Thallium (Tl)
For the plant – a competitor of potassium
Thallium
has been found in
plant and animal organisms. Among animals, jellyfish, sea anemones, starfish, and other marine inhabitants contain more thallium.
In terms of chemical behavior in the plant organism, thallium is similar to potassium and is a competitor for binding with sulfur-containing groups, and at elevated concentrations, thallium leads to disruption of enzyme system activity, respiration processes, and photosynthesis.
The thallium content in plants likely depends on its concentration in the soil. At the same time, thallium has been found in beets growing in soil where the element thallium could not be detected using the finest analytical methods. It was later established that even at minimal thallium concentrations in the soil, beets are capable of concentrating and accumulating it.
Herbaceous and woody plants contain more thallium than other plants. It has been established that the thallium content in herbs ranges from 0.02 to 1.0 mg/kg dry weight, in species of pine – from 2 to 100 mg/kg ash, with higher levels in needles than in the trunk. In edible vegetables, the concentration of thallium (in mg/kg dry weight) is within 0.02–0.125, in clover – 0.008–0.01, in meadow hay – 0.02–0.025.
In the analysis of herbaceous plants growing on soils above thallium mineralization zones, up to 17,000 mg of thallium per 1 kg of ash was found in the flowers of plants of the genus Galium L., Rubiaceae, while in other plants (in leaves and stems) it accumulated more than 100 mg/kg ash.
Thallium often accumulates in plants along with cadmium. Increased thallium content in plant tissues is toxic both to the plants themselves and to animals.
According to available information, microorganisms are relatively sensitive to thallium. The inhibition of nitrate formation in thallium-contaminated soils may affect crop yields. There is also an opinion that thallium is likely incorporated into the microbiological cycle as a result of methylation reactions.
At potassium fertilizer plants, metallurgical enterprises, and bituminous coal processing plants, plants contain elevated amounts of thallium – up to 2.8 mg/kg dry weight.
Some plants accumulate thallium during their life processes.
The thallium hyperaccumulator plant is
common beet Beta vulgaris L., Chenopodiaceae.
The thallium accumulator plant is bitter wormwood Artemisia absinthium L., Asteraceae.
Medicinal plants containing thallium:
• common vetch Vicia sativa L., Fabaceae (herb);
• white dead-nettle Lamium album L., Lamiaceae (herb);
• common oat Avena sativa L., Poaceae (straw);
• common raspberry Rubus idaeus L., Rosaceae (leaves);
• wild strawberry Fragaria vesca L., Rosaceae (leaves);
• stinging nettle Urtica dioica L., Urticaceae (leaves);
•
common millet Panicum miliaceum L., Poaceae (fruits);
•
common barley Hordeum vulgare L., Poaceae (fruits);
• blue bramble Rubus caesius L., Rosaceae (fruits);
• rowan Sorbus aucuparia L., Rosaceae (fruits);
• cinnamon rose Rosa cinnamomea L., Rosaceae (fruits).