Children, particularly under six years of age are the most at risk from exposure to lead in the household. This is because their metabolism and breathing are at higher rates than adults and so they can potentially absorb higher levels of this toxin through the lungs and intestinal lining, at a time when their bodies are developing and more susceptible to damage. That is why young children are recommmended to have lead paint testing if you suspect your home to contain lead paint.
Most commonly, lead poisoning comes from soil and dust with lead from paint in it.
Lead was added to paint to improve durability and other properties. Interior and exterior housepaint contained as much as 50 percent lead compounds up until the 1950’s. Lead levels in paint lessened over the years, until the late 1970’s, when the U.S banned paint with over .06 % lead by weight for residential use.
Paint with higher levels of lead that has chalked up or flaked off because of aging, or been damaged during cleaning or renovation is the biggest source of lead in household dust and dirt. Leaded paint on window frame sashes is particularly bad, as the paint is ground into fine dust over repeated opening and closing of the window. Doorways and baseboards are also hotspots for flaking and peeling.
The other source of lead in the household is from soil that has been tracked in to the house. Soil can contain lead from car exhaust, industrial pollution, and houses which have been repainted. Lead can also contaminate drinking water if a home has lead pipes in it.
When to Do Lead Paint Testing
Because of all these potential lead sources, it is advisable to have children younger than seven tested for blood levels of lead, whether you suspect your home of having lead based paint or not. A direct-lead test is done by a doctor or clinic; it is a simple finger stick blood analysis. A negative on the test indicates your home poses no health hazard in it’s present condition.
If you have plans to renovate that involve repainting or disturbing existing paint, it is a good idea to have the paint on the surfaces to be renovated tested for lead. Initial testing can be done yourself with a DIY lead testing kit, available at home centers, paint stores, hardware stores or directly from the suppliers. The kits contain either sodium sulfide or rhodizonate, which react with lead to turn color.
A warning: results from these kits should not be the final word in whether your paint is leaded or not, as they do not have a high level of accuracy. Because the test kits indicate the presence of lead by a color change, results can be affected by any pigments in the tested paint.
Test kits may also not detect lead in a product which has a protective or decorative coating. Test results are unreliable to interpret, since a positive indication does not necessarily mean that there is high enough lead levels in the product to be an exposure risk. Additionally, the test kits have a limited shelf life, and results may or may not be affected by the age of the kits.
Although there are various kinds of kits, the general procedure is the same for all of them. A few drops of the supplied chemical are applied to a paint chip or prepared painted surface and examined for color changes.
It is important to follow the test kit instructions exactly for preparation of the surface; it usually involves chiseling or sanding down to the paint through a few layers, taking care to not contaminate the sample surface with other materials. Lead presence in the paint beyond a certain threshold level will make the chemical turn color. If the test does not show any color change, then the lead levels in the paint are considered acceptable (see warning in the above paragraph).
Lead testing kits shouldn’t be used to test for lead in soil. It is recommended to contact your local agricultural extension office for an approved laboratory where you can send a soil sample for analysis.
Professional Lead Paint Testing
If initial results from a test kit are positive, you should get additional testing done by a professional service in order to verify the results and determine more accurately the level of lead present in your paint. You can also try collecting paint samples yourself and sending them to a lab for analysis, but you need to follow carefully the exact instructions for collection of material. Done properly, laboratory analysis is very accurate, although it requires chiseling away small areas of paint, which will have to be patched and repainted.
Professionals may collect samples for analysis in the lab, but usually rely on specialized handheld instruments such as the X-ray fluorescent analyzer, or the anodic stripping voltameter. Since these devices scan painted surfaces for analysis, they don’t require sanding or chipping of paint and readings are available immediately.
You can also test a many areas, covering more surfaces in the house than would be possible with other methods. Once you have confirmed the presence of lead based paint in your home, you can then make an informed decision on whether to proceed with lead paint removal.
Photo by orijinal, Creative Commons Attribution