According to scientific research published in the September issue of the International Journal of Environmental Protection, a variety of techniques, from chemical additives to the use of earthworms, can reduce the concentrations of toxic heavy metals in composed municipal and industrial solid waste. The report, “Reduction of Heavy Metals During Composting,” concluded that the use of biological processes is often favored because of lower costs, and is particularly useful for developing countries, as the United States already follows strict heavy metal concentration standards.