Soils contaminated with zinc from mining, refining, or fertilizing with zinc-bearing sludge can have various grams of zinc per kilogram of dry soil. Amounts of zinc in excessive of 500 ppm in soil interfere with the flexibility of crops to soak up other crucial metals, such as iron and manganese. https://waylonzdffc.blogoxo.com/28214006/5-simple-statements-about-infrared-zinc-sulfide-explained