Locals in San Antonio de los Cobres , Argentina have resistance to poison . Their water supply is contaminated with arsenic more than 137 million times level deemed safe . Scientists at Lund University in Sweden conducted genetic tests on locals . Inhabitants were found to have genetic variation that metabolises arsenic . The villages can still be poisoned by high levels but can tolerate low levels . Arsenic poisoning is thought to harm 20 people globally .
Locals in San Antonio de los Cobres , Argentina have resistance to poison . Their water supply is contaminated with arsenic 20 times level deemed safe . Scientists at Lund University in Sweden conducted genetic tests on locals . Inhabitants were found to have genetic variation that metabolises arsenic . The villages can still be poisoned by high levels but can tolerate low levels . Arsenic poisoning is thought to harm more than 137 million people globally .