Lowering arsenic levels in groundwater decreases death rates from chronic disease

Researchers at NYU Langone Health, Columbia University, and the University of Chicago published a new landmark analysis of groundwater contamination with important implications for public health. 

Water contamination from naturally occurring arsenic remains a serious issue worldwide. In the United States, more than 100 million people rely on potentially contaminated groundwater sources, especially private wells, for their drinking water. Arsenic is among the most common chemical pollutants.  

During the study, the drinking water and health records of 10,977 men and women in Bangladesh were monitored from 2002 to 2022 as part of the Health Effects of Arsenic Longitudinal Study (HEALS). Results showed that efforts over the 20 years to reduce arsenic in drinking water led to a 70% decrease in levels of the chemical, which in turn halved arsenic levels in tested urine in study participants.   

“The policy-driving findings from this latest investigation of a longitudinal study established more than 20 years ago underscores the value of NIH global health research investment and sustained international transdisciplinary collaboration”, said co-senior author and Principal Investigator of the Parent HEALS Cohort Habibul Ahsan, MBBS, Louis Block Distinguished Service Professor and Director of Institute for Population and Precision Health at the University of Chicago. 

Lower exposure, lower risk of disease 

Publishing in the Journal of the American Medical Association (JAMA) online Nov. 17, the researchers compared study participants whose arsenic exposure dropped to those whose arsenic exposure remained high. Results showed that those whose arsenic levels dropped had a 54% reduced risk of death from any chronic disease. Similar decreases were observed specifically for heart diseases (57%) and cancer (49%).  

“Our study provides the strongest evidence to date that lowering arsenic in drinking water can lower death rates from chronic disease,” said study co-lead investigator Fen Wu, PhD, a senior research scientist at the NYU Grossman School of Medicine. “Elevated arsenic levels in drinking water remains a pervasive public health issue because arsenic naturally accumulates in groundwater and has no taste or odor, so people can unknowingly consume unsafe levels for years.” 

“Our research supports switching to safer water sources as a strategy to improve long-term health around the world,” said study senior investigator Yu Chen, PhD, MPH, a professor in the Department of Population Health at the NYU Grossman School of Medicine. “Improved access to low-arsenic water, periodic testing, and clear signage to mark safer from higher-arsenic water — are useful tools to accomplish this goal.”  

Chen says previous research in regions of Taiwan and Chile with high arsenic levels (at greater than 600 micrograms per liter), tied trends of decreasing heart disease and cancer death rates to reducing arsenic levels in drinking water. However, she says her team’s study is the first to offer direct evidence by examining arsenic levels and mortality in each participant over two decades and in a region with moderate arsenic exposure (less than 200 micrograms per liter). 

Long term monitoring and mitigation 

As part of the study, researchers monitored more than 10,000 wells in and around the district of Araihazar, Bangladesh, where arsenic mitigation efforts started in 2000. Wells are labeled to indicate if arsenic levels are high or low;community educators encourage people to switch to safer wells, and new wells are being drilled with lower concentrations of arsenic. 

During the investigation, study participants volunteered to have their urine tested six times, periodically allowing researchers to track changes in arsenic exposure over time. Meanwhile, the research team recorded 1,401 deaths among the study participants from chronic disease, including 730 from cardiovascular disease and 256 from cancer.  

Bangladesh as a whole has one of the world’s most serious challenges with drinking water contaminated by arsenic. More than 50 million people are exposed to arsenic levels above the World Health Organization standard of 10 micrograms per liter.  

Funding support for this study was provided by National Institutes of Health grants R01ES035219, P42ES010349, and P4242ES033719.   

Adapted from a press release provided by NYU Langone Health.