The effect that drinking water substances have on our health continues to be a subject of much study and speculation. The EPA recognizes thousands of toxic compounds, but since testing individual substances can take years and cost millions of dollars, little it known about their health effects. Even when effects are well known, thinks aren’t always black and white.

The EPA always sets a Maximum Contaminant Level Goal (MCLG), which is often lower than the MCL. The MCL is based on accepted levels of risk, tempered by practical, economic factors. Actual health contaminant effects are not always certain.

• A particular contaminant may not affect health by itself, but may be harmful if combined with another contaminant.
• Sensitivity to a contaminant can vary from person to person. A substance that does not have any noticeable effect on an average adult can have an effect on an adult who is recovering from an illness, and this is more vulnerable. Age and weigh can also be contributing factors for a persons sensitivity to any particular substances.
• Some substances cause acute health problems soon after we are exposed to them. Some symptoms may include rashes, nausea, headaches and worse. Chronic health effects may not be apparent until we’ve been exposed to a contaminant for an extended period of time and the toxicity builds in our bodies. the outcome tends to be more serious: cancer, heart disease, nervous system damage and birth defects. Lead, benzene and vinyl chloride are all fairly well known and documented examples of these “chronic” offenders. All are identified by the EPA as serious problems that should be removed by public water suppliers.