The iAs represented N80% of the tAs in the rice grain, which is a very
high percentage considering that the geographical range varies from 10
to 90% (Williams et al., 2005). This high level is of concern, as iAs is considered
the most toxic fraction due to its carcinogenic nature (see e.g.
Meharg and Zhao, 2012). Higher percentages were obtained for other
plant parts, with mean values ranging from 83% in the stem to 90% in
the leaf