Arseno refers to the presence of arsenic within chemical compounds, highlighting its widespread occurrence in the environment. Arsenic is a naturally occurring metalloid found in the Earth’s crust, found in air, water, and land due to both natural geological processes and human activities. Exposure to arseno compounds can have various health implications, depending on the specific chemical form.
Understanding Arsenic’s Forms
Arsenic exists in both inorganic and organic forms, with differing toxicities to humans. Inorganic arsenic compounds, such as arsenite (AsIII) and arsenate (AsV), do not contain carbon and are more toxic. Arsenite is often more toxic than arsenate, as it can interfere with cellular processes and enzyme functions.
Organic arsenic compounds, in contrast, contain carbon atoms and are less harmful. Examples include arsenobetaine, arsenocholine, methylarsonic acid (MMA), and dimethylarsinic acid (DMA). While some organic forms like arsenobetaine are considered non-toxic and are rapidly excreted by the body, others like MMA and DMA are less toxic than inorganic forms but can still pose risks at high levels.
Where Arsenic Compounds Are Found
Arsenic compounds are widely distributed in the environment, leading to diverse human exposure sources. Natural geological formations containing arsenic can contaminate groundwater and well water, making drinking water a significant source of exposure in many regions worldwide, including parts of Asia, North, and South America. This natural contamination is often odorless, tasteless, and invisible, making detection challenging without testing.
Food also serves as a primary source of arsenic exposure for the general population. Rice is particularly prone to absorbing arsenic from soil and irrigation water, especially when grown in flooded conditions, making it a notable dietary source. Seafood, including fish and shellfish, also contains arsenic, though it is predominantly in the less toxic organic forms like arsenobetaine. Industrial activities, such as metal smelting, wood preservation, and the use of arsenical pesticides, can also contribute to arsenic contamination in air, soil, and water.
How Arsenic Affects Health
The health impacts of arsenic vary significantly depending on its chemical form, with inorganic arsenic posing the greatest risk. Acute exposure to high levels of inorganic arsenic can lead to severe gastrointestinal effects, including nausea, vomiting, abdominal pain, and severe diarrhea. Encephalopathy and peripheral neuropathy have also been reported in acute cases.
Long-term exposure to inorganic arsenic, often through contaminated drinking water, can result in chronic health problems. Characteristic effects include skin lesions such as hyperpigmentation (darkening of the skin) and keratosis (small corns or warts on palms, soles, and torso). Chronic exposure is also linked to an increased risk of various cancers, including those of the skin, lung, and bladder, and possibly the liver, kidney, and prostate. Other chronic non-cancer effects can involve cardiovascular disease, neurological effects like symmetrical stocking-glove neuropathy, and type 2 diabetes mellitus.
Arsenic exerts its toxicity by interfering with numerous cellular processes. It can inactivate enzymes involved in cellular energy pathways and DNA synthesis and repair by reacting with sulfhydryl groups in proteins. This interference can lead to increased oxidative stress, where an imbalance of reactive oxygen species damages cellular components like lipids, proteins, and nucleic acids. While common organic forms like arsenobetaine are considered non-toxic and are rapidly excreted from the body, recent research suggests that gut bacteria may convert arsenobetaine into more toxic arsenic compounds, including inorganic arsenic.
Reducing Your Exposure to Arsenic
Reducing arsenic exposure involves several practical steps, especially concerning water and food consumption. If your drinking water comes from a private well, it is advisable to test it regularly to ensure arsenic levels do not exceed the federal standard of 10 parts per billion (ppb). If levels are elevated, consider using bottled water for drinking and cooking or installing water treatment systems designed to remove arsenic.
Dietary adjustments can also help minimize exposure. For rice, which readily absorbs arsenic, rinsing it before cooking and preparing it like pasta (using six to ten parts water to one part rice and draining the excess water) can reduce inorganic arsenic content by 40% to 60%. Varying grain consumption and including other grains like oats or barley can also help reduce overall arsenic intake. While seafood primarily contains less toxic organic arsenic, being mindful of local fish advisories and avoiding certain types of seaweed, like hijiki, which can have higher inorganic arsenic levels.