Exon Publications, Brisbane, Australia
Arsenic in drinking water is a significant public health concern due to its association with skin cancer. Arsenic is a naturally occurring element found in rocks, soil, and water, but human activities like mining, agriculture, and industrial processes have increased its presence in water supplies. While trace amounts of arsenic are naturally present in water, they are usually harmless. However, when arsenic concentrations exceed safe limits, such as the 10 micrograms per liter (µg/L) standard set by the World Health Organization (WHO), the risk to human health increases. Chronic exposure to high levels of arsenic in drinking water can lead to skin damage, pigmentation changes, and the development of skin cancer. Long-term exposure may also contribute to other health conditions like cardiovascular disease, diabetes, and lung cancer. This article explores the sources of arsenic in drinking water, the health risks it poses, and the link between arsenic exposure and skin cancer.
Keywords: how arsenic affects the skin; how does arsenic get into drinking water; safe levels of arsenic in drinking water; should I be concerned about arsenic poisoning from drinking water; the link between arsenic and skin cancer; what is arsenic
Correspondence: Exon Publications, Brisbane, Australia. books@exonpublications.com
Cite as: Arsenic in Drinking Water and Skin Cancer: Education for the Public. Brisbane (AU): Exon Publications; 2024. Published on 18 Dec.
Doi: https://doi.org/10.36255/arsenic-drinking-water-skin-cancer-public-education
Copyright: Exon Publications.
License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 (CC BY-NC-ND 4.0) https://creativecommons.org/licenses/by-nc-nd/4.0/
Access to clean and safe drinking water is essential for human health and well-being. However, in many parts of the world, drinking water is contaminated with harmful substances like arsenic, a naturally occurring toxic element. Arsenic contamination in drinking water poses a significant public health challenge, particularly in regions where natural geological conditions or industrial activities increase arsenic levels in water sources. Arsenic exposure has been linked to a wide range of health issues, but its connection to skin cancer is one of the most well-documented risks (1–3).
While low levels of arsenic are naturally present in the environment, chronic exposure to elevated levels, particularly in drinking water, can result in skin damage, hyperpigmentation, and an increased risk of developing skin cancer. The World Health Organization (WHO) and regulatory bodies like the Environmental Protection Agency (EPA) have set drinking water safety limits for arsenic to reduce health risks. This article examines the sources of arsenic in drinking water, its impact on skin health, and the relationship between long-term exposure and the development of skin cancer.
Arsenic is a naturally occurring element found in the Earth's crust, soil, water, and air. It exists in both organic and inorganic forms, with inorganic arsenic being the most toxic to humans. Arsenic occurs naturally in groundwater, often dissolving from rocks and soil into water supplies. Human activities, such as mining, pesticide use, and industrial processes, can also release arsenic into the environment, increasing its concentration in drinking water sources.
In drinking water, arsenic is commonly found in two forms: arsenite (As III) and arsenate (As V). Both forms are toxic, but arsenite is considered more harmful due to its higher solubility and bioavailability. Once ingested, arsenic is absorbed into the bloodstream and transported to organs such as the liver, kidneys, and skin. The body naturally eliminates small amounts of arsenic through urine, but chronic exposure to high levels can lead to accumulation in tissues, causing long-term health effects.
Arsenic enters drinking water through natural processes and human activities. In regions where the bedrock contains arsenic-rich minerals, groundwater wells may become naturally contaminated. This is especially common in areas with high geological activity, such as parts of Bangladesh, India, and regions of South America. Arsenic leaches from rocks and soil into groundwater, contaminating wells and aquifers used for drinking water.
Human activities also contribute to arsenic contamination. Mining and industrial waste disposal can release arsenic into local water systems. The use of arsenic-based pesticides and herbicides in agriculture has historically contributed to soil and water contamination, although regulations have reduced their use in many countries. Industrial discharges from factories and wastewater treatment facilities can further introduce arsenic into rivers, lakes, and groundwater sources.
While low levels of arsenic are present in most water sources, health authorities have established safety limits to protect public health. The World Health Organization (WHO) recommends a maximum allowable concentration of arsenic in drinking water of 10 micrograms per liter (µg/L). The U.S. Environmental Protection Agency (EPA) has adopted a similar standard to protect communities from the harmful effects of arsenic exposure. This threshold is based on scientific evidence showing that long-term exposure to higher levels of arsenic increases the risk of cancer and other health issues.
The skin is one of the first organs to show signs of arsenic toxicity. Prolonged exposure to arsenic in drinking water can result in visible changes to the skin. Arsenic is transported to the skin through the bloodstream, where it affects keratinocytes, the primary cells of the skin's outer layer. This disruption in skin cell activity can result in a range of symptoms, including:
Areas of darkened skin, especially on the palms, soles, and trunk, are a hallmark of chronic arsenic exposure. The discoloration is due to an overproduction of melanin, a pigment responsible for skin color.
Chronic exposure to arsenic can cause small, rough patches of skin known as arsenical keratoses. These patches are often found on the hands, feet, and trunk. While benign at first, keratoses have the potential to become cancerous over time.
Arsenic-induced skin cancer typically manifests as squamous cell carcinoma or basal cell carcinoma. Unlike skin cancers caused by sun exposure, arsenic-related skin cancers often occur on non-sun-exposed areas of the body, such as the palms and soles.
The connection between arsenic exposure and skin cancer is well-established in scientific literature. Long-term exposure to arsenic in drinking water increases the risk of developing non-melanoma skin cancers, such as basal cell carcinoma and squamous cell carcinoma. Unlike sun-induced skin cancers, arsenic-induced skin cancers are more likely to occur on parts of the body that are not exposed to sunlight.
Research indicates that arsenic disrupts normal cellular processes in the skin, leading to DNA damage, oxidative stress, and altered gene expression. Chronic exposure to arsenic interferes with the body's ability to repair damaged DNA, which may promote the development of cancerous cells. Over time, the accumulation of genetic mutations can lead to the formation of skin tumors.
Certain groups are more vulnerable to the effects of arsenic exposure. People living in areas with high arsenic levels in groundwater face an increased risk of exposure. Agricultural workers and residents of mining communities are also at higher risk due to the presence of arsenic in soil, air, and water. Children are especially vulnerable because their developing organs are more sensitive to the effects of arsenic. People with pre-existing health conditions may also be more susceptible to the toxic effects of arsenic.
For most people living in countries with established water safety regulations, the risk of arsenic poisoning from drinking water is extremely low. Regulatory bodies like the World Health Organization (WHO) and the Environmental Protection Agency (EPA) have set strict limits on arsenic levels in public water supplies. In most Western countries, advanced water treatment systems are in place to ensure that arsenic concentrations remain well below harmful thresholds. It is important to note that health risks from arsenic exposure are typically linked to chronic exposure at levels significantly higher than these established safety limits. Occasional exposure or consumption of water with arsenic levels below regulatory limits does not pose a significant health threat.
However, in some low- and middle-income countries where water purification systems may not be as stringent, the risk of arsenic contamination can be higher. In regions where groundwater is used as the primary source of drinking water and arsenic testing is not consistently carried out, people may face an increased risk of long-term exposure. Certain areas, known as arseniasis-endemic regions, such as parts of Bangladesh, India, Taiwan, and some regions of South America, have naturally high arsenic concentrations in groundwater due to geological factors. In Taiwan, certain regions have reported cases of arseniasis, a condition caused by chronic exposure to arsenic-contaminated water, with health effects such as skin lesions, cancer, and other chronic illnesses. International health organizations are actively working with these countries to improve water quality monitoring and provide access to safer water sources. For those living in countries with strong purification standards, the likelihood of arsenic poisoning from drinking water is very low.
Arsenic in drinking water is a significant public health issue, especially in regions with naturally high arsenic concentrations in groundwater. Chronic exposure to arsenic beyond safe limits can lead to visible skin changes, such as hyperpigmentation and keratosis, and increase the risk of developing skin cancer. Arsenic-induced skin cancer is often found on areas of the body not exposed to sunlight, making it distinct from sun-related skin cancers. Vulnerable populations, such as people living in arsenic-prone areas, agricultural workers, and children, are at higher risk of exposure. Further research is needed to better understand the long-term health effects of arsenic exposure.
This article is part of the Public Education Series initiative by Exon Publications. It was written by professional medical writers for the general public in plain language, based on peer-reviewed articles indexed in PubMed, and further reviewed for scientific accuracy by experts. The views and opinions expressed in this article are believed to be accurate at the time of publication. However, the publisher, editors, and authors cannot be held responsible or liable for any errors, omissions, or consequences arising from the use of the information provided. The publisher makes no warranties, explicit or implicit, regarding the contents of this article or its use. The information in this article is intended solely for informational purposes and should not be considered medical advice.