Bee Population Decline Linked to Aluminum Exposure

Bee Population Decline Linked to Aluminum ExposureBee Population Decline Linked to Aluminum Exposure

A new scientific study has found very high amounts of aluminum contamination in bees, raising the question of whether aluminum-induced cognitive dysfunction is playing a role in the decline of bumblebee populations.

Aluminum is Earth’s most ubiquitous ecotoxicant and is already known to be responsible for the death of fish in acid lakes, forest decline in acidified and nutrient impoverished catchments, and low crop productivity on acid sulphate soils.

Now, a collaboration between Professors Chris Exley (Keele University) and Dave Goulson (University of Sussex) raises questions on the role of aluminum in the decline of the bumblebee, Science Daily reported.

Previous research, whose results were published in PLOS ONE, had suggested that when bees forage for nectar, they do not actively avoid nectar containing aluminum. This prompted the suggestion by Exley and Goulson that bees may be accumulating aluminum within their life cycle. Researchers at University of Sussex collected pupae from colonies of naturally foraging bumblebees and sent them to Keele University where their aluminum content was determined.

The pupae were found to be heavily contaminated with aluminum, with individual contents ranging from between and 13 and nearly 200 ppm. Smaller pupae had significantly higher contents of aluminum.

To put these aluminum contents in some context, a value of 3 ppm would be considered potentially pathological in human brain tissue. While preliminary, these data have shown the significant accumulation of aluminum in at least one stage of the bumblebee life cycle and suggest the possibility of another stressor contributing to the decline in its numbers.

Professor Exley, a leading authority on human exposure to aluminum from Keele University, said: “It is widely accepted that a number of interacting factors are likely to be involved in the decline of bees and other pollinators -- lack of flowers, attacks by parasites, and exposure to pesticide cocktails, for example.

“Aluminum is a known neurotoxin affecting behavior in animal models of aluminum intoxication. Bees, of course, rely heavily on cognitive function in their everyday behavior and these data raise the intriguing specter that aluminum-induced cognitive dysfunction may play a role in their population decline -- are we looking at bees with Alzheimer’s disease?”