The concentration of heavy metals in the environment are increasing every year due to numerous human activities. This represents a growing threat for human and animal health, with Cd being one of the most problematic metals. Cadmium is a heavy metal, which can be transferred through the food chain very easily due to its high mobility in soil and sediments. The most frequent is transfer from soil to plants and then to animals and humans. Cadmium is toxic and causes numerous side effects. Therefore, the purpose of this research work was to find out whether biofortification of plants with Se can mitigate toxicity of Cd in plants and further in the food chain. Selenium is an essential element for both humans and animals. Experiments were carried out on green lettuce (Lactuca sativa) and Spanish slugs (Arion vulgaris). On the lettuce we determined Cd toxicity by measuring photosynthetic activity of photosystem II and the contents of photosynthetic pigments. In slugs, fed with Cd contaminated lettuce with or without Se, accumulation of Cd in digestive gland was measured with ICP-MS method. We found that biofortification of lettuce with Se did not mitigate the Cd uptake from soil to lettuce and from lettuce to slugs. The combination of several heavy metals and high levels of Cd had negative effect on photosynthesis. Also, a combination of heavy metals had a negative effect on photosynthetic pigments. In slugs we found no correlation between mortality, growth or feeding rate and Cd load in lettuce. Cadmium accumulated predominantly in digestive gland. At high concentrations of Cd in lettuce Se increased Cd accumulation in the snail muscles but had no impact on accumulation of Cd in the digestive gland. We observed no toxic effects of Se on plants or animals.
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