This fact sheet discusses some of the more common groundwater contaminants and clarifies the potential health risks associated with them. Groundwater pollutants can be either organic or inorganic. Organic chemicals currently detected in the groundwater include solvents, degreasers, petroleum components, pesticides, certain industrial by-products, and viral and bacterial pathogens. Determining the health effect of pollutants present at such low levels is extremely difficult. Toxicity is the inherent ability to impair health.
Toxic substances can cause cancer, birth defects, and other illnesses.
The severity of the effect usually depends on the dose, defined as the weight of the contaminant consumed per day divided by body weight. Dosages are usually measured in milligrams per kilogram of body weight per day. Acute toxicity refers to a contaminant's ability to cause immediately detectable health problems. Chronic toxicity refers to a contaminant's ability to cause health problems years after a long-term exposure. Keep in mind that some contaminants that cause no detectable health problems at low doses can cause death at high doses.