Handheld XRF testing does not tell us everything about an item.
We will always be honest with you. We want to ensure that our readers have accurate information and realistic expectations for these kinds of analytical instruments and the screening we do for the blog.
XRF testing is not perfect. But it is a great option for testing random objects in the real world. Portable x-ray tube instruments calibrated to test consumer goods are excellent for detecting a range of heavy elements found in every day products. The instruments are precise and science-based. They can be used at any time, at any place, with minimal training, and do not damage the item being tested.
The Niton XL3t is fully capable of detecting lead in any material down to trace levels. When screening consumer goods, our instrument displays readings at a parts per million level with an error range for each element detected. We also see the list of elements that were not detected.
When we review consumer goods, there are certain things that XRF testing cannot tell us:
The XRF cannot reliably detect light elements like aluminum, beryllium, lithium, magnesium, phosphorus, silicon, or sodium. This particular model has a standard analytical range of 25 elements. We include all detected elements in our posts.
There are many toxic substances that are not detectable with XRF. For example, there are around 1,000 restricted substances under California’s Prop 65. While our blog posts are primarily concerned with heavy metals, we do consider these other substances.
At the minimum, we research and recommend products made without flame retardants and PFAs (“forever chemicals”) whenever possible. Without third party testing, we are reliant on what manufacturers tell us about their products. We also like to support American manufacturing so we sometimes recommend domestic suppliers. This choice is less of a safety concern and more of a preference, although generic products sold on international marketplaces can be riskier on matters of product safety and compliance.
Interference can effectively mask the presence of some elements in a XRF reading, rendering them invisible and impossible to accurately quantify. A common example of interference is when the presence of arsenic is masked by high quantities of lead. Unfortunately, interference is one of the potential drawbacks of using this type of analytical instrument. The primary benefit of XRF is its capacity to test a wide variety of samples without requiring costly and destructive lab testing.
The size of the sample can affect the reading. The scope on the XRF instrument is 8mm in diameter. If we test a small product like a ring under that scope, the total metals detected in parts per million is typically underreported. We discuss these drawbacks when they are likely to occur. We also work to ensure the background behind a small sample does not impact the reading. In the future, we would love to upgrade the XRF to screen smaller samples.
Handheld XRF testing is different from lab testing that meets a regulatory standard. Specific regulatory limits and certificates should be obtained using an approved laboratory as required by law. Laboratory testing provides excellent quantitative and replicable data and comes with added costs and more intensive processing. Handheld XRF is best suited for non-destructively testing consumer products in the field.
XRF testing cannot tell us whether the elements will migrate out of the product. Some toy standards require migration testing as a component of overall safety compliance. This is something the XRF instrument cannot do. We mention in the blog post when a toy is likely to be subject to metals migration testing.
Sometimes we can offer an educated opinion about the potential exposure for a lead-containing item based on the type of product and its condition, or based on the guidance from scientists, regulators, and environmental non-profits. For example, according to the CDC, old plastic toys can create hazardous lead dust when the plastic is exposed to air, sun, or detergents that weaken the bond between the lead and plastic.
XRF data is not the only factor we consider when we test products. Understanding the exposure concern of a product may require more information than the metals that are present. Although it makes sense to keep products high in lead away from children, some leaded items are made in such a way that they do not expose the consumer with typical use.
For example, a glazed dinner plate may contain high amounts of lead but it is required to pass leach test standards in the United States so that it does not pose a risk to consumers. The lead is fired at a high temperature and bound within the glaze. However, dishes made before 1971, ethnic imported pottery, or worn dishes may pose a lead and cadmium poisoning hazard.
We are not simply XRF testers but history explorers. We look at the ways toxic heavy metals were used in the past and the harm caused by using those products.
For example, arsenic was added to a variety of green products. Wallpaper containing arsenic-based colorants killed children in Victorian England. While doctors sounded the alarm, proponents of the deadly products denied reality to protect their own financial interests. One well-known proponent of arsenic laced wallpaper was Pre-Raphaelite artist William Morris, whose wallpaper designs graced fashionable Victorian parlors. His father’s company was the largest producer of arsenic in the world, and some employees reportedly died from arsenic-related health problems.
When examining history, we think it is meaningful to observe when business interests are levied against science and public policy, at the expense of human health. History has a tendency to repeat itself, and we want consumers to be informed and mindful about how corporate interests can shape (or hinder) the regulation of toxic substances. For many of the toxic metals we find using XRF, there are few if any restrictions of those metals in consumer goods.
XRF testing does not tell us whether a trace element was intentionally added or is a contaminant. We find trace toxic elements in products all the time. Some products contain high levels of lead and cadmium and we infer these are known components added because they confer material advantages (e.g., lower melting point, lower cost, machinability). But trace levels of toxic elements are usually unintended and may occur due to contamination from raw materials, processing, or equipment.
A good example of trace heavy metals in a product is lead in lipstick. Often the lead is a naturally occurring contaminant in the colorant. Good sourcing and rigorous testing can keep these contaminants to a minimum. Although we believe a product applied to face and lips should be as pure as possible, for most other consumer goods we do not have a concern for trace heavy metals unless they exceed a regulatory limit, such as total lead content in kid’s products (90-100 ppm), or they are at risk for being swallowed.
Handheld XRF cannot tell us which compounds are present. The instrument detects elements, not compounds. The potential toxicity of an item may be affected by which compound is present. For example, according to this article, the mercury-based colorant cinnabar (mercury sulfide) is poorly absorbed by the body and when heated to produce mercury vapor, requires about 1,000 times higher dose than methyl mercury to produce neurotoxicity. That does not mean that cinnabar is non-toxic or that we should buy fine art made with cinnabar, only that it is less bioavailable than other forms of mercury. Without context, we cannot identify which compound is likely present in a product. We test products for heavy metals and we steer consumers to options that are responsibly made without them. Please note that all lead and lead compounds are potentially harmful to children and total lead content is strictly limited in kid’s products.
We must look beyond the XRF and see the big picture. Why add lead to products when safer options are available? How can we reduce our use of lead and other toxic heavy metals so we can protect the environment and the people who make our things? These global workers are often people of color exploited for meager wages and their families are directly harmed by pollution and occupational poisoning.
How can we plan for a civilization that sustains itself for a thousand years, rather than one that damages the planet and the health of all its people within a few generations due to unsustainable, short-term thinking?
