Arsenic

Arsenic was a very rarely heard term in the water sector till a few decades back. However, in recent years, the number of areas reporting arsenic contamination have gone up drastically with over 20 countries from different parts of the world reporting arsenic contamination of groundwater (Bordoloi, 2012). With the constantly increasing number of occurrences, especially in the South Asian region, it is now recognized as a major public health concern affecting a large number of people around the world.

In South Asia, arsenic contamination in groundwater in the Ganga- Brahmaputra fluvial plains in India and Padma-Meghna fluvial plains in Bangladesh has been found to have a huge impact on human health and its consequences have been reported as the world’s biggest natural groundwater calamities. In India,  West Bengal, Jharkhand, Bihar, Uttar Pradesh in the flood plains of the Ganga, Assam and Manipur in the flood plains of the Brahamaputra and Imphal rivers and Rajnandgaon village in Chhattisgarh state have been reported to be affected by arsenic contamination in groundwater (Ghosh and Singh, nd)

What is arsenic?
Arsenic (As) is an odourless and tasteless metalloid widely distributed in the earth’s crust. Elemental arsenic is a member of Group VA of the periodic table, with nitrogen, phosphorus, antimony and bismuth. It has an atomic number of 33 and an atomic mass of 74.91.

What are the forms of arsenic available in nature?
Arsenic and its compounds occur in crystalline, powder,  amorphous or vitreous forms. It usually occurs in trace quantities in all rocks, soil, water and air. It is the 26th abundant element in the earth's crust.

Which form of arsenic is the most toxic?
Arsenite [As (III)] is most toxic form of arsenic and causes acute toxicity. Forms of arsenic such as As (III) and As (V) lead to chronic toxicity. Previously it was thought that methylated forms of arsenic [MMA (V), DMA (V)] were less toxic. However, current studies indicate that these two forms of arsenic are highly toxic.

What are the different exposure sources of arsenic?Health effects of arsenic pollution in West Bengal. Source: India Water PortalThe exposure sources of arsenic in the environment include natural and anthropogenic sources:
Natural – Leaching of ambient arsenic in groundwater from sediments containing arsenic bearing minerals; leaching and percolation of arsenic in soils.
Anthropogenic – Agrochemicals, wood preservatives, industrial sources, mineral processing, acid mine drainage, burning of fossil fuels etc.

How does arsenic enter the human body?
Arsenic can get into the human body through drinking water as well as eating food that has been contaminated with arsenic

How does arsenic get into drinking water?
Because it occurs naturally in the environment and as a by-product of some agricultural and industrial activities, it can enter drinking water through the ground or as runoff into surface water sources.

How does arsenic become a part of the food cycle?
When agricultural fields are irrigated with arsenic contaminated groundwater, inorganic forms of arsenic get absorbed by the plants and hence arsenic enters the food cycle.

Is arsenic always harmful in food?
Arsenic present in inorganic forms  as arsenite and arsenate is toxic. However, organic forms of arsenic like arsenobetaine, arsenocholine, arsenosugar, are non-toxic (these forms are mainly present in sea foods).

What happens to the arsenic that gets inside the human body?
Arsenic in drinking water is absorbed through the intestine into the bloodstream through which it reaches the various organs. The human body normally gets rid of smaller amounts of arsenic through urine. However, if there are large amounts of arsenic, the remaining arsenic accumulates inside the body and can lead to adverse health effects. However, the mechanisms underlying the adverse health effects by arsenic are not completely known. The level of accumulated arsenic can be known by investigating nail and hair samples.

What is Arsenicosis?
Arsenicosis is the medical word for arsenic poisoning, which occurs due to accumulation of large amounts of arsenic in the body.
Arsenicosis leads to adverse health effects through inhibition of essential enzymes, which ultimately leads to death from multi-system organ failure.

What are the health effects of arsenic poisoning?
Arsenic causes or increases the risk of numerous illnesses. It leads to skin damage including keratosis and skin cancer, internal cancers such as that of the lung and bladder, and diseases of the vascular system. Other health problems, such as diabetes, cancers of the other organs and adverse reproductive outcomes have been observed, but the evidence is not yet conclusive, although it keeps increasing.

What is the accepted standard of arsenic concentration in drinking water?
The guideline value or maximum contaminant level (MCL) for arsenic in drinking water is 10 ppb (according to WHO) followed by most of the developed countries. In developing countries including India and Bangladesh, 50 ppb is considered as the accepted level for arsenic in drinking water.

How much exposure to arsenic contaminated water is expected to result in skin lesions?
Evidence from the field has indicated that people drinking arsenic contaminated water for a couple of years may show arsenical skin lesions. The risk has been found to be more among people who are exposed to water contaminted with arsenic above levels of  500 μg/l . However, studies also indicate that even when exposed to a similar risk, all individuals do not display symptoms of skin lesions. The exact reason for this is not yet known.

Can one use surface water and rainwater and dugwell water as an arsenic free drinking water source? How?
These sources can be used for drinking after proper treatment against bacterial contamination and other toxins. Most of the dugwells are arsenic safe, but some of the dugwells could be contaminated with arsenic. Surface water is not usually contaminated with arsenic.

Does boiling remove arsenic from water?
No, arsenic cannot be removed by boiling as it is not a volatile substance. Rather, its concentration increases as water evaporates during boiling.

Is arsenicosis contagious?
No, it is not contagious.

How can one know if their tubewell is arsenic contaminated?
Arsenic has no distinctive taste, colour and odour. After proper collection and preservation, the water sample has to be analyzed for arsenic from an authorized analytical laboratory. Certified field kits can also serve the purpose, but these kits are only indicative in nature and not conclusive.

What are the biomarkers of arsenic?
Hair, nails, urine and skin scales of the person consuming arsenic contaminated water.

Are results based on field kit analysis a reliable method to assess the presence of arsenic in water?
Field kit analysis results may be accepted as an indicative result and may be conclusively accepted only after verification with laboratory procedures of testing. In the past, it has been observed that field kit analysis results have often turned out to be inaccurate.

Can arsenic affect an unborn child?
Although there is no evidence that arsenic can harm pregnant women or their fetuses, studies in animals have shown that doses of arsenic that are large enough to cause illness in pregnant females may cause low birth weight, fetal malformations, or fetal death.

References

The Arsenic Knowledge Network

What is the Arsenic Network?Arsenic knowledge network logo
The Arsenic Network is a knowledge-driven dynamic network of partner organizations and individual members, anchored by SaciWATERs and Arghyam, for sharing a common vision of bringing systematic and structural changes in arsenic mitigation strategies across India.

The Network is an attempt to create a repository of knowledge in arsenic studies across South Asia and enable action based on this knowledge, towards addressing the issue on ground by supporting coordinated efforts for arsenic mitigation.

To join the network, please mail us at contact@indiawaterportal.org.

Featured Articles
February 13, 2022 A study provides new evidence that drinking water contaminated with arsenic can lead to still births, recurrent pregnancy loss and infertility among women.
A well in Rajasthan (Image Source: IWP Flickr photos)
August 29, 2021 A study shows that high arsenic contamination of groundwater in Bihar is linked with increase in cancer cases. Districts located near the Himalayan river basins have more people with cancer.
Drinking water in Bihar, linked to cancer (Image Source: IWP Flickr photos)
March 3, 2021 Need to remove arsenic from the food chain and not just drinking water in endemic areas
Median excess lifetime cancer risk of 2 per 10,000 from food arsenic exposure in Bihar. (Image: Wikimedia Commons)
July 25, 2019 A young college graduate shares his experience working with Tata Trusts in Assam on water issues.
Stream Network in Tezpur, Assam. Image credit: Rohit Sar
May 30, 2019 Study finds 2.34 crore people in rural UP exposed to high levels of arsenic in groundwater
Arsenic concentration in groundwater of Uttar Pradesh shown by blue, green and red circles. Image courtesy: India Science Wire
March 18, 2019 Chemical contamination of drinking water is a significant health concern in India, one we haven’t realised the magnitude of. Practitioners across sectors must come together to tackle this issue.
Photo courtesy: Arjun Swaminathan
Dealing with arsenic in rural Bihar - Evaluating the successes and failures of mitigation projects
Arsenic is a toxin that is commonly found in the ground water of shallow aquifers in the Ganges River Delta.This research focuses on the social and economic factors that influence the successes and failures of different arsenic mitigation projects and will provide a strategy on how to handle the arsenic issue in the upcoming years. Posted on 21 Feb, 2013 11:51 PM

Article Courtesy: Delft University of Technology

Author(s): Matthijs Brouns, Merijn Janssen, Andrew Wong

Influence of anthropogenic contamination on fluoride concentration in groundwater: A study of Mulbagal town, Kolar district, Karnataka
Groundwater contamination is a serious, but relatively ignored issue in the country. This contamination occurs in either through geogenic or anthropogenic means. This paper analyses the Fluoride contamination, one such example of geogenic contamination, widely found in the Kolar district of Karnataka. Posted on 15 Feb, 2013 04:53 PM

Groundwater contamination is a serious, but relatively ignored issue in the country. This contamination occurs in either through geogenic or anthropogenic means. Fluoride contamination is one such example of geogenic contamination that is widely found in the Kolar district of Karnataka. However, the fluoride levels in the town of Mulbagal are lower than those in the surroundings. Earlier, a study was conducted on the impact of pit toilets on the groundwater in the area. The present paper investigates the presence of any link between these two phenomena.View of Mulbagal Town, Kolar District, Karnataka

Water, sanitation and health situation in select villages of Nadia district, West Bengal
To assess the exact level of water contamination in Nadia district of West Bengal, India Water Partnership commissioned a brief study to one of its east zone partners - Kalyani Institute for Study, Planning & Action for Rural Change (KINSPARC). KINSPARC conducted a comprehensive base-line survey of a cluster of villages in Nadia, based on which Iswaripur and Chandamari village were identified for in-depth study. Awareness and attitudinal changes among people generated by this survey may be interpreted as a step towards mitigating the threat of an impending disaster. Posted on 13 Jan, 2013 03:45 PM

Guest post: Veena Khanduri, India Water Partnership

The Gangetic river basin in Eastern India receives heavy monsoon rainfall, much higher than the rest of India. Nonetheless, the region suffers from both the problem of year round water availability as well as poor quality of drinking water. Due to excessive exploitation, the groundwater aquifers in the region have been depleting alarmingly, surface water is highly limited & poorly maintained and consequently cannot count up as a major source of safe drinking water.

Drought mitigation measures through climate adaptation for securing agricultural livelihoods in Uttar Pradesh
Prolonged and recurrent drought, being experienced in India and various parts of south Asia, is the manifestation of climate change, partly caused by human interventions. Posted on 13 Jan, 2013 02:43 PM

Prolonged and recurrent drought, being experienced in India and various parts of south Asia, is the manifestation of climate change, partly caused by human interventions. Drought has been one of the primary reasons for widespread poverty and environmental degradation including deteriorating water quality and water security. The world has been more drought-prone during the past 25 years and the vulnerability of tropical countries to drought is likely to increase (Inter-governmental Panel on Climate Change, 2007).

Effect of drinking arsenic-contaminated water in children- Article in Indian Journal of Public Health
This paper in Indian Journal of Public Health sheds light on the specific impact of arsenic on health of children based on the review of literature on the subject. Posted on 09 Jan, 2013 10:44 PM

This paper in Indian Journal of Public Health sheds light on the specific impact of arsenic on health of children based on the review of literature on the subject. The effects of chronic arsenic toxicity under the following aspects:

  • Psychological
  • Skin abnormalities
  • Lung diseases
  • Defect in intellectual function
  • Genetic issues

Briefing papers on ‘Jal kothis’, ‘Matka filter’, 'Dug wells' and ‘Phayedemand shauchalaya’: Local innovative solutions in flood prone Bihar by Megh Pyne Abhiyan (2011)
Megh Pyne Abhiyan, supported by Arghyam, has been working towards self-reliance and access to safe drinking water and secure sanitation, in 22 panchayats of five flood-prone districts of north Bihar. Included below are four briefing papers that describe innovative localised solutions implemented by Megh Pyne Abhiyan to deal with the problems arising out of the recurrent flood situation in the state of Bihar Posted on 29 Dec, 2012 03:14 PM

The briefing papers include the following:

Highlights from the 10-year water policy research programme of the International Water Management Institute and the Sir Ratan Tata Trust discussed at the IWMI - TATA Annual Partners' Meet at Anand, between 28-30 November, 2012
IWMI -Tata water policy research programme aims to draw upon research carried out throughout the country to identify solutions for India's water stress and present these as policy recommendations Posted on 05 Dec, 2012 02:06 PM

IWMI-Tata water policy research programme is a collaborative initiative between the International Water Management Institute (IWMI) and the Sir Ratan Tata Trust (SRTT). 

Drinking water treatment technologies - A handbook by National Environmental Engineering Research Institute & Ministry of Drinking Water and Sanitation
This handbook prepared by National Environmental Engineering Research Institute aims to build capacities to identify appropriate water treatment technologies suiting to local conditions. Posted on 30 Nov, 2012 10:22 PM

This handbook prepared by National Environmental Engineering Research Institute has eight chapters:

Chapter 1 introduces the objectives and approaches adopted to prepare the handbook.

Solar water purification system: A technology developed by Sustainable Living Centre, Puttaparthi, Andhra Pradesh
The 5 stage solar water purification system gives 1500 litres of drinking water in 24 hours in Puttapurhi, Anantapur district, Andhra Pradesh Posted on 12 Sep, 2012 09:58 PM

The Sustainable Living Centre is located at Puttaparthi, Anantapur District, Andhra Pradesh.  The 5 stage solar water purification system gives 1500 litres of drinking water in 24 hours, if it is running continuously and if it has a constant source of water supply connected to it.

River diversion schemes versus waste water recycling for Bangalore city - An article in Current Science
The author of this paper argues that it is pertinent to look at the water problem from a river basin perspective to manage the water crisis of Bangalore city Posted on 26 Aug, 2012 12:02 AM

This article published in the journal Current Science has been written in response to the earlier article published in Current Science that highlights the acute water scarcity t

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