First it was cashew hulls. Now scientists say that onions and garlic also may be effective in soaking up hazardous heavy metals including arsenic, cadmium, iron, lead, mercury and tin. This according to a paper published in International Journal of Environment and Pollution. According to a press release, researchers at GGS Indraprastha University in Delhi, India, found them to be particularly effective in extracting lead, one of the most troublesome metallic environmental pollutants. Since ferns are used to leach arsenic from contaminated soil, these findings make me wonder if planting garlic and onions could in the yard could lessen the toxicity of soil contaminated with lead paint flakes from houses.