Thursday, January 17, 2008


Hello again……
This is the third article in this series on recreational vehicle fresh water management. In this article we are going to explore the more common contaminants that may be found in our water. If I were to do this article correctly, it would be the size of a Tom Clancy novel. So, we will look at the highlights and provide you with web links to drill down more deeply if you so desire. Now, I do not want to scare you with the following. I do want to get your attention. So, here goes.

Contaminants come in basically two forms; particulate and dissolved. Some contaminants in the particulate column are living organisms, such as bacteria, virus, protozoa, algae, fungus and worms. Soluble or dissolved compounds may be present such as chlorine, trihalomethanes, nitrates, nitrites, heavy metals (lead, mercury, arsenic) and several other substances found in industrial waste. The list of known contaminants is very long and growing every day. A list along with the maximum allowable level of contamination may be found at EPA contaminants. Keep in mind that this list only applies to public water sources. Bottled water does not have to meet the EPA requirements.

Something we are going to talk about in this article is particle size. Particles are measured in microns. One micron is equal to 0.00003937 inches or in scientific notation 1x10-6. Expressed another way, one inch equals 25,400 microns. When we talk about a water filter’s ability to remove particulates, it is a function of the “pass-no pass” ability of the filter media. If the filter media is rated at 5 microns, any particle smaller than that will pass.

Some harmful contaminants may affect us immediately while others are insidious and can slowly accumulate in our body to a toxic level. Some contaminants are readily noticeable such as hydrogen sulfide, a bacteria supported reaction in the water heater that throws off a strong sulphur smell. It is important to remember that water may look, taste and smell okay. That does not mean it is safe. None of the contaminants are visible to the eye. The larger particles, such as Cryptosporidium, are generally 4 to 10 microns in size. Virus particles can be as small as .0004 microns. Most other particulates fall between these sizes. The smallest particle the normal human eye can see is about 50 microns.

An obvious contaminant in water is turbidity or cloudiness caused by particulates. Although turbidity in itself is generally benign, it is distasteful and its presence may indicate unacceptable levels of harmful contaminants. Turbidity is measurable as expressed in Nephelolometric Turbidity Units (NTU). The water picks up turbidity, or dirt, as it moves through the soil and rocks and eventually into the ground water supply. It becomes visible at levels above 5 NTU’s. The EPA maximum allowable level of turbidity is 1.0 NTU for our public water supplies. Turbidity can be reduced or removed by filtration. The prefilter in our RVF-1 system typically reduces turbidity to .01 NTU or lower.

A big concern and probably the most commonly found water contaminant are bacteria. Believe it or not, bacteria were the first life forms on earth. Bacteria are single cell critters that do not have a nucleus. Here is an interesting fact to ponder - there are approximately ten times more bacteria cells than human cells in the human body.

Some bacteria are good for us and live in our digestive system. These good bacteria produce vitamins and amino acids. Bacteria also aid digestion by breaking down consumed food into simple sugars and other nutrients. These good bacteria also crowd out bad bacteria as they enter our body. There is a relatively new wave of science heralding the virtues of these good bacteria that you may already know about. An interesting article on good bacteria can be found at probiotics. Bad strains of bacteria can cause illnesses like Cholera and Typhoid Fever, Legionellosis, Tuberculosis, Syphilis, Leprosy and the Bubonic Plague. Other strains cause Staph and Strep infections. My wife just went through a bad bout of Cellulitus, caused by Staphylococcus.

Bacteria particles range in size from about 1 to 10 microns. Bacteria may be neutralized with chlorine or iodine. Boiling water before use also is effective. It is also possible to remove them with an appropriately sized filter. Laboratory tests we conducted on the RVF-1 system resulted in 100 percent removal of the live E-coli test bacteria. Generally speaking, a bacterial infection can be treated with antibiotics. New strains of bacteria are emerging that appear to be resistant to this treatment, however. A website that offers a further look at various bacteria can be found here.

Virus is the smallest of the pathogens. The word “virus” comes from Latin and means poison. Characteristically, virus requires a host to grow. The viral organism will invade a host cell, then use the host for nourishment and reproductive purposes. It is not unusual to find viral organisms riding along with bacteria. Viruses cause hepatitis, meningitis, poliomyelitis, chicken pox, the common cold, flu, AIDS, pneumonia and many other illnesses. These pathogens generally range in size from .0004 to 0.2 microns. Unlike other infectious organisms, virus can sometimes remain viable forever, even dried or frozen. Although difficult, virus can be removed or significantly reduced from water by filtration. In our laboratory test program of the RVF-1 system we used a large concentration of Hepititus A. The system was able to remove 99.99 percent of these extremely small particles. Virus may be neutralized using chemical agents such as chlorine. Medically, viral infections are very hard to treat. The best preventative is removal from our food and water.

Algae and diatoms are common contaminants that, with some exception, are single-cell plants. These little organisms live in mostly stagnant water and can group into colonies. The algae we hear about most often is Blue-Green or Cyanobacteria. In warm, undisturbed surface water, algae may form blooms that become visually apparent. All algae are objectionable in our drinking water. Some algae produce toxins that can pose a health risk. Nervous system disorders, liver damage, skin problems, ear, nose and throat irritation, inflammation of the respiratory system and death are complications of algal exposure. Chlorination is an effective tool for neutralizing algae. Filtration is also very effective.

Now to what I refer to as "THE BUGS". This group of contaminants includes Protozoa such as Cryptosporidia and Giardia. There are also Amoeba, worms and many other little bugs in this group that will make us sick. The word “protozoa” means “little animal”. There are at least 60,000 different forms of these microscopic, ubiquitous beasts. Like bacteria, some are friendly toward humans while others are not.

The most common form of protozoan transmission is through the feces of infected animals. Entry into the human body is through ingestion or inhalation. Many of these animals enter our body in an oocyst stage (thick walled egg sac). Once inside the body, these critters crawl out of the egg sac and start doing their dirty work. Not long ago, 400,000 people were infected with Cryptosporidium in Wisconsin. 100 of these folks died. Every year there are reports of outbreaks in the United States. As recent as September, 2007 there was an outbreak of Crypto in the western United States, extending from the southern Rockies to Montana and Idaho.

These bugs usually measure around 4 to 10 microns in size and can be removed through filtration. Chemical treatment is not very effective in killing some in this group of pathogens because of the protection they get from the tough egg sac. Boiling water will usually neutralize them, but does not remove their bodies. So, we wind up with a little more protein in our diet. Want to see what some of these bugs look like? Check this out- prime water. Click on the “micro organisms” button at the bottom of the page.

Soluble contaminants can be found in all of our drinking water. These contaminants may include chlorine (a carcinogen), heavy metals, nitrates, nitrites, and trihalomethanes. Many solubles fall into a class called Volatile Organic Chemicals, such as benzene, styrene and trichlorethylene. Another class of concern is inorganic chemicals including asbestos, cyanide and selenium. Yet another group of chemicals is synthetic organic chemicals that includes alachlor, atrazine and lindane. Solubles cannot be removed from water through screening or mechanical filtration. Boiling will generally not remove them. The most effective way to deal with solubles is with carbon filtration. Carbon has the unique ability to capture solubles through a process called adsorption. More on this in the next article.

It is difficult to reliably test for many contaminants with any degree of accuracy. You can test today and find nothing. Test again in a few days and find the water contaminated. That is why our public water systems are tested frequently every day. For obvious reasons, we should consider any water we use as contaminated. If we accept that premise, we can respond to it by cleaning our water before we consume it.

For a very well done synopsis and further detail on water contaminants, go to this website The left side column has links to some really interesting reading. Now the publisher of this website sells reverse osmosis (R.O.) equipment, so ignore the sales hype. We will review R.O. and other processes in the next article.

I have not covered the foregoing in any depth. My goal is to provide you with a little knowledge that may peak your interest enough to further explore the issues. There is an abundance of information on the Internet and in our libraries. I encourage you to take some time to study this subject further. It is not all doom and gloom and my intent is not to malign our water supply. As stated previously our water in America is generally okay. But some knowledge of what can be lurking in your water may give you an advantage in combating water-borne contaminants, whether they are only aesthetic or real health risks. Keep in mind that, according to data tracked by the government, up to 7 million cases of water-borne illness are reported every year here in the United States.

In the next article we will discuss the more popular techniques to clean water. As before, please feel free to email me at Until the next time…….

Happy Trails,

Jim Worden

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