Public Lab Research note


Evaluating Low-cost Lead Screening Products

by read_holman | | 54 views | 1 comments |

Read more: publiclab.org/n/19078


Background

A number of products are commercially available that allow for the low-cost screening for the presence of lead.

These are easily found and available online and in department stores. These products are packaged and sold at around the 10-30 dollar price-point. Each package may include one or a handful of tests. They are marketed to consumers — parents, citizens, and the like — who are seeking to better understand whether or not there is lead in their environment. Typically these individuals are seeking to test for the presence of lead in the paint in their home, paint on an old dresser or piece of furniture, dust in a windowsill, or for the presence of lead in their home drinking water. Some people also test for lead on other items, like pottery or dishware.

Currently there are only these types of mediums that can be tested: Paint (painted surfaces), Dust, and Water. There are no low-cost commercial products for the testing of lead in soil.

These low-cost screening products fill an important part of the lead testing marketplace. Other options are much more expensive (from hundreds of dollars) or require working with your local government (which may have a backlog based upon priority).

What is the reliability of these products? What should consumers know about these products before purchasing them? Are there particular cases where they are more reliable? Certain conditions in which they are less reliable? Is there variation across the products, with some better than the others? This note is devoted to exploring these questions.


Note: If you are looking for the various ways to test for lead in your home, these low-cost screening products are only one option. See the following for a complete list: How to Test for Lead in Your Environment. Other options include working through your local government, hiring a contractor, and using a mail-in-service.


How these products work (Methods)

These low-cost screeners deploy a colorimetric approach to screening. Low-cost screeners for lead in paint tend to require a pen or pens (sometimes referred to as swabs) that are rubbed onto the surface in question. Those in water use a piece of litmus paper that is set within a cup of the water that is in question.

Whether paint, dust, or water, the concept is the same: The presence of lead would cause a chemical reaction to take place that changes the color of the testing device. This change in color is compared against a standard to determine if there is reason to be concerned or not.

Here are examples of what results look like:

image description

For this product (3M's LeadSwab) which tests paint/surfaces, if it turns red, this indicates the presence of lead. Photo courtesy Jana Martin.

image description

For this product (WaterSafe's Lead Test) which tests water, you compare the two lines that show up. If one is darker than the other, this is supposed to indicate a positive finding. Photo from Amazon user R Young.

Results are subject to interpretation. These pictures show results that are fairly easy to read: The red is very red! The one line is definitely darker than the other! Importantly, these types of tests are not always easy to interpret. Their results are qualitative and subject to user-interpretation. Indeed, in 2007 Consumer Reports and the Consumer Product Safety Commission, conducted the same tests but came up with different results; the difference was explained simply by the interpretation of the colors (the evaluations were of paint/surface screeners).

Results benchmarked against legally allowable limits, not health. These are screening for whether or not there is lead above the regulatory limits. For example: The EPA's "Action Level" for the lead in water is 15ppb. The lead-in-water screening tests claim to compare against this 15ppb standard. However, all lead is bad; there is no safe amount of lead. These are not designed to detect for low-level presence of lead. [NOTE: verify this / provide source; also a paint example may be more useful than water]


Commercial Products Available

Taken together, there are around 14 products commercially available on the market. These are listed below (note: we attempt to be exhaustive; however, our approach to finding these merely relied on our ability to use search engines and navigate the web.)

Most of these products have not been formally evaluated. Those that have been evaluated are noted.

Paint/Surfaces...

  • ESCA Tech, Inc. D-Lead Paint Test Kit. EPA "Validated" for negative results only (PDF))
  • 3M LeadCheck Swabs (EPA "Validated" for negative results only (PDF))
  • ANDalyze Lead-in-Paint Test Kit. Evaluated by the EPA in 2010 (PDF). This product failed to meet the RPP criteria so has not been "validated" by the EPA in any way.)
  • Silver Lake Research LeadAVERT Test Kit. Evaluated by the EPA in 2010 (PDF). This product failed to meet the RPP criteria so has not been "validated" by the EPA in any way.)
  • PRO-LAB Lead Surface DIY Kit
  • First Alert LT1 Premium Lead Test Kit
  • ChemSee Detection Kits for Lead

Dust...

  • ESCA Tech, Inc. D-Lead Dust Test Kit

Water...

  • Health Metric Drinking Water Test
  • Baldwin Meadows 14-in-1 Drinking Water Test Kit
  • JNW Direct 15-in-1 Test Strips
  • Health Metric Heavy Metals Test
  • Test Assured Complete Water Analysis Test Kit
  • Silver Lake WaterSafe Home Drinking Water Test for Lead

What does the Government have to say about these?

The EPA has a formal “Lead Testing Kit Evaluation” website devoted to its Environmental Technology Verification program. This program evaluates exactly these types of products against standards established by the Renovation, Repair, and Painting (RPP) Rule, a rule applicable to paint/surfaces but not for water.

The RPP criteria (simplified) requires that a negative response less than or equal to 5% of the time must be met; and that a positive response less than or equal to 10% must be met. The products that fail to meet either of these RPP criteria thus have high false-negatives and high false-positives. That is: They aren't reliable. A couple of those are noted in the above list.

A couple products are EPA Validated for negative results only. These products are D-LEAD, which is included in our list shown above. And a product manufactured by Hybrivet. Hybribet, in 2011, was acquired by 3M. The 3M LeadCheck, as is the D-Led product, is included in the list above. These products are the only ones that have any "validation" from the EPA. However, only the negative results are trustworthy; the rate of false-positives is high.

These evaluations occurred in 2012. As noted already, negative results found by these products are considered “EPA validated”; positive findings are not. This is because the evaluations found high-rates of false positives. Indeed:

[The EPA states that] to-date, no product has met the standard for both negative and positive findings per the RPP.


What Does the Internet Say About These Products

Consumer-facing outlets

Blogs, media articles, and the like discuss these products in a colloquial way. These are non-conclusive at best, misleading at worst, and generally lack original research; relying instead on other research (or lack thereof) evaluating these products. All note that a professional test is the best way to go, or at least a mail-in service such as that provided by your local government.

A few examples:

Peer-reviewed Literature

An environmental scan of peer-reviewed literature found very little. Here is the only article we found:

Government Websites, Programs, and Reviews

EPA evaluations on specific products are listed above in the list of products. A couple other government sites:

Citizen/Community Science

One effort by a member of the Public Lab community found the following:


Conclusion

Summarizing the above, we can conclude the following:

  • Most of the products available for sale have not been formally evaluated.
  • Most of the literature, formal and soft, is over 8 years old. For example, 2007 seemed to have been a year when attention was given to this topic by major institutions like Consumer Reports.
  • There are known issues with the reliability of these types of products: They are prone to giving bad results (false-positives and false-negatives); and are subjective to user-interpretation.
  • The two products that are EPA validated for their negative findings were evaluated 6 years ago. While this is not an incredibly long time, it's sufficient time for the products to have changed. For example: The company of one of those products (Hybrivet) has been bought out by another company (3M). [NOTE: Timelines don't exactly line up here... figure this out]
  • There might be a way to use these products in a reliable way, but it'd be a hack. For example, if you conduct 10 tests on the same water and they all provide very clear and readable results, then the results are more trustworthy.
  • All this to say: Use with caution. And: More research is needed.

An Argument for a Formal Evaluation?

All of this argues for renewed attention to these products by research and governmental institutions.

Lacking that attention, the Public Lab community may need to conduct an evaluation of products on its own. We won't be so scientific as to equal the EPA's Evaluation Technology Program, but we hope to be rigorous enough in our methodology to be useful. And perhaps to spur more formal evaluations by larger institutions.

If you're interested in this idea, please let us know in the comments below or by emailing read@publiclab.org. We’re seeking input and conversation on this idea (broadly) and on the approach to evaluating these (more specifically).



1 Comments

Hi @read_holman! Sorry to respond slowly here.

I do think we could try for an accessible evaluation. How much would it cost to buy 2x of each of these methods, and what might an evaluation look like?

Also, what would we consider the "standard" test?

Thanks for this listing and idea, Read!

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