Yang said many risk factors are included in her research.
In one county where locals had similar lifestyles, the incidence of cancer among those who drank water from the river was much higher than those who had alternative drinking water sources, she said.
Generally speaking, "villages along the polluted river tended to have a higher cancer occurrence", she said.
But conditions appear to be improving, according to the study. The polluted areas have dwindled since 2005 thanks to government actions, including shutting down many factories that were polluting the river.
For villager Guo Heling in Shenqiu, whose brother was diagnosed with nasal cancer four years ago and is now bedridden, his hopes are attached to his two sons, who work in Shanghai.
"I hope that my sons can buy houses in some other place. That is the only way we can leave the polluted land forever," he said.
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