Consumers and Health

Arsenic in drinking water and its health implications

February 26, 2025

1114

Arsenic (As) presence in drinking water poses significant public health risks, particularly in regions where groundwater contamination is prevalent. This toxic heavy metal is indeed a well-documented carcinogen and environmental pollutant, classified as a Class 1 carcinogen by the International Agency for Research on Cancer (IARC), and its presence in water is also relevant for food safety.

A recent study, conducted by Antonella Litta, Giovanni Ghirga, and Mauro Mocci from the International Society of Doctors for the Environment (ISDE) – Italy, examines the health impacts of chronic low-dose arsenic exposure, focusing on its role in non-communicable diseases (NCDs) such as cancer, cardiovascular diseases, and endocrine disruptions. And the unresolved crisis in certain areas of Central-Southern Italy.

Table of Contents

Background and objectives

Arsenic is a naturally occurring element in the Earth’s crust, but human activities such as industrial processes, mining, and agriculture have significantly increased its environmental presence. Chronic exposure to arsenic, even at levels below the current regulatory limit of 10 µg/L, has been linked to a wide range of health issues, including cancers, cardiovascular diseases, diabetes, and neurodevelopmental disorders. The World Health Organization (WHO) recommends reducing arsenic levels in drinking water to below 5 µg/L, with an ideal target close to zero, to minimise health risks.

The study aims to:

Analyse the environmental and health impacts of arsenic in Italy, particularly in regions like Lazio, Toscana, and Campania,
Highlight the risks associated with chronic low-dose exposure, even within legal limits;
Explore technological solutions and regulatory measures to reduce arsenic exposure.

Methodology

The study employs a comprehensive review of existing scientific literature, epidemiological data, and regulatory frameworks. Key methodological approaches include:

Literature review. The researchers reviewed over 4,824 scientific publications on arsenic in drinking water, focusing on studies that examine chronic low-dose exposure and its health effects;
Epidemiological analysis. The study references several Italian cohort studies, including the SEpiAs project, which monitored populations in arsenic-affected areas like Viterbo and Monte Amiata. These studies used biomonitoring (urine analysis) and clinical assessments to evaluate arsenic exposure and its health impacts;
Regulatory analysis. The authors examined the evolution of arsenic regulations in the European Union (EU) and Italy, including the use of derogations that temporarily allowed higher arsenic levels in drinking water.
Case studies. The study highlights specific regions in Italy where arsenic levels exceed regulatory limits, such as Viterbo, and discusses the health outcomes in these populations.

Major outcomes

Chronic exposure to arsenic, even at levels below the current regulatory limit of 10 µg/L, is associated with significant health risks. Studies have shown that long-term exposure to low-dose arsenic can lead to cardiovascular diseases, diabetes, and neurodevelopmental disorders, particularly in vulnerable populations such as children and pregnant women.

The International Agency for Research on Cancer (IARC) and the World Health Organization (WHO) have emphasised that there is no safe threshold for arsenic exposure, as even minimal doses can cause long-term harm.

Arsenic acts as an endocrine disruptor, interfering with hormone production and receptor binding. This disruption can lead to metabolic disorders such as type 2 diabetes and reproductive health issues. Prenatal exposure is particularly concerning, as arsenic can cross the placental barrier and affect fetal brain development, increasing the risk of neurodevelopmental disorders such as autism spectrum disorder and attention-deficit/hyperactivity disorder (ADHD).

Technological solutions offer hope for reducing arsenic levels in drinking water. Advanced treatment methods, such as reverse osmosis and adsorption filters, have been successfully implemented in countries like Denmark and the United States, where arsenic levels have been reduced to 5 µg/L or lower. These technologies demonstrate that achieving safer arsenic levels is feasible with adequate investment and infrastructure.

The Italian case at the Court of Justice of the European Union

In Italy, historical derogations have permitted arsenic levels in drinking water to surpass the European Union’s limit of 10 µg/L. Notably, in the province of Viterbo, arsenic concentrations have exceeded this threshold, up to 50 µg/L during derogation periods, exposing populations to heightened health risks. A population-based study conducted in the Viterbo province evaluated the effects of chronic exposure to low-medium arsenic levels via drinking water. The research found associations between lifetime arsenic exposure and increased mortality from cancers and chronic diseases, highlighting the public health concerns in regions with elevated arsenic concentrations.

The European Commission referred Italy to the European Court of Justice due to prolonged exceedances of arsenic and fluoride levels in drinking water, particularly in areas of the Lazio Region, including Viterbo. This action underscores the health implications of such violations, especially for vulnerable groups like children. The Court of Justice of the European Union (CJEU), in a judgment dated 7 September 2023, addressed Italy’s failure to fulfill obligations under Potable Water Directive 98/83/EC (repealed by Directive 2020/2184). The court emphasized the necessity for Italy to adopt remedial actions to ensure water quality meets the prescribed standards, particularly regarding arsenic and fluoride levels.

Discussion and implications

The study underscores the urgent need for stricter arsenic regulations and better enforcement of existing laws. It highlights the importance of adopting the precautionary principle, which advocates for reducing arsenic levels to as low as technically feasible, even below current regulatory limits. The authors also emphasise the need for targeted public health interventions, including biomonitoring and early diagnosis programs, particularly for vulnerable populations such as children and pregnant women.

Conclusion

Arsenic in drinking water remains a significant public health challenge, particularly in regions with high natural or industrial contamination. The study provides compelling evidence that chronic low-dose exposure to arsenic poses serious health risks, even at levels below current regulatory limits. It calls for a comprehensive approach that combines stricter regulations, advanced water treatment technologies, and public health interventions to reduce arsenic exposure and protect vulnerable populations.

Dario Dongo

References

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(16) Case C-197/22: Judgment of the Court (Tenth Chamber) of 7 September 2023 — European Commission v Italian Republic (Failure of a Member State to fulfil obligations — Environment — Directive 98/83/EC — Water intended for human consumption — Article 4(1)(b) — Measures necessary to ensure water quality — Compliance with the minimum requirements set out in Annex I, Parts A and B — Article 8(2) — Adoption of the necessary remedial action as soon as possible — Obligation to achieve a result — Annex 1, Part B — Parametric values for arsenic and fluoride — Concentrations above those values — Continued exceeding of those values) (OJ C, C/2023/196, 23.10.2023, ELI: http://data.europa.eu/eli/C/2023/196/oj).