Radioactive material can emit radioactive particles (alpha and beta) or gamma rays which, like an X-ray, can penetrate humans through external exposure. All types of radiation exposure (external or internal) can alter the genetic make-up of cells. A large enough dose will kill cells.

     Radiation exposure can occur either externally or internally. External exposure occurs as radioactive by-products descend from the sky as fallout from the stacks at Hanford and are carried by the wind in different directions and speeds depending on the size and chemistry of the material and the weather conditions. Internal exposure occurs by the direct inhalation of airborne radioactive material or by ingestion principally through food or water that has been exposed to radioactive material.

     Once inside the body, many radionuclides concentrate in a specific organ and continue to irradiate that organ until the radiation decays or is eliminated from the body. Iodine-131, for example, normally concentrates in the thyroid gland. There is not only a concentration by virtue of the fact that most of all iodine intake is localized there, but there is a further concentration by virtue of the great disparity in size between the thyroid gland and the body as a whole. Certain other materials, such as phosphorous and plutonium, are generally deposited in the bone, where they may do considerable damage to the radiation sensitive bone marrow, the center of the body's blood cell-forming processes.

     Radioactive elements and non-radioactive hazardous materials, can reach the human population in a variety of ways including through air, water and the food chain. Each pathway operates differently.

AIR

     The air is probably the most obvious method for humans to be exposed to radiation. The Hanford Dose Reconstruction Project estimated that 740,000 curies of iodine-131 (I-131) were released into the air from Hanford during its operation from 1944 through 1972. More than half ot the total I-131 was released during 1945.  The radioactive iodine, as well as the other radionuclides released from the facility, exposed humans to radiation both externally and internally.

     The recent release of the National Cancer Institute (NCI) study on the atmospheric testing of atomic weapons confirmed that areas of Washington, Oregon, and Idaho received radioactive air releases from the above ground nuclear tests conducted in Nevada in the 1950s. One of the primary fission materials in the fallout is iodine-131. Thus, some people were exposed to radioactive materials from both Hanford operations, and weapons testing at the Nevada Test Site (NTS).

WATER

     Operations at Hanford discharged radioactive materials into the Columbia River. Hanford's reactors received their cooling water from the Columbia River. Impurities in the water were irradiated inside the reactor, and the contaminated water was then discharged into the Columbia River. Additional releases of radioactivity to the river resulted from ruptures in fuel elements and chemical purges of reactor piping systems.

     As a result of the reactor operations, substantial amounts of various radioactive materials, including, among others, phosphorus, neptunium, zinc, arsenic and chromium, were released into the Columbia River from 1944 to 1971.  The highest releases of radioactive materials from Hanford to the Columbia River occurred from 1957 to 1965.

     The discharges from Hanford exposed people who ate fish and waterfowl, swam or boated on the river, irrigated their fields with water from the river, or simply drank the water from the Columbia River (such as residents of Pasco and Kennewick). The exposures to radioactive materials through the water pathway increase a person's total exposure to radiation when coupled with exposure through the air emissions.

VEGETATION, FOOD and WATER

     There are several ways in which vegetation can be contaminated by radioactive fallout. Radionuclides can fall on the foliage, stick to the leaves, fruits, vegetables or seeds. Radioactive material can be washed down from the air by rain or snow and absorbed directly by the leaves and surface roots of plants. Radioactive materials can also enter the soil and get into the plant via the underground roots just like a soil nutrient.

     Radionuclides in or on plants reach humans by our consumption of foods or plants or through the consumption of milk or meat from animals that have grazed on contaminated plants or grain. Animals and plants can concentrate radiation thousands of times the concentration in the surrounding environs. Various factors, such as metabolic behavior of the specific radionuclide, and animal feeding and management practices, influence the relationship between the amount of radionuclides eaten by the animal and the amount deposited in tissues and in secretions, such as milk.

     Children, usually the largest consumers of milk, are more susceptible to the harmful effects of radiation than adults. One pathway for babies being exposed to radioactive materials, such as iodine-131, is through a mother's breast milk. Like any other living organism, nursing mothers who consume contaminated plants or animals, drink radioactive milk or water, inhale radioactive material or are otherwise exposed to radiation, also secrete harmful radionuclides into their milk and pass it along to suckling babies in a more concentrated form.

     Humans can also receive radioactive contamination through consumption of fisheries products or waterfowl. Like a grazing land animal, fish and waterfowl of the Columbia River accumulated contamination from eating plankton, algae and other aquatic food sources. The radiation was then distributed throughout the fish and waterfowl and, depending on the chemical form, concentrated in a particular organ. For example, phosphorous-32 was concentrated mainly in the bones, whereas zinc-65 was more evenly spread throughout the body.

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Radioactive Materials Known to Have Been Released into the Air by Hanford 1944-1972

Radioactive Materials Known to Have Been Released into the Columbia River 1944-1971

Other Hazardous Substances (Non-Radioactive) Discharged into the Columbia River