An international research team has analyzed samples of household dust and found that nearly half of them contained potentially toxic chemicals that are commonly used in television, smartphone, and computer displays. The scientists are warning that liquid crystal monomers, which are found in many different products including flat screens and solar panels, could be dangerous to people and animals. The findings have been reported in the Proceedings of the National Academy of Sciences (PNAS).
"These chemicals are semi-liquid and can get into the environment at any time during manufacturing and recycling, and they are vaporized during burning. Now we also know that these chemicals are being released by products just by using them," said environmental toxicologist John Giesy, Canada Research Chair in Environmental Toxicology at the University of Saskatchewan (USask). "We don't know yet whether this a problem, but we do know that people are being exposed, and these chemicals have the potential to cause adverse effects," he added.
The scientists assessed 362 liquid crystal monomers for their toxic potential, and went on to test monomers that are often used in six popular smartphones. Specific monomers that were present in the smartphones were found to be potentially hazardous. These chemicals had properties that are known to disrupt gallbladder and thyroid function and nutrient digestion in animals; they are similar to flame retardants and dioxins that are known as for their toxic effect on wildlife and humans.
In this work, dust was gathered from seven different locations in China: a student dorm, teaching building, hotel, residence, laboratory, and an electronics repair facility. Out of the 53 samples collected, about half were found to contain liquid crystal monomers. Of the monomers that were detected, ninety percent had chemical characteristics that concerned the researchers; the chemicals could build up in organisms, be easily moved in the atmosphere over long distances, or tended to resist degradation. Around a quarter of the compounds had all of those properties.
"Ours is the first paper to list all of the liquid crystal monomers in use and assess their potential to be released and cause toxic effects. We looked at over 300 different chemicals and found that nearly 100 have significant potential to cause toxicity. There are currently no standards for quantifying these chemicals, and no regulatory standards," said Giesy. "We are at ground zero."
LCDs ( liquid-crystal displays) tend to be made in one of three countries: Japan, China, or South Korea. Around 198 square meters of LCD were generated last year alone, which is enough to coat Aruba. Huge amounts of electronics are thrown away, including LCDs, and released into the environment.
"Since there are more and more of these devices being made, there's a higher chance of them getting into the environment," said Giesy. "Right now, there are no measurements of these monomers in surface waters. Our next steps are to understand the fate and effect of these chemicals in the environment."
Previous research led by Giesy showed that perfluorinated and polyfluorinated chemicals were contaminating the planet, and ultimately led to their ban around the world.
Sources: AAAS/Eurekalert! via University of Saskatchewan, PNAS
