نتایج جستجو برای: pb

تعداد نتایج: 36420  

Journal: :The Science of the total environment 2014
N Walraven B J H van Os G Th Klaver J J Middelburg G R Davies

In this study the origin, behaviour and fate of anthropogenic Pb in sandy roadside soils were assessed by measuring soil characteristics, Pb isotope composition and content. In 1991 and 2003 samples were taken at different depth intervals at approximately 8 and 75 m from two highways in The Netherlands. The Pb isotope composition of the litter layer ((206)Pb/(207)Pb=1.12-1.14) differs from the ...

2010
Michael E. Ketterer David A. Lane James A. Jordan

Unusually radiogenic Pb has been found in sediments of a portion of the Ashtabula River (80 o 48’ W, 41 o 54’ N) near its confluence with Lake Erie. Pb isotopic compositions have been determined by quadrupole ICPMS, revealing that the Pb results from mixing of three sources: crustal Pb, common Pb from industrial pollutant sources, and highly radiogenic Pb associated with U-containing accessory ...

Journal: :Environmental pollution 2013
A K Mackay M P Taylor N C Munksgaard K A Hudson-Edwards L Burn-Nunes

Lead (Pb) concentrations and isotopic compositions from soils, dusts and aerosols from public land and residential lots adjacent to the copper and Pb mine and smelter at Mount Isa, Australia, were examined to understand the sources and risks of environmental Pb exposure. Urban soil samples contain elevated Pb concentrations (mean 1560 mg/kg), of which 45-85% of the Pb is bioaccessible. The Pb i...

1996
Rod Downey Carl G. Jockusch Michael Stob

A class of r.e. degrees, called the array nonrecursive degrees, previously studied by the authors in connection with multiple permitting arguments relative to r.e. sets, is extended to the degrees in general. This class contains all degrees which satisfy a 00 > (a 0 0) 0 (i.e. a 2 GL 2) but in addition there exist low r.e. degrees which are array nonrecursive (a.n.r.). Many results for GL 2 deg...

Journal: :British journal of industrial medicine 1976
G I Benson W H George M H Litchfield D J Seaborn

Biochemical measurements were carried out on 20 workers entering employment in a lead industry. Blood lead (Pb-B) urinary delta-aminolevulinic acid (ALA), and coproporphyrin (CP) levels were determined before entry and then at approximately weekly intervals for the first 12 weeks of employment. Levels of blood lead began to increase in all men within one week rising from an average pre-employme...

2011
Marisela Rubio-Andrade Francisco Valdés-Pérezgasga J Alonso Jorge L Rosado Mariano E Cebrián Gonzalo G García-Vargas

BACKGROUND To study the changes of children lead exposure in the city of Torreon during the last five years, after environmental and public health interventions, using the timeline of lead in blood concentration as the biomarker of exposure and its relation to lead in soil concentrations. METHODS This follow-up study started in 2001 and consisted of 232 children living in nine neighborhoods i...

Journal: :Environmental science & technology 2015
Hong-Bo Li Kai Chen Albert L Juhasz Lei Huang Lena Q Ma

Fingerprinting based on stable isotopes of lead (Pb) in blood and environmental media helps to identify Pb exposure pathways in children. However, previous studies used stable isotopes of total Pb in media. In this study, a wire rope production town in China (Zhuhang) was selected for investigating the effectiveness of using isotope ratios in bioaccessible Pb to identify childhood Pb exposure p...

Journal: :Environmental pollution 2011
Guo-Xin Sun Xin-Jun Wang Qin-Hong Hu

Lead isotopes and heavy metal concentrations were measured in two sediment cores sampled in estuaries of Xiangjiang and Lishui Rivers in Hunan province, China. The presence of anthropogenic contribution was observed in both sediments, especially in Xiangjiang sediment. In the Xiangjiang sediment, the lower (206)Pb/(207)Pb and higher (208)Pb/(206)Pb ratio, than natural Pb isotope signature (1.19...

Journal: :The Science of the total environment 2009
Neal Michelutti Antonio Simonetti Jason P Briner Svend Funder Robert A Creaser Alexander P Wolfe

Concentrations and stable isotope ratios of lead (Pb) from lake sediments were used to quantify temporal patterns of anthropogenic Pb pollution in the Clyde River region of Baffin Island, Arctic Canada. Surface sediments from eight lakes on eastern Baffin Island and one from northern-most Greenland, spanning a gradient of 20 degrees latitude, showed great variability with respect to Pb concentr...

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