These investigations
have shown that anthropogenic activities such as industrial
production, mining and transportation release a high amount of
heavy metals to the water and soil sources used in the rice cultivation.
Rice cropped even from non-polluted areas may be contaminated
because of fertilizers, pesticides and sewage that are used in
farm, containing cadmium, lead and other heavy metals (Jahed
Khaniki & Zazoli, 2005; Nriagu & Pacyna, 1988).