Studies suggest that arsenic is associated with skin cancer. Studies also indicate that arsenic in small amounts may be an essential element for normal human development. Arsenic contamination of water is most often caused by leachate from solid waste landfills, or from use of pesticides. The primary drinking water standard for barium is 1.0 milligrams per liter. Small doses are not harmful.
Large amounts can cause increased blood pressure, nerve damage or cardiovascular disease.
Barium pollution may come from natural sources or can enter water supplies through industrial waste discharges. The primary drinking water standard for cadmium is 0.01 milligrams per liter. Cadmium in high concentrations can cause short-term intestinal illness. Since cadmium tends to accumulate in the body, long-term effects may occur, including intestinal, lung and kidney damage. Cadmium contamination may be caused by disposal of waste from photographic, metal plating or pesticide manufacturing industries.