Telltale hairs reveal mercury in Peruvian miners’ bodies

A new study shows that mercury from wildcat gold mining in the Peruvian Amazon is accumulating in the bodies of miners and other people in Peru’s southeastern Madre de Dios region. The analysis of mercury in hair samples reinforces a study by Peruvian health officials in 2010, which found high levels of mercury in some miners’ urine.

In the new study, published last week in the on-line journal PlosOne, Katy Ashe of Stanford University analyzed hair samples from 100 people (38 men and 62 women) in three mining camps and 104 people (60 men and 44 women) inPuerto Maldonado, the capital of Madre de Dios. The highest levels were found in men in the mining camps and in people who reported eating fish more than 12 times a month.

Mercury accumulates in the tissues of organisms. Large fish eat mercury-contaminated smaller fish, and they, in turn, become meals for humans. The effect biomagnifies it goes up the food chain. Mercury is linked to neurological and developmental problems in humans and is especially dangerous to developing fetuses.

Ashe’s study sample was small and not scientifically designed, largely to protect study participants and the researchers from possible aggression by people in the mining camps. She concludes that further study is warranted. And her work highlights a critical point that has gotten lost amid protests by miners fighting recent legislation aimed at curbing wildcat gold mining: mercury in the environment is a long-neglected public health problem in Peru.

Ashe K (2012) Elevated Mercury Concentrations in Humans of Madre de Dios, Peru. PLoS ONE 7(3): e33305. doi:10.1371/journal.pone.0033305

Peru and Beyond

Dammed if they do …

Sunday, September 29, 2013

It’s been one dam story after another in South America in the past week or so. The 2,750 Mw HidroAysén dam in southern Chile got the green light from an appeals court after a…

Alluvial gold mining

Sunday, September 29, 2013

The Andes Mountains are rich in minerals, including gold. Over millions of years, erosion has carried gold down the eastern slope of the Andes and deposited it along river beds,…

Andes mountains

Sunday, September 29, 2013

The uplift of the Andes mountains over millions of years has been due to a combination of plate tectonics and volcanism. Tectonic plates are sections of the earth’s crust that are in…


Sunday, September 29, 2013

More people moving to Amazonia usually mean more deforestation. Regionwide, most deforestation is due to clearing for agriculture, but in some areas of Madre de Dios, deforestation for alluvial…