Why arsenic is toxic to human beings

Mercury is highly toxic, so it is crucial to know when to see a doctor. It can have serious side effects…. Lead poisoning is a serious risk for young children. Exposure to old paints, water from lead pipes, and fumes from leaded fuels can cause lead to…. In this article, we examine the symptoms of poisoning from organophosphate, a form of insecticide. We also look at the risks and treatment options.

A feeling of tingling in the feet or hands can have a variety of causes. Many are related to peripheral neuropathy or nerve damage, but others include…. What is arsenic poisoning? Medically reviewed by Alana Biggers, M. What is arsenic? Symptoms Causes Diagnosis Treatment Arsenic poisoning, or arsenicosis, happens when a person takes in dangerous levels of arsenic.

Share on Pinterest The effects of arsenic are dangerous, but overexposure to it is very rare. Share on Pinterest Groundwater possesses trace amounts of arsenic. On occasion, these levels may exceed the amount a human can safely ingest. Exposure to air pollutants may amplify risk for depression in healthy individuals.

Costs associated with obesity may account for 3. How to reduce food waste. Are pesticides in food harmful?

WHO publish report on microplastics in drinking water. Related Coverage. What is penicillamine? Medically reviewed by Zara Risoldi Cochrane, Pharm. Lead poisoning in children and in adults. Medically reviewed by Stacy Sampson, D. What to know about organophosphate poisoning. What could cause tingling in the feet or hands? Medically reviewed by Seunggu Han, MD. Therefore, arsenic measured via urine sample is currently the most appropriate method for use in epidemiological studies.

In the general population, measurement of arsenic in the urine has been accepted as the most suitable method. In a study by Bae et al. Another study by Eom et al. In a high-risk area for arsenic exposure in Bangladesh, the total urine arsenic concentration was However, these findings cannot be generalized to the South Korean population; thus, further studies regarding arsenic exposure level using representative data in South Korea are needed.

When collection data on total arsenic concentration can be difficult to clearly determine the state of arsenic exposure. As such, analysis of the exposure level by separation and quantification of each type of arsenic is needed. In addition, subsequent assessments of arsenic exposure are needed to establish appropriate management policies.

Given its toxicity, arsenic exposure is an important issue in public health, and more research is warranted. Cancers of the skin, lungs, and bladder have been confirmed to be associated with arsenic exposure, while human data on liver cancer, kidney cancer, prostate cancer, and leukemia are limited.

For diabetes and other disorders, further research regarding its non-carcinogenic toxicity is needed. Recent, previous studies have investigated the health effects of chronic exposures to low concentrations of arsenic, but additional studies are required. To determine the level of arsenic exposure and its associated health effects in the South Korean population, biological monitoring data that can objectively assess human exposure must be developed.

However, data on the total arsenic exposure level and that by arsenic species are lacking in the Korean population; therefore, further research of this kind is needed to support effective public health management.

The authors have no conflicts of interest with the material presented in this paper. National Center for Biotechnology Information , U. J Prev Med Public Health. Published online Sep Author information Article notes Copyright and License information Disclaimer. Received Aug 17; Accepted Sep 3. This article has been cited by other articles in PMC.

Abstract Arsenic is a unique element with distinct physical characteristics and toxicity whose importance in public health is well recognized. Keywords: Arsenic, Health effects, Carcinogenicity. Skin cancer Several studies have reported an association between arsenic exposure and skin cancer.

Lung cancer Hopenhayn-Rich et al. Bladder cancer Incident bladder cancer and arsenic exposure through drinking water has been verified by studies in Taiwan and Bangladesh [ 33 ]. Liver cancer Although previous studies conducted in Argentina, Chile, Denmark, and other regions have reported a relationship with liver cancer, no consensus has been made on this relationship mostly because of a limited availability to representative data [ 37 , 38 ].

Prostate cancer The association between exposure to high concentrations of arsenic and prostate cancer was reported in Taiwan [ 5 ]. Leukemia Very few studies have investigated the association between arsenic exposure and leukemia. Non-carcinogenic Effects Neurological effects, memory, and intellectual function Arsenic accumulated in the body during childhood may induce neurobehavioral abnormalities during puberty, and neurobehavioral changes as an adult [ 42 ].

Diabetes Recently, the possibility of arsenic exposure affecting the incidence of diabetes has been suggested. Effects on the skin Several studies have examined the incidence of various skin disorders because of arsenic exposure. Effects on cardiovascular disorders Lee et al. Effects on the reproductive system Pregnancy complications because of arsenic exposure from drinking water have been reported [ 50 ]. Acknowledgments This work was supported by the Dong-A University research fund Footnotes The authors have no conflicts of interest with the material presented in this paper.

Important considerations in the development of public health advisories for arsenic and arsenic-containing compounds in drinking water. Rev Environ Health. Arsenic trioxide and melarsoprol induce apoptosis in plasma cell lines and in plasma cells from myeloma patients. Cancer Res.

Identification of dimethylarsinous and monomethylarsonous acids in human urine of the arsenic-affected areas in West Bengal, India. Chem Res Toxicol. Environmental Protection Agency An exposure and risk assessment for arsenic. What is the best biomarker to assess arsenic exposure via drinking water? Environ Int. Association of arsenic levels in soil and water with urinary arsenic concentration of residents in the vicinity of closed metal mines.

Int J Hyg Environ Health. Placental permeability of arsenate ion during early embryogenesis in the hamster. Carcinogenic and systemic health effects associated with arsenic exposure: a critical review. Toxicol Pathol. Urinary excretion of inorganic arsenic and its metabolites after repeated ingestion of sodium metaarsenite by volunteers. Int Arch Occup Environ Health. Arsenic in drinking water and health issues.

Metal contaminants in New Zealand: sources, treatments, and effects on ecology and human health. Christchurch: Resolutionz Press; Arsenic: health effects, mechanisms of actions, and research issues. Environ Health Perspect.

Goyer RA. Toxic effects of metals. New York: McGraw-Hill; Hughes MF. Arsenic toxicity and potential mechanisms of action. Toxicol Lett. Environmental pathology and health effects of arsenic poisoning: a critical review. Managing arsenic in the environment: from soil to human health. Human health effects from chronic arsenic poisoning: a review. Arsenic and cancers. Investigation of skin manifestations of arsenicism due to intake of arsenic-contaminated groundwater in residents of Samta, Jessore, Bangladesh.

Arch Dermatol. Marked increase in bladder and lung cancer mortality in a region of Northern Chile due to arsenic in drinking water.

Am J Epidemiol. Int J Epidemiol. Evidence that arsenite acts as a cocarcinogen in skin cancer. Toxicol Appl Pharmacol. Serum beta-carotene level, arsenic methylation capability, and incidence of skin cancer. Cancer Epidemiol Biomarkers Prev. Arsenic and urinary bladder cell proliferation. Inorganic arsenic and basal cell carcinoma in areas of Hungary, Romania, and Slovakia: a case-control study.

Lung cancer and arsenic concentrations in drinking water in Chile. Increased mortality from lung cancer and bronchiectasis in young adults after exposure to arsenic in utero and in early childhood.

Unlike many other known chemical carcinogens, arsenic does not cause damage to DNA or cause mutations in genes. Instead, it appears to indirectly modify the way cells behave in ways that increase their probability of becoming cancer cells, perhaps in combination with other carcinogens such as cigarette smoke or other environmental contaminants.

The effect arsenic has on living things is strongly governed by its form or species. Although metals are simple elements, metal atoms can combine into different forms that vary in chemical and biological properties. Some forms of arsenic are highly toxic; others are essentially non-toxic. The reasons are rooted in basic chemistry.

Atoms are made up of a nucleus — a mixture of positively charged particles called protons and neutral particles called neutrons — around which negatively charged particles called electrons orbit. Atoms can gain or lose electrons to change their ionic charge, and the sharing of electrons is primarily how atoms bond together to form molecules. These two forms can be readily converted back and forth both in nature and inside our bodies depending on the local chemical environment — such as changes in acidity pH , the presence of oxygen or iron, and what other molecules are present.

Arsenite is believed to be slightly more toxic than arsenate, but since they are so easily inter-converted, both forms are considered a health risk. When arsenic binds to elements such as sulfur, oxygen, and chlorine it forms molecules known as inorganic compounds; when arsenic binds to molecules containing carbon it forms organic compounds. Inorganic forms of arsenic are, in general, more toxic to humans since they are less stable and may allow arsenic to interact with important cellular molecules.

Both the inorganic and organic forms of arsenic are readily eliminated from the body through the urine. When we are exposed to inorganic arsenic, the body routinely changes, or metabolizes, it into one or more organic forms by successively adding carbon atoms to it. Scientists once believed that this process — known as methylation — was a natural arsenic detoxification process for both humans and other animals.

But new findings have challenged that idea. Animal species that do not methylate arsenic are not only able to excrete inorganic arsenic efficiently but appear to be no more sensitive to its toxic effects than animals that methylate.

More recently, scientists have found that a simple methylated form of arsenic called mono-methylarsenic III can cause cancer in animals.

So although fish may have high amounts of arsenic in them, it is primarily in a form that is not a health risk to humans. There is evidence that humans and other animals can build up tolerance to the toxic effects of arsenic.

Rasputin was reported to regularly ingest arsenic to build tolerance and to protect himself from poisoning. Like any other poison, whether an exposure to arsenic is harmful largely depends on its chemical and physical form and how one is exposed. Toxicologists use the terms dose, duration and route of exposure, meaning the amount of a substance taken in, the period of time the exposure lasts, and the way the substance enters the body. One way of being exposed to arsenic is by breathing it in as a dust.

This primarily occurred in workplace settings where arsenic or products containing arsenic were used, and before new knowledge led to the development of modern worker safety measures.

There is normally little or no uptake of arsenic through the skin at environmental levels, though it was of concern in previous workplace exposures such as long-term use of arsenic-containing pesticides or through use of arsenic-containing medications applied directly to the skin. The route of exposure of most concern today is ingesting arsenic, particularly through drinking water contaminated by inorganic arsenic. The concentrations of arsenic found in the heavily contaminated drinking water of Bangladesh are between and micrograms per liter A microgram is a millionth of a gram.

By contrast, a person would have to ingest more than 70, micrograms of arsenic all at once to be fatally poisoned by a single dose. Nevertheless, exposure over a long period of time to concentrations of arsenic such as those found in Bangladesh is associated with a wide range of illnesses. Few studies have examined the effects of lower doses on people over long periods of time.

Dartmouth researchers are conducting epidemiological studies to determine the health effects of drinking water containing arsenic at the elevated levels found in certain regions of the United States. These levels -typically between 50 and micrograms per liter — are much lower than those of Bangladesh but are still considered high enough to be of concern. On the one hand, arsenic is one of a handful of chemicals that is well established as a human carcinogen based on direct evidence in human populations.

On the other hand, arsenic has been shown to be effective as a cancer chemotherapy drug and can be used to induce complete cures in certain forms of cancer. Surprisingly, it has been difficult to demonstrate that arsenic can increase the incidence of cancer in animals despite the strong human epidemiological data. This is also true of several other carcinogenic metals including chromium, cadmium and nickel. The reasons are unclear, but one view is that these agents act indirectly, by increasing the risk of cancer from other factors.

This would not be evident in experiments in which animals are raised in a relatively pristine laboratory environment and exposed only to the metal in question. Beginning around the s, the Chinese began to systematically experiment with the use of arsenic to treat certain cancers. Most of these studies were published in the Chinese medical literature, which did not become accessible to the western world until the late s.

In particular, the Chinese demonstrated that use of arsenite -inorganic arsenic trioxide — was highly effective in treating certain leukemias. Arsenite was particularly useful for people whose leukemias were resistant to chemotherapy treatment using retinoic acid, a derivative of vitamin A. The results of these arsenic studies were recently confirmed in a small U. These studies suggest that arsenic may prove to be an effective anti-cancer agent for other malignancies in the coming years.

Arsenic has been the poison of choice since antiquity because it is difficult to detect in food and water and because the symptoms of poisoning by arsenic can be mistakenly attributed to many other ailments. The effects of arsenic poisoning differ depending upon whether the exposure is acute — a large dose in a short period of time — or chronic — lower doses over an extended period of time.

At a very high, single dose arsenic can cause severe shock, general paralysis, delirium and then death within a few hours. At a somewhat lower dose the primary symptoms are nausea, headache, intense gastrointestinal pain, vomiting and diarrhea. This can be followed by extensive gastrointestinal bleeding, loss of blood pressure and a decrease in brain function followed by death. These effects are rare except in cases of intentional poisoning or suicides. Workers and others who have been exposed to arsenic over long periods of time, principally by breathing it or ingesting it, can exhibit symptoms that include melanosis, a change in pigmentation of the skin similar to freckling; hyperkeratosis, an extensive thickening of the skin, especially the palms of the hands and soles of the feet; damage to heart and blood vessels; a decrease in both red and white blood cell production; and severe inflammation of the liver.

These symptoms are also seen in people who live in regions where drinking water contains between and 1, parts per billion of arsenic.

Drinking-water arsenic at these levels is also associated with an increased risk of diabetes mellitis type 2 or adult-onset diabetes , with damage to heart and blood vessels and, in some areas of the world, a condition called blackfoot disease.

Arsenic is cleared from the body quickly, so the most important remedy for arsenic poisoning is eliminating exposure. The most serious effects of arsenic, such as cancer and diabetes, are believed to require long, continuous exposures perhaps lasting 20 years or more. In cases of extreme poisoning, chemical compounds called chelating agents can be used as an antidote. Medical tests can detect arsenic in the human body, but these tests are not part of a routine physical.

They may be ordered when there is reason to suspect a person has received a harmful dose of arsenic. The body routinely excretes arsenic in urine, so a urine test may show whether a person is taking in harmful amounts of arsenic.

But since the body metabolizes and eliminates arsenic quickly, a urine test is not useful in telling if someone has taken in arsenic in the past. Hair, fingernails and toenails are made primarily of keratin — a stable protein that contains sulfur — so they provide a good means of detecting arsenic exposure in people.

Hair and nails grow slowly over time, leaving a record of arsenic exposure for six months to a year. Toenail arsenic is considered the most accurate measure of exposure information because, unlike hair and fingernails, they are less susceptible to contamination from arsenic in soaps, shampoos, air pollution and other sources in the environment.

One way the EPA controls the safety of public water supplies is by setting and enforcing a safety standard, or Maximum Contaminant Level MCL , for drinking water pollutants. The MCL for arsenic of 50 parts per billion was set in , when far less was known about the effects of arsenic on human health. Most other countries of the western world have a current MCL for arsenic of 10 parts per billion.