Mercury contamination : The Synchrotron sheds light thanks to… a hair

sep article

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IN SHORT – We know how to detect mercury in organisms, but up to now, we knew less about how to identify the origin of the contamination. Experiments carried out on a hair by a team of international researchers at the European Synchrotron in Grenoble have shed light on these grey areas

 

 

 

Researchers, like Alain Manceau (shown here) have used the Synchrotron light to analyse a human hair, and have traced the origin of mercury contamination. © ESRF

Researchers, like Alain Manceau (shown here) have used the Synchrotron light to ana­lyse a human hair, and have tra­ced the ori­gin of mer­cury conta­mi­na­tion. © ESRF

Mercury is found in fish or rice, in den­tal amal­gam, some vac­cines and also in medi­cines.

 

Even though we know how to detect this power­ful neu­ro­toxin, which accu­mu­lates in orga­nisms, nota­bly through urine ana­ly­sis, iden­ti­fying the source of conta­mi­na­tion with mer­cury toxi­co­logy risk assess­ment and imple­men­ting a treat­ment, has always been rela­ti­vely hazar­dous.

 

Researchers from the CNRS, the University of Bordeaux, the Grenoble Alpes University, the ESRF, the European syn­chro­tron in Grenoble and the University of Illinois in Chicago have just found the solu­tion by deve­lo­ping new tech­niques of ana­ly­sis to iden­tify the che­mi­cal forms of mer­cury *.

 

Using two lines of syn­chro­tron light from the ESRF, they dis­co­ve­red that a spike in mer­cury, obser­ved on a hair, came from the remo­val of den­tal amal­gam. Experiments conduc­ted in Grenoble can even date the expo­sure per­iod to within one or two days.

 

Indeed, with an ave­rage growth rate of one cen­ti­metre per month, hair can cap­ture events of conta­mi­na­tion with high tem­po­ral reso­lu­tion ; a key wit­ness, which has sha­ken a few cer­tain­ties.

 

 

From mercury, to other toxic metals ?

 

 

“The epi­de­mio­lo­gi­cal stu­dies of conta­mi­na­tion with mer­cury by eating fish make the hypo­the­sis that mer­cury in hair comes only from this source”, explains Kathryn Nagy, Professor of Earth & Environmental Sciences at the University of Illinois in Chicago. “Our results show that this is not neces­sa­rily true.”

 

“We did not expect to find that the micro­sco­pic peak of mer­cury, at just 2.5 nano­grammes, has a dif­ferent mole­cu­lar signa­ture from that of methyl­mer­cury, which is rela­ted to fish consump­tion”, conti­nues Alain Manceau, Director of research at the CNRS-University Grenoble Alpes. “However, to ensure that the mer­cury came from amal­gam, it was essen­tial to know its mole­cu­lar form, and espe­cially how it was atta­ched to pro­teins in the hair. This, tho­rough inves­ti­ga­tive work has taken seve­ral months and requi­red the use of super­com­pu­ters to model the data.”

 

 

Patricia Cerinsek

 

 

* The results have been publi­shed in the Environmental Science & Technology jour­nal.

 

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