## 3 Results and Discussion
### Effect of Peeling on the Content of Pesticides
Peels of citrus fruits are not used for direct consumption, with the exception of lemons, whose peel has some spice value. Peels of citrus fruits can be processed and used as an additive in confectionery products, or they can be raw materials for the production of essential oils. In 2012, in the peel of citrus fruits, two more pesticides were identified relative to the results for the fruit flesh, i.e., pyriproxyfen (insecticide) and thiabendazole (fungicide). If we compare the normative requirements relating to the peels of citrus fruits to those relating to citrus fruits, instances of levels in excess of the MRL value (0.01 mg/kg [25])  
\begin{table} \begin{tabular}{c c c c c c c c c} \hline \multirow{3}{*}{**Pesticide**} & \multirow{3}{*}{**Group**} & \multicolumn{4}{c}{**Range of Pesticides Concentration**} & \multirow{3}{*}{**MRL**} & \multirow{3}{*}{**LOQ**} \\ \cline{3-3} \cline{5-8}  & & \multicolumn{2}{c}{**Citrus Pulp**} & & & & & & mg/kg \\ \cline{3-3} \cline{5-8}  & & **2012** & **2020** & **2012** & **2020** & **2012** & **2020** \\ \hline chlorpyrifts & A, I & \textless{}LOQ-0.0070 c & \textless{}LOQ d & 0.0000-1.1350 a & \textless{}LOQ-0.1380 b & 0.01 mg/kg [25] & not approved & 0.001 mg/kg [26] & 0.0001 \\ \hline imazalli & F & 0.0050-0.0190 c & 0.0050-0.0210 c & 0.0160-0.3860 b & 0.4320-1.10 a & 5 mg/kg [44] & 5 mg/kg [5] & 0.0005 \\ \hline prochloraz & F & \textless{}LOQ-0.0080 b & \textless{}LOQ c & \textless{}LOQ-0.8840 a & \textless{}LOQ c & 10 mg/kg [51] & 0.03 mg/kg [88] & 0.0002 \\ \hline pyrimethani & F & \textless{}LOQ-0.0180 c & \textless{}LOQ-0.0180 c & 0.0090-1.5550 b & 0.0100-1.8000 a & 10 mg/kg [39] & 8 mg/kg [38] & 0.0005 \\ \hline pyriproxyfen & I & \textless{}LOQ b & \textless{}LOQ b & \textless{}LOQ-0.0720 a & \textless{}LOQ b & 0.6 mg/kg [25] & 0.6 mg/kg [54] & 0.0001 \\ \hline thiabendazole & F & \textless{}LOQ b & \textless{}LOQ b & \textless{}LOQ-0.0640 a & \textless{}LOQ b & 5 mg/kg [30] & 7 mg/kg [89] & 0.0001 \\ \hline sprirotetramat-end & \textless{} Spirotetramat-end & \textless{} & \textless{}LOQ-0.0330 a & - & \textless{}LOQ b & \begin{tabular}{c} 1 mg/kg \\ (expressed as \\ spirotetramat) \\ \end{tabular} & 0.01 \\ spirotetramat & \textless{} & \textless{}LOQ-0.0290 a & - & 0.0090-0.0240 a & \
\begin{tabular}{c} 1 mg/kg \\ (50) \\ \end{tabular} & 0.001 \\ \hline acetamiprid & I & - & \textless{}LOQ b & - & \textless{}LOQ-0.0170 a & 1 mg/kg [39] & 0.9 mg/kg [59] & 0.0001 \\ \hline heyythiazox & A, I & - & \textless{}LOQ b & - & \textless{}LOQ-0.0110 a & 1 mg/kg [33] & 1 mg/kg [33] & 0.0001 \\ \hline \end{tabular} 
\begin{tabular}{c c were noted only in the case of chlorpyrifos in all of the analysed samples, with detected concentrations in the range from 0.030 mg/kg to 0.045 mg/kg (lemons), 0.040 mg/kg to 0.096 mg/kg (oranges), and from 0.541 mg/kg to 1.135 mg/kg (grapefruits). In samples of the peel of citrus fruits from 2020, six pesticides were identified, i.e., chlorpyrifos, imazalli, pyrimethanil, spirotetramat-enol-glucoside, acetamiprid and hexythiazox. As in 2012, in the samples of citrus fruit peels from the year 2020, excessive levels of pesticides were noted only in the case of chlorpyrifos--in two samples of grapefruit peels the values were 0.074 mg/kg and 0.138 mg/kg, and in one sample of orange peels the assayed value was 0.12 mg/kg (the MRL was unchanged relative to earlier regulations and equalled 0.01 mg/kg [26]). The levels of pesticide residues in the flesh of citrus fruits have been presented in the preceding subchapter (Figures 4 and 5). The results clearly indicate a high accumulation of pesticides in the peels of citrus fruits. In the case of the flesh of citrus fruits, residues of plant protection agents were identified in minimal amounts and never exceeded the valid MRL values. Similar conclusions were formulated by [PERSON] et al. [81] following an experiment on various citrus fruits: lemons, oranges, mandarins, grapefruits, limes, pomelo and kumquats.