New 2013

***Q. Though radio waves, FM, infrared comes under the category of non-ionizing radiation. Are these waves really harmful for human? I know this is quite a controversy these days but what is your comment on it?
A. In a sense, it is no different than chemical toxicity, the dose determines the response.  There is zero proof these cause cancer directly.  The only effect proven is tissue heating, which of course can destroy tissue, but it takes very high doses for this – cooking. 

Q. One area found a little fuzzy was the E and H fields, one is magnetic and one is electric, but what really is the point of them?
A. The point is that in the near field you need two different kinds of meters.

Q. [Ghost Detectors] One thing I found foggy was the concept of ghost hunting. Although I wouldn’t consider that central to the text, but I just wanted some clarification. Would that be the ‘metaphysical’ way of saying people, for fun or experiments, using meters to identify the presence of electromagnetic force or waves in an area?
A. I was just trying to be funny.  It has nothing to do with the course. 

New 2009

**Q. The measurement of TLV of the max power that a person should be exposed to, that it has to be measured separately at low frequencies but not at higher frequencies.  Do you have any practical examples of this?  I don’t have much experience in this area.  
A. Yes it is complicated.  But see
http://www.faculty.uaf.edu/ffrap/EQE_649/Module_06/Submodule6A/Submodule6A_4.htm
For example radio frequency for an AM radio station would be between 520 to 1610 khz, while FM radio is 87.5 to 108 mhz.  So if you were standing near a transmitter for your favorite FM station, you could see what the TLV would be for E and H, and you would need a separate meter for each.  If it was a radar, at 30 ghz, you would only need to measure the E field and need only one meter.  If you did not know the frequency, you would need a special device to determine that.  As a practical matter, all manufactures of electrical equipment will give you that or it is stamped on the device.  Some industrial equipment, heating, for example, might have a range of values – see you local industrial hygienist. 

OLD

***Q. (TLV's for electromagnetic radiation) On submodule 6A, when you are discussing TLV's. I do not understand at all what the "result" is from the chart. Can you take another stab at this explanation?
A. Actually, I tried to avoid it by telling you not to worry about the details, just realize that the TLV's are a function of both the power and the frequency. The chart derives from the fact that close to the source of EM radiation, there is something called the "near field" at which the electric and magnetic fields are separated. This range is a function of wavelength. At low frequency = long wavelength, the near field extends out to where people are affected. So at low frequencies, you must measure both E and H. The human health effects are different for E and H, so there is a different TLV for each.

**Q. The reading states the typical annual exposure in the US is 360 mrems. Yet the EPA recommend a maximum of 100 mrems….what gives there?
A. So the EPA would have us evacuate the Utah plateau. Yes, the EPA recommendation recognizes the natural occurring burden.

**Q. Something that wasn't straightforward to me was about the regulating bodies for radiation hazards. Is this under OSHA? Does the EPA regulate environmental limits for residents? I'm assuming it's the same for other hazards but what's the specific role of the Nuclear Safety Committee, and where does the DOE fit in to all of this? I liked the comparison page in the power point presentation from Hanford but what is the structure of Japan's regulating bodies for employee safety and exposure? (Not that it is essential to the module, just curiosity)
A. I can answer that in the US. OSHA regulates worker health and safety for all non-government employee and federal employees. State and local governments were exempt, but most of these have passed similar laws. OSHA recognizes the National Council on Radiation Protection and Measurements (NCRP) for standards and ACGIH references the International Commission on Radiological Protection for its standards. I suspect the numbers are very similar. So determining if workers must wear a dosimeter and how many RADs they can be exposed to is an OSHA issue. The EPA controls emissions to the environment. That is, if a plant was dumping its cooling water in the river, EPA would determine how much radioactivity would be permitted. (Remember an early Simpson's episode with the three-eyed carp? That was an EPA issue.) The Federal Nuclear Regulatory Commission (NRC) regulates the licensing of uses of nuclear energy, including devices. So if you were manufacturing a radioactive source for X-raying welds, you would need a license from NRC. Disposal of radioactive waste depends on its level. I'll stop there.

**Q. What is the exposure from a typical dental x-ray? Medical x-ray?
A. Dental is probably 0.5 to 3 mrem, but that is directly to you. The technician is around hundreds of mrem each day, but he is farther away and wearing a lead apron. Medical is higher and depends on the procedure.

**Q. I didnt quite understand - why is it needed to measure electromagnetic
radiation when the frequency is low, below say 1 MHz? for what purposes? if it
was harmful we wouldnt have all these apliances at home...
A. I wasn't saying it was harmful at that frequency, because harm depends on both power and frequency. The point was that at low frequencies you need to measure the magnetic and electric fields separately.

*Q. I knew that cell phone created brain damage. I don't know of any credible scientific evidence for that. The damage lots when people who are talking on them while driving automobiles crash into you or me.

*Q. I did read the section covering threshold limit values as set forth by the ACGIH. I have to admit it is a little fuzzy to me. The example was okay but how to apply that to where I work is unclear.
A. The ACGIH defers to another standards-setting organization for ionizing radiation, International Commission on Radiological Protection. In turn, the ICRP lets ACGIH publish the standards ICRP has developed.

*Q. I have a couple of questions around the non-ionizing radiation chart (the one that shows the visible and non-visible spectrum and has both frequency and wavelength…) The example in the reading asked us for the wavelength of 60Hz and gave the answer of 5000km. Using the formula, I also come up with 5000km (L*f = c. L * 60Hz = 3*1010 cm/sec. L = 500,000,000 cm.) But, looking at the chart this doesn't seem to add up…60 Hz would be between the 1 and 102 on the frequency scale, right? That lines up with 107 on the wavelength scale. 107 doesn't equal 5000. What am I looking at incorrectly on that chart?
A. The scale is in meters, so 10^7 is 10,000 km, I played with the scale and got about 7,000 km, so the pictorial scale is a little distorted.

* Q. Speaking about Radium Girls accident… The girls were exposed to chronic effect of radium (probably high doses). But only in a few years the symptoms of poisoning have been revealed. On the other hand, workers in the Tokaimura story were exposed to acute doses of uranium and they felt sick at once. Is there some information about the dose-effect correlation on humans?
A. Yes, lots of information. The radium girls had very high doses to the mouth and GI tract. This caused cancer, which takes several years to develop. The Tokaimura workers were blasted with much higher doses that destroyed tissue, especially bone marrow, and killed them rather quickly. Other workers and the fire fighters may develop cancer in a few years, too. However their dose was likely to be much smaller than the radium girls.

* Q. Also, some of my friends when analyzing different biochemical processes use radioactive C, P, S to track aminoacids, DNA or RNA etc. In Biology the investigations with the usage of radioactive markers are considered to be carried out on high level and generally to be the best. But is it safe for laboratory workers to use radioactive elements?
A. Remember, "safe" is a relative word and depends on who the risks are acceptable to. In general, college and industry research labs are extremely safety conscious and these radioactive elements are tightly controlled. So the exposures are likely to be close to zero, unless there is a mistake. Human error is always possible.

Question: So, there's a microwave in a certain village school kitchen that is about 25 years old. The fact that the light and fan come on when you open the door is a little alarming...but a girl has got to eat and clif bars won't cut it. So, the radio was on in the kitchen. When I opened the door the light and fan came on with no change to the radio. However, when I started the microwave the radio turned to static until the old man in the kitchen got annoyed enough to turn off the radio. Should the chef be concerned? Does the radio interference mean the microwave is leaking radiation more than your average microwave? Does the lack of interference when the door is opened (it sounds like it's running) mean it really is only the light and fan, not the microwave that's on?
A. You're hitting close to home there. Mine does the same. The light and fan relate to the door on mine. If I slam the door hard, they go off. And mine interferes with the TV and the cordless phone. I don't worry however. The microwave frequencies are far from the TV, so it's unlikely leaking radiation is causing the interference. More likely it is the motors in the oven, but outside the cavity that are causing the interference. My coffee grinder makes static also.

Q. I did not know before the whole Tokaimura case. On the "The EMF Safety Superstore" page was stated, that it is recommendable to check up all microwave ovens with a Microwave Leakage Detector for radiation. It that really a serious problem, I have never heard about it?
A. It is true some microwave ovens can leak some, but I would not worry about it.

Q. Why is there so much controversy about the microwave range and health effects (i.e. cell phones and microwaves have a lot of web pages and conflicting press about their health issues)? Is it that people just don't know a lot about these technologies and so they deem them unsafe or hazardous, or in fact they are hazardous and we just don't know it yet because of the long term effect (i.e. the radium watch dial workers story)?
A. In academia, the answer is always, "More research is needed." My analysis is that the health hazard from cell phones comes from the people who drive with them in their ears, not the radiation.

Q. Why do we specifically delve into radiation, when knowledge of other hazards such as flame types and reactivity of common materials would be more helpful in the workplace? I think this should still fall under the management of hazardous waste. It was however a very interesting module as I know almost nothing about nuclear waste.
A. Good comment. "Real" nuclear radiation is almost always associated with weapons or power production. Here the risk is very real and very high, but carefully controlled and highly regulated. All users need to be licensed, workers are highly trained, and facilities are inspected. Medical and industrial radiation risks are much lower, and these are well regulated, but not nearly so well as energy production. Most of the radiation waste issues I am familiar with deal with low-level radiation. Here it was not controlled and the cleanup is not well regulated regarding the radiation, although once it is in the drums, its transportation and final disposal are highly regulated. So we are tempted to use the terminology of Tokimura and say that high radiation exposure from low level radioactive waste is "not credible." Hmmm.

As to fire, we did not do much. Fire protection is always an issue at hazardous waste cleanups. I will think about that some more, maybe I can add something in. Or may lack of treatment may be a localism. Here at UAF we have a nearby "community college" which offers an "associates degree" in "fire science." When I teach this in the classroom I go there and borrow some equipment to show the students.