Arsenic in U.S. Groundwater: A Growing Public Health Concern

Table of Contents

Beneath the earth’s landscape lies treasures of groundwater. Though largely out of sight, it supplies drinking water to more than half the U.S. population and nearly every rural household, The Groundwater Foundation notes. Unfortunately, many Americans dependent on this precious resource may be exposed to an incredibly toxic chemical element: arsenic.

According to the scientific journal Environmental Science & Technology, water wells in more than 25 states contain dangerously high arsenic levels, with 2.1 million people potentially drinking water tainted with the toxin. This is concerning because even tiny doses of arsenic can pose a serious health risk. Worse yet, many of the resulting symptoms can be irreversible or fatal.

Now, you’re probably wondering: how exactly did this poisonous substance end up in groundwater, and what are the potential risks for public health? Furthermore, how do I know if my drinking water contains arsenic, and how do I remove it? If so, stick around as we dig into the research and answer these and other crucial questions.

A Bit About Arsenic

Arsenic is a naturally occurring element widely distributed in the earth’s crust but may also be found in air, water, and various food products. It has no discernable color, taste, or odor and is highly toxic in its inorganic form, the World Health Organization (WHO) points out.

Due to these qualities, arsenic was favored as a lethal poison from Roman times to the mid-nineteenth century, earning the nicknames “The King of Poisons” and “Poisons of Kings.” Its hazardous effects also made it a valuable ingredient in various consumer products, including pesticides and wood preservatives. While many of these uses have been phased out due to health concerns, arsenic remains persistent in groundwater supplies across the U.S.

How does arsenic get into groundwater, and which states have the highest levels?

The primary pathways for arsenic to enter groundwater are through natural processes, such as the weathering, oxidation, and erosion of certain rocks. As water journeys through rock and soil containing arsenic-rich minerals, it can dissolve and transport arsenic to water wells or public treatment plants. In regions with volcanic activity or frequent forest fires, rainwater can capture arsenic from plumes of dust and ashes and carry it down to the earth, where it can infiltrate groundwater.

While nature is the prime contributor, the rising arsenic levels in U.S. groundwater also result from human activity. Agricultural practices involving arsenic-based fertilizers or pesticides and industrial operations like mining can release massive amounts of arsenic into the environment. Once there, it can leach into groundwater supplies through runoff or other mediums.

Not all states face the same level of arsenic contamination, however. Data from the Environmental Working Group (EWG) and the U.S. Geological Survey (USGS) shows that levels of arsenic are highest in Southwestern states, including Arizona, New Mexico, California, and Nevada, and portions of the Midwest, such as the Dakotas, Minnesota, and Michigan. Northeastern states, particularly Maine and New Hampshire are also reported to have higher-than-normal arsenic concentrations in groundwater.

Even if your state didn’t make the list, you should still be wary of what’s in your drinking water, as ingesting arsenic can increase your risk for several severe health issues.

What are the potential health risks of arsenic exposure?

Remember the movie Arsenic and Old Lace? While the story was fictional, the science was real. Arsenic is, indeed, a potent poison. Possibly the worst case of arsenic poisoning in history occurred in Bangladesh, where an estimated 80 million people were poisoned by arsenic in groundwater supplies.

Because of this and other incidences, scientists have been carefully studying the effects of arsenic on human health. Interestingly, they have found substantial evidence linking exposure to a host of significant health risks, including the following:

Cardiovascular Disease

When you think of possible causes of heart disease, arsenic exposure likely isn’t one of them. But as it turns out, it’s also a factor, according to a study by the Columbia University Mailman School of Public Health.

The research, published in the journal Environmental Health Perspectives, examined the connection between arsenic exposure through community water supplies below the current regulatory limit and cardiovascular disease (CVD). It analyzed data from 98,250 participants, including 6,119 cases of ischemic heart disease (IHD) and 9,936 cases of broader CVD. Notably, it excluded individuals over 85 years old or those with pre-existing cardiovascular conditions to paint a clearer picture of arsenic’s role in CVD incidences.

The researchers found that long-term exposure to arsenic levels, even below the U.S. Environmental Protection Agency’s (EPA) regulatory limit of 10 ppb, significantly increased the risk of IHD. Per the study, participants exposed to arsenic levels between 5 and 10 ppb had a 20% higher risk of IHD compared to those exposed to less than one ppb. Exposure at or above the EPA limit doubled the risk to 42%.

Kidney Cancer and Various Other Cancers

Another reason to limit your arsenic exposure? It may damage your kidneys. A recent study from Texas A&M University School of Public Health found that even small amounts of arsenic in drinking water can significantly increase the risk of kidney cancer.

The researchers examined data from 28,896 cancer cases in adults across 240 Texas counties. The study focused on arsenic exposure levels in public and private water systems alongside risk factors such as obesity, smoking, diabetes, and pesticide exposure. In line with prior research (including this systematic review), they found that arsenic concentrations as low as 1 to 5 parts per billion (ppb) raised kidney cancer risk by 6%. In contrast, levels above five ppb led to a staggering 22% increase. Plus, every time the amount of arsenic doubled, the risk of kidney cancer rose by 4%.

Beyond kidney cancer, the American Cancer Society (ASC) says respected organizations, including the IARC, NTP, and EPA, have linked arsenic exposure to incidences of skin and lung cancer and internal cancers such as liver, bladder, colon, and prostate cancers in humans. Seeing these findings, all three agencies classify arsenic and inorganic arsenic compounds as “known to be human carcinogens,” meaning they can cause cancer.

Learn more: Carcinogens in Drinking Water: Is Your Water Raising Your Cancer Risk? | 7 Potential Cancer-Causing Contaminants in Tap Water–And How to Remove Them

Type 2 Diabetes

Ask most people for tips on reducing your risk of type 2 diabetes, and you’ll hear things like “Eat healthy, be active, stress less, and maintain a healthy weight.” While this is sound advice, there’s another trick you should add to that list: limiting your arsenic exposure.

A recent study investigated the risk of arsenic in drinking water for type 2 diabetes (T2D) in two U.S. cohorts: the Strong Heart Family Study (SHFS) and the Multi-Ethnic Study of Atherosclerosis (MESA). The researchers analyzed 1,791 SHFS and 5,777 MESA participants free of T2D at baseline and tracked whether they developed T2D over 5.6 years and 14 years, respectively.

Per the findings, the participants’ T2D risk increased by 10% for every doubling of arsenic levels in community water systems, more so in females and individuals with a BMI under 25. Arsenic in private wells showed a weaker but suggestive link with T2D in the SHFS group. Ultimately, the researchers concluded that even low to moderate arsenic levels (<10 ppb) were associated with increased T2D risk, further emphasizing the need for stricter arsenic regulation in drinking water.

Arsenicosis

Continuous exposure to high doses of arsenic in the short term could lead to arsenic poisoning or arsenicosis. This condition often develops gradually over months or years, depending on the level of arsenic exposure, according to research.

In its early stages, arsenicosis may exhibit non-specific symptoms, such as fatigue, headaches, numbness in the extremities, and gastrointestinal issues like abdominal pain or diarrhea. One may also experience skin issues, such as skin lesions, pigmentation changes, and hard patches on the palms and soles of the feet (hyperkeratosis). These symptoms typically occur after a minimum exposure of approximately five years and may be a precursor to skin cancer, the Agency for Toxic Substances and Disease Registry (ATSDR) reports.

In severe cases, arsenicosis can cause peripheral vascular disease, leading to gangrene of the limbs (Blackfoot disease) and systemic effects like neurological damage or cardiovascular complications. Chronic exposure also disrupts enzyme function in the body, affecting multiple organ systems and possibly causing death.

Impacts on Maternal and Fetal Health

We break down the adverse health effects of arsenic exposure during pregnancy in a previous article, so here, we’ll give you a quick run-down of the findings.

Studies like this one have shown that pregnant women and their babies are most vulnerable to the harmful effects of arsenic exposure. According to the scientific review Maternal Exposure to Arsenic and Its Impact on Maternal and Fetal Health: A Review, arsenic can easily cross the placenta and expose the fetus to concentrations similar to the mother’s. This can lead to complications like miscarriage, stillbirth, gestational diabetes, anemia, and high blood pressure during pregnancy.

For babies, arsenic exposure is associated with lower birth weight, reduced head circumference, shorter gestational age, and impaired growth, according to researchers at the Dartmouth Geisel School of Medicine. Long-term effects on children may include developmental delays, neurotoxicity, and an increased risk of diseases like cancer and cardiovascular issues later in life.

Learn more: Effects of Arsenic in Drinking Water During Pregnancy

Is There a Safe Level of Arsenic in Drinking Water?

The EPA’s legal limit or maximum contaminant level (MCL) for arsenic in public drinking water supplies is 10 parts per billion (ppb). For years, arsenic concentrations of up to 50 ppb were allowed but lowered to 10 ppb in 2001 after new studies found arsenic was far more toxic than previously estimated.

Still, drinking water with arsenic levels at or below the new EPA standard can increase your risk for various cancers and other health problems (as discussed earlier). Realizing this, the EPA has set a maximum contaminant level goal (MCLG) of zero ppb for arsenic in drinking water. That means, ideally, your drinking water should contain no arsenic.

Please note, however, that the EPA doesn’t regulate private wells. Therefore, it’s up to well owners to check their water quality and put systems in place to remove all contaminants, not just arsenic.

How Do You Know If Arsenic is in Your Drinking Water?

With doubts surrounding the EPA’s “safe” arsenic limit in drinking water and the known dangers of arsenic, it’s natural to wonder whether your drinking water has been compromised. But since you can’t see, taste, or smell arsenic in water, it’s virtually impossible to know if it’s in your water supply without proper testing.

Here are two ways to investigate the quality of your water:

Ask your water provider.

If you’re on city water, you should receive an annual water report called a Consumer Confidence Report (CCR). This document typically includes detailed information on the water tests performed in your area, testing dates, the final results, etc. But even after obtaining a CCR, it’s still good to test your water at least once a year in case a contamination issue solely affects your water supply.

Learn more: How to Read Your Water Quality Report

Have your water tested.

When evaluating your water quality, you can either do it at home or have it done by a laboratory (preferably one that’s state-certified). While many do-it-yourself kits are available, they aren’t always the most accurate. Professional laboratory testing provides more detailed and accurate insights into your drinking water quality, which is crucial if your water comes from an unregulated private well.

With laboratory testing, you purchase a water test kit from your preferred testing facility, and they’ll send you a kit to collect your sample. Once they receive it, experts can perform tests and look for hard-to-detect chemicals like arsenic, VOCs, and microorganisms (bacteria, viruses, and parasites). They can also check for many chemical pollutants like pesticides, herbicides, pharmaceuticals, PFAS (per- and polyfluoroalkyl substances), and PFCs (perfluorinated compounds). If you’re concerned about arsenic in your water, also make sure to request that the lab checks for iron and manganese (more on this below).

Learn more: 10 Common Problems a Water Test Can Detect in Tap Water

What Can You Do About Arsenic in Your Drinking Water?

Arsenic is usually one of the trickier compounds to remove from drinking water. One reason is the presence of co-contaminants like iron and manganese that can interfere with the arsenic filtration process. The good news is that you can use different systems or a single unit that combines multiple filtration methods to combat arsenic and other potentially toxic water pollutants.

Reverse osmosis (RO) is considered the most effective method for removing arsenic from well water. RO systems treat water by forcing it through a selective membrane with microscopic pores that allow water molecules through while trapping larger, inorganic molecules like arsenic.

Learn more: Reverse Osmosis Water Filtration Explained

The Best Water Filter to Remove Arsenic from Drinking Water

If you’re looking for a reliable and budget-friendly arsenic removal filter with remarkable filtration capabilities, the Moen Reverse Osmosis Water Filtration System is an excellent option. This RO system provides the best quality drinking water for you and your family by reducing contaminants, including arsenic, fluoride, TDS, bacteria, viruses, lead, mercury, chlorine, and pharmaceuticals, in your cold water and improving the water’s taste, odor, and clarity. It’s also a point-of-use (POU) system attached to a dedicated faucet, so you can access cleaner, healthier, arsenic-free water for drinking, cooking, making ice, etc.

There’s one caveat, though: If there is a significant amount of iron or manganese in your water, you’ll need to treat them first so more of the arsenic gets removed at the RO stage. Luckily, our whole-house iron filter is designed to do just that, eliminating up to 7 parts per million (ppm) of iron and one ppm of manganese. It also removes up to 8 ppm of hydrogen sulfide, notorious for imparting a “rotten egg” odor in drinking water.

Final Thoughts

Arsenic may be a centuries-old poison, but it’s still a modern concern, particularly in U.S. groundwater. Testing your water should be a top priority if your water comes from a private well or you want extra peace of mind with city water. Professional laboratory testing can reveal vital information about your water quality. With these insights, you can select the best water filtration system to help combat arsenic and other “hidden” contaminants possibly lurking in your water supply. Or, if you need expert help, you can contact Springwell for help finding the ideal solution based on your needs and budget.