One of the principal contaminants present in groundwater is arsenic. Arsenic is poisonous and can cause a variety of health issues.

Let us understand the concept of arsenic poisoning in water. We shall also look at the sources of exposure, the harmful effects, and ways to eliminate arsenic from water.

Arsenic

Here are some key facts of arsenic poisoning in a nutshell.

Arsenic is a naturally occurring metalloid present in groundwater in many countries.

There are two forms of arsenic of which the inorganic form is highly toxic. You find this inorganic form of arsenic in groundwater.

Arsenic in its inorganic form can contaminate water. Using such contaminated water for drinking, preparation of food and irrigation can pose considerable threats to our health.

Arsenic is carcinogenic. Hence, long-term exposure to arsenic through water and food can cause cancer. People exposed to arsenic poisoning have also suffered from cardiovascular diseases and diabetes.

Unborn children have also been affected by arsenic poisoning. It has a detrimental effect on cognitive development and is a cause of premature deaths in young adults.

Arsenic risk areas worldwide

What is arsenic?

Arsenic, a metalloid, is naturally available in the earth’s crust. You can find traces of arsenic in rocks, air, soil, and most importantly water. It is a metalloid because it has many properties that metals have.

Arsenic is present in two forms, inorganic, and organic. The inorganic arsenic is the more common of the two. Countries like India, China, Bangladesh, the USA, Mexico, Argentina, and Chile contain significant amounts of inorganic arsenic in groundwater. You find organic food in seafood. It is a comparatively milder toxic form of arsenic.

Sources of arsenic

We have already seen that arsenic is present in the earth’s crust in its natural form. However, the greatest threat to humans comes from consuming water and food contaminated with arsenic. Let us look at the different sources of arsenic.

Industrial Processes Drinking water and foodTobacco

Arsenic is an important alloying agent used in the glass, pigments, textiles, paper, metal adhesives, wood preservatives, and ammunition manufacturing industries. You can also find arsenic in the tanning industry, and to some extent in the pesticides and pharmaceutical industry.

Inorganic arsenic are present in high quantities in groundwater. Crops irrigated with water conta

Plants like tobacco absorb arsenic directly from the soil. Therefore, people habituated to smoking tobacco products are at a higher risk of exposure to arsenic.

How does arsenic get into the body?

Arsenic can enter our human body in a variety of ways. The most common entry is through contaminated food and water. There have been instances of people inhaling arsenic or absorbing it through the skin.

What happens to the arsenic that enters the human body?

The intestine absorbs the arsenic that you consume through drinking water or food. It then passes through the bloodstream to various organs in the body.

The immunity system of the body is capable of eliminating small amounts of arsenic through urine. However, if the contamination is high, the arsenic accumulates inside the body and causes a condition known as Arsenicosis (Arsenic Poisoning).

Effects of Arsenic

Inorganic arsenic is a cancer-causing agent. Exposure to arsenic can cause acute as well as long-term effects. We shall look at the immediate symptoms of arsenic poisoning.

A person swallowing arsenic will show the following symptoms within 30 minutes.

  • A persistent headache
  • Confusion
  • Severe diarrhoea
  • Feeling of drowsiness

Inhaling arsenic or consuming it in a less concentrated form is also harmful. The symptoms can take some time to develop. The patient starts experiencing convulsions as the poisoning progresses. You can even notice the decolourisation of the fingernails.

Here are the symptoms generally associated with severe cases of arsenic poisoning.

  • A lingering metallic taste in the mouth accompanied by garlicky breath
  • Secretion of excessive saliva
  • Difficulties in swallowing
  • Passage of blood in the urine
  • Experience cramping muscles
  • Suffer from hair loss
  • Stomach cramps and convulsions
  • Excessive sweating
  • Vomiting coupled with diarrhoea

Heavy poisoning can induce seizures and shock leading to coma and eventually, death.

Complications linked to long-term consumption of arsenic

Extensive consumption of arsenic over a long period can have disastrous effects on the overall health of the individual. We have seen that arsenic is a dangerous carcinogenic agent. The complications associated with long-term consumption of arsenic are as follows.

  • Difficulties in digesting food
  • Complications in the nervous symptoms such as hearing problems or loss of sensations in the limbs
  • Diabetes
  • Liver disease
  • Cancer

How do you diagnose arsenic poisoning?

Pathological testing is the right way to diagnose arsenic poisoning. Urine tests carried out within a day or two of suspected arsenic poisoning can give you an accurate measure of when the poisoning occurred. These are the preliminary tests carried out to determine arsenic poisoning.

In case of acute poisoning, pathological tests of the patients’ hair, blood, and fingernails can confirm the presence of arsenic in the body. However, these tests offer accurate results if the exposure to arsenic is for over a period of 12 months.

The diagnostic tests do not show the effects arsenic can have on the patient’s health.

Treatment methods

The treatment depends on the type and the stage of the arsenic poisoning.

There are ways to remove arsenic from the body before it causes damage. Some methods aim to minimize or repair the damage after it occurs.

Here are some of the treatment methods.

  • People working in industries where arsenic contamination is common should remove the clothes that could be contaminated with arsenic
  • They should wash their clothes thoroughly before using them again
  • Similarly, they should clean and rinse the affected areas of the skin
  • In case of arsenic contamination in blood, the best treatment is to have blood transfusions
  • If your heart shows signs of failing, it is advisable to take heart medications
  • Use mineral supplements that can lower the risk of heart rhythm problems
  • Observe kidney functions and take immediate remedial action in case of detection of arsenic in the urine.

Another conventional treatment method is Bowel Irrigation. This method involves the passing of a particular medicinal solution through the gastrointestinal tract whereby it helps flush out the contents. This method is beneficial in removing traces of arsenic as it prevents the absorption of arsenic into the gut.

Chelation therapy is also a popular treatment method. Here, you use special chemicals like dimercaptosuccinic acid and dimercaprol that helps in isolating arsenic from the blood proteins.

Prevention and control of arsenic exposure

Installing RO water purifiers can help prevent and control arsenic exposure.

The arsenic molecules are larger and heavier than the regular water molecules. The RO membrane can trap these heavy metals and eliminate them. Other technologies that help eliminate arsenic are oxidation, coagulation-precipitation, absorption, and ion exchange.

These water purification systems can reduce the arsenic levels at the destination. However, this is not a long-term solution until you can deal with arsenic contamination at the source.

Examine the water at the source of the presence of arsenic in it. Usually, groundwater has a high concentration of arsenic contamination. Substituting such high-risk sources of water with low-arsenic water such as rainwater or treated surface water is one way of preventing arsenic poisoning.

You can use the low-arsenic water for consumption and irrigation purposes while reserving the use of high-arsenic for activities like washing clothes.

Discriminate between low-arsenic and high-arsenic sources by marking the hand pumps or tube wells in different colours.

Educating people about the ill-effects of arsenic and teaching them to discriminate between the low-arsenic and high-arsenic sources is one of the most significant methods of preventing and controlling arsenic exposure.

Rainwater harvesting is an excellent way of reducing the levels of arsenic in groundwater.

Deepening the wells can also ensure dilution of arsenic from the well water.

Acceptable levels of arsenic in groundwater

It will be excellent if there are no traces of arsenic in groundwater. However, it is not practically possible. Therefore, the World Health Organization has stipulated the maximum acceptable levels of arsenic in groundwater as 10µg/litre.

Different countries have specified their national standards depending on the levels of arsenic contamination. For example, Bangladesh, one of the worst affected countries, has specified the national standard of 50µg/litre.

However, the US National Research Council has estimated that 1 in 100 additional cancer-related deaths are because of lifetime exposure to drinking water containing arsenic up to 50µg/litre.

Frequently Asked Questions about Arsenic Poisoning

Is arsenic in food always harmful?

Inorganic arsenic such as Arsenite and Arsenate is toxic. However, there are organic forms of arsenic such as arsenobetaine, arsenocholine, and so on that are non-toxic. You find these forms of arsenic in seafood.

What is Arsenicosis?

Arsenicosis is the medical word for arsenic poisoning. It occurs because of accumulation of arsenic in the body.

How much exposure is required for patients to develop skin lesions?

Usually, people drinking water contaminated with arsenic for two years or more tend to develop skin lesions. Arsenic levels over 500µg/litre can cause skin lesions. However, not all individuals exposed to these levels of arsenic develop skin lesions.

Does boiling water remove arsenic?

Arsenic is not a volatile substance. Hence, boiling water does not remove arsenic. On the other hand, it increases the concentration of arsenic as you lose a substantial quantity of water through evaporation.

Is arsenic contagious?

No, it is not.

Can arsenic affect unborn children?

There is no evidence today to suggest that arsenic affects the health of unborn children. However, pregnant women having exposure to large doses of arsenic are at risk of falling ill. This illness can cause low birth weight, foetal malformations, or even foetal death.

Sources: Wikipediamedicalnewstoday, WHO, TimesofIndia

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Sumeet
Sumeet
April 3, 2019 5:56 am

Shiva,
What motivates to write about water pollution?