246 research outputs found
Uptake of uranium by lettuce (Lactuca sativa L.) in natural uranium contaminated soils in order to assess chemical risk for consumers
Uranium mining activity in Cunha Baixa
(Portugal) village has left a legacy of polluted soils
and irrigation water. A controlled field experiment
was conducted with lettuce (Lactuca sativa L.) in an
agricultural area nearby the abandoned mine in order
to evaluate uranium uptake and distribution in roots
and leaves as well as ascertain levels of uranium
intake by the local inhabitants from plant consuming.
Two soils with different average uranium content (38
and 106 mg/kg) were irrigated with non-contaminated
and uranium contaminated water (100 ÎĽg/l).
A non-contaminated soil irrigated with local tap water
(<1 ÎĽg/l uranium) was also used as a control. Uranium
in lettuce tissues was positively correlated with soil
uranium content, but non-significant differences were
obtained from contaminated soils irrigated with different water quality. Uranium in plants (dry weight)
growing in contaminated soils ranged from 0.95 to
6 mg/kg in roots and 0.32 to 2.6 mg/kg in leaves.
Lettuce bioconcentration is more related to available
uranium species in water than to its uranium concentration.
Translocated uranium to lettuce leaves corresponds
to 30% of the uranium uptake whatever the soil
or irrigation water quality. A maximum uranium daily
intake of 0.06 to 0.12 ÎĽg/kg bodyweight day was
estimated for an adult assuming 30 to 60 g/day of
lettuce is consumed. Although this value accounts
for only 10% to 20% of the recommended Tolerable
Daily Intake for ingested uranium, it still provides
an additional source of the element in the local
inhabitants’ die
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