Linked Life Data

11841061

Source:http://linkedlifedata.com/resource/pubmed/id/11841061

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2002-2-11
pubmed:abstractText
Lead pollution of the environment is synonymous with civilization. It has no known biological function, and is naturally present in soil, but its presence in food crops is deemed undesirable. The concern regarding Pb is mostly due to chronic human and animal health effects, rather then phytotoxicity. However, not much is known about the chemistry and speciation of Pb in soils. We determined the activity of Pb2+, in near neutral and alkaline soils, representative of alluvial, desertic and calcareous soils of Egypt, using the competitive chelation method. Lead activity ranged from 10(-6.73) to 10(-4.83) M, and was negatively correlated with soil and soil solution pH (R2 = -0.92, P < 0.01 and R2 = -0.89, P < 0.01, respectively). It could be predicted in soil solution from the equation: log(Pb2+) = 9.9 - 2pH. A solubility diagram for the various Pb minerals found in soil was constructed using published thermodynamic data obtained from the literature, and our measured Pb2+ activities compared with this information. The measured Pb2+ activities were undersaturated with regard to the solubility of PbSiO3 in equilibrium with SiO2 (soil). However, they were supersaturated with regard to the solubilities of the Pb carbonate minerals PbCO3 (cerussite) and Pb3(CO3)2(OH)2 in equilibrium with atmospheric CO2 and hydroxide Pb(OH)2. They were also supersaturated with regard to the solubilities of the Pb phosphate minerals Pb3(PO4)2, Pb5(PO4)3OH, and Pb4O(PO4)2 in equilibrium with tricalcium phosphate and CaCO3. The activity of Pb2+ was not regulated by any mineral of known solubility in our soils, but possibly by a mixture of Pb carbonate and phosphate minerals.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0047-2425
pubmed:author
pubmed:issnType
Print
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
162-7
pubmed:meshHeading
pubmed:articleTitle
Soil solid-phase controls lead activity in soil solution.
pubmed:affiliation
Soil Science Dep., Faculty of Agriculture, Cairo Univ., Giza, Egypt. sbadawy4@hotmail.com
pubmed:publicationType
Journal Article