Immersed in a Sea of Radiation

You don’t have to look far to find radiation in the world around us. In fact, the vast majority of radiation that we are exposed to throughout our lives comes from natural sources. Naturally Occurring Radioactive Materials (NORM) are very common in the environment and can be found in many products in our homes and cars. These materials generally pose very little, if any threat to our health, and it may surprise you how many everyday items have radioactive properties.

This rock from southern Utah contains Thorium-232.

The most common NORM contain radioactive isotopes of uranium, thorium, and potassium, as well as the isotopes these decay into (such as radium and radon). Although  much of the earth’s surface contains very low concentrations of radioactive materials, NORM is concentrated in many raw industrial products and activities such as the following:

Coal: although other rocks in the earth’s crust have approximately the same concentration of NORM, the large quantities of coal needed to fuel much of the world’s energy demands are responsible for a sizable amount of radiation and a wide variety of isotopes including potassium, lead, and radium. An interesting fact about NORM in coal is that the naturally occurring uranium contained in coal could be a fuel source more powerful than the coal itself if used in a certain type of nuclear reactor¹. 

Phosphate Rock: mainly used for fertilizers, phosphates can have much more concentrated amounts of NORM than other mining products. The radioactive content of phosphates has attracted media attention after European fertilizer manufacturing had been found responsible for radioactive material in the Atlantic.

Granite: this type of stone has traces of uranium in it, which means that many federal buildings such as the United States Capitol are faintly radioactive. We’ve found that the MiniRad-D (a small radiation detector) reads a constant radiation level of 2 around the perimeter of the Utah State Capitol, which has a granite facing on its exterior. Radiation measurements on granite surfaces can even show comparable levels to those from low-grade uranium mine tailings.

Oil and gas production: most of the radioactive material brought out of the ground in oil and gas production is deposited in pipes and other equipment. The concentration of NORM has made the resale of used equipment more difficult in recent years.

Although industrial activities are responsible for large amounts of NORM, many common household items also have significant amounts of radiation. Here are a few examples:

Smoke detectors: one of the most radioactive items in a home is the smoke detector, which uses an isotope of americium to sense the presence of airborne particles carried by smoke.

A small Americium-241 pellet from a smoke detector is contained in the plastic holder on top of the MiniRad-D device.

Ceramics: some of the most famous antique radioactive items are Fiesta Ware ceramics, which were produced from 1936-1943². The red glaze on these dishes contains Potassium-40, as do  the glazes of other ceramics with red, yellow, green, and black colors. The clay itself used in some ceramics can also contain NORM. Ceramic products such as bathroom tiles and porcelain can also show up on a radiation detector.

Cat litter: the main ingredient of cat litter is clay, which like that used in ceramics, often contains low levels of NORM.

Colored glass: uranium was commonly used as a coloring agent in yellow and green glass produced in the first half of the 20^th century. You can find antique dinnerware, home décor, and even children’s marbles that emit a measurable amount of radiation.

These antique marbles contain trace amounts of uranium.

Glossy paper: Kaolin, a substance known as “white gold” for its versatility and value, was commonly used to create glossy paper on magazines in the early 1900s. Kaolin contains clay with low concentrations of uranium and thorium.

Instrument dials: due to its ability to fluoresce, radium was used in paint for marking instruments and watch dials. This paint exhibits a bright green color when fluorescing.

Spark plugs: dating back to 1940, some old spark plugs contain an isotope of polonium that was used to make a more brittle alloy that readily creates sparks.

Lantern Mantles: old Coleman lantern mantles contain low levels of Thorium-232, an isotope with a 14 billion year half-life. Special care should be used when dealing with used mantles to ensure the radioactive dust isn’t breathed in.

A Coleman lantern mantle with a MiniRad-D detector.

Food: many foods contain trace amounts of radiation, including potatoes, bananas, kidney beans, and Brazil nuts. Salt substitute, which contains potassium chloride instead of sodium chloride, may also have a low level of radiation due to the presence of Potassium-40.

1) http://www.world-nuclear.org/info/inf30.html

2) http://www.orau.org/ptp/collection/consumer%20products/consumer.htm

D-tect Systems is supplier of advanced radiation and chemical detection equipment sold around the world. www.dtectsystems.com.