The Largest Mass Poisoning in History: Arsenic Contamination of Well Water in Bangladesh.

Arsenic is a naturally occurring compound that is widely distributed in trace quantities in the environment. Levels toxic to humans have been found contaminating certain regions of the world and their groundwater, leading to deleterious effects. In fact, an estimated 150 million people are affected by arsenic contamination worldwide. Arsenic poisoning leads to several adverse health effects, including cancer of the lung, bladder, and kidney, neurologic disorders, cardiovascular disease, peripheral vascular disease, hypertension, pulmonary disease, and diabetes mellitus. Skin lesions are a common manifestation of arsenic poisoning. Early findings include diffuse or spotted melanosis, leukomelanosis, and depigmentation. Years of chronic arsenic poisoning can lead to acral keratoses and squamous cell carcinoma of the skin..