A joke that has gone viral online goes something like this: An air passenger is forced to take off all his clothes but still sets off an alarm while walking through a metal detector at a foreign airport. At first, the security personnel are puzzled, but then they realize that passenger is from China and thus has an unusually high concentration of heavy metals in his body. The joke reflects Chinese people's frustration with environmental pollution and the health risks it poses.

In fact, there is enough scientific evidence - as highlighted by many netizens - to show that Chinese people are indeed part of a "heavy metal band". For instance, the New York Health Examination and Nutrition Survey reveals that immigrants from the Chinese mainland have "higher blood levels of lead, cadmium, and mercury than either reference group". The report published in the Journal of Immigrant & Refugee Studies also says that the high level of heavy metals in Chinese immigrants is probably associated with their diets, that is, the contaminated food they eat.

While the US report may not be applicable to people across the Chinese mainland, illegal dumping of untreated industrial effluents and the high concentration of heavy metals in some food products have indeed become public health hazards.