Every year, the world discards about 45 million tons of cellphones, computers, televisions, copy machines and other electronics—enough to fill a line of dump trucks stretching halfway around the globe, according to StEP, the United Nations University's e-waste mitigation initiative. A large portion of that electronic junk is shipped to China, where it is dismantled and its components are melted, burned or otherwise broken down so that valuable metals can be recovered. In a study published last week in the journal Environmental Research Letters, researchers from Zhejiang University in Hangzhou, China, reported that human cells cultured in a lab suffered inflammation, stress and DNA damage when exposed to airborne pollutants commonly found near e-waste dismantling sites. While that isn't direct evidence of human health risk, it demonstrates that the potential is there, according to environmental chemist Fangxing Yang, the lead author of the report. Inflammation and DNA damage can be precursors to cardiovascular disease and cancer.
That e-waste can harm human health is not a new concept, but researchers wanted to test it in a controlled laboratory setting. So they sampled air in Taizhou, in western China, where every year about 2 million tons of e-waste are dismantled, often crudely, for recycling. An estimated 60,000 people in Taizhou work in scrapping e-waste, and many of them do so without protections like gloves, masks or goggles. Most also live in the area, so they are constantly exposed to the airborne byproducts of e-waste processing.
Yang and her colleagues collected air samples from two rooftops in Taizhou, about 1 mile and 2.5 miles, respectively, downwind of a large industrial park dedicated to dismantling e-waste. They used water and organic solvents to pull airborne chemicals out of the samples, then exposed human lung cells in a culture dish to the extracted pollutants. They then tested the cells for three indicators of cellular disruption: Interleukin-8 (IL-8), a protein that indicates an inflammatory response; Reactive Oxygen Species (ROS), molecules that can damage cells in high quantity; and p53, a protein from a tumor-suppressor gene that activates in response to DNA damage. Cells that were dosed with the pollutants showed all three stress markers at higher levels than control cells that were not exposed to them: The pollutants from the organic solvent, for instance, increased p53 production about sixfold. In addition, the air samples from the site closer to the dismantling center caused stronger reactions than the samples from farther away.
Previous tests of e-waste recycling areas have identified potentially carcinogenic molecules like polycyclic aromatic hydrocarbons, which form when petroleum products are burned, and polychlorinated biphenyls, heat-resistant chemicals that were commonly used in plastics, electrical equipment and some industrial products until they were banned in the U.S. in 1979. Heavy metals like cadmium, lead and arsenic are also released when e-waste is broken down.
Scientists and environmental groups have long been concerned about e-waste's potential health impact, according to Stephanie Adrian, an environmental health specialist at the EPA. The problem is that they don't have the numbers to quantify the harm. "There is not a lot of data," she says, "so studies like this are really important." In May, the EPA pledged $2.5 million to an international effort, led by the United Nations University, to reduce the impact of e-waste. The initiative will focus on tracking e-waste as it's shipped and processed, reducing illegal exports, and helping countries where it's dismantled develop procedures that are safe and environmentally sound.
Yang believes improvements need to be made on both ends of the e-waste life cycle: Manufacturers should use safer materials in their electronic products, and recyclers should provide masks, gloves, protective eyewear and ventilation fans to keep pollutants out of the air and out of workers' bodies. "The open dismantlement of e-waste must be forbidden, and the workers must get proper protection during their work," Yang says.