Abstract:
Major contribution (over 90 %) to the
world’s rice production is coming from Asia, where
metal contamination of agricultural lands is often
reported. Thus the present paper reviews the sources
and current status of heavy metal contamination of
paddy lands in the region. Apart from the natural
sources, agrochemicals, wastewater irrigation, sewage
sludge application, livestock manures, mining and fly
ash etc., could be identified as the key sources of metal
contamination in Asia. Accumulation of heavy metals
and metalloids (Cd, Zn, Cu, Pb, Cr, Ni, Fe, Zn, Co, Hg
and As) in different parts of the rice plant (roots, straw,
hull and grain) is reported at varying degrees. Rice
grain accumulates the least amount of toxic metals
compared to hull, straw and roots. Most importantly, a
greater number of investigations confirmed that the
metal contents in rice grains are within the permissible
limits of Codex recommendations of joint Food and
Agriculture Organization/World Health Organization
Food Standards Programme and/or food regulations
imposed by the respective governments. However, due
to the fact that rice is a main route of human exposure to heavy metals, appropriate preventive and remedial
measures should be enforced in the areas with potential risk of metal contamination