Q: What dangers can there be in drinking water?
A: There are several problems that can endanger the quality of drinking water. A number of these problems are summed up here. One can detect Coliform bacteria in drinking water. Coliform bacteria are a group of microorganisms that are normally found in the intestinal tract of humans and other warm-blooded animals, and in surface water. When these organisms are detected in drinking water this suggests contamination from a subsurface source such as barnyard run-off. The presence of these bacteria indicates that disease-causing microorganisms, known as pathogens, may enter the drinking water supply in the same way if one does not take preventive action. Drinking water should be free from Coliform. Yeasts and viruses can also endanger the quality of drinking water. They are microbial contaminants that are usually found in surface water. Examples are Giardia and Cryptosporidium. Giardia is a single cell organism that causes gastrointestinal symptoms. Cryptosporidium is a parasite that is considered to be one of the most significant causes of diarrhoeal disease in humans. In individuals with a normal immune system the disease lasts for many days causing diarrhea, vomiting, stomach cramps and fever. People with weakened immune systems can suffer from far worse symptoms, caused by cryptosporidium, such as cholera-like illnesses.

Nitrate in drinking water can cause cyanosis, a reduction of the oxygen carrying capacity of the blood. This is particularly dangerous to infants under six months of age. Lead can enter the water supply as it leaches from copper pipelines. As the water streams through the pipes, small amounts of lead will dissolve in the water, so that it becomes contaminated. Lead is a toxic substance that can be quickly absorbed in the human systems, particularly those of small children. It causes lead poisoning. Legionella is a bacterium that grows rapidly when water is maintained at a temperature between 30 and 40 degrees for a longer period of time. This bacterium can be inhaled when water evaporates as it enters the human body with aerosols. The bacteria can cause a sort of flue, known as Pontiac fever, but it can also cause the more serious deathly illness known as legionellosis.

Q: What is the major source of water pollution?
A: The major source of water pollution is rain. The same rain that helps fill reservoirs, swells rivers, and makes plants, trees and crops grow washes over cattle feed lots in the Midwest, over dirty city streets, over piles of industrial waste, etc. Eventually the fallen rain, now called `runoff' goes directly into surface drinking water sources or seeps down through the ground into underground water sources called 'aquifers', carrying germs or chemicals, or both with it.

Q: How do chemicals get into my water?
A: Many of them, such as calcium, magnesium, iron, and others, occur naturally in water, and most of these "natural" chemicals are not harmful to your health. However, rain seeping through a hazardous waste dump eventually carries unwanted chemicals into underground sources and surface runoff pollutes reservoirs and rivers. But people are also responsible for a lot of the problem. For instance, if you paint your house with an oil-based paint, clean your brushes with paint thinner, and dump the paint thinner in the backyard, you can contaminate an aquifer that may be someone's water supply.

Q: How does lead get into my drinking water?
A: Although sometimes found in natural deposits near drinking water sources, lead contamination generally occurs from the corrosion of lead pipes either between the water main and a customer's home (lead service lines) or in a home or building's plumbing system. Even in homes not served by a lead service line, corrosive water may cause lead to leach from lead pipes, lead solder, and brass fixtures.

FAQ's - Microorganisms in Water

Q: Why should be a water supply tested for bacterial contamination?
A: The water may look crystal clear to the naked eye but may harbor numerous non-visible microorganisms in every drop. Most waterborne microorganisms are harmless. However, a few called pathogens may cause diseases, such as diarrhea; dysentery; gastroenteritis; eye, ear and skin infections; and even hepatitis. When fecal waste accidentally migrates to the water, pathogens may be present. Once they are outside the body, waterborne pathogens are very hard to detect. Fortunately, coliforms are bacteria that can be readily detected wherever waterborne pathogens are found. Coliform bacteria typically come from the intestines of warm-blooded animals and are considered as fecal pollution indicators. Evidence of Coliform bacteria in the water means there is a good chance that fecal contamination, and therefore that waterborne pathogens might be present. Water contamination by sewage or excrement presents the greatest danger to public health associated with drinking water. It has been stated that bacteriological testing provides the most sensitive means for the detection of such pollution.

Q: Why are coliforms used as indicator bacteria to monitor fecal contamination in water?
A: Various pathogenic microorganisms may be present in water and to check each drinking water supply for each possible pathogen would be difficult, laborious and costly. In practice, indicator bacteria are used instead. These are bacteria that are associated with the intestinal tract of warm-blooded organisms, whose presence in water indicates fecal contamination. The most widely used fecal pollution indicators are the Coliform bacteria. These bacteria are common inhabitants of human and warm-blooded animals, and are generally present in the intestinal tract in large numbers. When excreted into the water environment, the coliforms eventually die, but they do not die at any faster rate than most waterborne pathogenic microorganisms, and both the coliforms and the pathogens behave similarly during water purification processes. Thus, it is likely that if coliforms are found in water sample, the water has received fecal contamination, not sufficiently purified and may be unsafe for drinking.

Q: Why is E-coli also used, in addition to coliforms, as indicator bacteria to monitor fecal contamination in water?
A: The Coliform group includes a variety of organisms of the enteric bacteria group. It includes common intestinal bacteria, but also few other less common intestinal bacteria, such as Klebsiella and Enterocbacter species. Rarely, Coliform bacteria, such as if Klebsiella and Enterocbacter of non-fecal origin, may be present in water that are safe for drinking. Hence, the presence of Coliform bacteria in water, as the only indicator, could falsely alarm. A more specific indicator is E-coli, which belongs to the Coliform group. E-coli bacteria originate from the intestinal tract of human and warm-blooded animals, and from nowhere else. Therefore, the presence of E-coli in water is considered a reliable indication of fecal pollution.