Levels of organophosphate esters (OPEs) — compounds widely used as flame retardants and plasticizers to increase durability — found on cell phones and other handheld devices could be significantly associated with the amount of OPE metabolites in the urine, warn Canadian researchers.

OPEs have been linked to adverse health outcomes, such as reduced cognitive abilities in children and papillary thyroid cancer in adults, as well as worse in vitro fertilization outcomes.

Congqiao Yang, PhD, Department of Earth Sciences, University of Toronto, Ontario, Canada, and colleagues looked at OPE exposure through air and dust on home and electronic devices in more than 50 women.

The research, which was published online December 4 in Environment International, revealed that the women were exposed to several OPEs, with a significant correlation between the compounds found on their hands and the presence of metabolites in the urine.

In a press release, senior author Miriam L. Diamond, PhD, also of the University of Toronto, said: “What we don’t know for certain though is whether electronic devices are the source of the chemicals or an indicator of total exposure from other sources, or both.”

She continued, “Earlier this year the US Consumer Product Safety Commission granted a petition to ban the use of certain harmful flame retardant chemicals in electronics and other products.”

“The OPEs identified in this new study are often used as replacements for the banned chemicals, and increasing evidence indicates that these replacement chemicals are harmful as well.”

Children Especially Vulnerable: Wash Devices and Hands

The new findings come amidst calls for increased focus on the environmental and human health impacts of electronics. Existing electronics industry standards cover thermal, electrical, optical, and even acoustic product safety, but do not specify how materials should be screened for possible toxicological impacts.

Diamond told Medscape Medical News that exposure to chemicals such as those tracked in this study is of particular concern among children. She explained this is not only because of cumulative lifetime exposure, “but it’s also because kids are more vulnerable.”

“They’re vulnerable because their organ systems are still developing, so we want to be particularly cautious about kids’ exposures to toxic chemicals.”

In any case, she recommends that all phone and handheld device users be conscious about the amount of time they spend using their devices and to clean them from time to time. “Washing your hands is a good idea,” she said, “and washing your phone periodically is a good idea.”

“Very few people actually wash their phones,” Diamond pointed out, adding: “Your phone picks up the signal of all the things that your hands have been touching plus what’s in the phone itself.”

Diamond added that, for their next study, she and her colleagues would “like to look at children’s exposure through electronic devices, particularly because kids are given electronic devices at younger and younger ages.”

She continued, “You have really small kids being looked after by a cell phone now rather than by a human, so you wonder what the implications are.”

“Kids have a lot of hand to mouth contact, kids are always putting their hands in their mouths, so we’re very keen to look at what happens with little kids and electronic devices.”

Are Cellphones the Chicken or the Egg of OPE Exposure?

To investigate the sources of exposure to OPEs, Yang and her team recruited 51 participants in a population-based, case-control study of women with and without breast cancer.

The median age of the women was 41 years, and 78% had breast cancer. The women were predominantly white, highly educated homeowners, with 54% reporting an average household income of over $100,000.

The women completed a questionnaire about home characteristics, including thermal insulation type; personal demographic and lifestyle data, including use of personal care products and hand washing frequency; and presence and usage of major electronic devices and upholstered furniture.

The team also performed two in-home assessments, separated by approximately 3 weeks, to record particle levels in respirable air and floor dust in bedrooms (n = 51) and the most commonly used rooms (n = 26).

The palms and backs of hands of participants were wiped. Surface wipes of electronic products that operated at elevated temperatures or were in frequent contact with hands were also taken.

Forty-four participants also provided urine samples an average of 2 months before the first home visit. Overall, 23 OPEs were analyzed in the air, dust, and wipe samples, and eight OPE metabolites were assessed in the urine samples.

Six of the 23 OPEs tested were detected in over 80% of air samples, and seven had detection frequencies over 70% in dust samples, with no significant differences between the bedroom and most-used room.

Palms had higher concentrations of OPEs than the backs of the hands.

For all nine OPEs detected on electronic devices, concentrations on handheld devices (for example, cell phones, home phones, and tablets) were significantly higher than those seen for non-handheld devices, such as TVs (P ≤ .001).

Statistical analysis using hand wipes, cell phone wipes, and dust explained 8% of 33% of the variation in creatinine-adjusted urinary metabolites; air concentration did not have explanatory power.

The team writes, “Our results showed that exposure of some OPEs in these women can be explained by levels found on their cell phones.”

“The results do not allow us to distinguish between whether the cell phone is acting as a source of OPEs or rather a time- and space-integrated indicator of OPE exposure; likely both explanations are reasonable.”

They add, “Cell phone wipes could provide an integrated indicator of exposure to flame retardants and plasticizers accumulated from multiple microenvironments, particularly since most people are in frequent contact with their cell phones that are infrequently washed.”