Mobile phone casings could be a good indicator of general chemical exposure, according to a recently published Canadian study.
After analysing samples collected from the surfaces of electronic devices in the homes of 51 women in Toronto and Ottawa, the study team found a number of chemicals taken from mobile phone surfaces matched those found on their owners' hands.
It is not yet clear whether the chemicals come from the mobiles themselves, or if they indicate total exposure from other sources, write the researchers in the journal Environment International.
Led by Miriam Diamond at the University of Toronto, the researchers used wipes to pick up the chemicals from the devices and the hands. They also analysed air, dust and urine samples for organophosphate ester (OPE) flame retardants and plasticisers.
Five OPEs were detected in more than 80% of the samples, with tris(2-butoxyethyl)phosphate (TBOEP) the most abundant on mobile phones, followed by triphenyl phosphate (TPHP) and tris(2-chloroisopropyl)phosphate (TCPP).
Mobile phone wipes had the highest OPE levels, followed by home phones and tablets, with the lowest levels from desk-top computers, televisions and stereos.
Phone in hand
The study found that OPEs in hand wipes most frequently and strongly correlated with levels on handheld electronic devices, rather than those in dust or air. In particular, six OPEs found in hand wipes "strongly correlated" with those in mobile phone wipes.
The team, which included scientists from Health Canada, believes that it is "highly unlikely" that so many flame retardants would be added to electronic devices or that so many OPEs would be used as plasticisers.
"Mobile phones contain only very small amounts of flame retardants and most of them are used in interior parts of the phone and are unlikely to come in contact with the skin," confirmed the Phosphorus, Inorganic and Nitrogen Flame Retardants Association (Pinfa), a Cefic sector group. "There is also no requirement by law or technical standard to add flame retardants to the phone's casing," it added.
Pinfa points out that some OPEs mentioned in the research are not commonly used as flame retardants in handheld mobile devices but are more likely to be found in furniture and construction materials.
The Canadian team suggests that chemicals in indoor air could perhaps form a film on electronic surfaces, aided by skin oils. The mobiles could also accumulate chemicals transferred from hands after touching other flame retardant-containing products.
The researchers suggest that mobile phone wipes could provide an integrated indicator of exposure to flame retardants and plasticisers, accumulated from multiple sources.
"Our study opens up many questions," said Professor Diamond. "Are these devices holding up a mirror to the chemicals to which we are exposed, or are our handheld devices adding to our exposures?"
Pinfa has compiled a list of flame retardants used by its members in electronic devices. "Electric and electronic appliances, such as laptops and mobile phones, are among the largest users of flame retardants globally," it added.
"The use of flame retardants in these appliances is crucial for consumer safety because plastics materials coming in contact with electric voltages and currents face an increased risk of fire."