Knowing whether lead is present in homes is crucial because of the danger the toxic metal poses to families, particularly those with children. Even in small amounts, lead exposure can contribute to serious neurological and behavioral issues, such as learning disabilities and developmental delays.
To determine whether lead is present in homes, U.S. housing authorities recommend professional inspections using an expensive X-ray fluorescence (XRF) device, which are typically conducted only after a confirmed case of child lead poisoning and can take several weeks for results to be shared with families.
A new study led by University of Washington School of Public Health and Boston University School of Public Health researchers has validated a much faster method to screen for lead in homes from paint or a “take-home exposure” — instances in which individuals who work in hazardous conditions unknowingly transfer lead from their workplace to their home through clothing, shoes and other items, consequently exposing other household members.
Colorimetric wipes, which change to a red or orange color when they detect lead on surfaces or skin, are an effective tool that families can use to immediately know whether lead is in their homes, according to the study in the Journal of Exposure Science & Environmental Epidemiology. The analysis assessed the performance of these wipes in the homes and vehicles of Boston-based construction workers with at least one child living in the home.
Helping families detect lead on the cheap
Developed by the National Institute for Occupational Safety and Health, the wipes detected lead on nearly 60 percent of home surfaces and 71 percent of vehicles. The samples were able to correctly identify the majority of contaminated and uncontaminated surfaces, with a low rate of false negatives and similar results from a subsequent laboratory analysis.
Although colorimetric wipes are sold commercially, federal guidelines only recommend their use in occupational settings, due to a lack of data on how they perform in residences. But the new findings show that these wipes, which cost about $2-$10 per sample (compared to $60-$160+ for lab tests), are a reliable and low-cost screening tool that can be used in cases of suspected residential lead exposure, enabling affected families to take protective action as quickly as possible.
“Validating these wipes for use in workers’ homes helps provide under-resourced health departments with practical tools for lead investigations,” said Diana Ceballos, assistant professor in the UW Department of Environmental & Occupational Health Sciences, who has used the wipes in health hazard evaluations for more than 15 years.
Stemming take-home exposures in construction
For the study, a team led by Ceballos collected 104 colorimetric wipes to assess lead levels on surfaces from nine homes and seven vehicles belonging to lead-exposed construction workers living with children in Boston. In the presence of lead, the wipes changed to a light orange, orange, or red color to indicate a low, medium, or high level of lead, respectively.
In both homes and cars, the wipes were able to swiftly identify lead on surfaces and items such as floors, shoes, laundry room appliances, and trunks, as well as lead on painted home surfaces, such as windowsills.
The colorimetric wipe samples indicated that kitchens had the highest lead levels, followed by entrances, living rooms, bedrooms, and laundry rooms. In cars, the highest lead levels were in the trunk, followed by back seats and front seats.
Adapted from the original story at Boston University School of Public Health.
