In the south of Sardinia, as in many other places in the world, mining activity generates a fabulous quantity of spoil that, accumulating in time, forms huge piles dense with heavy metals and toxic elements. The combined action of water and wind, makes these substances enter the food chain.
Vetiver hedges are capable to withstand great concentrations of the polluting elements,
as this study shows, by reducing the volatility of it and erasing the leachate sinking in the ground waters.
A different matter is to plant this huge piles,
in Venezuela, for instance they do it like this.