Thursday, August 30, 2012


Published in the Williamson County Sun 8-26-12

Mercury from a broken thermometer was so much fun to play with.  I would put it on a saucer and break it into tiny beads with a toothpick, and then watch the beads pop back together into a big, shimmery ball.  Genie Vogler told me she would squish a dime into the mercury to make the dime real shiny.  What our mothers didn’t know when they gave us mercury as a toy was that those bits of quicksilver were vaporizing into toxic gases, inhaled into our curious little brains.  We all survived those multiple small exposures, and even went to college, but sometimes when I watch CSPAN I wonder if there could have been a lingering effect on our generation.


Remember Alice in Wonderland and the Mad Hatter?  In 1865, when Lewis Carroll wrote the novel, mercuric nitrate was used to make felt hats.  Hatters were chronically exposed to mercury vapors and suffered tremors, hallucinations, and erratic behavior.  Carroll grew up near the center of England’s hat industry, so he would have been acquainted with the condition.  The center of America’s hat making industry was Danbury, Connecticut, where factories dumped waste mercury into the Still River.  Although the use of mercury for making felt was banned in 1941, the river sediment is contaminated with mercury to this day.


Mercury has no essential role in animal physiology, but it has become a ubiquitous pollutant.  Every year, fifty tons of mercury is released into American air as the result of burning coal for electricity.  You guessed it:  Texas is Numero Uno, with more than twice the emissions of the distant number 2, Ohio.  The problem with all that mercury in the air is that it settles into our lakes and oceans where bacteria convert it into methylmercury, a neurotoxin that accumulates in the muscle tissue of fish.  The higher the fish is on the food chain, the more mercury it accumulates, so the big carnivorous fish like tuna and shark have the most mercury.  Eating large doses of methylmercury can cause permanent brain damage, especially in a fetus or young child.  This fact creates a dilemma for me.  In my freezer is a big filet of king mackerel, caught recently by my son-in-law at Port Aransas.  It is super-delicious, which I know because I ate the other half of that fish before realizing that king mackerel is on the Food and Drug Administration’s “Do Not Eat” list for pregnant women and young children.  I’m not pregnant, of course, but knowing about the mercury in that fish sucks the joy right out of eating it.


Mercury can also bypass the air and enter directly into our water supply.  Dentists’ offices that place or remove amalgam fillings (the silver ones which are 43% mercury) flush 3.7 tons of mercury a year into municipal wastewater systems, according to an estimate by the EPA.  Ninety percent of that mercury will settle out with the biosolids and can re-enter the environment if the biosolids are incinerated or applied to land as fertilizer.  The other ten percent remains in the treated water and returns to our lakes and streams.  The quantity in the water is too little to hurt you if you drink it, but it can be converted to methylmercury and concentrated in fish.  Mercury never goes away.  It just moves around.


Although in most states it is still perfectly legal for dentists to flush waste amalgam down the drain, the American Dental Association recommends that it be carefully captured and recycled.  Dr. David Hennington was kind enough to show me his amalgam separator, a special filter that removes amalgam fragments from his surgical wastewater.  Dr. Hennington prefers to fill cavities with the new tooth-colored composite resins and doesn’t use amalgam for filling teeth anymore, but often he has to remove an old silver filling that has failed.


Interestingly, another way that dental amalgams contribute to mercury pollution is by cremations.  When a body with amalgam fillings is cremated, the high temperatures vaporize the mercury.  The EPA estimates that every year several tons of mercury go up in smoke from cremated teeth.


There is a lot of controversy about possible health effects of having amalgam fillings in your mouth.  It is well known that there are mercury emissions even from cured amalgam fillings, but the amount is so small that it is difficult to prove any detriment to health.  The argument will rage on, but neither Dr. Hennington nor the American Dental Association recommends removing amalgam fillings that are functioning well.  If a dentist advises you to remove all your old amalgam fillings to avoid mercury toxicity, put your hand over your wallet and get a second opinion.  Dr. Hennington belongs to the Eco-Dentistry Association, and not even they recommend removing intact amalgam fillings.  They do, however, recommend that you save water by turning off the tap while you brush your teeth.

Dr. David Hennington and his amalgam separator

Sunday, August 12, 2012

"Smart" Meters - published in the Sun August 11, 2011

Aldo Salinas, a supervisor with Texas Meter and Device,
 is in charge of installing smart meters in Georgetown

A controversy about “smart” electric meters is raging through the internet.  Some say the meters are exposing us to dangerous radiation; others believe the meters are prying into our private affairs.  The city of Georgetown is currently in the process of installing new meters that measure the amount of electricity used by a home in 15 minute intervals.  The data is stored, and then several times a day the information is sent wirelessly to the utility company, as if the meter were sending a text message.  This transmission is the crux of the concern.

The truth is that Georgetown residents have already been using meters with wireless technology since 1998.  The old meters transmitted only once a day, but the wholesale market for electricity operates on a 15 minute standard, so the old meters were obsolete, and they were wearing out anyway.

Currently customers pay the same price for electricity no matter what time of day it is consumed, but at some future date the new meters could be used for time-of-use pricing, offering customers the option to pay lower rates for electricity during off-peak hours.  For example, rather than running the dishwasher at 6:30 pm when demand is high, it could be run at 11 pm for discounted rates.  This shift would not only save customers money, but would allow the city to avoid buying expensive electricity during periods of high demand.

The smart meters are clearly useful from an energy standpoint.  What about possible health effects?

Human beings have always lived in a soup of electromagnetic energy from the sun, coming at us in a broad spectrum of wavelengths and frequencies.  We are most familiar with the center of the spectrum, visible light, because that is the frequency our eyes evolved to receive.  Higher frequency energy, like X-ray, carries more energy than visible light.  Because X-rays have a very short wavelength, they can penetrate all the way through your body to make a picture, but you can’t feel anything at all because you have no sensory receptors for X-rays.  X-rays are called “ionizing” radiation because their extremely high energy enables them to knock electrons off molecules in DNA, which can lead to mutations and even cancer.

In contrast, microwaves and radio waves are less energetic than visible light.  These waves are called “non-ionizing” radiation because they are too weak to knock electrons off DNA molecules.  They can however cause vibration of molecules in biologic tissue.  A microwave oven uses a 2450 megahertz signal to vibrate water molecules in food, heating it up.  This is called thermal effect.  Radio waves are even lower frequency than microwaves, but thermal effect has caused serious burns in workers or military personnel who stood directly in front of a powerful radar antenna for a prolonged time.  Sailors used to believe that the thermal effect from radar could make them infertile for 24 hours.  Unfortunately for women on shore, this method of contraception did not prove to be reliable.

Just as sound waves can be loud or soft, radio signals can be generated with differing power densities.  The inside of a microwave oven is going to have a very strong power density, because it is designed to create a thermal effect, which only occurs at power densities greater than 100 milliwatts/centimeter2.  The power density of a cell phone is less than 1 milliwatt/centimeter2, so the energy dissipates too quickly to heat tissue.  Even so, a cell phone can be pressed to the ear for hours at a time, so the Federal Communications Commission regulates the output of all cell phones and other devices that use wireless transmission.

Power density decreases rapidly with distance.  A smart meter on the outside wall of the house is a thousand times less exposure to a resident inside than talking on a cell phone would be.  Even baby monitors, cordless phone bases, and wireless routers expose you to more radio waves than smart meters.  Some people claim that they experience headaches or nausea when exposed to these devices, but controlled experiments have demonstrated that people experience the same symptoms if they are just told that they are being exposed but really aren’t.  Humans cannot perceive radio waves, just as they cannot perceive X-rays.  We do not have “eyes” for those frequencies.  Put the issue in perspective:  if you are comfortable with a cell phone, don’t worry about the much smaller risk from a smart meter.

The other main objection to smart meters is that they are an invasion of privacy, that the city might check how often you use your margarita machine.  Electricity is electricity; a meter cannot distinguish your toaster from your hair dryer and it can’t figure out what kind of videos you are watching.  A “smart” meter is just not that smart.  Once again, your phone is the guilty party.  Your service provider knows who you call, what you Google, and where you are at any moment of the day.