Science - September 15, 2011

Flying metal detector

Honey-bees can do far more than simply pollinate plants or make honey. The busy creatures also make excellent environmental monitors, as bee researcher Sjef van der Steen has demonstrated. He used swarms of bees to measure the concentration of metals in Maastricht, Buggenum and Hoek van Holland. It seems bees make excellent informers.

Using bees as a bio-monitor is not new but Van der Steen says earlier studies were limited to the detection of heavy metals such as cadmium, lead and cobalt. His bees let him detect no less than eighteen common metals. The method he used is simple. The bees collect metal particles while hunting for pollen and nectar. In fact they hoover up dust that then sticks to the bees, and this dust contains the metal particles.
The researcher then carries out measurements of the bees at fixed time points, which give a kind of fingerprint of the environmental quality of the bees' habitat. Incidentally, this procedure means the end of the bee, which is dissolved in an acid bath. Spectral analysis provides information about the kind of metal and the quantities involved.
Van der Steen says the great thing about bees as bio-indicators is that they are a relatively simple measurement instrument. ‘Many parts of the world don't have access to complicated measurement systems but bees are everywhere. In principle you could use other insects, but the nice thing about bees is that they congregate at a central point. What is more, they cover quite a large area in looking for food, about seven square kilometres.'
Van der Steen is currently drawing up a kind of metals map of the Netherlands on the basis of the bee indicator. He is using swarms in 150 locations across the country. That work still has to be published.
Environmental Monitoring and Assessment, online, soon to appear in print

Rocket fuel detector

Rockets ‘flying' on the fuel dimethylhydrazine are regularly launched from Baikonur in Kazakhstan. A filthy, neurotoxic product, says environmental technologist Tim Grotenhuis. ‘Even smelling it causes damage.' Whenever a rocket is launched, fuel is released in the area of Kazakhstan lying between the launch platform and the capital Astana. ‘You could use bees to get a good picture of the pollution there', says Tim Grotenhuis. As co-author of the bee study, he proposed the method to the Kazakhstan authorities. ‘Nomads live in that area. This would help give them better protection.' No response so far.