Smelting, lead contamination

Palmer KT, Kucera CL. 1980. Lead contamination of sycamore and soil from lead mining and smelting operations in eastern Missouri. Journal of Environmental Quality 9 106-111. 

Suppose EPA scientists are investigating lead contamination of soil near an abandoned mining and smelting operation. How should the soil be sampled so that the analytical results obtained on the individual samples provide a reliable indication of the range and distribution of contamination of the entire site ... 

At a fonner lead smelting facility in Benicia, California, approximately 11,500 tons of lead-contaminated soil were treated and placed in an on-site repository. According to the vendor, the stabilization costs were 70 per tons of soil treated. The contracting and reagent costs for the project were 805,000 (D113382, p. 9). 

Modern industry practice can be extremely effective in limiting lead emissions from recycling facilities. Facility emissions have been a cause of historic concern, with speculation that increased use of lead-acid batteries in electric and/or hybrid electric vehicles might result in unacceptable levels of lead contamination. For example. Lave et al. [23] estimated that emissions to water and air associated with primary lead production, secondary lead production, and battery prodnction were 4, 2, and 1%, respectively, of the total amount of lead processed. In contrast, Socolow and Thomas [24] estimated that secondary smelting and refining were associated with system losses of up to only 0.01% of material processed. 

But, although in this respect the responsibility is being shifted back to the employer, there remain subtle ways in which the lead smelting industry continues to hold workers responsible for the problem. This is facilitated by the way in which lead contamination is measured. There are two common types of measurement lead-in-blood and lead-in-air. Lead-in-blood measurements are clearly more relevant from a medical point of view. But lead-in-blood measurements leave the way open to holding the victim responsible in a manner which is not possible with lead-in-air measurements. The point is that a focus on lead-in-air leads to a policy of containing lead emissions at their source, clearly a management responsibility. A focus on lead-in-blood throws up the additional possibility of encouraging workers to wear personal protective equipment—... 

It is critical to point out that cumulative Pb emissions and rates of emissions to the various environmental compartments are not equivalent to lead production and consumption, at least in the near term. Over the long term, i.e., over the hfetime of cultures and societies, aU lead present in human consumption channels can be viewed as potential lead contamination. Overall, and by estimating lead release dispersal across categories of lead production and consumption, a report of the National Academy of Sciences (NAS/NRC, 1980) estimated that at least 50% of cumulative lead production eventually becomes lead emissions. This fraction in quantitative terms translates to 150 million MT of a total global estimate of 300 million MT produced since the invention of successful smelting (Regal and Smith, 1992). 

The principal direct raw materials used to make sulfuric acid are elemental sulfur, spent (contaminated and diluted) sulfuric acid, and hydrogen sulfide. Elemental sulfur is by far the most widely used. In the past, iron pyrites or related compounds were often used but as of the mid-1990s this type of raw material is not common except in southern Africa, China, Ka2akhstan, Spain, Russia, and Ukraine (96). A large amount of sulfuric acid is also produced as a by-product of nonferrous metal smelting, ie, roasting sulfide ores of copper, lead, molybdenum, nickel, 2inc, or others. 

Atmospheric contaminants from smelting works or combustion processes eventually enter the natural drainage system as fall out, and are carried into the rivers. It is probable that the deposition of sediments and the higher pH of marine water, which leads to precipitation, results in a build-up of the heavy metal pollutants in the river estuary. An assessment of this build-up is essentially an analytical problem. 

The Advanced Recovery Systems, Inc. (ARS) developed the patented, ex situ DeCaF hydrometallurgical technology to decontaminate fluoride by-products and to recover recyclable metals. The technology uses a proprietary acid mixture to digest the fluoride matrix, freeing radioactive contaminants (e.g., uranium, thorium, or radium) and hazardous contaminants (e.g., lead, arsenic, or chromium). Radioactive elements are recycled or disposed. Metals are also recycled, and fluoride is recovered as a high-value salt for aluminum smelting. 

Ragaini RC, Ralston HR, Roberts N. 1977. Environmental trace metal contamination in Kellogg, Idaho, near a lead smelting complex. Environ Sci Technol 11 773-781. 

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