Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Lead solubility in seawater: an experimental study

Lead solubility in seawater: an experimental study Environmental contextMany trace metals including lead are only sparingly soluble in seawater and may exist in both dissolved and particulate forms (e.g. as precipitates). Aquatic organisms may experience different toxic effects from exposure to dissolved and particulate trace metals. This study reports the limits to lead solubility in seawater that influence the exposure to these forms of lead in the field and the laboratory.AbstractA combination of laboratory investigations and thermodynamic modelling were conducted in order to gain an understanding of the factors controlling lead solubility in seawater. In experiments where increasing amounts of lead were added to seawater (in order to avoid supersaturation) and equilibrated for up to 28 days, the maximum solubility was ~2mgL1 (pH 8.15, 22C). However, at higher added lead concentrations, which caused the rapid formation of lead precipitates, the solution chemistry became dynamic and the observed solubility was markedly lower, varying with both reaction time and precipitate concentration. For instance, when seawater solutions were spiked with 10mgL1 of total lead, precipitation occurred immediately and only 1.6mgL1 of dissolved lead was measured after 1h, with this concentration decreasing to 1.3mgL1 after 28 days. The solubility of lead in artificial seawater (0.68mgL1) was much lower than in natural seawater. This difference was attributed to the significant role played by natural organic matter in complexing dissolved lead. X-Ray diffraction and elemental analysis data suggest that the phase controlling lead solubility is a previously unidentified lead chlorocarbonate, which rapidly transforms to hydrocerussite on washing with deionised water. These observations are of particular relevance to toxicity tests where organisms are exposed to wide ranges of metal concentrations in order to obtain doseresponse curves. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Environmental Chemistry CSIRO Publishing

Lead solubility in seawater: an experimental study

Loading next page...
 
/lp/csiro-publishing/lead-solubility-in-seawater-an-experimental-study-ovHAsmWNg8

References

References for this paper are not available at this time. We will be adding them shortly, thank you for your patience.

Publisher
CSIRO Publishing
Copyright
Copyright © The Author(s). Published by CSIRO Publishing
ISSN
1448-2517
eISSN
1449-8979
DOI
10.1071/EN15150
Publisher site
See Article on Publisher Site

Abstract

Environmental contextMany trace metals including lead are only sparingly soluble in seawater and may exist in both dissolved and particulate forms (e.g. as precipitates). Aquatic organisms may experience different toxic effects from exposure to dissolved and particulate trace metals. This study reports the limits to lead solubility in seawater that influence the exposure to these forms of lead in the field and the laboratory.AbstractA combination of laboratory investigations and thermodynamic modelling were conducted in order to gain an understanding of the factors controlling lead solubility in seawater. In experiments where increasing amounts of lead were added to seawater (in order to avoid supersaturation) and equilibrated for up to 28 days, the maximum solubility was ~2mgL1 (pH 8.15, 22C). However, at higher added lead concentrations, which caused the rapid formation of lead precipitates, the solution chemistry became dynamic and the observed solubility was markedly lower, varying with both reaction time and precipitate concentration. For instance, when seawater solutions were spiked with 10mgL1 of total lead, precipitation occurred immediately and only 1.6mgL1 of dissolved lead was measured after 1h, with this concentration decreasing to 1.3mgL1 after 28 days. The solubility of lead in artificial seawater (0.68mgL1) was much lower than in natural seawater. This difference was attributed to the significant role played by natural organic matter in complexing dissolved lead. X-Ray diffraction and elemental analysis data suggest that the phase controlling lead solubility is a previously unidentified lead chlorocarbonate, which rapidly transforms to hydrocerussite on washing with deionised water. These observations are of particular relevance to toxicity tests where organisms are exposed to wide ranges of metal concentrations in order to obtain doseresponse curves.

Journal

Environmental ChemistryCSIRO Publishing

Published: Nov 30, 2015

References