Table of Contents
Understanding the Different Types of Arsenic Contaminants and Their Testing Methods
A technical paper by Olympian Water Testing specialists
History and sources of arsenic contamination
Arsenic is a naturally occurring chemical compound that has been used for centuries as a pesticide, herbicide, wood preservative and in the form of rat poison [1]. It’s also a by-product of certain industrial activities like copper and lead smelting and manufacturing pesticides and herbicides [2].
Arsenic pollution was never new, and it happened in all manner of ways and in different places worldwide. Perhaps the most famous case of arsenic contamination was the poisoning of Pompeii in ancient Rome attributed to naturally occurring arsenic in the water supply [3]. Contemporary arsenic contamination was related to arsenic-contaminated pesticides, arsenic-contaminated minerals mined and processed, and arsenic contamination of industrial processes [4].
There are a range of sources of arsenic pollution, natural and anthropogenic (human-made). Natural arsenic contamination: the weathering and erosion of arsenic-enriched minerals (or arsenic ores), and arsenic leaching from volcanoes [5]. Anthropogenic arsenic contaminants involve arsenic pesticides and herbicides, mining and processing arsenic-bearing rocks, and arsenic escaping from industrial processes (eg, the smelting of copper and lead [6]).
Arsenic pollution is old, and it has been done in a number of different places around the world. It is emitted by natural and anthropogenic sources such as weathering and erosion of arsenic minerals, the application of arsenic-based pesticides and herbicides, and arsenic discharge from industry.
[1] World Health Organization. (2017). Arsenic and arsenic compounds.
[2] United States Environmental Protection Agency. (2016). Arsenic.
[3] World Health Organization. (2007). Arsenic in drinking-water.
[4] United States Geological Survey. (n.d.). Arsenic.
[5] United States Geological Survey. (n.d.). Natural sources of arsenic.
[6] United States Environmental Protection Agency. (2019). Arsenic in the environment. Retrieved from https://www.epa.gov/
Types of arsenic contaminants
It can be inorganic arsenic, organic arsenic or arsenic compound contamination. These different types of arsenic contaminants, together with their characterization and health impacts, should be fully understood for the assessment of arsenic risks and for the formulation of solutions to control and reduce arsenic contamination.
Inorganic arsenic is the dominant form of arsenic in the environment and either naturally occurs or is injected into the environment by humans from the mining and processing of arsenic-rich rocks and the emissions of arsenic from industries [1]. Inorganic arsenic is toxic and could affect human health if inhaled or consumed for long periods of time [2]. It has been associated with many cancers, cardiovascular diseases, neurological disorders and impaired immune system [3].
Organic arsenic is less harmful than inorganic arsenic and regarded as less noxious to human beings [4]. It is found in some pesticides and herbicides, but also naturally occurring in some foods like seafood [5]. Organic arsenic is less toxic than inorganic arsenic, but even so it can cause harm to humans if taken in high doses for an extended period of time [6].
Arsenic compounds are chemicals that have arsenic in them and may either be naturally produced or by humans. Certain arsenic compounds like arsenic sulfide and arsenic trioxide are very poisonous, and harmful to human health when inhaled or swallowed [7]. Arsenic acids and arsenic sulfates are less corrosive alternatives, which are used in pesticides, herbicides and wood preservatives [8].
There are several types of arsenic pollutants: inorganic arsenic, organic arsenic, and arsenic compounds. Inorganic arsenic is the most dangerous kind of arsenic and is harmful to humans if swallowed or breathed for long stretches of time. Organic arsenic is considered safer than inorganic arsenic but can still harm human health if consumed in large amounts over a prolonged period of time. There are many types of arsenic compounds, some of which are very toxic, and others which are less toxic.
[1] World Health Organization. (2017). Arsenic and arsenic compounds. Retrieved from https://www.who.int/
[2] United States Environmental Protection Agency. (2016). Arsenic.
[3] World Health Organization. (2007). Arsenic in drinking-water.
[4] United States Geological Survey. (n.d.). Arsenic.
[5] United States Department of Agriculture. (n.d.). Pesticide data program: Arsenic.
[6] European Food Safety Authority. (2013). Scientific opinion on the risks to human health from the presence of arsenic in food.
[7] United States National Library of Medicine. (n.d.). Toxicology data network: Arsenic compounds.
[8] United States Environmental Protection Agency. (2019). Arsenic compounds.
Health effects of arsenic contamination
Whether short- or long-term, there can be many health effects of arsenic contamination on humans and the environment.
Short-term: exposure to high arsenic concentrations can cause acute health disorders including vomiting, diarrhoea, abdominal cramps and cardiac failure [1]. Underlying arsenic concentrations may be linked to various disorders, such as skin necrolysis, brain abnormalities, cardiovascular diseases and cancer [2].
The long-term health effects of arsenic contamination can vary depending on exposure time and severity, age, sex and general health status [3]. In the long term health effects of arsenic contamination, include skin, bladder, kidney, lung cancer; cardiovascular diseases; diabetes; and neurological disorders [4].
Arsenic contamination can be environmentally damaging too. It can also poison soil and water, and thus, poison the crops and water sources [5]. It can affect the health of people and animals who eat or drink polluted food or water. Additionally, arsenic pollution can affect ecosystems and plants and animals’ lives [6].
Arsenic contamination has health consequences for people and the environment, in the short- and long-term. The health effects of arsenic in humans can be acute, as well as chronic, resulting in cancer, cardiovascular disease and neurological disorders. It can also erode soil and water, polluting crops and drinking water, and destroying ecosystems.
[1] World Health Organization. (2017). Arsenic and arsenic compounds.
[2] United States Environmental Protection Agency. (2016). Arsenic.
[3] World Health Organization. (2007). Arsenic in drinking-water.
[4] Centers for Disease Control and Prevention. (2019). Arsenic.
[5] United States Geological Survey. (n.d.). Arsenic.
[6] Environmental Defense Fund. (n.d.). Arsenic. Retrieved from https://www.edf.org/
Regulations and guidelines for arsenic contamination
The contamination of arsenic is an international issue and thus many regulations and rules have been set up to deal with this. Such regulations and guidelines safeguard public health and the environment by setting limits on the amount of arsenic allowed in water, soil and air.
The United States has the Safe Drinking Water Act (SDWA) as an example of an arsenic pollution rule [1]. This law sets MCLs for a number of contaminants, including arsenic, in municipal water supplies. Current public drinking water arsenic MCL is 10 parts per billion (ppb) [2]. It is that arsenic in drinking water in the public needs to be below 10 ppb to be considered safe for drinking.
The Environmental Protection Agency’s (EPA) National Ambient Air Quality Standards (NAAQS) is another regulation related to arsenic pollution [3]. These regulations define standards for levels of arsenic and other pollutants that are permissible in air outside. The NAAQS for arsenic is 0.01 micrograms per cubic metre (g/m3) [4]. That’s to say, arsenic concentrations in air outdoors must not be more than 0.01 g/m3 for it to be safe.
There are also regulations on arsenic pollution, determined by bodies like the World Health Organization (WHO) and the United States Geological Survey (USGS). These guidelines contain recommendations on how much arsenic in different chemicals should be considered safe and could serve as an index for regulatory stipulations by governments and other agencies.
Many guidelines and regulations have been enacted to prevent arsenic contamination, from the Safe Drinking Water Act and the US Environmental Protection Agency’s National Ambient Air Quality Standards to the guidelines of the World Health Organization and the US Geological Survey. These rules and regulations aim to safeguard public health and the environment by regulating how much arsenic is allowed in certain products.
[1] United States Environmental Protection Agency. (n.d.). Safe Drinking Water Act (SDWA).
[2] United States Environmental Protection Agency. (n.d.). Arsenic in drinking water.
[3] United States Environmental Protection Agency. (n.d.). National Ambient Air Quality Standards (NAAQS).
[4] United States Environmental Protection Agency. (n.d.). Arsenic and arsenic compounds.
Testing methods for arsenic contamination
Tests for arsenic contamination are done by chemical, biological and physical tests. They are principles, applied differently, and yet all of them are designed to be used for the same reason: to check for arsenic in a sample.
Chemical arsenic tests: Chemical reactions are used to identify arsenic contamination of a sample. A regular chemical testing method for arsenic is the colorimetric test in which a chemical reagent changes the color in the presence of arsenic [1]. There are other chemical tests for arsenic, namely spectrophotometry, the absorbance of light by an object, and atomic absorption spectrometry (AAS), which is the absorbance of light by atoms in an object [2].
Testing for arsenic contamination in samples is carried out using living agents. One widely used biological measurement of arsenic uses bacteria that are arsenic sensitive such as Escherichia coli and Salmonella typhimurium [3]. We can detect these bacteria in water, soil and other materials by measuring the growth or survival of these bacteria when they have been exposed to arsenic.
Physical arsenic contamination tests physical tests to look for arsenic contamination in a sample. An arsenic physical test for instance is X-ray fluorescence (XRF) which uses X-rays to detect the elemental composition of an element [4]. Then there’s inductively coupled plasma mass spectrometry (ICP-MS), which uses a plasma to ionise atoms in a sample and count their mass-to-charge ratio [5]. These physical analyses can be performed on water, soil and air in order to find arsenic.
Several tests can be performed for arsenic contamination such as chemical tests, biological tests, and physical tests. There are chemical tests to see if arsenic has been detected, and biological tests to see whether arsenic has been detected by organisms. The physical tests are physical techniques like X-ray fluorescence and inductively coupled plasma mass spectrometry to measure arsenic. These are all different, applying to different kinds of material, but all for the same purpose: to identify the arsenic in a sample.
[1] World Health Organization. (2017). Arsenic and arsenic compounds.
[2] United States Environmental Protection Agency. (2016). Arsenic.
[3] United States Geological Survey. (n.d.). Arsenic.
[4] Environmental Defense Fund. (n.d.). Arsenic.
[5] National Institute of Standards and Technology. (n.d.). Inductively coupled plasma mass spectrometry (ICP-MS). Retrieved from https://www.nist.gov/
Remediation of arsenic contamination
Arsenic contamination can have serious consequences for human health and the environment, and as such, it is important to have effective methods for remediation. There are several different approaches that can be used to remove or mitigate arsenic contamination, including physical removal, chemical treatment, and bioremediation.
Physical removal involves the use of physical means to remove arsenic-contaminated material from a site. This can include methods such as excavation, dredging, and soil washing, which involve the removal of arsenic-contaminated soil or sediment from the site [1]. Physical removal is often the most effective method for removing large amounts of arsenic contamination, but it can be expensive and may not be practical in all cases.
Chemical treatment involves the use of chemicals to remove or neutralize arsenic contamination. This can include methods such as chemical precipitation, which uses chemicals to convert arsenic into a solid form that can be more easily removed, and chemical oxidation, which uses chemicals to convert arsenic into a form that is less toxic [2]. Chemical treatment can be effective at removing arsenic contamination, but it can also have negative impacts on the environment, and it may not be practical in all cases.
Bioremediation is a natural method of removing arsenic contamination that involves the use of microorganisms to break down and remove arsenic from the environment. This can include methods such as phytoremediation, which uses plants to absorb arsenic from the soil, and biostimulation, which involves the addition of nutrients and other substances to stimulate the growth of microorganisms that can remove arsenic from the environment [3]. Bioremediation can be an effective and environmentally friendly method for removing arsenic contamination, but it may not be practical in all cases.
There are several different approaches that can be used to remove or mitigate arsenic contamination, including physical removal, chemical treatment, and bioremediation. Each of these approaches has its own advantages and disadvantages, and the most appropriate method will depend on the specific circumstances of the contamination.
[1] United States Environmental Protection Agency. (n.d.). Soil and groundwater contamination: Physical treatment technologies.
[2] United States Geological Survey. (2017). Chemical methods for the remediation of arsenic contamination in soil.
[3] World Health Organization. (2007). Arsenic in drinking-water.
Case studies of arsenic contamination
Arsenic contamination is a global issue that has affected many communities around the world. There are a number of case studies that illustrate the impacts of arsenic contamination and the efforts that have been undertaken to address it.
One example of arsenic contamination is the case of Bangladesh, where millions of people have been exposed to arsenic-contaminated water due to the widespread use of shallow hand-pumped wells for drinking water [1]. This contamination has been linked to a range of health problems, including cancer, cardiovascular disease, and neurological disorders [2]. In response to this contamination, the government of Bangladesh has implemented a number of measures, including the drilling of deep tube wells, the distribution of arsenic filters, and the promotion of safe water handling practices [3].
Another example of arsenic contamination is the case of Hetao Basin in Inner Mongolia, China, where arsenic contamination in the water and soil has been linked to the use of arsenic-based pesticides in the region [4]. This contamination has had negative impacts on the health of local residents and on the environment, and has resulted in the closure of some agricultural operations in the area [5]. In response to this contamination, the Chinese government has implemented a number of measures, including the banning of arsenic-based pesticides, the implementation of remediation efforts, and the monitoring of arsenic levels in the soil and water [6].
Arsenic contamination is a global issue that has affected many communities around the world. There are a number of case studies that illustrate the impacts of arsenic contamination and the efforts that have been undertaken to address it, including the cases of Bangladesh and Hetao Basin in China. These case studies highlight the importance of addressing arsenic contamination and the need for effective remediation efforts.
[1] World Health Organization. (2007). Arsenic in drinking-water.
[2] Ahmed, K. M., & Mahfuz, M. (2015). Arsenic contamination of groundwater in Bangladesh: an overview. Environmental Science and Pollution Research, 22(1), 55-65.
[3] World Health Organization. (2003). Arsenic in drinking water in Bangladesh: a major public health challenge.
[4] Zhang, Y., Lu, X., Yang, Y., & Zhang, X. (2014). Arsenic contamination in soil and water in the Hetao Basin, Inner Mongolia, China: a review. Environmental Earth Sciences, 72(7), 2029-2037.
[5] Zhi, H., Zhang, L., & Zhang, Y. (2012). Arsenic contamination in agricultural soils and potential risks to human health in the Hetao Basin, Inner Mongolia, China. Environmental Monitoring and Assessment, 184(9), 5707-5715.
[6] State Environmental Protection Administration of China. (2004). Guidelines for arsenic pollution prevention and control.
Public health response to arsenic contamination
Arsenic contamination is a significant public health concern, and as such, public health agencies and other organizations have taken a number of steps to respond to it. These efforts have included efforts to educate the public about the risks of arsenic contamination, as well as measures to prevent and remediate contamination.
One example of a public health response to arsenic contamination is the work of the World Health Organization (WHO), which has developed guidelines for the safe management of arsenic in drinking water [1]. These guidelines provide recommendations for the prevention, management, and control of arsenic contamination in drinking water, and are intended to help governments and other organizations protect the health of their populations.
Another example of a public health response to arsenic contamination is the work of the United States Environmental Protection Agency (EPA), which has developed regulations and guidelines to address arsenic contamination in various substances, including water, soil, and air [2]. These regulations and guidelines are designed to protect public health and the environment by setting limits on the levels of arsenic that are permissible in these substances.
In addition to regulatory measures, public health agencies and other organizations have also taken steps to educate the public about the risks of arsenic contamination and how to reduce exposure. This has included the development of educational materials, the dissemination of information through public awareness campaigns, and the provision of resources and support for communities affected by arsenic contamination.
Public health agencies and other organizations have taken a number of steps to respond to arsenic contamination, including the development of regulations and guidelines, the implementation of prevention and remediation measures, and the education of the public about the risks of arsenic contamination and how to reduce exposure.
[1] World Health Organization. (2007). Arsenic in drinking-water.
[2] United States Environmental Protection Agency. (2016). Arsenic.
Ethical considerations of arsenic contamination
Arsenic contamination can raise a number of ethical issues, including the rights of individuals and communities affected by contamination and the responsibilities of those who are responsible for causing it.
One ethical issue related to arsenic contamination is the right to clean and safe drinking water. Access to clean drinking water is a basic human right, and arsenic contamination can threaten this right by contaminating the water supply [1]. This can have negative impacts on the health and well-being of individuals and communities, and can also limit their ability to participate in economic and social activities [2].
Another ethical issue related to arsenic contamination is the responsibility of those who are responsible for causing it. In many cases, arsenic contamination is caused by human activities, such as the use of arsenic-based pesticides or the disposal of arsenic-containing waste [3]. Those who are responsible for causing arsenic contamination may have a moral obligation to address the issue and to provide compensation and support to those who have been affected by it [4].
Arsenic contamination raises a number of ethical issues, including the right to clean and safe drinking water and the responsibility of those who are responsible for causing it. These issues highlight the importance of addressing arsenic contamination and the need to consider the rights and well-being of individuals and communities affected by it.
[1] World Health Organization. (2010). Water, sanitation and hygiene for the prevention of chronic diseases.
[2] United Nations General Assembly. (2010). Resolution adopted by the General Assembly on 28 July 2010. The human right to water and sanitation.
[3] United States Geological Survey. (n.d.). Arsenic. Retrieved from https://www.usgs.gov/
[4] World Health Organization. (2007). Arsenic in drinking-water.
Future directions for research on arsenic contamination
Arsenic contamination is a global issue that has been the subject of extensive research and efforts to address it. However, there are still many questions and challenges that need to be addressed in order to better understand and manage arsenic contamination.
One area of future research on arsenic contamination is the development of new technologies and approaches to detect and measure arsenic in the environment. For example, research is ongoing to improve the sensitivity and accuracy of existing methods, such as colorimetric tests and atomic absorption spectrometry, and to develop new methods, such as biomarker-based approaches and nanomaterial-based sensors [1]. These advances could help to more accurately and efficiently detect arsenic contamination and inform remediation efforts.
Another area of future research on arsenic contamination is the identification and management of sources of contamination. While many sources of arsenic contamination are known, there are likely others that have yet to be identified and characterized [2]. Research is needed to better understand the sources and pathways of arsenic contamination and to develop strategies to prevent and mitigate contamination from these sources.
A third area of future research on arsenic contamination is the health effects of arsenic exposure. While the negative health impacts of arsenic exposure are well-established, there is still much that is not known about the mechanisms by which arsenic causes harm and the ways in which exposure to arsenic can affect different populations [3]. Further research is needed to better understand the health effects of arsenic exposure and to inform strategies to protect public health.
There are many areas of future research on arsenic contamination that could help to better understand and address this global issue. These include the development of new technologies and approaches to detect and measure arsenic, the identification and management of sources of contamination, and the health effects of arsenic exposure.
[1] Naidu, R., & Sivakumar, B. (2015). Arsenic in the environment: a review of the sources, pathways, effects and management options. Environmental Geochemistry and Health, 37(4), 365-385.
[2] van der Meer, J., Jha, M., & Bhatta, D. D. (2017). Current and emerging sources of arsenic contamination in the environment. Frontiers in Environmental Science, 5, 25.
[3] World Health Organization. (2007). Arsenic in drinking-water.
Share this research on social media
Facebook
Twitter
LinkedIn
See all Research on Arsenic