In a finding that challenges current water safety standards, researchers at Columbia University’s Mailman School of Public Health have discovered that arsenic in drinking water poses cardiovascular risks at levels below federal limits. The study, spanning decades of data and following over 98,000 participants, presents the first comprehensive look at how low-level arsenic exposure affects heart health over time.
Summary: An extensive Columbia University study reveals that long-term exposure to arsenic in drinking water increases cardiovascular disease risk, even at levels currently considered safe by federal regulations. The research provides compelling evidence that existing standards may need strengthening to protect public health.
Estimated reading time: 8 minutes
In a finding that challenges current water safety standards, researchers at Columbia University’s Mailman School of Public Health have discovered that arsenic in drinking water poses cardiovascular risks at levels below federal limits. The study, spanning decades of data and following over 98,000 participants, presents the first comprehensive look at how low-level arsenic exposure affects heart health over time.
The Hidden Risks in Our Water
Arsenic, a naturally occurring element in groundwater, has long been known to pose health risks at high concentrations. But this new research reveals a more nuanced and concerning picture. The study found that exposure to arsenic levels even half of the current federal limit of 10µg/L increased the risk of ischemic heart disease by 20 percent.
“Our findings shed light on critical time windows of arsenic exposure that contribute to heart disease and inform the ongoing arsenic risk assessment by the EPA,” said Danielle Medgyesi, a doctoral Fellow in the Department of Environmental Health Sciences at Columbia Mailman School. “This study offers resounding proof of the need for regulatory standards in protecting health and provides evidence in support of reducing the current limit to further eliminate significant risk.”
Time Matters: The Decade-Long Window
The research team made a crucial discovery about timing. By analyzing different exposure periods, they found that the previous decade of arsenic exposure showed the strongest correlation with cardiovascular disease risk. This finding mirrors research from Chile, where peak heart attack mortality was observed about ten years after high arsenic exposure.
The study’s scope was unprecedented. Working with California’s Office of Environmental Health Hazard Assessment, researchers gathered three decades of water arsenic data (1990-2020) from community water systems. They matched this information with healthcare records from the California Teachers Study cohort, tracking participants from 1995 through 2018.
A Clear Pattern of Risk
The results revealed a stark pattern: compared to those exposed to the lowest levels (<1 µg/L), participants faced increasingly higher risks as arsenic concentrations rose:
- 5-6% increased risk at 1 to <5 µg/L
- 20% increased risk at 5 to <10 µg/L
- 42% increased risk at ≥10µg/L
Environmental Justice Concerns
Perhaps most troubling, the study exposed significant disparities in exposure. Higher arsenic concentrations, including those exceeding current standards, disproportionally affect Hispanic and Latina populations and residents of lower socioeconomic status neighborhoods. This finding adds an environmental justice dimension to the already pressing public health concern.
Columbia Mailman’s Tiffany Sanchez, senior author, emphasized the broader implications: “Our results are novel and encourage a renewed discussion of current policy and regulatory standards. However, this also implies that much more research is needed to understand the risks associated with arsenic levels that CWS users currently experience.”
Looking Forward: Policy Implications
The study’s findings arrive at a critical time. While the EPA reduced the maximum contaminant level for arsenic from 50µg/L to 10µg/L in 2006, this research suggests even this stricter standard may not adequately protect public health. The natural occurrence of arsenic in groundwater affects regions across New England, the upper Midwest, and the West, including California, making this a national concern.
Glossary of Terms
- Arsenic: A naturally occurring element found in groundwater that can contaminate drinking water
- Community Water Supplies (CWS): Public water systems serving residential populations
- Ischemic Heart Disease: Heart problems caused by narrowed heart arteries
- Maximum Contaminant Level (MCL): Legal threshold limit for contaminants in drinking water
- µg/L: Micrograms per liter, a measure of concentration
- Environmental Justice: The fair treatment and meaningful involvement of all people regarding environmental regulations
Quick Quiz
- What percentage increased risk of heart disease was found at arsenic levels just below the current EPA limit?
- Which exposure window showed the strongest correlation with cardiovascular disease risk?
- What significant environmental justice finding did the study reveal?
Answers:
- 20% increased risk at 5-10 µg/L
- The previous decade (10 years) of exposure
- Higher arsenic concentrations disproportionally affect Hispanic and Latina populations and lower socioeconomic status neighborhoods
For more information: https://doi.org/10.1289/EHP14410
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