6. Conclusions
The DI of THg in 33 sampling sites analyzed in this study
exceeded the acceptable daily intake (ADI) of THg of both cows
(ADI = 1.4 mg d−1) and sheep (ADI = 0.28 mg d−1), in view of
food safety associated with THg in animal kidneys. Furthermore,
estimated daily intake of OrgHg for grazing animals was up to
220 μg d−1 (for cows) and up to 33 μg d−1 (for sheep). These
results suggest that feed crops are an effective way of entry of
OrgHg into the terrestrial feed and food chain which may represent
a threat to animal and human health.
At themoment, feed quality controlmeasures (particularly European
Directive 2002/32/EC, EC 2002) only include the measurement of THg
concentrations. This study suggested that solely monitoring the levels
of THg in soils and feedmay not allowto adequately taking into account
accumulation of OrgHg in feed crops and properly address risks associated
with the high toxicity of OrgHg required to obtain an accurate
assessment of risks posed by metal mobilization from soils into the
food chain to animal (and human) health. In the future, ADIs for
OrgHg for livestock should be set. Also, limits for OrgHg in feed and
animal products for human consumption should be included in legislation
for feed quality and food safety.