A three-year evaluation of pesticide residue profiles in managed and wild honeybees across traditional and reclaimed agricultural lands of Egypt

Abstract

Pesticide contamination in honeybees directly endangers vital pollinators and serves as a bio-indicator of regional agricultural practices. This is especially important in North Africa (Egypt), which has a unique balance between traditional methods and newly reclaimed lands. This study provides a comprehensive multi-residue screening of 341 pesticides in managed (Apis mellifera) and wild bee species across these contrasting agricultural zones, using a modified QuEChERS extraction combined with GC-MS/MS and LC-MS/MS analysis. The results showed that, although 45% of samples contained no residues, 27 pesticides were detected in the contaminated samples. Tau-fluvalinate, carbendazim, and thiophanate-methyl were the most common, with maximum concentrations of 0.114, 0.03, and 0.14 µg/g, respectively. Higher pesticide levels were linked to intensive farming, unregulated chemical use, and poor beekeeping practices. Tau-fluvalinate was the main contaminant in established agricultural areas and the third most common in reclaimed zones. The highest residue levels were found in Apis mellifera from Sharqia (traditional land) and Ismailia (reclaimed land). Additionally, many Apis florea specimens were contaminated with pesticides, with one containing 0.25 µg/g of acetamiprid. These findings emphasize the impact of unregulated pesticide use in both traditional and reclaimed lands and inadequate hive management on the managed and wild bees in Egypt.