Health effects of arsenic

4.5.1

Arsenic is an element that has had an essential role in the history of humankind from many aspects. Almost everybody knows when they hear the word “arsenic” that it is something dangerous and highly poisonous. However, many forgot that arsenic and human civilization have a very long joint journey. This short history is based on the article published in LinkedIn 2014 (Martikainen, 2014).

Arsenic was used in many tinctures, potions, and medications for hundreds of years. As late as the early 1940s, arsenic compounds were used to treat, for example, syphilis. At that time, arsenic mixed with a tiny amount of mercury was the only cure. In treating syphilis, arsenic was replaced with penicillin when it was introduced as a treatment in 1943. However, the usage of arsenic compounds in medicine continued to the 1950s.

Arsenic has a strange effect on human physiology; in very, very small doses, it gives a healthy glow, clear skin, rosy cheeks, sparkly eyes and in general, “appearance of flourishing health”. However, when the arsenic dose is slightly increased, the result is death. The human body and arsenic is a strange couple. When slowly increasing arsenic consumption, the human body becomes tolerant to even lethal levels of arsenic dosages.

This was the key to the “arsenic culture” of the 19th century.

By the mid-19th century, the arsenic craze was its highest, and the usage was widespread in external and internal medications and cosmetics. Of the various arsenic compounds, one of the most common ones was “Fowler's Solution”. Fowler's solution is a 1% solution of potassium arsenite, KH2AsO3, developed by Dr Fowler in 1786. Fowler's solution was prescribed in the United States until the late 1950s for various diseases from malaria to syphilis.

Arsenic was not only used in medicine and cosmetics. It was used in enormous quantities in colour pigments, especially in gold pigments (arsenic sulphide As2S3) and green pigments like Emerald Green (mixture of arsenic and verdigris), Paris Green (copper aceto arsenite) and Schlees´s Green (copper arsenite). Green arsenic colours were so popular from the end of the 1800s to the early 1900s that they were used in everything from dyeing clothes and wallpapers and making paints. Wallpapers could contain 1-5%

of arsenic. However, this widespread use of arsenic in various applications caused lots of deaths due to arsenic poisoning. One of the first findings of the green pigment toxicity was related to the wallpapers. It was eventually found out that the humid conditions in basically every home in the 19th century generated mould to the wallpaper. Mould would start a biological process that turned arsenic dyes into extremely toxic arsenic gases like arsine AsH3 and trimethylarsine.

In general, Arsenic’s effects on human health and toxicology got wind under its wings when it was found out that it could be poisoning beer drinkers. When something threatens

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beer drinkers, there is no limit on resources one uses to find the cure. In the early 1900s, there were a series of strange poisonings that were found out to be related to the beer.

Initially, they were assumed to be alcohol poisonings, but the truth was more horrific.

First, it was found out that the sulphuric acid used in the sugar processes (manufacturing fructose and glucose for beer-making) contained high amounts of arsenic. As high content as 10% of arsenic could be found from sulphuric acid. The reason for arsenic was the pyrite mineral FeS2 used for sulphuric acid production. The pyrite that came to England from mines located in Spain had very high arsenic content. Moreover, from the pyrite mineral, the arsenic ended to the sulphuric acid and from the sulphuric acid to the fructose and eventually to the beer. The second arsenic source contaminating beers was the arsenic-containing coke used in a process called malting. Arsenic would vaporize from the coke and end up to the malt, and from malt, it would end up to the beer. Thus, the campaign for “Pure Beer” (1896-1903) started, and the first regulations related to food safety were initiated.

4.5.2

Arsenic was one of the first chemicals recognized as a cause of cancer. As early as 1879, the connection between inhaled arsenic and high lung cancer rates of the miners in Saxony were made. A few years after this, it was learned that medicines containing arsenic caused skin cancer. In the 1930s, findings in Argentina showed that arsenic in drinking water could cause skin cancer, and later it became evident that different internal cancers are caused by arsenic from drinking water (Smith, et al., 2002).

Nowadays, it is a known fact that inorganic arsenic can cause lung cancer, skin cancer, bladder cancer, liver cancer, kidney cancer, and prostate cancer. Figure 4.7 is shown the odds ratio of skin lesions versus arsenic dose from drinking water. Skin lesions are the first signs of arsenic poisoning and can develop later on skin cancer (Yoshida, et al., 2004).

In Figure 4.8 woman from Bangladesh is presenting changes in the skin of her hands due to arsenic poisoning.

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Figure 4.7. The odds ratio for the prevalence of skin lesions versus the average arsenic exposure dose over the past five years [N = 62 (Men: 32; Female: 30)]. Skin lesions are defined as the existence of hyperkeratosis on the palm or sole and depigmentation of significant areas of the skin (Yoshida, et al., 2004).

Figure 4.8. A woman from Bangladesh shows symptoms of arsenic poisoning (Horizon International - Yale University Department of Biology, n.d.).

Besides cancer, other symptoms associated with exposure to arsenic include diabetes, skin diseases, chronic cough, toxic effects in the liver, kidney, cardiovascular system, peripheral- and central nervous systems (Mandal & Suzuki, 2002). A representation of the arsenic toxicity to human health is shown in Figure 4.9.

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Figure 4.9. Arsenic toxicity in humans (Siddique, et al., 2020).

The World Health Organization has estimated that long-term exposure to arsenic concentrations over 500 µg/L in groundwater used as drinking water causes death in 1 in 10 adults (Halem, et al., 2009). In addition, the estimated cancer risk at the current WHO drinking water guideline of 10 µg/L is in the range of 1/1000 to 1/100 (Vahter, et al., 2006).

Consuming arsenic-contaminated drinking water is not the only possible source of arsenic. For example, if arsenic-containing groundwater is used for irrigation, this will lead to widespread soil contamination and additional arsenic exposure to humans via vegetables grown in that soil. Arsenic is concentrated primarily in the green parts of plants. This means that vegetables like cabbage, where the edible part is the green leaves, are the source of arsenic. Rice, for example, does not accumulate arsenic since the edible part is the grains. The indirect route of arsenic exposure is through contaminated water used to prepare food and beverages. In addition to vegetables, animal-based food items like milk, eggs, and meat can identify potential pathways for arsenic.