## 4 Discussion
### Selected Heavy Metals
A BMDL\({}_{01}\) of 0.5 ug Pb/kg of body weight per day (for developmental toxicity) and BMDL\({}_{01}\) of 0.63 and 1.50 ug Pb/kg of body weight per day (for kidney and cardiovascular effects, respectively) were established by the EFSA panel for contaminants in the food chain [24; 37]. In the present study, these limits were not exceeded for arsenic, cadmium and lead levels, assuming a potential consumption of young shoots of 20 g per day. As for aluminium, it has been found that it is the third most common element in the Earth's crust. Obviously, acid rain can elevate the aluminium concentration in the soil to toxic levels. As a result, it can then be detected in plants, food and groundwater sources, particularly in drinking water [38; 39]. Aluminium generally occurs as oxides and aluminosilicates, which are non-toxic to plants, but as the soil pH decreases (pH \(\leq\) 5), aluminium undergoes transformation into toxic Al\({}^{3+}\), which can be easily absorbed by plants [39; 40]. Industrial food packaging, for example beverage boxes, baking trays, etc., are responsible for as much as 20% of aluminium use [38]. The main sources of food contamination are also industrial products and processed foods [41]. However, the main adverse effect of aluminium, as a toxic element, is its accumulation in the lungs, liver, kidneys, thyroid gland and brain. This element, with long-term exposure, can also be a strong neurotoxin, leading to impaired mental development and, when incorporated into infant bones, may result in weakened bone structure [38; 42]. The exposure of humans to aluminium has been recognized as a potential cause of neurodevelopmental and neurodegenerative diseases (e.g., multiple sclerosis or Alzheimer's diseases) [38; 40; 43]. The PTWI (provisional tolerable weekly intake) value for all aluminium compounds in food (including food additives) of 2 mg kg\({}^{-1}\) of body weight was set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) [38; 44; 45]. On the other hand, the TWI (Tolerable Weekly Intake) for aluminium in all food sources has been established by the European Food Safety Authority (EFSA) at 1 mg kg\({}^{-1}\) of body weight [38; 42]. In a study by [PERSON] et al. [26], the aluminium content of three species of wild-growing microgreens was determined at 4.73 mg per 100 g fresh weight of the vegetable, which was many times higher than the values obtained in the present work, which were averaged 0.01 (young safflower shoots) and 0.03 mg (young camelina and nigella shoots) after converting from 100 g dry matter to 100 g fresh matter. Antimony occurs in soil mainly in its inorganic form, in its fifth and third oxidation states; some scientists have also reported the presence of methylated antimony compounds in surface soil layers. Regardless of the form of its occurrence, antimony is hardly extractable from soil [21; 46; 47]. Only inorganic and methylated forms of this element have been identified in plant samples. As antimony is used in the production of plastics, an obvious direction for the study of the speciation of this element would seem to be food products for which polymers are used as packaging [48; 49]. There are no data in the available literature on the content of elements such as antimony, titanium and thallium in microgreens. Until now, it has not been confirmed that chromium plays any biological role in plant physiology. An excess of this element, on the other hand, can provoke biochemical and morphophysiological processes in plants. The element is potentially harmful to plants, but it can be absorbed from the soil by forming complexes with aspartic acid, oxalic acid or citric acid [29; 50]. Chromium toxicity strongly depends on the degree of its oxidation. Cr(III) is considered a micronutrient essential for normal lipid, glucose and protein metabolism in mammals. Cr(VI), in turn, exhibits strong mutagenic and genotoxic effects and is therefore classified by the IARC as a Group 1 human carcinogen, whereas Cr(III) is classified as a Group 3 carcinogen [22]. [PERSON] et al.