Arsenic is a naturally occurring element within the earth and when it comes in contact with water, it dissolves naturally into the water. In Illinois, it is found in deep bedrock formations and shallow glacial materials. If not properly tested and resolved arsenic can be harmful to the human body. Read more
Arsenic is a contaminant that is harmful to the human body when not property treated. It has caused cancer and other health issues in humans. The acceptable contaminant level is 50mg/L, but private wells do not have a governing body to regulate each household.