Answer to Question #3802 Submitted to "Ask the Experts"

We are conducting a Preliminary Environmental Hazard Site Investigation on a former waste transfer site that has reported violations of transferring red and yellow bags of radiological and biological medical waste and improper disposal handling. What guidelines are there to follow when investigating soils at sites with potential radiological and medical waste? What precautionary measures should be taken? What equipment should be used to detect the presence/absence of radiological medical waste? For health and safety plan preparation what requirements should be met to safeguard the field sampling/investigation team?

Field sampling and investigation activities at a former waste transfer site certainly warrants a careful assessment of the hazards present in order to develop a protective health and safety plan. There are a number of potential hazards that must be addressed, including physical, environmental, chemical, biological, and radiological hazards. A historical site assessment should be performed to better understand the nature of the radiological and medical (biological) waste handled at this site. For instance, what radionuclides and radioactivity levels are expected to be present? It may be of interest to note that the US Nuclear Regulatory Commission (NRC) issued an Information Notice (99-33) that addressed the management of wastes contaminated with radioactive materials and specifically mentioned incidents involving ^99mTc and ¹³¹I identified at waste transfer stations. Radioactive medical wastes from university/hospital facilities often include ³H, ¹⁴C, ³⁵S, ¹²⁵I, and ³²P. These radionuclides are generally difficult to detect (with ³²P being the exception). ³H, ¹⁴C, and ³⁵S are low-energy beta emitters, ¹²⁵I is a low-energy gamma/x-ray emitter, and ³²P is a short-lived (14-day half-life), high-energy beta emitter. Radiation survey instruments might include those that are sensitive to low energy beta radiations for example, gas proportional detectors, GM detectors, and plastic scintillators) and low-energy gamma radiation (thin crystal NaI detectors). The detectability of these low-energy radiations will be impacted by the shielding provided by the soil.

Radiation protection controls should be considered when performing characterization/investigation surveys where the potential for significant levels of residual radioactivity is unknown. The investigation team should approach the site with the survey meter "on"; exposure rates around the site can be measured with a portable ion chamber or microrem meter. ANSI N13.49 Performance and Documentation of Radiological Surveys (available on this Web site to Health Physics Society members only) recommends that appropriate protective clothing (for example, safety glasses/goggles, gloves, lab coats, safety shoes), dosimetry devices, and other protective equipment be worn by the surveyor, and that surveys be performed to minimize personnel radiation exposure-for example, remote monitoring and extended probe instruments may be used to accomplish this objective.

Finally, it is nearly impossible to list all the potential hazards that you should consider in preparing a health and safety plan for the field sampling/investigation team. I'll provide a listing of several that come to mind. Physical hazards to consider during the planning effort include slip, trip and fall hazards, heat stress, severe weather, and underground utilities. Environmental hazards might include insects, poisonous snakes, plants, and animals. Chemical hazards might include lead, PCBs, mercury, benzene, asbestos, etc. Biological hazards (blood-borne pathogens) from contact with contaminated medical equipment or medical waste or sharps, tick and mosquito bites that may transmit Lyme disease and West Nile virus, respectively. Extraordinary care should be taken to avoid accidental injuries from sharp objects (needles, scalpel blades, syringes, lab instruments) when investigating soils with potential wastes in handling waste. In conclusion, the health and safety plan should incorporate procedures for identifying and eliminating, avoiding, or minimizing these potential safety hazards. The process of identifying hazards associated with a particular work scope, and then developing controls for these hazards, is called Integrated Safety Management.

Eric W. Abelquist, CHP