This regression model suggests that BAFs for IHg in shoots decrease
with increasing levels of soil IHg contamination and increase proportionally
with concentration of IHg in roots.
The mean, median (and range) of BAFs for OrgHg were 3.3 and 1.8
(0.18–22) for roots and 1.5 and 0.46 (0.040–13) for shoots (Fig. 4).
Accumulation of OrgHg was observed at 26 sites in roots and at 8 sites
in shoots where the BAF was higher than 1. These BAF values for
OrgHg in shoots are comparable to those obtained in vegetation
samples from Slovenia (mean BAF values for vegetation from different
areas varied between 0.18 and 2.7) (Gnamus et al., 2000), and slightly
lower than those reported by Zhang et al. (2010b) for rice (mean values:
4.4–6.9). The BAF values for OrgHg were on average 13 times higher
than the respective values for IHg. Higher accumulation of OrgHg
when compared with IHg was also previously observed in vegetation
and rice samples (Gnamus et al., 2000; Zhang et al., 2010b).