Current status of heavy metal contamination in Asia’s rice lands英文电子书.pdf

Rev Environ Sci Biotechnol (2013) 12:355–377 DOI 10.1007/s11157-013-9323-1 REVIEW PAPER Current status of heavy metal contamination in Asia’s rice lands K. K. I. U. Arunakumara • Buddhi Charana Walpola • Min-Ho Yoon Published online: 30 October 2013 Springer Science+Business Media Dordrecht 2013 Abstract Major contribution (over 90 %) to the to heavy metals, appropriate preventive and remedial world’s rice production is coming from Asia, where measures should be enforced in the areas with metal contamination of agricultural lands is often potential risk of metal contamination. reported. Thus the present paper reviews the sources and current status of heavy metal contamination of Keywords Heavy metals Sources of paddy lands in the region. Apart from the natural contamination Accumulation in rice sources, agrochemicals, wastewater irrigation, sewage Permissible limits Remedial measures 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 1 Introduction and As) in different parts of the rice plant (roots, straw, hull and grain) is reported at varying degrees. Rice Heavy metal contamination in soil and water due to grain accumulates the least amount of toxic metals intensified Agriculture, rapid urbanization, industrial- compared to hull, straw and roots. Most importantly, a ization and mining activities, has become a matter of greater number of investigations confirmed that the global concern (Singh et al. 2011a; Krishna et al. metal contents in rice grains are within the permissible 2013). Many of them are toxic, persistent and/or limits of Codex recommendations of joint