Probably the words most frequently heard by a chemist or lab manager when a well owner brings in a sample of water to be tested are, "I just want to know if it's safe!" These days, people are highly conscious of their health and what they are consuming. They want to know that their air, food, and water supplies are free of contaminants that could change or shorten their family's lives.

98% of the wells in Illinois are privately owned supplies
Folks who get their drinking water from a public water supply may not have to worry quite as much about their water quality as those who have a well in their back yards. Public water supplies are regulated by federal and state standards. When these standards are not met, the utility is required to notify its customers of the problem. However, the 1.3 million Illinoisans who drink from their own wells have to take the responsibility for checking their water quality themselves. How do they decide whether their water is contaminated or not? How much contamination can they allow in their well water before they must be concerned about it? And where is the contamination coming from, anyway?

How does water become contaminated?
One definition of contamination may be that which makes the water unfit for a particular use. In the case of drinking water, then, a contaminant would be anything that makes the water unpleasant or unhealthy to consume. Bad odors or tastes can make the water unpleasant. Nobody enjoys drinking water that smells like rotten eggs or tastes salty or bitter. On the other hand, some contaminants that cannot be seen, smelled, or tasted can be a danger to health. Many bacteria, trace metals, organics, etc., can go undetected by human senses but can cause sickness or even death.

Contaminants can be found in water due to human activities or may occur in water naturally. As rain water seeps into the ground it dissolves minerals and nutrients from the soil and rocks. Anything that is normally found in the earth's geology can end up in well water. Likewise, anything that has been spread upon the earth's surface or buried in the soil by man can also be picked up by rain or surface water and end up in the well water.

What are some examples of contaminants?
The Federal Safe Drinking Water Act (SDWA) limits the kinds of contaminants and the amount of the contaminant that are allowed in public water supplies. The Environmental Protection Agency has also issued Health Advisories for some contaminants that may not be regulated by the SDWA. These two resources provide good guidelines by which to evaluate the private well water of rural citizens. Some of the contaminants are measured in milligrams per liter (mg/L). An equivalent expression is parts per million (ppm). Other contaminants are measured in micrograms per liter (ug/L), also known as parts per billion (ppb). 1 mg/L = 1 ppm; 1 ug/L = 1 ppb; 1 ppm = 1000 ppb 1 ppb = 1 drop of water in 13, 210 gallons of water (equivalent to a 24' x 4' round swimming pool) Contaminants that can be found naturally in water include radon gas and radium. These are products of radioactive decay and are known to be carcinogens (cancer-causing agents). Some trace metals occur in

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nature. Arsenic, barium, cadmium, mercury, and silver can be found in geologic formations and may affect the nervous system, the circulatory system, and some organs. Coliform bacteria are indicators of the sanitary quality of water. Although these bacteria are found almost everywhere, their presence in well water indicates possible contamination by organisms that can cause stomach and bowel problems as well as typhoid fever, cholera and other diseases.

Although nitrates can be found naturally in well water, any amount near the SDWA limit of 10 ppm as N is usually due to the actions of man. Large amounts of nitrates in water are probably due to nitrogen fertilizers or to human or animal wastes. Infants are most susceptible to nitrate poisoning, in which a condition known as methemoglobinemia can occur. Pesticides spread by man can work their way into groundwater and cause nervous system and organ disorders. Solvents and cleaning agents such as benzene and carbon tetrachloride might contaminate well water from leaking storage drums or improper disposal and are possible carcinogens. Lead in drinking water can cause nervous system damage and is usually due to corrosion of plumbing system materials.

People are not the only creatures concerned with safe drinking water. Livestock and pets need water free from contaminants if they are to survive and reproduce. Rural water well users must take the initiative to see that they protect their water supply from contamination and must routinely make a check of their well water quality. These actions will help ensure that they are not jeopardizing their health or livelihood.

For more information obtain a copy of "Safe Drinking Water: Testing and Treating Home Drinking Water" from your local Cooperative Extension Service Office or contact your local health department. •

Page 18 / Illinois Municipal Review / July 1991