When it comes to protecting your health from unsafe drinking water, you need to know as much as possible about the types of waterborne bacteria, viruses and cysts that exist and how to prevent them. Please read on for valuable information about Preventing Waterborne Disease, a detailed description of Common Waterborne Disease, Bacteria, Viruses and Cysts and finally an overview of Common Methods of Water Purification.
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Preventing Waterborne Disease, Bacteria, Viruses and Cysts
Waterborne disease is easily transmitted when contaminated water is used for any of the following purposes: drinking, making ice cubes, washing uncooked fruits and vegetables, making baby formula, brushing teeth and washing dentures or contact lenses. Take the following precautions as applicable when faced with any water that may be unsafe.
- Don’t trust bottled water. Reports of locals filling bottles with tap water, sealing and then selling as purified water have come out of several countries. Since Aquatabs have no unpleasant taste or colour, play it safe any time you are faced with suspect water.
- If you're visiting or living in an area with poor sanitation, be especially wary of the water.
- If your local Medical Officer of Health has issued a Boil Water Advisory for your community, take the advice seriously.
- Do not drink untreated water from a spring, stream, river, lake, pond or shallow well. Assume it is contaminated with animal, bird and/or human feces. Disinfect with Aquatabs or boil for 1 to 5 minutes depending on elevation.
- Prevention is easier than seeking medical treatment once infected. Aquatabs produce no unpleasant taste or colour and are safe and simple to use. If you run out of Aquatabs, boil all suspect water for 1 to 5 minutes depending on elevation.
- NOTE : Unlike water treated with Aquatabs, boiled water contains no residual chlorine protection from recontamination.
- NOTE: Not all filters are capable of removing many bacteria and viruses. Check manufacturers claims carefully and be wary of filters that are not capable of removing viruses. When in doubt, treat with Aquatabs after filtration.
- Ask for drinks without ice unless the ice is made from bottled or boiled water. Avoid popsicles and flavored ices that may have been made with contaminated water.
- In many places, the food can be as risky as the water. You should be especially suspicious of salads, uncooked fruits and vegetables, unpasteurized milk, raw meat, shellfish, and any foods sold by street vendors. Avoid eating raw fruits and vegetables unless peeled in your presence. Avoid raw milk and products made from raw milk. Drink only pasteurized or boiled milk.
- Practice good hygiene such as frequent hand washing and disinfection of cutlery, cutting boards, etc. Wash hands thoroughly and frequently using soap, in particular after contact with pets or farm animals, or after having been to the toilet.
- A simple rule of thumb is "Disinfect >or boil it, cook it, peel it, or forget it.
Common Waterborne Disease, Bacteria, Viruses and Cysts
- Travellers' Diarrhea
- Giardia and Cryptosporidium
- Escherichia coli 0157:H7 (E. coli)
- Typhoid Fever
- Hepatitus A
- Hepatitus E
DESCRIPTION - Travellers’ Diarrhea
- Also known as Aztec two-step, Delhi belly, Hong Kong dog, Montezuma's revenge, Rangoon runs, Tourist trot, Travelers diarrhoea, Travelers' diarrhea, Turista Travelers' diarrhea is the most common illness affecting travelers. Each year between 20%-50% of international travelers, an estimated 10 million persons, develop diarrhea.
- The onset of Travellers’ Diarrhea usually occurs within the first week of travel but may occur at any time during travel, and even after returning home.
- The most important determinant of risk is the traveler's destination. High-risk destinations are the developing countries of Latin America, Africa, the Middle East, and Asia. Attack rates are similar for men and women. The primary source of infection is ingestion of fecally contaminated food or water.
- Bacterial enteropathogens cause approximately 80% of Travellers’ Diahrrea. The most common causative agent isolated in countries surveyed has been enterotoxigenic Escherichia coli (e. Coli).
- Besides e. Coli and other bacterial pathogens, a variety of viral and parasitic enteric pathogens also are potential causative agents.
SYMPTOMS - Travellers’ Diarrhea
- Most cases of Travelers’ Diarrhea begin abruptly. Typically, a traveler experiences four to five loose or watery bowel movements each day.
- Other commonly associated symptoms are nausea, vomiting, diarrhea, abdominal cramping, bloating, fever, urgency, and malaise.
- The good news is that Travellers’ Diarrhea is rarely life-threatening. The natural history is that 90% of cases resolve within 1 week, and 98% resolve within 1 month.
Giardia and Cryptosporidium
DESCRIPTION - Giardia and Cryptosporidium
- Giardia and Cryptosporidium are microscopic parasites or cysts that can be found in water.
- Giardia causes an intestinal illness called giardiasis or "beaver fever." During the past 2 decades, Giardia infection has become recognized as one of the most common causes of waterborne disease (found in both drinking and recreational water) in humans in North America. Giardia are found worldwide and within every region of Canada and the United States.
- Cryptosporidium is responsible for a similar illness called cryptosporidiosis.
- Giardia are often found in human, beaver, muskrat, and dog faeces.
- Cattle faeces appear to be the primary source of Cryptosporidium, although these parasites have also been found in humans and other animals.
- Drinking water sources become contaminated when faeces containing the parasites are deposited or flushed into water. If treatment is inadequate, drinking water may contain sufficient numbers of parasites to cause illness.
- Other sources include direct exposure to the faeces of infected humans and animals, eating contaminated food, and accidental ingestion of contaminated recreational water.
- Anyone can get Giardiasis. Persons more likely to become infected include international travellers, backpackers, hikers, campers who drink unfiltered or untreated water, people who swallow water from contaminated sources, people who drink from shallow wells and swimmers who swallow water while swimming in lakes, rivers, ponds and streams.
- Several community-wide outbreaks of giardiasis have been linked to drinking municipal water or recreational water contaminated with Giardia.
- Low levels of both parasites, especially Giardia, were detected in a national survey of drinking water conducted by Health Canada. Only a small fraction of the parasites appeared to be viable and their ability to infect humans was not determined. Nevertheless, outbreaks of illness linked to these parasites in drinking water have been reported in several provinces.
SYMPTOMS - Giardia and Cryptosporidium
- Diarrhea, abdominal cramps, gas, malaise, and weight loss are the most common symptoms caused by Giardia. Vomiting, chills, headache, and fever may also occur.
- These symptoms usually surface six to 16 days after the initial contact and can continue as long as one month.
- The symptoms of cryptosporidiosis are similar; the most common include watery diarrhea, abdominal cramps, nausea, and headaches.
- These symptoms occur within two to 25 days of infection and usually last one or two weeks; in some cases they persist for up to a month.
DESCRIPTION - Dysentery
- Dysentery refers to any case of infectious bloody diarrhea and is also known as the bloody flux, flux, travelers dysentery and Montezuma Revenge.
- Dysentery kills as many as 700,000 people worldwide every year. Most victims live in developing areas with poor sanitation, but sporadic cases do present around the world.
- The causative organism is frequently found in water polluted with human faeces, and is transmitted via the faecal-oral route.
- Dysentery is the body's response to an unwanted visitor in the digestive system. The possible causative agents include a parasitic amoeba called Entamoeba histolytica or a number of bacteria, including salmonella and shigella. An infection of E. histolytica is called amoebiasis, and any resulting bloody diarrhea is called amoebic dysentery. Infections of shigella bacteria, called shigellosis, can lead to bacillary dysentery.
- Every year, bacillary dysentery kills roughly six times as many people as amoebic dysentery does.
- The E. histolytica amoeba and the shigella bacteria often thrive in food and water contaminated by human feces. Large outbreaks of bacillary dysentery have occurred in communities where sewage mixes with drinking water.
- Amoebic dysentery is transmitted by contaminated water, and is well known as travelers dysentery because of its prevalence in developing nations, although it is occasionally seen in industrialized countries.
- An estimated 18,000 cases of shigellosis occur annually in the United States. Infants, the elderly, and the infirm are susceptible to the severest symptoms of disease, but all humans are susceptible to some degree.
SYMPTOMS - Dysentery
- People afflicted with amoebic dysentery often suffer profuse, bloody diarrhea along with a fever, intense stomach pain, and rapid weight loss.
- Bacillary dysentery causes small, frequent stools mixed with blood and mucus. Cramps are common, and a patient may occasionally strain painfully, without success, to evacuate the bowels.
- Symptoms may range from mild abdominal discomfort to full-blown dysentery characterised by cramps, diarrhea, fever, vomiting, blood, pus, or mucus in stools or tenesmus. Onset time is 12 to 50 hours.
DESCRIPTION - Salmonella
- Salmonellosis is an infection caused by the bacteria called Salmonella, which has been known to cause illness for more than 100 years.
- There are many different kinds of Salmonella bacteria, and they are spread through human or animal feces.
- Salmonella lives in the intestines of many animals including chickens, cows, pigs, sheep, and pets such as dogs, cats, chicks, ducklings, turtles, tortoises, snakes and iguanas.
- Salmonella is found in every region of the United States and throughout the world. Millions of germs can be released in a bowel movement of an infected human or animal.
- Drinking water can be contaminated when humans, and wild or domestic animals leave their droppings in or near surface water sources such as springs, streams, rivers, lakes, ponds or shallow wells.
- Salmonella may be found in water sources that have been contaminated with the feces of infected humans or animals. Waste can enter the water through various ways, including sewage overflows, polluted storm water runoff, and agricultural runoff.
- Other common sources of infection are undercooked poultry and other meats, undercooked eggs and egg products, unpasteurized milk, and other contaminated food and water.
SYMPTOMS - Salmonella
- The most common symptoms of salmonellosis include diarrhea, fever, vomiting and abdominal cramps. Dehydration can also occur, most notably in infants.
- Sometimes a person can be infected and have no symptoms. In general, symptoms last 4 to 7 days and most people recover without treatment. When the infection is in the blood, it can be serious with potentially fatal outcomes, requiring hospitalization and treatment with antibiotics.
- People at most risk from a Salmonella infection include infants, young children, the elderly and the immune compromised.
Escherichia coli 0157:H7
DESCRIPTION - Escherichia coli O157:H7
- E. coli O157:H7 (Ee Koe-lie) is one of the hundreds of strains of the bacterium Escherichia coli. Most strains are harmless and live in the intestines of healthy humans and animals. However, this strain, O157:H7, produces a powerful toxin that can cause severe illness. The bacteria can be found on a small number of cattle farms and can live in the intestines of healthy cattle.
- Eating meat, especially ground beef, that has not been cooked sufficiently to kill E. coli O157:H7 can cause infection. Other known modes of infection include: Eating contaminated sprouts, lettuce, or salami; Drinking unpasteurized milk or juice; Swimming in or drinking sewage-contaminated water.
- Millions of germs can be released in a bowel movement from an infected human or animal. E. coli O157:H7 may be found in water sources that have been contaminated with feces from infected humans or animals. Waste can enter the water through various ways, including sewage overflows, polluted storm water runoff, and agricultural runoff.
SYMPTOMS - Escherichia coli O157:H7
- E. coli O157:H7 infection often causes severe bloody diarrhea and abdominal cramps although sometimes the infection causes non bloody diarrhea or no symptoms at all.
- Usually there is little or no fever, and the illness goes away in 5-10 days.
- In some persons, particularly children under 5 years of age and the elderly, the infection can also cause a complication called hemolytic uremic syndrome (HUS), which causes kidney failure. About 2%-7% of E. coli 0157:H7 infections lead to this complication.
DESCRIPTION - Typhoid Fever
- Typhoid fever is a life-threatening illness caused by the bacterium Salmonella Typhi. S. typhi is in the same family of bacteria as the type spread by chicken and eggs, commonly known as "salmonella poisoning," or food poisoning.
- In the United States about 400 cases occur each year, and 75% of these are acquired while traveling internationally. Typhoid fever is still common in the developing world, where it affects about 21.5 million persons each year including Mexico, Peru, Chile, India, and Pakistan.
- Salmonella Typhi lives only in humans. Persons with typhoid fever carry the bacteria in their bloodstream and intestinal tract. In addition, a small number of persons, called carriers, recover from typhoid fever but continue to carry the bacteria. Both ill persons and carriers shed S. Typhi in their feces (stool).
- S. typhi must be ingested to cause disease.
- You can get typhoid fever if you eat food or drink beverages that have been handled by a person who is shedding S. Typhi or if sewage contaminated with S. Typhi bacteria gets into the water you use for drinking or washing food. Therefore, typhoid fever is more common in areas of the world where handwashing is less frequent and water is likely to be contaminated with sewage.
- Once S. Typhi bacteria are ingested, they multiply and spread into the bloodstream. The body reacts with fever and other signs and symptoms.
- Typhoid fever is common in most parts of the world except in industrialized regions such as the United States, Canada, western Europe, Australia, and Japan. Therefore, if you are traveling to the developing world, you should consider taking precautions. Over the past 10 years, travelers from the United States to Asia, Africa, and Latin America have been especially at risk.
SYMPTOMS - Typhoid Fever
- Persons with typhoid fever usually have a sustained fever as high as 103° to 104° F (39° to 40° C).
- They may also feel weak, or have stomach pains, headache, or loss of appetite.
- Other symptoms of typhoid fever include constipation (at first), extreme fatigue, headache, joint pain, and a rash across the abdomen known as rose spots. The only way to know for sure if an illness is typhoid fever is to have samples of stool or blood tested for the presence of S. Typhi.
- If your symptoms seem to go away, you may still be carrying S. Typhi. If so, the illness could return, or you could pass the disease to other people. In fact, if you work at a job where you handle food or care for small children, you may be barred legally from going back to work until a doctor has determined that you no longer carry any typhoid bacteria.
DESCRIPTION - Cholera
- Cholera is an acute, diarrheal illness caused by infection of the intestine with the bacterium Vibrio cholerae.
- Approximately one in 20 infected persons has severe disease characterized by profuse watery diarrhea, vomiting, and leg cramps. In these persons, rapid loss of body fluids leads to dehydration and shock. Without treatment, death can occur within hours.
- Cholera is a water-borne disease caused by the bacterium Vibrio cholerae, which is typically ingested by drinking contaminated water , or by eating improperly cooked fish, especially.
- Cholera has been very rare in industrialized nations for the last 100 years; however, the disease is still common today in other parts of the world, including the Indian subcontinent and sub-Saharan Africa.
- Cholera is transmitted through ingestion of feces contaminated with the bacterium. The contamination usually occurs when untreated sewage is released into waterways, affecting the water supply, any foods washed in the water, and shellfish living in the affected waterway it is rarely spread directly from person to person.
- A person may get cholera by drinking water or eating food contaminated with the cholera bacterium.
- The resulting diarrhea allows bacteria to spread to other people under unsanitary conditions.
SYMPTOMS - Cholera
- Symptoms include those of general GI tract upset, including profuse diarrhea.
DESCRIPTION - Hepatitis A
- Hepatitis A is a liver disease caused by the hepatitis A virus (HAV), which can affect anyone. In the United States, hepatitis A infections can occur in isolated situations or in widespread epidemics.
- Hepatitis A virus is found in the stool of persons with hepatitis A. HAV is usually spread from person to person. It occurs by putting something in your mouth that had been contaminated with the stool of a person with hepatitis A. For this reason, the virus is more easily spread in areas where there are poor sanitary conditions or where personal hygiene is poor.
- Persons with hepatitis A can spread the virus to others who live in the same household.
- When water sources are contaminated with feces from infected humans, the water will spread the hepatitis A virus. The virus can enter the water through various ways, including sewage overflows or broken sewage systems.
SYMPTOMS - Hepatitis A
- The most common symptoms of hepatitis A include: Jaundice or yellowing of the skin and eyes, dark urine, fatigue, loss of appetite, nausea, vomiting, fever and stomach pain.
- Three out of four adults who are infected by HAV will develop symptoms, usually over a period of several days. The symptoms generally appear 2 to 6 weeks after infection with the virus. Children who are infected often have no symptoms.
DESCRIPTION - Hepatitis E
- Hepatitis E is caused by infection with the hepatitis E virus. Spread most often by contaminated drinking water, HEV infection occurs mainly in developing countries where human waste is allowed to get into drinking water without first being purified.
- Consumption of faecally contaminated drinking water has given rise to epidemics, and the ingestion of raw or uncooked shellfish has been the source of sporadic cases in endemic areas.
- Hepatitis E (HEV) was not recognized as a distinct human disease until 1980.
- The highest rates of infection occur in regions where low standards of sanitation promote the transmission of the virus. Epidemics of hepatitis E have been reported in Central and South-East Asia, North and West Africa, and in Mexico, especially where faecal contamination of drinking water is common. In the United States and Canada no outbreaks have been reported, but persons traveling to an endemic region may return with HEV.
SYMPTOMS - Hepatitus E
- There are at least two strains of HEV, one found in Asia and another in Mexico. The virus may start dividing in the gastrointestinal tract, but it grows mostly in the liver, after an incubation period (the time from when a person is first infected by a virus until the appearance of the earliest symptoms) of two to eight weeks
- Typical signs and symptoms of hepatitis include jaundice (yellow discoloration of the skin and sclera of the eyes, dark urine and pale stools), anorexia (loss of appetite), an enlarged, tender liver (hepatomegaly), abdominal pain and tenderness, nausea and vomiting, and fever, although the disease may range in severity from subclinical to fulminant.
- Most often the illness is mild and disappears within a few weeks with no lasting effects but on rare occasions the acute illness damages and destroys so many liver cells that the liver can no longer function. This is called fulminant liver failure, and may cause death
- Children younger than 14 years and persons over age 50 seldom have jaundice or show other clinical signs of hepatitis.
DESCRIPTION - Campylobacter
- Campylobacters are bacteria that are a major cause of diarrheal illness in humans and are generally regarded as the most common bacterial cause of gastroenteritis worldwide. Campylobacteriosis is the disease caused by the presence of campylobacters.
- In developed and developing countries, they cause more cases of diarrhea than, for example, foodborne Salmonella bacteria. The high incidence of campylobacter diarrhoea, as well as its duration make it highly important from a socio-economic perspective.
- In developing countries, campylobacter infections in children under the age of two years are especially frequent, sometimes resulting in death.
- In almost all developed countries, the incidence of human campylobacter infections has been steadily increasing for several years. The reasons for this are unknown.
- Campylobacters are widely distributed and occur in most warm-blooded domestic, production and wild animals. They are prevalent in food animals such as poultry, cattle, pigs, sheep, ostriches and shellfish; and in pets, including cats and dogs.
- The main route of transmission is generally believed to be foodborne, via undercooked meats and meat products, as well as raw or contaminated milk. The ingestion of contaminated water or ice is also a recognized source of infection.
SYMPTOMS - Campylobacter
- The onset of disease symptoms usually occurs two to five days after infection, but can range from one to ten days.
- The most common clinical symptoms of campylobacter infections include diarrhoea (frequently with blood in the faeces), abdominal pain, fever, headache, nausea, and/or vomiting.
- The symptoms typically last three to six days.
- A fatal outcome is rare and is usually confined to very young or elderly patients, or to those already suffering from another serious disease such as AIDS.
- Complications such as bacteremia, hepatitis, pancreatitis (infections of the blood, liver and pancreas respectively), and abortion have all been reported with various degrees of frequency.
- Post-infection complications may include reactive arthritis (painful inflammation of the joints which can last for several months) and neurological disorders such as Guillain-Barré syndrome, a polio-like form of paralysis that can result in respiratory and severe neurological dysfunction or death in a small, but significant, number of cases.
Common Methods of Water Purification
With all the different methods of water purification available, how do you decide? Hopefully we can help.
Chlorine is universally accepted as a safe and effective water disinfectant. Free chlorine or hypochlorous acid is the most commonly used method of water purification in the world and has saved millions of lives since it became popular in the 1920’s. Chlorine has virtually eliminated widespread epidemics of waterborne disease where implemented. Chlorine comes in a variety of different formats including liquid, granules and tablets as well different base agents including calcium hypochlorite and sodium hypochlorite. Other forms of chlorination include what are called halazone tablets. Chlorine is very effective against almost all bacteria, viruses and cysts.
There a few things to be aware of regarding water purification using Chlorine. Many Chlorine tablets are considered a dangerous good and need to be handled very carefully. Direct contact with chlorine tablets or resulting dust can cause severe skin and respiratory irritation. Chlorine tablets are also highly flammable and potentially explosive when mixed with acids or other common chemicals. The biggest complaint that is reported by those using Chlorine tablets for water purification is the taste. Halazone tablets, household bleach or calcium / sodium hypochlorite create a very strong “chlorine” taste and odour in the water. Many indigenous populations around the world refuse to use water purification tablets made from Chlorine because the resulting water is so unpalatable. The concern of course is that users from any population will not use the water purification tablet because of the resulting taste and odour, and will risk drinking unsafe water.
- Popular brands include: Lifesystems Chlorine tablets and RediChlor water purification tablets
When added to water Sodium Dichloroisocyanurate (NaDCC) water purification tablets dissolve to release a measured dose of hypochlorous acid or free available chlorine which is universally recognized as a safe and effective water disinfectant. NaDCC is not chlorine. Rather it reacts within water to create free chlorine. The difference is substantial. Chlorine itself, calcium or sodium hypochlorite (household bleach) is hazardous to handle in either tablet or liquid form and produces very strong tastes and odours when used for water purification. NaDCC is not dangerous to handle, is completely stable and inert as a tablet and when used to purify water produces free chlorine without the traditional chlorine taste and odour.
In laymans terms, it's like getting the best of both worlds – the benefits and effectiveness of free Chlorine without the negative tastes and odours. It is for these reasons that NaDCC has become so widely accepted as the most popular form of water purification tablet. NaDCC is comparable to Iodine for effectiveness and efficacy against waterborne bacteria, viruses, cysts and disease but has no unpleasant taste or colour and more importantly, has no negative health effects. For more information about the effectiveness of free Chlorine for water purification please refer to the section above titled “Chlorine”. NaDCC (ACL 60) is certified to SNF/ANSI Standard 60 and has been approved for drinking water treatment by the U.S. EPA (Environmental Protection Agency) and the WHO (World Health Organization)/JECFA.
NaDCC is effective against the cyst Giardia when used in sufficient strength and for a sufficient contact time. AQUATABS® Extra Strength 8.5 mg tablets are effective against Giardia when used as directed at both 15 C and 5 C.
- Popular brands of NaDCC water purification tablets include: AQUATABS® Water Purification Tablets.
Iodine is one of the oldest forms of water purification. Iodine comes either as a water purification tablet or a disinfectant solution continually charged by Iodine crystals. Iodine itself does a pretty good job in making water safe from bacteria, viruses and some cysts. Water to be purified should be clear before treatment. Iodine is however sensitive to light and must be kept in a dark bottle. For inactivation of Giardia, the source water must be at least 21 C (68 F). If the water is colder (as it usually is), you will need to let it sit longer - possibly overnight for cold stream water.
The biggest challenge when using Iodine for water purification is the resulting taste, odour and colour. Iodine often causes a yellowing of the water upon treatment and produces a taste and odour that many find unpalatable. Most suppliers of Iodine tablets often provide a “taste neutralizer” tablet to help counteract the harsh taste. The concern of course is that users will not purify suspect water because of the resulting taste and odour, and will risk drinking unsafe water.
CAUTION! Some people are allergic to Iodine and cannot therefore use it to purify water that they will drink. Many studies have also linked serious health risks and side affects to Iodine exposure resulting from water purification. Persons with thyroid problems or on lithium, women over fifty and pregnant women should consult their physician prior to using Iodine for water purification. There are also reports that some people who are allergic to shellfish are also allergic to Iodione.
- Popular brands of Iodine water purification tablets or liquids include: Coghlan’s Water Purification Tablets, Potable Aqua, Polar Pure, Betadine and Lugol’s Solution.
The most effective means of water purification is boiling. Keeping water at a vigorous and rolling boil for 1 to 3 minutes depending on elevation will eliminate all bacteriological contaminants. The challenges in using boiling as a means of water purification include finding a heat source, finding electricity or fuel, waiting for the water to cool down before it can be consumed and protecting it from recontamination. It is for exactly this reason that municipalities use chlorine in their drinking water systems. Chlorine provides the treated water with ongoing protection from recontamination. Any bacteria or virus that comes into contact with the treated water is inactivated by the chlorine that exists in the water. If you are purifying water by boiling, it is strongly recommended that you use a water purification tablet such as AQUATABS® to provide your water with protection from recontamination.
Purifying water by filtration is not as simple as it sounds. There are hundreds of different types and sizes of filters to choose from. Some filters only remove sand, grit and sediment while others remove more. Very few are capable of removing common waterborne viruses. Some require electricity, some require manual pumping. Even the most compact filters are not something to be carried around in ones shirt pocket or purse. Are you prepared to find a source of electricity or huddle over a pump during lunch? Filters of course also need to be cleaned or replaced when fouled. When using a water filter, be sure that you know how to clean it, when to clean it, or when to change it. Improper maintenance of a water filter can in fact lead to dangerous levels of bacteria building and growing within the actual filter, similar to a dirty kitchen sponge. Charcoal filters are especially at risk for bacteria buildup.
Purifying water by filtration also leaves water prone to recontamination. As soon as the water leaves the filter it is immediately susceptible to any sort of bacteria or virus that may be in the air, in the receptacle or bottle receiving the water, etc. It is for exactly this reason that municipalities use chlorine in their drinking water systems. Chlorine provides the treated water with ongoing protection from recontamination. Any bacteria or virus that comes into contact with the treated water is inactivated by the chlorine that exists in the water. If you are using a filter to purify water, it is strongly recommended that you use a water purification tablet such as AQUATABS® to provide your water with protection from recontamination.
Chlorine Dioxide is an entirely different water purification agent than Chlorine. Chlorine Dioxide has traditionally been used to purify water as a gas but recent developments in technologies has seen the creation of tablets and two part liquids that when introduced to water creates Chlorine Dioxide. While very effective as a water purification chemical, Chlorine Dioxide generation via tablets or liquids is quite a new technology and consumers should read all directions, claims, etc. very carefully. The origins of Chlorine Dioxide for water purification come from its use in releasing odour causing bacteria in various applications.
The downfall of Chlorine Dioxide when used to purify water includes both cost and taste. Chlorine Dioxide water purification liquids or tablets are quite expensive generally listing between $20 – 25 on the shelf for 30 tablets. Chlorine Dioxide liquid products generally require two liquids to be mixed together and then allowed to sit for a set time before introduction into the raw water. This of course requires both time and concentration and may not be suitable in many settings.
- Popular brands include: Portable Aqua, Micropur MP1 and Pristine Water Purification Treatment.