POPs change DNA in Greenlandic Inuit -- perhaps for generations.
Rusiecki, JA, A Baccarelli, V Bollati, L Tarantini, LE Moore and EC Bonefeld-Jorgensen. 2008. Global DNA hypomethylation is associated with high serum persistent organic pollutants in Greenlandic Inuit. Environmental Health Perspectives 116(11):1547–1552.
This is the first study to look at the association between persistent industrial chemicals and modified DNA function in a human population.
The authors examined changes to DNA methylation. DNA contains the genetic instructions of life. Methylation of DNA can modify these genetic instructions. Methylation of DNA can be disrupted by environmental chemicals. Methylation of DNA can also be passed along generations.
In this study researchers found that in general, Inuit with higher blood levels of persistent organic pollutants (POPs) also had decreased methylation of their DNA. Although long-term health consequences are not known, altered methylation patterns have been associated with cancer.
Prior laboratory studies find similar results in animals. In the laboratory, the DNA methylation changes may last for multiple generations. Whether people are also affected for multiple generations is of concern and needs to be resolved.
Despite living thousands of kilometers away from industry, Greenlandic Inuit have some of the world’s highest levels of industrial pollutants in their bodies. Air currents carry the compounds north. The chemicals fall to the Earth in the cold Arctic temperatures where they contaminate soil, water and wildlife. The Inuit's exposure to industrial pollution -- mostly through their food -- is believed to be harming their reproductive, endocrine and nervous systems.
POPs are considered some of the most dangerous chemicals in the world because they are widespread, long lived, collect in fat and are associated with cancer and other diseases in wildlife and humans. Most have been banned from production/use through a global POPs treaty, but exposure continues because they persist in the environment.
In this study, scientists measured several industrial pollutants -- including DDT and PCBs -- in blood samples collected through the Arctic Monitoring and Assessment Program (AMAP). DNA methylation was determined in the same blood samples. The influence of age, smoking and other variable were taken into account in the study.
The researchers examined 71 blood samples from people between the ages of 19 and 67. The POPs levels measured in the samples "rank among the highest in the world," according to the authors.