This study was performed in two phases of work. In the first stage, alkaline leaching of lead and zinc from an Iranian low-grade oxide ore was examined and the influence of the operating variables including stirring speed, leaching temperature, NaOH concentration and liquid to solid ratio was determined experimentally. The optimum condition was found to be NaOH concentration of 4 M, liquid to s...

BACKGROUND Blood lead levels have decreased in Mexico since leaded fuel was banned in 1997, but other sources remain, including the use of lead-glazed ceramics for food storage and preparation. Zinc deficiency is present in almost 30% of children aged 1-2 years. Previous studies have documented negative associations of both lead exposure and zinc deficiency with stature, but have not considered...

Accumulation of Cu, Zn, Cd, and Pb in the sediment of seagrass ecosystems was examined using mesocosm experiments containing Zostera marina (eelgrass) and reference pools. Lead was approximately 20-fold higher in the surface sediment in the eelgrass pool than in eelgrass leaves and epiphytes on the eelgrass leaves, whereas zinc and cadmium were significantly lower in the surface sediment than i...

An automatic system for the determination of Zn, Cd, Pb and Cu by anodic stripping potentiometry using the oxygen dissolved in the sample as oxidant is reported. The system relies on the use of a PC-compatible computer for instrumental control and data acquisition and processing.

We studied the relation between the concentrations of lead in blood (PbB) and zinc protoporphyrin in blood (ZPP) in a group of 801 men occupationally exposed for more than one year to lead or inorganic lead compounds. Linear regression of PbB on log ZPP provided 95% tolerance intervals for PbB values for a given ZPP value. The intervals we found are too large to warrant the estimation of PbB on...

One of the world's largest concentrations of sediment-hosted stratiform zinc-lead-barite deposits is (Figure 1). The largest and most developed of these is located in the Gataga area of northern British Columbia the CirqueiSouth Cirque deposit, with estimated geological reserves of 38.5 million tonnes averaging 8.0% Zn, 2.2% Pb and 47.2 gitonne Ag at Cirque and gitonne Ag at South Cirque (M...

Lead has been shown to produce cognitive and motor deficits in young rats that could be mediated, at least in part, by inhibition of the zinc-containing heme biosynthetic enzyme delta-aminolevulinate dehydratase (ALA-D). In the present study we investigated the effects of lead and/or zinc treatment during the second stage of rapid postnatal brain development on brain, kidney and blood ALA-D spe...