Arsenic can occur naturally in groundwater due to the weathering of rocks and minerals, but it can also be introduced through industrial activities (such as mining and smelting) and agricultural practices (such as the use of certain pesticides and fertilizers).

Lead exposure can cause a wide range of health effects, including neurological damage (such as learning disabilities and behavioral problems), kidney damage, and reproductive problems (such as infertility and miscarriage).

Mercury occurs naturally in the environment, but human activities have significantly increased its levels. Natural sources of mercury include volcanic activity and the weathering of rocks and minerals. Human sources include mining, burning fossil fuels, and industrial processes.

Radon is a radioactive gas that can cause lung cancer. It is the second leading cause of lung cancer in the United States, after smoking.

Asbestos is a naturally occurring mineral that can be found in rocks and soil. However, human activities, such as mining and construction, can release asbestos fibers into the air, where they can be inhaled.

Asbestos exposure can cause a variety of health effects, including asbestosis (a scarring of the lungs), lung cancer, and mesothelioma (a cancer of the lining of the lungs or abdomen).

Benzene is a naturally occurring compound that is also produced by human activities. Natural sources of benzene include forest fires and volcanic eruptions. Human sources include oil refining, chemical manufacturing, and gasoline emissions.

Benzene exposure has been linked to an increased risk of leukemia, non-Hodgkin lymphoma, and multiple myeloma.

TCE is a synthetic compound that is used in a variety of industrial processes, including metal degreasing, dry cleaning, and the manufacture of certain chemicals. It can also be found in some consumer products, such as paint strippers and adhesives.

TCE exposure can cause a variety of health effects, including liver damage, kidney damage, and neurological damage.

PCE is a synthetic compound that is used in a variety of industrial processes, including dry cleaning, metal degreasing, and the manufacture of certain chemicals. It can also be found in some consumer products, such as spot removers and degreasers.

PCE exposure can cause a variety of health effects, including liver damage, kidney damage, and neurological damage.

Vinyl chloride is a synthetic compound that is used in the manufacture of PVC and other plastics. It can also be found in some consumer products, such as adhesives and paints.

Vinyl chloride exposure can cause a variety of health effects, including liver damage, kidney damage, and cancer.

Dioxins are a group of toxic chemicals that are produced by a variety of human activities, including the incineration of waste, the manufacture of certain chemicals, and forest fires.

Dioxin exposure has been linked to an increased risk of cancer, reproductive problems, and immune system dysfunction.