Lead, cycling environmental

In conclusion, accurate and precise measurements of lead, including environmental and human lead burdens relative to natural levels, lead cycling and metabolism, and lead biomolecular speciation, are required to fully evaluate the problem of lead contamination and toxicity in the biosphere. Current data demonstrate that environmental lead levels are often more than 10-fold and sometimes more than 10,000-fold higher than natural levels. Although regulation of many lead-containing products in some industrialized countries has resulted in a reduction in some lead discharges into the biosphere, the demonstrated persistence of contaminant lead indicates that environmental lead levels will remain substantially elevated for a protracted time. 

The European Parliament has set out where it believes EC policy should focus in tackling the environmental and health problems posed by PVC. In a resolution adopted in April, it called for a phase-out of lead and cadmium stabilisers, legislation to ensure the separate collection of discarded PVC products, and a complex strategy for substitution of PVC based on life-cycle comparisons with competing products. 

Since FAS can be produced either from vegetable oil based or petrochemical-based fatty alcohol (Fig. 4.9), both types have been evaluated in a life-cycle analysis with a positive overall result for the natural based product. With vegetable-based fatty alcohol sulfate, the analysis starts with the harvesting of the oil fruits (palm kernels or coconuts) and their processing to isolate the desired plant oil. Subsequent transesterification and hydrogenation of the methyl ester intermediates lead to the fatty alcohols, which are finally sulfated to produce the desired product. Based on this analysis the environmental impact of vegetable oil based fatty alcohol sulfate compared with the petrochemical based product is as follows ... 

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