1Humans do not have an exclusive role when it comes to pollution. Certain Bolivian ecosystems have the potential to naturally form methyl mercury, a particularly toxic organometallic neurotoxin. The concentrations of this toxin vary on a seasonal basis and above all over the course of a day. This “natural” pollution is difficult to study as the collection, chemical treatment and laboratory analysis of water samples are complex and costly procedures. Passive sensors, which could easily concentrate methyl mercury in water, must be immersed in the environment for several days to obtain a measurement. As a result, it is impossible to detect and study daily changes in methyl mercury concentrations.

Tracesense, pollution measurement device.

2This technical limitation led to the development of another measuring instrument. The idea, tested on a laboratory bench, is to use a nanostructured material to increase the absorption surface and accelerate the capture of the target molecule using a pulsed vibration system. With the help of an electronics engineer, a field prototype was created to capture the trace element, combined with temperature, light and position sensors connected to a smartphone application. With this device, methyl mercury can be captured in a few minutes, although measurement takes longer: once removed from the water, disposable nanostructured plates must be analysed in a laboratory to determine the level of concentration.

3The cost price and the detection threshold of this technique are much lower than traditional approaches. These “Tracesense” sensors, patented in 2016 and currently undergoing testing, are very easy to use and could be deployed by non-specialists. In theory, with some adjustments they could also be used to detect other metals or endocrine disruptors.