Similarly to IHg concentrations, there was an increase in OrgHg
from site 1 to site 9, with samples 9a, 9b and 9c (0–10 cm) showing
the highest levels of the dataset (84–130 μg kg−1 d.w.). The OrgHg
concentration in soils was significantly positively correlated with
the respective IHg concentration (r = 0.96, p b 0.01). A positive
significant correlation was also observed between the organic
carbon content of soils and the concentration of OrgHg (r = 0.91,
p b 0.01). This is in line with previous studies reporting that OrgHg
in soils have a great affinity for organic matter that contributes for
the retention of the metal in the soil solid matrix (Jen-How, 2005).
Similarly to IHg, there were no statistically significant differences
between OrgHg concentrations in both depths (p N 0.05), with the
exception of site 9 that showed significantly higher levels in the 0–
10 cm depth (84–130 μg kg−1 d.w.), compared to the 10–20 cm layer
(11–27 μg kg−1 d.w.).