Specificities of changes in the concentrations of heavy metals in milk thistle (Silybum marianum (L.) Gaertn.)

Aim. To investigate the content of heavy metals in the seeds of milk thistle (Silybum marianum (L.) Gaertn.) and in the product of its processing – oil. To reveal possible changes in the concentration of heavy metals in the years of cultivating this plant. Methods. The fi eld and spectrometric methods were applied; the results were processed using the technologies, common for agriculture, plant production and statistics. Results. The content of heavy metals in the seeds of milk thistle was defi ned. It was determined that their concentration exceeds maximal acceptable coeffi cient for the medicinal plant material. It was established that in 2013 the seeds of milk thistle accumulated several times more Ba, Ca, Fe, Mg, Mo, Sr, V compared to the indices of 2014, while Al, Co, Ag were found only in the samples of the seeds, harvested in 2013. Conclusions. As the regulatory documents regarding many relevant elements, which belong to heavy metals, do not specify maximal accept- able coeffi cients for the content of the latter in the medicinal plant material, it is reasonable to conduct complex studies, involving the specialists of relevant fi elds, in order to stipulate this gradation. In the Kyiv region the milk thistle plants accumulate a large amount of such heavy metals as cadmium, manganese, strontium, and zinc, which exceeds maximal acceptable degrees of accumulation and testifi es to partial pollution of region soils. It was established that the concentration of the main part of heavy metals in the product of processing milk thistle – oil – is decreased to the value under the threshold of analytic devices. This fact proves the pros- pects of growing milk thistle for industrial processing purposes.