M. Haitzer
J. N. Ryan
K. Nagy
George Aiken
Boutron C.Ferrari C.
G. Aiken
2003
<p><span>Experiments were conducted using organic matter isolated from various surface waters in the Florida Everglades to study the interactions between dissolved organic matter (DOM) and Hg (II). Conditional distribution coefficients ( </span><img src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img1.gif" border="0" alt="$K_{DOM^\prime}$" width="49" height="26" align="MIDDLE" data-mce-src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img1.gif"><span>), obtained using an equilibriurn dialysis ligand exchange method, were strongly affected by the Hg/DOM concentration ratio. Very strong interactions ( </span><img src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img2.gif" border="0" alt="$K_{{\rm DOM}^\prime}$" width="46" height="26" align="MIDDLE" data-mce-src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img2.gif"><span> = 10 </span><img src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img3.gif" border="0" alt="$^{23.2 \pm 05}$" width="43" height="15" align="BOTTOM" data-mce-src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img3.gif"><span> L kg </span><sup>-1</sup><span>), indicative of Hg-thiol bonds, were observed at Hg/DOM ratios below approximately 1 </span><img src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img4.gif" border="0" alt="$\mu$" width="11" height="25" align="MIDDLE" data-mce-src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img4.gif"><span>g Hg per mg DOM. Above approximately 10 </span><img src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img4.gif" border="0" alt="$\mu$" width="11" height="25" align="MIDDLE" data-mce-src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img4.gif"><span>g Hg per mg DOM much lower </span><img src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img2.gif" border="0" alt="$K_{{\rm DOM}^\prime}$" width="46" height="26" align="MIDDLE" data-mce-src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img2.gif"><span> values ( </span><img src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img5.gif" border="0" alt="$10^{10.7\pm 05}$" width="57" height="14" align="BOTTOM" data-mce-src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img5.gif"><span> L kg </span><sup>-1</sup><span>) were obtained. DOM-Hg interactions were also studied by HgS (log K </span><img src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img6.gif" border="0" alt="$_{\rm sp}=-52.4$" width="68" height="25" align="MIDDLE" data-mce-src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img6.gif"><span>) dissolution and precipitation experiments. In the dissolution experiments, a significant amount of Hg was released from cinnabar in the presence of DOM, suggesting strong interactions. Conversely, precipitation of HgS was strongly inhibited in the presence of low concentrations ( </span><img src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img7.gif" border="0" alt="$\leq$" width="14" height="25" align="MIDDLE" data-mce-src="https://jp4.journaldephysique.org/articles/jp4/abs/2003/05/jp4pr5p029/img7.gif"><span>3 mg C/L) of DOM. In both the dissolution and precipitation experiments, organic matter rich in aromatic moities was more reactive with HgS than less aromatic fractions and sulfur-containing model compounds. These results suggest that DOM can influence the geochemistry of inorganic complexes of Hg in the Everglades, especially HgS, by strong Hg-DOM binding and colloidal stabilization.</span></p>
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10.1051/jp4:20030235
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ECO Sciences
Interactions between dissolved organic matter and mercury in the Florida Everglades
article