Remediation of chromium and lead polluted soils and impact of lead pollution on soil biological acti...

مرکز و کتابخانه مطالعات اسلامی به زبان های اروپایی

منو

" Remediation of chromium and lead polluted soils and impact of lead pollution on soil biological activity "
R. Cifuentes W. C. H. Lindemann, Dean M.

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1112968
Doc. No	:	TLpq304213693
Main Entry	:	R. Cifuentes
	:	W. C. H. Lindemann, Dean M.
Title & Author	:	Remediation of chromium and lead polluted soils and impact of lead pollution on soil biological activity\ R. CifuentesW. C. H. Lindemann, Dean M.
College	:	New Mexico State University
Date	:	1995
student score	:	1995
Degree	:	Ph.D.
Page No	:	123
Abstract	:	This study was conducted to determine: (1) the removal of Cr (III and VI) from solution by soils and A. niger and reduction of Cr (VI) in spiked soils, (2) the mole fraction of Pb-EDTA in EDTA treated soils polluted with Pb from human activities as well as soil and chemical factors that influence Pb extraction, and (3) the relationship between soluble inorganic Pb and microbial numbers and activities. The maximum removal of Cr (III) from solution was 409 mmole kg in the Belen clay loam soil, whereas removal of Cr (VI) was minimal (26-60 mmole kg) and independent of soil type. A. niger removed more Cr (VI) than Cr (III). However, soil amendment with freeze-dried A. niger would be of limited value in remediation of Cr contaminated soils or solutions. Organic amendment of a Cr (VI) spiked soil resulted in both direct sorption of Cr (VI) and reduction to Cr (III). Cr reduction was primarily by indigenous microorganisms and inoculation with Cr tolerant P. maltophilia was of little benefit. Except for the acid mine tailings from which no Pb was extracted, high concentrations of Pb were extracted by EDTA at acid pH values in the polluted soils. The Pb-EDTA mole fraction decreased with increasing usd\rm EDTA:Pbusd ratios as a result of a decrease in Pb solubility as Pb was removed. Calcium competed with Pb for EDTA complexation in alkaline soils, whereas Fe competed with Pb under acid conditions. EDTA extracted Pb from all Pb compartments and the magnitude of Pb extracted from each compartment was soil dependent. Addition of Ca(Cl)2 indirectly increased Pb extraction by reducing the pH of the extracting solution through Ca complexation to usd\rm K\sb2H\sb2EDTA.usd Most biological variables measured were sensitive to Pb and inversely related to soluble inorganic Pb. The order of sensitivity was dehydrogenase usd\approxusd heterotrophic bacteria > arylsulphatase > acid phosphatase > alkaline phosphatase > N mineralization > NO3\sp--N concentration > C mineralization. Soluble inorganic Pb may be useful to monitor the effect of Pb pollution on soil microorganisms.
Subject	:	Biological sciences
	:	bioremediation
	:	chromium
	:	Environmental science
	:	Health and environmental sciences
	:	lead