Ever since gold fever hit the Amazon region in the 1980s, more than two thousand tons of mercury has ‘disappeared’. Delft and Brazilian researchers have found the mercury in the hair of Amazon Indian tribes.
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Taking a blood sample from an Indian in the Amazon jungle is out of the question, says Dr. Peter Bode, researcher at the Interfaculty Reactor Institute (IRI). ”Indians consider their body as part of their soul, so you may not take anything from it.” However, using gentle persuasion and negotiation, Bode%s Brazilian colleague, Dr. Marina Vasconcellos, was able to get hold of tufts of hair from the Indians of Xingu Park, a reserve tucked away deep in the Amazon jungle. She wanted to measure the mercury level in their head hair to see if these Indians had suffered from gold mining during the past two decades.
Besides the mercury concentration in hairs, Vasconcellos also wanted to determine the selenium level. Brazilian nuts contain high amounts of the trace element selenium, and from this fact a true health hype has originated: Selenium allows antioxidants to work properly and is also very good at mercury detoxication. In Finland, selenium is added to bread, as fluorine is to drinking water and iodine to salt.
With a bag full of hair samples and exciting tales of giant spiders and jungle photographs (the Indians didn’t want their picture taken), the Brazilian researcher arrived at Bode%s laboratory in Delft. ”We have automated element analyses here, which allows us to examine many samples in a short period. At her research institute in Sao Paulo, Marina had to deal with long delays and had to do everything by hand. So she turned to me.”
Poisoning
Bode advised her to investigate many more elements as well, because this can be done easily in Delft, requiring only one instrumental neutron activation analysis experiment. First, the sample is bombarded with neutrons in a reactor; then, by measuring the frequency and intensity of the radiation, it%s possible to determine the concentration of forty different elements in one go. TU Delft is one of the few institutions that are officially qualified to perform this complex work. The entire experiment takes a few weeks.
Although the Xingu Park reserve doesn’t directly border the gold mining areas, the Indians have twenty times as much mercury in their bodies as an average inhabitant of Brazil does; but the level is still lower than the World Health Organisation%s standard for ‘noticeable mercury poisoning’. Other striking differences are the high levels of soil originated elements, aluminium, iron, scandium, and low levels of cadmium and antimony. The amount of selenium is,despite the nuts, not significantly higher in the Indians% hair.
That the gold rush is blamed for the high mercury concentrations is logical, because for every kilogram of extracted Amazon gold, three kilograms of mercury disappear into the environment. Moreover, for the protein in their diet, the Indians rely on fish, a known collector of heavy metals.
Gesture
Still, accusing gold mining companies directly is too simple, according to Vasconcellos, because some of the mercury can derive from natural sources: forest fires or high concentration levels in river water due to intense sunlight. Despite her fear of spiders, Vasconcellos hopes to return to the jungle to gather ground and food samples for further investigation.
The high levels of aluminium, iron and scandium can be explained by the Indians% habit of covering themselves from head to foot in red earth. Bode: ”We think this contaminates their hair. All the hair samples were washed, but if the Indians rub themselves with it for years, the hair becomes saturated.”
Washing the hair is a tough job. Milligram portions of hair, cut into tiny pieces, have to be scrubbed individually. Then, the hairs are dried and, having become static, must be put into plastic sample bottles.
Good news for the Indians, however, is the low levels of cadmium and antimony: Living far from factories and highways, their environment is still spared these pollutants.
Cooperation with Sao Paolo will continue for the time being, Bode says, but not only as a friendly and socially considered gesture to Brazil: ”The relation between feeding pattern health aspects can be found in other research done in our group as well. Soon, I expect two thousand toenails to arrive from America, which we%ll analyse to see if there’s a connection between certain eating habits and coronary diseases. It’s a big research project by the Johns Hopkins School of Hygiene in Baltimore.” You are what you eat, or not, that is the next big question.
Ever since gold fever hit the Amazon region in the 1980s, more than two thousand tons of mercury has ‘disappeared’. Delft and Brazilian researchers have found the mercury in the hair of Amazon Indian tribes.
Taking a blood sample from an Indian in the Amazon jungle is out of the question, says Dr. Peter Bode, researcher at the Interfaculty Reactor Institute (IRI). ”Indians consider their body as part of their soul, so you may not take anything from it.” However, using gentle persuasion and negotiation, Bode%s Brazilian colleague, Dr. Marina Vasconcellos, was able to get hold of tufts of hair from the Indians of Xingu Park, a reserve tucked away deep in the Amazon jungle. She wanted to measure the mercury level in their head hair to see if these Indians had suffered from gold mining during the past two decades.
Besides the mercury concentration in hairs, Vasconcellos also wanted to determine the selenium level. Brazilian nuts contain high amounts of the trace element selenium, and from this fact a true health hype has originated: Selenium allows antioxidants to work properly and is also very good at mercury detoxication. In Finland, selenium is added to bread, as fluorine is to drinking water and iodine to salt.
With a bag full of hair samples and exciting tales of giant spiders and jungle photographs (the Indians didn’t want their picture taken), the Brazilian researcher arrived at Bode%s laboratory in Delft. ”We have automated element analyses here, which allows us to examine many samples in a short period. At her research institute in Sao Paulo, Marina had to deal with long delays and had to do everything by hand. So she turned to me.”
Poisoning
Bode advised her to investigate many more elements as well, because this can be done easily in Delft, requiring only one instrumental neutron activation analysis experiment. First, the sample is bombarded with neutrons in a reactor; then, by measuring the frequency and intensity of the radiation, it%s possible to determine the concentration of forty different elements in one go. TU Delft is one of the few institutions that are officially qualified to perform this complex work. The entire experiment takes a few weeks.
Although the Xingu Park reserve doesn’t directly border the gold mining areas, the Indians have twenty times as much mercury in their bodies as an average inhabitant of Brazil does; but the level is still lower than the World Health Organisation%s standard for ‘noticeable mercury poisoning’. Other striking differences are the high levels of soil originated elements, aluminium, iron, scandium, and low levels of cadmium and antimony. The amount of selenium is,despite the nuts, not significantly higher in the Indians% hair.
That the gold rush is blamed for the high mercury concentrations is logical, because for every kilogram of extracted Amazon gold, three kilograms of mercury disappear into the environment. Moreover, for the protein in their diet, the Indians rely on fish, a known collector of heavy metals.
Gesture
Still, accusing gold mining companies directly is too simple, according to Vasconcellos, because some of the mercury can derive from natural sources: forest fires or high concentration levels in river water due to intense sunlight. Despite her fear of spiders, Vasconcellos hopes to return to the jungle to gather ground and food samples for further investigation.
The high levels of aluminium, iron and scandium can be explained by the Indians% habit of covering themselves from head to foot in red earth. Bode: ”We think this contaminates their hair. All the hair samples were washed, but if the Indians rub themselves with it for years, the hair becomes saturated.”
Washing the hair is a tough job. Milligram portions of hair, cut into tiny pieces, have to be scrubbed individually. Then, the hairs are dried and, having become static, must be put into plastic sample bottles.
Good news for the Indians, however, is the low levels of cadmium and antimony: Living far from factories and highways, their environment is still spared these pollutants.
Cooperation with Sao Paolo will continue for the time being, Bode says, but not only as a friendly and socially considered gesture to Brazil: ”The relation between feeding pattern health aspects can be found in other research done in our group as well. Soon, I expect two thousand toenails to arrive from America, which we%ll analyse to see if there’s a connection between certain eating habits and coronary diseases. It’s a big research project by the Johns Hopkins School of Hygiene in Baltimore.” You are what you eat, or not, that is the next big question.
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