Arsenic is a metallic element that forms various toxic compounds, typically found in nature in low concentrations, mainly combined with oxygen, chlorine, and sulfur. These are known as inorganic arsenic compounds. In the natural world, arsenic in plants and animals binds with carbon and hydrogen, forming organic arsenic, which is generally less harmful than its inorganic counterpart. Most arsenic compounds lack a distinct odor or taste. Inorganic arsenic compounds are predominantly used to preserve wood and manufacture insecticides and herbicides. Additionally, copper and lead ores often contain trace amounts of arsenic.Once arsenic enters the environment, it does not evaporate. Instead, it can be released into the air through the burning of contaminated materials. It then settles to the ground, where it does not degrade but can transform between different forms. Many arsenic compounds are water-soluble. Fish and shellfish tend to accumulate organic arsenic in their tissues, but most arsenic in fish is non-toxic.Exposure to arsenic can occur through:- Inhaling air in workplaces filled with sawdust or smoke from burning arsenic-treated wood- Consuming contaminated water, soil, or air near waste sites- Consuming contaminated water, soil, or air in areas with naturally high arsenic levelsInorganic arsenic is highly poisonous to humans, while organic arsenic poses less risk. Consuming high levels of inorganic arsenic through food or water can be lethal, with dangerous levels being 60 parts of arsenic per million parts of food or water (60 ppm). Arsenic can damage numerous tissues, including the nerves, stomach, intestines, and skin. Breathing in high concentrations can lead to a sore throat and irritated lungs.Exposure to lower levels of inorganic arsenic might result in:- Nausea, vomiting, and diarrhea- Reduced production of red and white blood cells- Irregular heartbeats- Damage to blood vessels- A tingling sensation in the hands and feetProlonged exposure to inorganic arsenic may cause skin darkening and the development of small "corns" or "warts" on the palms, soles, and torso. Direct skin contact can cause redness and swelling.Arsenic is recognized as a carcinogen. Inhaling inorganic arsenic raises the risk of lung cancer, while ingesting it increases the chances of developing skin cancer and tumors in the bladder, kidney, liver, and lungs.Tests can determine exposure to high arsenic levels, though they are not commonly conducted in a doctor's office. The most reliable test is measuring arsenic in urine, which must be done soon after exposure since arsenic does not remain in the body for long. Tests on hair or fingernails can identify arsenic exposure over the past 6-12 months, but they are not very effective for detecting low-level exposures and do not predict potential health effects.The US Environmental Protection Agency (EPA) regulates the amount of arsenic that industrial sources can release and has restricted or canceled many uses of arsenic in pesticides, with the possibility of imposing further restrictions. The EPA has set a maximum arsenic level of 0.05 parts per million (ppm) in drinking water, which may be lowered in the future. The US Occupational Safety and Health Administration (OSHA) has established a workplace airborne arsenic exposure limit of 10 micrograms per cubic meter (µg/m³).
