Final answer:
Arsenic is the most dangerous and ubiquitous chemical found in drinking water. It causes various health problems and has caused the largest mass poisoning of a population in history in Bangladesh due to naturally occurring arsenic in wells.
Step-by-step explanation:
The most dangerous and ubiquitous chemical found in drinking water is Arsenic. Arsenic has been recognized by the World Health Organization (WHO) as one of the most serious inorganic contaminants in drinking-water worldwide. It enters the water supply naturally from weathering of arsenic-rich minerals and from human activities such as coal burning and smelting of metallic ores.
Arsenic poisoning can occur from drinking small concentrations of arsenic in water over a long period of time. The worst case of arsenic poisoning occurred in Bangladesh, where millions of shallow water wells were provided by the United Nations in the 1970s to combat pathogenic diseases. Unfortunately, many of these wells produced water naturally rich in arsenic, leading to the largest mass poisoning of a population in history.
Toxic levels of arsenic can cause various health problems, including diarrhea, cholera, and even death. It is important to ensure that drinking water is properly treated to remove harmful levels of arsenic.