Accumulation of Heavy Metals in Different Rice Varieties

Abstract

Field experiments were conducted on the heavy metal contents (Cd, Pb, Cr, inorganic As, and total Hg) of the 129 main cultivated rice varieties in southern China. We analyzed the effects of different varieties and types of rice on the absorption capacities of these heavy metals. The results showed that the Cd content in 35 brown rice of early rice was 0.35-0.60 mg·kg-1, exceeding the standard rate of 100%. The Pb content in brown rice was 0.08-0.30 mg·kg-1, exceeding the rate of 14.29%. The Cd content in 54 brown rice of medium rice was 0.03-0.45 mg·kg-1, exceeding the rate of 33.33%. The Cd content in 40 brown rice of late rice was 0.08-0.20 mg·kg-1, which did not exceed the national standard. Early, middle, and late rice all showed that the Cd content of three-line hybrid rice was higher than that of two-line hybrid rice, but the difference was not obvious. The contents of Cr and total Hg in brown rice of three-line hybrid rice in early rice were significantly higher than that of two-line hybrid rice. There was a significant positive correlation between Cd content in brown rice and Pb and total Hg content in medium rice, and there was a significant negative correlation between inorganic Cd content and inorganic As content, whereas there was no significant correlation between Cd and Cr content. In short, rice's absorption and accumulation of heavy metals is greatly affected by genetic background, species types, and heavy metal interactions.