Arsenic is a tasteless, odorless element in the environment that can be found naturally in rocks and soil, water, air, plants, and animals. It can also be released into the environment from some agricultural and industrial sources.

Arsenic is usually part of chemical compounds, including inorganic compounds (combined with oxygen, iron, chlorine, and sulfur), and organic compounds (combined with carbon and other atoms).

Inorganic arsenic compounds are found in industry, in building products (in some “pressure-treated” woods), and in arsenic-contaminated water. Soil and water contamination also can occur as a result of mining and smelting activities. Past use of arsenic-containing herbicides has resulted in soil contamination, and some food crops grown in these soils take up the arsenic. Inorganic arsenic compounds are more toxic than organic arsenic compounds, and inorganic arsenic has been strongly linked to cancer of the bladder, lungs, and skin. Additionally, inorganic arsenic has been linked to some types of kidney cancers, as well as liver and intrahepatic bile duct and prostate cancers.

We typically take in small amounts of inorganic arsenic in the food we eat (in particular, rice and fish), the water we drink, and the air we breathe. Arsenic is also present in tobacco smoke. People may be exposed to higher levels of arsenic at work in certain industries, but such exposures are now rare in the United States. People may also be exposed to greater amounts of arsenic if they live near current or former industrial or agricultural sources of arsenic, live in areas where arsenic is naturally high in drinking water, or eat a lot of seafood (although the organic form predominantly found in seafood is likely to be much less harmful). Major dietary sources of inorganic arsenic include rice and rice products.

Both short- and long-term exposure to arsenic can cause health problems. Breathing in high levels of arsenic may cause a sore throat and irritated lungs. Swallowing high levels of arsenic can be fatal. Exposure to lower levels of arsenic over longer periods of time can result in liver and kidney damage. Moreover, arsenic and cigarette smoking exposure act synergistically to increase the incidence of lung cancer.

We present exposure data on the 95th percentile of the population, representing people with the greatest exposure. The 95th percentile level means that 95% of the population has concentrations below that level. Public health officials use such reference values to determine whether groups of people are experiencing an exposure that is unusual compared with an exposure experienced by the rest of the population. For more information, see the National Report on Human Exposure to Environmental Chemicals, published by the Centers for Disease Control and Prevention.

To calculate whether the differences between 95th percentiles for two different time points are statistically significant, we used a different statistical methodology than that used by the National Center for Environmental Health, which publishes the National Report on Human Exposure to Environmental Chemicals from which our data are derived. Our estimates may differ slightly from those in the original report due to differences in statistical procedures used. [Methodology]

Because arsenic is measured from urine, the concentration of arsenic may be affected by urine diluteness. Analyte concentrations within urine also may vary with time, due to changes in the water concentration within urine. We use creatinine as a reference analyte to adjust for urine concentration and obtain measures of arsenic that are comparable, whether they are from concentrated or dilute urine samples.

Centers for Disease Control and Prevention, National Center for Health Statistics, National Health and Nutrition Examination Survey (NHANES).

The Cancer Trends Progress Report uses NHANES data through 2017-2018. The 2019-2020 cycle was not completed due to the COVID-19 pandemic. More information is available at NHANES Questionnaires, Datasets, and Related Documentation.

There are no Healthy People 2030 targets regarding urinary concentration of arsenic.

Healthy People 2030 is a set of goals set forth by the Department of Health and Human Services.

Non-Significant Change
Chemical Exposures