## 4 Discussion  
### Selected Heavy Metals  
The results of the analyses were presented per dry weight of the vegetable. However, the discussion also included references to the results converted to fresh vegetable weight. Conversions to the fresh weight of the vegetables were carried out on the basis of the results of their basic composition, including dry weight, presented in an earlier publication by [PERSON] et al. [20], which is complementary to the present study. In plants, the tendency to uptake and accumulate arsenic is closely related to the similarity of this element to phosphorus. Inorganic forms of arsenic are usually taken up and accumulated in the root part of the plant, while organic forms, on the other hand, can be absorbed via leaves or tree bark [21]. The International Agency for Research on Cancer (IARC) has documented and then classified inorganic arsenic compounds as a human carcinogen (as a Group 1 carcinogen) [22]. A series of benchmark dose lower confidence limits (BMDL\({}_{01}\)) were established by the Panel on Contaminants in the Food Chain of the European Food Safety Authority (EFSA). The limits ranged from 0.3 to 8 \(\mu\)g/kg of body weight daily for the increased frequency of lung, skin and bladder cancers, as well as skin lesions [23,24]. The benchmark dose lower confidence limits elaborated by the Joint Expert Committee (FAO and WHO) on Food Additives (JECFA) varies from 2 to 7 \(\mu\)g/kg of body weight daily for increased incidences of lung and bladder cancers, as well as skin damage [24,25]. [PERSON] et al. [26] determined, among others, the chromium, cobalt, aluminium, arsenic, cadmium and lead, as well as nitrates, concentrations in the microgreens of wild leafy species (_Sinapis arrensis_ L., _Sanguisorba minor Scop._, and _Tararaxacum officinal [PERSON]_) grown in a controlled environment and using a hydroponic system. As for the arsenic, cadmium and lead contents, the authors determined these to be 0.0013, 0.0004 and 0.0122 mg per 100 g fresh matter, respectively [26]. In this study, after converting the results from dry to fresh matter, the amounts of arsenic were markedly lower and averaged 0.0001 mg for the young safflower and amelina shoots and 0.0009 mg per 100 g of fresh matter for the young nigella shoots. There are a lot of microgreens that are being grown, but there is not a lot of research on the young shoots of uncommon oilseeds like nigella, safflower or amelina. With regard to cadmium, its contents averaged 0.0032 (young safflower shoots) \begin{table}
\begin{tabular}{c c c c c c} \hline \multirow{2}{*}{**Compounds**} & \multicolumn{2}{c}{**Young Shoots of Nigella**} & \multicolumn{2}{c}{**Young Shoots of Safflower**} & \multicolumn{2}{c}{**Young Shoots of Camelina**} \\  & \multicolumn{2}{c}{**(_Nigella sativa L._)**} & \multicolumn{2}{c}{**(_Carthamus tincorris L._)**} & \multicolumn{2}{c}{**(_Camelina sativa L._)**} \\ \cline{2-6}  & **First Harvest \({}^{\star}\)** & **Second Harvest \({}^{\star\star}\)** & **First Harvest \({}^{\star}\)** & **Second Harvest \({}^{\star\star}\)** & **First Harvest \({}^{\star}\)** & **Second Harvest \({}^{\star\star}\)** \\ \hline
**Nitrates** & 5159 \(\pm\) 196 \({}^{\circ}\) & 2712 \(\pm\) 122 \({}^{\ddagger}\) & 9752 \(\pm\) 303 \({}^{\ddagger}\) & 10240 \(\pm\) 245 \({}^{\circ}\) & 10883 \(\pm\) 615 \({}^{\rm{b}}\) & 11985 \(\pm\) 264 \({}^{\rm{a}}\) \\ \hline
**Nitrites** & _nd_ & _nd_ & _nd_ & _nd_ & _nd_ \\ \hline \end{tabular}  
* The results obtained from the analysis of three individual samples (\(n\geq 3\)) are shown as mean \(\pm\) SD. The values within rows containing distinct letters are significantly different (_Duncan_ test at \(p\leq 0.05\)). \({}^{\circ}\) Plants had cotyledons and their first proper leaf. ** Plants had 1-2 proper leaves each. _nd_—not detected.  
\end{table}