Actually, one of most dangerous substances that can be collected by honey bees are pyrrolizidine alkaloids. It has very destructive effect on liver.

I ahve attached a link of my friend publishes paper:

Article Pyrrolizidine alkaloids in floral honeys of tropical Ghana: ...

salam, thanks a lot

Also minerals are transported by honeybees from the flower nectar to the honey, and therefore influence the taste of the honey. The avocado nectar contains high concentration of minerals, mainly Potassium and Phosphorus, which are transferred to the honey and influence its unique taste. Due to its nectar high mineral concentration the avocado bloom is relatively unattractive to honeybees, but still very attractive to some Central America stingless bee species, which are its native pollinators.

See in the bellow papers:

The effect of avocado (Persea americana) nectar

composition on its attractiveness to honey bees

(Apis mellifera). Ohad AFIK, Arnon DAG, Sharoni SHAFIR.

Apidologie 37 (2006) 317–325. DOI: 10.1051/apido:2005064

Analyses of Avocado (Persea americana) Nectar Properties and their Perception by Honey bees (Apis mellifera). O. Afik & A. Dag & Z. Kerem & S. Shafir,

J Chem Ecol (2006) 32: 1949–1963, DOI 10.1007/s10886-006-9120-1

You may find these two articles here in ResearchGate:

Article Analyses of Avocado (Persea americana) Nectar Properties and...

Article The effect of avocado (Persea americana) nectar composition ...

thanks a lot. are there any toxic mineral such as pb, cu etc in the nectar?