Hair Analysis for Uranium
I know several people who have had their hair analyzed for uranium, and they were told that the results were elevated. If occupation, food, and water can be excluded as sources of elevated uranium values in hair, can it be reasonably concluded that the hair analysis may be in error?
Uranium is a naturally occurring heavy metal, and trace amounts of uranium are present in everything in our world—soil, water, rocks, and all living things. All people have some natural uranium in their bodies. Natural uranium is radioactive but only weakly so, and its radiotoxicity is correspondingly quite low. However, as a heavy metal it exhibits chemical toxicity, similar to that of lead, and its chemical toxicity is of much greater concern than its radiotoxicity. The acute lethal dose for uranium is several grams (g), and the amount typically present in the adult male body is on the order of a few tens of milligrams (mg).
As a heavy metal, uranium is excreted in the hair. There is no standard or scientifically accepted method of determining the amount of uranium in the body, let alone a toxic level from hair analysis. While it is possible to accurately measure the amount of uranium in a small sample such as a hair sample, hair analysis for uranium is subject to anomalous and erroneous results. Laboratory measurements need to made under highly controlled conditions so as not to introduce any exogenous uranium into the sample, for even a tiny amount of additional uranium coupled with the very small amount of hair analyzed can lead to large overestimates of the uranium concentration in hair. Thus ultrapure reagents and clean glassware and other laboratory equipment are a strict necessity.
Even if the measurement made by the analytical laboratory is perfectly performed, there are numerous other factors that may introduce contamination with exogenous uranium from natural sources. Many of these relate to the sample submitted to the laboratory which may not be representative of what is in the hair. Soaps, shampoos, hair dressings, and pomades all contain uranium and can leave behind small amounts on the hair or chemically bound to the hair (and thus not removable by washing). Wash water itself can contaminate hair. Even dust (which cannot be seen) that settles on the hair sample can result in an anomalously high reading, as can contact with objects of any kind unless these have been determined to be essentially free of uranium. The hair itself may be a problem, for uranium is not uniformly distributed throughout the hair. The normal amount of uranium in the hair is highly variable and determined largely by dietary factors and the amount of uranium in drinking water. Some well water may be higher in uranium concentration than water from municipal supplies, and some foods such as certain seaweeds may have relatively high trace levels of uranium. However, it is virtually impossible to acquire anywhere near an acute toxic dose level of uranium from these sources.
So we all have trace amounts of natural uranium in our bodies. This is normal.
As for a confirmatory test for your hair analysis, the amount of uranium in your body can be calculated by standard, scientifically accepted models using data obtained from a uranium urinalysis. An effort should be made to determine from the hair analysis lab exactly what the measured levels of uranium in your hair samples were, what value was used for the toxic range, and how the lab determined that you were on the border of the toxic range.
You are on the right track in wanting to know the range of values for uranium in well drinking water so you can better understand the results of your hair analysis. However, hair analysis, while it does detect uranium, is not an accepted method for determining the amount of uranium in the body and is subject to many errors. Don't place a great deal of reliance on the results of a hair analysis for uranium. Readings are frequently high because uranium is present in various amounts in many materials, including soil and dust, and given the low weight of a hair sample, even a tiny amount of dust could produce an artificially high result. And there are other sources of contamination as well, including shampoos. Also, the rate of excretion of uranium via the hair is not known.
The amount of uranium in well drinking water covers a very wide range of values and is by and large determined by the rock strata from which the well water is obtained. Levels would be higher (but typically below the safety standards set by the EPA) in areas such as the Rocky Mountain plateau, upstate New York, along the Redding prong, or near Spokane, Washington, where uranium levels in the soil are relatively high.
The range of concentrations of uranium in untreated well water ranges from about 0.02 to 200 micrograms of uranium per liter of water (µg L-1), and most water typically contains less than 10 µg L-1. The concentration in sea water is relatively constant at about 2 to 3.7 µg L-1. If you are concerned that the concentration of uranium in your well water may be excessive and exceed the safety limits, you may want to contact your state health department for assistance.
You have posed a very good question and one which many people who have high levels of natural uranium in their drinking water have as well. First, by way of background, note that the primary hazard from natural uranium in drinking water is from the chemical toxicity of uranium and not its radioactivity. Uranium is only weakly radioactive, but like all heavy metals, also exhibits kidney toxicity. The chemical toxicity of uranium is about the same as that of lead.
Clearly, however, the level of uranium in your drinking water was elevated, and you are quite right to be concerned about whether your health may have been adversely affected. If you haven't already, you may want to confirm the uranium levels in your water by contacting your state's drinking water well program. The U.S. EPA provides information on programs in each state at https://www.epa.gov/privatewells/private-drinking-water-well-programs-your-state.
Adverse effects, if any (note that the recommended permissible levels have a very large safety factor), would first appear in the form of minor damage to the kidneys, which can easily be tested by a simple (and very inexpensive) urinalysis. If the urine shows any indication of kidney toxicity (such as proteinuria or elevated beta-2-globulin), then your physician will likely want to do additional tests before determining what treatment may be indicated. However, adverse kidney effects have not been demonstrated in epidemiologic studies of populations in Canada and Europe that consumed water containing high levels of natural uranium for decades, so it is quite likely that you and your family are free of any discernable effect on the kidneys.
The elevated level of uranium reported from the analysis of your son's hair is not surprising, but also not very meaningful. Although often highly touted by those who sell the service, hair analysis is notably unreliable for many reasons. There are no generally accepted standards for what is the normal level of uranium in hair, and this level will vary depending on dietary and other factors. Also, the analysis for uranium in hair is quite often poorly done and subject to many sources of error, including contamination from environmental sources of uranium, which would give an erroneously high reading.
1 The uranium concentration is given here in pCi L-1 (called traditional units) because that is the unit used by the Environmental Protection Agency. However, the Health Physics Society has adopted the SI (International System) of units and these are given in parentheses.