Selenium is a naturally occurring metal that most often enters water supplies as discharge from petroleum refineries or mines and, more rarely, from erosion of natural deposits. Potential health effects of short-term exposure to Selenium include hair or fingernail changes, numbness in fingers or toes, fatigue, and irritability.  Long-term exposure can cause more serious effects like hair and fingernail loss, circulatory and nervous system damage, and damage to kidneys.

Simazine is a widely used herbicide that has been associated with endocrine disruption and cancer in experimental studies.

Styrene is a pollutant from plastics, rubber and other industrial chemical factories and from landfill leachate.