Heavy metal accumulation and the possible correlation with acetylcholinesterase levels in honey bees from polluted areas of Alexandria, Egypt

This study aimed to use honey bees, Apis mellifera L., as bioindicator for a regional survey of heavy metal pollution in Alexandria city, Egypt. Honeybees were obtained from four different sites namely Abu Qir (AQ), Agricultural Road (AR), Khorshid (KR) and El-Sabahia (SB). Correlation between heavy metals and acetylcholinesterase (AChE) as a biomarker was also examined. The mean concentration of measured elements (mu g/g) ranged from 2.20-5.78, 1.53-0.83, 3.95-11.40,19.10-44.43 and ND-4.25 (ND = not detected) for Cr, Ni, Cu, Zn, Pb and Cd, respectively. The highest mean value of metal quantities over a period of 5 months was Zn and the highest concentration mean for Zn and metals as a total occurred at the KR site. The highest mean values of AChE activity were noted in honey bees sampled from SB and KR followed by AQ and AR. However, AChE was found to positively correlate significantly with Zn. Our results suggest that AChE could be useful as a biomarker in honey bees exposed to Zn and may constitute a valuable biomonitor to assess environmental pollution by metals.