# Comparison of the Biological Potential and Chemical Composition of Brazilian and Mexican Propolis
## 4 Propolis Contamination
### Xenobiotics in Propolis
#### 4.1.2 Toxic Metals in Brazilian and Mexican Propolis  
As described above, propolisols is composed basically of a mixture of substances that can be contaminated by metals of different sources such as bees, air, water, plants, and soil ([PERSON], 2016; [PERSON] et al., 2017). Anthropogenic actions (industrial activities, mining, increased urbanization, fertilizers, and pesticides) or natural process (eruptions, leaching) also contribute to the contamination of the environment and consequently bees and their products ([PERSON], 2016; [PERSON], 2016). In the survey of studies referring to toxic metals in samples of Brazilian propolisols, six studies were found (Table 5). Lead and cadmium are the toxic metals found in most conducted researches. Other toxic compounds found were As, Cr, and Cd. [PERSON] et al. (2014) found As, Cd, and Pb in 26.3%, 5.2%, and 73.9% of the 19 samples evaluated. \begin{table}
\begin{tabular}{p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt}} \hline \multicolumn{2}{p{42.7 pt}}{**Mexican Propolis**} & \multicolumn{1}{p{42.7 pt}}{} & \multicolumn{1}{p{42.7 pt}}{} & \multicolumn{1}{p{42.7 pt}}{} & \multicolumn{1}{p{42.7 pt}}{} & \multicolumn{1}{p{42.7 pt}}{} \\ \hline \multicolumn{2}{p{42.7 pt}}{**Number of Samples**} & \multicolumn{1}{p{42.7 pt}}{**Geographical Origin**} & \multicolumn{1}{p{42.7 pt}}{**Elements Analyzed**} & \multicolumn{1}{p{42.7 pt}}{**Toxic Elements Found**} & \multicolumn{1}{p{42.7 pt}}{**Analytical Methods**} & \multicolumn{1}{p{42.7 pt}}{**References**} \\ \hline \multirow{4}{*}{N/E} & \multirow{4}{*}{South} & Dichloros, & & & \\  & & Diazimon, Methyl & & & \\  & & & marathon, & & \\  & & Malathion, & & & \\  & & & and Coumaphos & & & \\ \hline \multirow{4}{*}{4} & \multirow{4}{*}{South} & Dichloros, & & & & \\  & & Diazimon, Methyl & & & \\  & & & marathon, & (\(\leq\)025 \(\mu\)g/mL) & GC-MS & [160] \\ \cline{1-1}  & & & Malathion, & & & \\ \cline{1-1}  & & and Coumaphos & & & & \\ \hline \multicolumn{2}{p{42.7 pt}}{**Brazilian Propolis**} & \multicolumn{1}{p{42.7 pt}}{} & \multicolumn{1}{p{42.7 pt}}{} & \multicolumn{1}{p{42.7 pt}}{} & \multicolumn{1}{p{42.7 pt}}{} & \multicolumn{1}{p{42.7 pt}}{} \\ \hline \multirow{4}{*}{19} & Northeast (Ba, Se, Al); & AMPA & AMPA & & & \\  & South (SC, Pr). & & Atrazine & (10.2 \(\pm\) 1.39–11.3 \(\pm\) 2.65) & HPLC & [15] \\  & Southeast (MG) and & Glyphosate & Atrazine & & \\  & Centersouth (MT) & Pictoram & (9.7 \(\pm\) 0.11–17.4 \(\pm\) 2.60) & & \\ \hline \multirow{4}{*}{50} & \multirow{4}{*}{South (SP)} & Organochlorines, & & & & \\  & & Organophosphates, & & & \\  & & Pryethroids, & & & \\ \cline{1-1}  & & Carbamates, & & & (GC/ECD), & \\ \cline{1-1}  & & Herbicides, & & & (GC/NPD) & [165] \\ \cline{1-1}  & & Fungicides, & & & \\ \cline{1-1}  & & and Acaricides & & & \\ \cline{1-1}  & & any pesticide & & & \\ \hline \end{tabular}
\end{table} 
Table 4: Pesticides research in Brazilian and Mexican propolisols. Substances originating from plants as raw material for propolis production (resins) can be sources of contamination, as mentioned above. Researchers have shown that the primary botanical sources (_Baccharis dracunculifolia_) for the production of propolis can accumulate cadmium [180], turning this plant into a possible source of contamination. Other sources of this toxic metal can be agricultural inputs, such as fungicides, used in plantations in Santa Catarina (SC) and Rio Grande do Sul (RS) [31; 34; 181; 182], where Cd was found in pollen samples. Heavy metals in Argentinian raw propolis have been detected concentrations in ppm of Zn (15.2), Pb (7.73), and Cu (2.45) [183]. Although, in the research by [PERSON] et al. [162], in Chilean and Spanish processed propolis have been reported heavy metals, such as, Cr (17.7), Ni (7.01), Cu (6.44), Zn (6.44), and Pb (7.21 ppm).