napolitano et al. 1994) and copper mobilization in the root tips (Knbchel... 

As for the exchangeable fractions of cadmium, the influence of the microbial effect was same for the soils under the influence of root exudates (Fig. 11) and root pad (Fig. 12), for example, microbial activity facilitated the mobilization of cadmium in the soil rhizosphere ( + and bars). Even though both root pad and addition of root exudate caused increases in the exchangeable copper fractions (as shown by -I- in Figs. 11 and 12), the effects of microbial activity were in opposite directions in the two cases. It appears that microorganisms inhibited the copper mobilization in the rhizobox but accelerated the change in the soil receiving root exudate. 

The function of ceruloplasmin in the mammalian organism is presently unknown although there have been suggestions that it is required for the efficient incorporation of iron into transferrin (103), and that it is an essential component of copper mobilization (104—106). These have been the subject of considerable debate (107, 108 and references therein), and will not be of further concern here. 

Although concentrations in soils did not exceed the geochemical background, zinc turned out to be more mobile than copper. Mobile (fraction 1) and exchangeable (fraction 2) fractions of both metals corresponded very well with each other, reflecting first of all soil texture and the clay content. However, while fractions 4 and 2 were the main fractions of copper in most soils, the predominant concentrations of zinc were found in fractions 7 and 6, in sandy soils in fractions 6 and 2. Detailed results of metal speciation are presented in Tables 6.4-6.6 (on the following pages). 

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