## 3 Results and Discussion
### Effect of Peeling on the Content of Pesticides  
Figures 7 and 8 present the residues of pesticides in the peels of apples from the years 2012 and 2020. In 2012, in apple peel, 31 compounds were identified (Figure 7, Table 1), compared to 26 compounds identified in whole apples (Figure 1). The pesticide group identified the most frequently in apple peels in 2012 was that of insecticides (52%), followed by fungicides (42%), growth regulators (6%) and herbicides (3%), whereas in 2020, residues of nine pesticides were detected in apple peels (Figure 8) compared to eight identified in whole apples (Figure 2, Table 1). Among the pesticides identified in apple peels in 2020, eight represented compounds from the group of fungicides (89%), and one represented the group of insecticides (acetamiprid, 11%). Analysing the levels of individual pesticides in apple peels in the years 2012 and 2020, one should note that only in 2012 was the value of MRL exceeded in the cases of chlorpyrifos (MRL 0.05 mg/kg [25]) in 33% of the samples (from 0.102 mg/kg to 0.269 mg/kg), and disulfoton (MRL 0.01 mg/kg [32]) in 78% of the samples--within an 8-19-fold range compared to the allowable levels (from 0.077 mg/kg to 0.186 mg/kg). Pesticide concentrations in apple peels were significantly higher than in whole apples. It should be emphasised that the European Commission decided not to renew the approval for two active substances: chlorpyrifos and chlorpyrifos methyl, after acquiring the opinion of the European Food Safety Authority (EFSA). According to EFSA, plant protection agents containing those substances may have a negative impact on human health, and on children in particular. The fundamental argument is focused on the potential effect of the genotoxicity and developmental neurotoxicity of those chemical compounds, this being supported by epidemiological data indicating the occurrence of such effects in the population. Chlorpyrifos and chlorpyrifos methyl raise controversy not only in Europe, but also in the USA. The Californian Environmental Protection Agency arrived at similar conclusions to the EFSA, perceiving an effect of those substances on brain damage in children. While as of the 31 st of December 2020, farmers in California could not possess nor use plant protection agents containing chlorpyrifos and chlorpyrifos methyl, in all other states of the USA the registration of these insecticides is currently extended till 2022. The Implementing Regulations (EU) No. 2020/18 [84] and 2020/17 [85] on the nonrenewal of the approval for the above active substances were finalised on 10 January 2020. The licence for chlorpyrifos and chlorpyrifos methyl expired on 31 January 2020. By 16 February 2020, all permits for plant protection agents containing chlorpyrifos and chlorpyrifos methyl as active substances were annulled. From that date, new batches of such insecticides could not be placed on the market, and those already on the market before 16 February 2020 could only be offered for sale until 1 April 2020. The ultimate deadline for the use of those insecticides in the territory of the European Union was the 16 April 2020. The fact that no instances of identification of chlorpyrifos in samples of apples in 2020 were noted shows that the producers of plant protection agents have complied with the above regulations. For comparison, the content of pesticides in the flesh of fruits was determined after peeling off the peels. Figures 9 and 10 present the levels of pesticide residues in the flesh of apples in the years 2012 and 2020. In the flesh of apples from 2012, 24 pesticides were identified, i.e., two fewer than in whole apples and seven compounds fewer than in the peels acquired from those apples (31 pesticides), whereas in the flesh of apples from 2020, only six pesticides were detected (with identification of captan metabolites), i.e., one pesticide fewer than in the whole apples and three fewer than in peels peeled off the apples.