This study investigates the dosimetric dependence of the dimension of a lead (Pb) layer for shielding using clinical electron beams with different energies. Monte Carlo simulations were used to generate phase space files of the 4, 9 and 16 MeV electron beams produced by a Varian 21 EX linear accelerator using the EGSnrc-based BEAMnrc code, and validated by measurements using films. Pb layers wi...

measurement of availability and mobility of heavy metals in river sediments is required in order to understand the behavior of these metals and to prevent potential toxic hazards. leaching column experiments were conducted for four sediment samples to determine the degree of mobility and the distribution of zn, cd, ni, cu, and pb because of an application of spiked heavy metals in sediments. se...

In retrospective radon measurements, the 22-y half life of (210)Pb is used as an advantage. (210)Pb is often considered to be relatively immobile in glass after alpha recoil implanted by (222)Rn progenies. The diffusion of (210)Pb could, however, lead to uncertain wrong retrospective radon exposure estimations if (210)Pb is mobile and can escape from glass, or lost as a result of cleaning-induc...

Concerns have been expressed that dust from the minerals processing facilities at Karumba Queensland Australia have resulted in elevated lead (Pb) concentrations in rain water tanks. The ores derived from the Century mine some 304 km from the port. High precision Pb isotopic measurements on environmental samples have been undertaken to evaluate the source of Pb in rainwaters and acid digests fr...

heavy metals such as cu(ii) and pb(ii) are among the hazardous pollutants that lead to severe ecological problems and have a toxic effect on living organisms. the removal of cu(ii) and pb(ii) by iranian bentonite experiment were conducted in single component and multi component systems. the bentonite from the birjand area was characterized by x-ray diffraction pattern and ftir spectroscopy. the...

A pilot-scale field demonstration was conducted at a Pb-contaminated site to assess the effectiveness of Pb immobilization using P amendments. The test site was contaminated by past battery recycling activities, with average soil Pb concentration of 1.16%. Phosphate amendments were applied at a 4.0 molar ratio of P/Pb with three treatments: T1, 100% P from H(3)PO(4); T2, 50% from H(3)PO(4)+50% ...

Establishment of water quality criteria (WQC), intended to protect aquatic life, continues to rely principally on water hardness (i.e. Ca(2+)) for lead (Pb) despite growing evidence that other chemical parameters also strongly influence toxicity. To more clearly define the water chemistry parameters mediating Pb toxicity, we evaluated the effects of hardness as CaSO(4) and dissolved organic car...

A long-term field-scale demonstration project on the feasibility of using P to immobilize Pb in a Pb-contaminated urban soil was conducted. Phosphate was applied at an average rate of 3040 mg Pykg soil based on a PyPb molar ration of 4.0, with four treatments: T , no P application; T , H PO only; T , 1y2 H PO q1y2 CaH PO ; and T , 0 1 3 4 2 3 4 2 4 3 1y2 H PO q1y2 phosphate rock. Soil samples w...