A new study has found that even short-term exposure to e-cigarette vapour can deliver toxic metals deep into the lungs, where they build up and interfere with important biological processes, especially the body’s ability to regulate iron.
Researchers from the University of Technology Sydney exposed mice to nicotine-containing vape aerosols over four days and then analysed the e-liquids, the vapour and the animals’ lung tissue. They discovered that metals from the vape liquid can quickly enter the lungs and start to accumulate, even after only a few days of use.
The e-liquid tested in the study contained surprisingly high levels of several toxic metals. Zinc was the most common, followed by aluminium, copper, nickel and arsenic.
When compared to safety limits used for inhaled medicines, some of these metals were present at extremely high levels. For example, arsenic was nearly 500 times higher than recommended limits, nickel was 250 times higher, and mercury was 180 times higher.
The researchers also found that these metals weren’t just present in simple forms. Some were part of chemical compounds known as ‘organometallics,’ which are more easily absorbed by the body because they can pass through cell membranes more readily. This makes them potentially more harmful.
When the team looked at lung tissue, they found that metals didn’t spread evenly. Instead, they built up in specific areas. For instance, lead, nickel and tin were concentrated in certain regions of the lungs, while zinc was more common in others. In some cases, metal levels increased sharply – lead levels were up to 25 times higher in exposed mice and copper levels tripled.
One of the most concerning findings was a significant drop in iron levels in the lungs after exposure to vape aerosols. Iron is essential for many body functions, including immune defence and maintaining healthy cells. In the study, iron levels fell from over 4,000 nanograms per gram in healthy lungs to as low as around 600 in exposed mice.
Even the lowest level of exposure in the study, equivalent to just a few puffs twice a day for four days, was enough to cause measurable changes in metal levels in the lungs. The way these metals built up wasn’t always directly linked to the dose, suggesting the body processes and clears them in complex ways.
Although the study used a refillable vaping device, the researchers noted that disposable e-cigarettes may release even higher levels of some metals, including nickel, copper and lead.
Lead researcher Dr Dayanne Bordin said: ‘From a risk perspective, the findings reveal under‑recognised hazards associated with vaping.
‘Metal emissions and their biological effects are rarely incorporated into current safety assessments or public understanding. Unlike cigarettes, which are a relatively consistent products, e-cigarettes and devices are often manufactured with poor quality control involving materials and components with unknown toxicological relevance.
‘The metal profiles observed are consistent with emissions from heating coils and electrical components, identifying the device itself as a critical source of exposure and highlighting important gaps in how vaping risks are evaluated.’
The full research can be read here.
Photo: Chiara Summer
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