Format

Send to

Choose Destination
See comment in PubMed Commons below
Environ Sci Technol. 2013 Mar 19;47(6):2831-8. doi: 10.1021/es3022107. Epub 2013 Feb 22.

Modeling rhizotoxicity and uptake of Zn and Co singly and in binary mixture in wheat in terms of the cell membrane surface electrical potential.

Author information

1
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing 210008, China.

Abstract

The usually negative, but variable electrical potential (ψ0) at the cell membrane (CM) surface influences the surface activities of free ions and the electrical driving force for the transport of ions across the CM. The rhizotoxic effects and uptake of Zn(2+) and Co(2+) singly and in binary mixture in wheat ( Triticum aestivum L.) at three pH values (4.5, 5.5, or 6.1) were examined in terms of the free ion activities of Zn(2+), Co(2+), and H(+) at the CM surface (these ions are denoted {M(n+)}(0)). Toxicity and uptake of Zn(2+) or Co(2+) singly to roots were better correlated with {M(2+)}(0) than with their bulk-phase activities. Studies of toxicant interactions using the electrostatic approach and a response-multiplication model for toxicant mixtures indicated that {Co(2+)}(0) significantly enhanced the toxicity of {Zn(2+)}(0), but {Zn(2+)}(0) did not significantly affect the toxicity of {Co(2+)}(0). {H(+)}(0) substantially enhanced the toxicity of both metal ions. Taking ψo into account improved the correspondence (denoted r(2)) between observed and predicted uptake of both Zn(2+) and Co(2+), and each inhibited the uptake of the other. Results showed that r(2) increased from 0.776 to 0.936 for Zn uptake and improved from 0.805 to 0.951 for Co uptake. Thus electrostatic models for metal toxicity and uptake proved superior to models incorporating only bulk-phase activities of ions.

PMID:
23405885
DOI:
10.1021/es3022107
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for American Chemical Society
    Loading ...
    Support Center