Lead isotope ratios are widely used to identify original sources of Pb in the environment. Such source apportionment depends on the ability to distinguish potential sources on the basis of their isotopic composition. However, almost all terrestrial Pb is co-linear in some of the plots i.e. (206)Pb/(208)Pb versus (206)Pb/(207)Pb and (206)Pb/(204)Pb versus (206)Pb/(207)Pb commonly presented in th...

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 ...

geometrical computation with accumulations: Beyond the Blum, Shub and Smale model

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 ...

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...

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...

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...

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...