Have You Heard the Buzz? Neonicotinoid Insecticides Increase Crop Yield, but Can Affect Our Bees!

A quick search on neonicotinoids will show you that this class of insecticide is less toxic for birds and mammals than other classes of pesticides, however, other side effects have created large cause for concern.  Honeybee colony collapse disorder may be caused or influenced by honeybees exposed to neonicotinoids and when your primary pollinators are affected, many other adverse effects happen downstream.  Throughout the world, many governments, including the US, EU, and Canada have all established regulations limiting the use of, or outright banning the use of neonicotinoids. 

A recent article from BBC News brought neonicotinoids back into the spotlight.  A new UK policy permitted the emergency use of a single neonicotinoid insecticide, thiamethoxam, which has largely been banned in the EU.  This was a cause for concern, but as the emergency conditions weren’t met an announcement was made that thiamethoxam wouldn’t be used to treat sugar beets this year.

As honey comes from the nectar bees carry to the hive, honey can be used to determine the exposure of honeybees to multiple pesticides including neonicotinoids and determine the health of a colony or determine what might have gone wrong, should the colony have collapsed. 

A couple years ago, we spiked pesticides into multiple food matrices, one of which was honey, and measured our ability to detect and recover them using QuEChERS sample preparation followed by analysis using LC-MS/MS.  Accordingly, we spiked the LC Multiresidue Pesticide Kit (cat.# 31971) into honey to determine how well a QuEChERS extraction with dSPE cleanup extracted pesticides from various matrices including honey. Included in the LC pesticides kit we spiked into the commodities were neonicotinoids commonly used in the US.  A matrix matched calibration curve was used to determine the recovery of a 10 ppb spike into our matrix.  The results can be found below.

Name	Mix	Recovery	Calibration (R2 )
Acetamiprid	LC Mix #4	107%	0.9962
Dinotefuran	LC Mix #4	91%	0.9952
Clothianidin	LC Mix #5	102%	0.9981
Imidacloprid	LC Mix #4	117%	0.9886
Nitenpyram	LC Mix #4	106%	0.9934
Thiamethoxam	LC Mix #5	105%	0.9944
Thiacloprid	LC Mix #5	108%	0.9956

In our experiment we combined honey with water, 10 mL acetonitrile and internal standards, and spiked pesticides if we were evaluating pesticide recovery.  A schematic of our general workflow is shown below.

Curious to see what endogenous pesticides we might find, Dr. Jamie York and I tested five different kinds of honey, purchased from a supermarket.  Of the five honey samples we tested, two had detectable levels of neonicotinoid pesticides among some other pesticides detected below actionable levels.  One honey sample contained 0.16 ppb acetamiprid and another honey sample contained 0.011 ppb thiacloprid both calculated using a matrix matched calibration curve.  These values were within compliance levels.  While this study was very small in scope, a larger study by Mitchell et al.¹ indicated that 75% of all honey samples tested worldwide contain at least one neonicotinoid and 45% of samples contained two.  While the detected levels were safe for human consumption, these results indicate that the majority of the world’s honeybee population is exposed to these pesticides.

Consequently, it’s more important than ever to find testing methods that are quick, easy, cheap, effective, rugged and safe for determining the levels of contaminants that exist in our foods and have the potential to affect essential elements, like honeybees, that keep our food supply chain humming, and buzzing, along.

Citations:

1. https://science.sciencemag.org/content/358/6359/109 (A worldwide survey of neonicotinoids in honey, BY E. A. D. MITCHELL, B. MULHAUSER, M. MULOT, A. MUTABAZI, G. GLAUSER, A. AEBI; SCIENCE06 OCT 2017 : 109-111)