## 4 Discussion  
Biomonitoring studies within the Legnica-Glogow Copper Area in south-western Poland (impact of the \"Glogow\" and \"Legnica\" smelters and the \"Zelazny Most\" tailings pond) have focused, so far, on determining the level of toxic metals in the blood [21]. In contrast with blood, the use of extracted third molars for orthodontic or surgical indications does not raise ethical concerns. Completely impacted teeth are a useful biomonitor of environmental exposure to many toxic metals [12]. They basically exclude exposure to toxic metals contained in cigarette smoke or contaminated food. In the conducted research, the content of manganese, chromium, nickel, copper, cadmium, and zinc did not depend on the place of residence. The results from L-G Copper Area patients were comparable to our control group. However, the concentration of iron and lead was significantly higher in the removed teeth from the L-G Copper Area patients (3.86 vs. 1.81 and 0.53 vs. 0.31). This may indicate environmental pollution of lead and zinc in the L-G Copper Area. Human exposure to lead can cause numerous adverse effects [22], such as hypertension, slow nerve conduction, mood swings, fatigue, and impaired concentration. In addition, it contributes to fertility disorders and decreased sex drive [23; 24]. [PERSON] et al. [25] described the effects of cadmium, lead, and mercury on the female reproductive system. A high concentration of toxic metals may contribute to endometrial dysfunctions, implantation failure, premature delivery, subfertility, spontaneous abortions, and preeclampsia. In our study, a positive Spearman's correlation was observed between the content of all toxic metals and the age of patients. The correlation between the concentration of vitamin D3 in the capillary blood and toxic metals was mainly negative, apart from copper, cadmium, and lead (rho 0.02; 0.16; 0.04). These results may be related to the stimulation of co-absorption by vitamin D [10]. Biomonitoring studies using teeth in industrialized areas have also been conducted in other parts of Poland [5; 8; 12; 26; 27; 28]. [PERSON] et al. [8] examined the content of toxic metals in impacted third molars and adjacent bone tissue in patients from the Wroclaw district and residents of the city of Wroclaw. They observed that the cadmium contents in both the tooth and bone tissue were \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Toxic Metal** **(**ug/g**)} & \multicolumn{2}{c}{**Age (Years)**} & \multicolumn{2}{c}{**Vit. D3 (ng/mL)**} \\ \cline{2-5}  & **Correlation** & \multirow{2}{*}{_p-Value_} & **Correlation** & \multirow{2}{*}{_p-Value_} \\  & **Coefficient (rho)** & & & \\ \hline Mn & 0.23 & 0.097  & \(-\)0.29 & 0.038  \\ \hline Cu & 0.31 & 0.027  & \(-\)0.13 & 0.377 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Correlations between levels of toxic metals and continuous variables such as age and vitamin D3 concentration in patients residing in the LG Cooper Area (\(n\) = 49). Spearman correlation analysis was used for testing the data. statistically significantly higher in patients living in Wroclaw (\(p<0.05\)). In our study, the level of cadmium was comparable in patients from the L-G Copper Area and from Wroclaw (0.07 vs. 0.06). According to [PERSON] et al. [26], the concentration of zinc in the bone of rats decreased with age. In the research of [PERSON] et al. [8], the concentration of zinc did not depend on the patient age. The results obtained from our own study showed a positive correlation between age and the content of zinc in the removed teeth (\(p\)-value \(<0.001\)). [PERSON] and [PERSON] [27] evaluated trace elements in the hard dental tissues of third retained molars in patients from urban and rural areas of Mazovia. The concentration of lead, cadmium, manganese, and chromium was higher in the patients from the city. In turn, [PERSON] et al.