Radioactive Wastes From Medical Facilities: Where Do They Go??

Every day medical procedures as well as research utilize radioactive dyes such as radioiodine. This results in production of large amounts of radioactive wastes. An environmental waste consultant company called EcoEndeavors was commissioned to examine the sludge at an Ann Arbor, Michigan, Waste Water Treatment Plant, which receives waste from the University of Michigan hospital complex. The diagram below demonstrates the major contributors of wastewater from the various hospitals in the complex and the relationship between the wastewater plant and the Huron River. Radioactive releases from these institutions flow into a municipal wastewater treatment plant and are processed with other wastes into sludge matter that is removed, dehydrated, and either land-applied or incinerated. The treated effluent (or water) is then dumped into the Huron River. The sewage effluent may contain suspended particles and entrapped radioactivity not removed in the primary treatment.

The sludge from the wastewater treatment plant is stored in primary and secondary sludge basins and will either be incinerated or applied to land as a fertilizer treatment. The burning of sludge produces ashes and atmospheric releases that potentially contain radioactive materials. The land treatment may also contain residual radioactive wastes.

What We Need to Know

What does "radioactive" mean?
What is radioactive iodine used for in medical research and routine procedures?
What are biological consequences of radioactivity?
What does the diagram reveal about the possibility of contamination reaching the people of Ann Arbor?
How long does radioactivity remain hazardous to biological systems?

Radioactive sodium iodide (Na 131-I) is a common compound used in medical treatment for thyroid disease. About 750,000 diagnostic thyroid scans are performed each year in the United States. Each procedure utilizes about 0.01-0.1 millicuries of I-131. Treatment for an enlarged thyroid requires many times that amount. Patients who have been injected with the iodine will eventually excrete the material in their urine or feces mostly while in the hospital.

The EcoEndeavor Corporation was consulted as a matter of routine safety in order to comply with OSHA standards. The scientific research team specifically tested the amount of radioactivity in the sewer system following the treatments of two patients with thyroid disease. The patients were Vietnam veterans who were patients in the VA Medical Core. When the amount of 400 mCi was administered to each of the two vets, at least 340 mCi would have been excreted with the urine into the waste coming from the VA hospital.

What We Need to Know

Who regulates the medical use for radioactive material in the United States?
What are the federal regulatory limits on radioactive release?
What is a "microcurie?"
What is the estimated "safe" dosage for a person exposed to I-131?
What is known about radioactive effects over time?

A hospital epidemiologist noticed that some local farmers and other citizens of Ann Arbor were developing cancer at higher rates than the normal U.S. population. The nearest residence was about 500 meters downwind in the prevailing direction for the site studies. It appeared that the Ann Arbor plant had a transport time for radioiodine which was much longer than for a more typical sewage plant. The average rate of sludge production at the treatment plant is about 530,000 liters per day. Incineration of this amount of contaminated sludge could release as much as 100 million Bq of I-131 per day.

What We Need to Know

As a citizen with this information, would you be concerned about the health of the environment as well as the population?
Why might I-131 cause an increase in cancer rate among citizens of Ann Arbor?
What are the consequences of increased or decreased sludge transport time?

Assignment

Investigate the above information. If you were a farmer obtaining sludge to fertilize your fields would you be concerned? Do your own research and report to the farmers' cooperative in your area about your findings.

Design an experiment to determine the effects of the sludge in a biological system.

RESOURCES

National Research Council. Radiation in medicine. 1966. Washington: National Academy Press.

Moss C.E. 1973. Control of radioisotope release to the environment for diagnostic isotope procedures. Health Physics. 25:197.

Pritchard. H.M.; T.F. Gessel; and E. David. 1981. Iodine-131 levels in sludge and treated municipal wastewaters near a large medical complex. Am. J. Public Health. 71:47.

Sodd, V.J.; R.J. Velten; and E.L. Saenger. 1975. Concentrations of the medically useful radionuclides--technecium-99 and iodine-131 at a large metropolitan wastewater treatment plant. Health Physics. 29:355.

http://www.rfa.mas.lu.se/research/envir_rad/environ.html