Bloomberg Línea — A US government study has revealed that nearly half of the faucets in the country contain “persistent chemicals” that can cause cancer and other health problems. The synthetic compounds, known as PFASs, are contaminating drinking water supplies in several cities and towns, both in private wells and public systems.
The US Geological Survey (USGS) conducted the research, building on previous scientific findings showing that PFASs are present in everyday consumer products, such as nonstick pans, food packaging and water-resistant clothing, and have now been detected in water supplies.
Researchers at Columbia University’s Mailman School of Public Health revealed that drinking water contains worrisome levels of uranium and arsenic, and found a relationship between areas with a higher proportion of minority populations and a higher concentrations of these metals.
Communities with higher proportions of Hispanic-Latino, Alaska Native American, and African-American residents had higher concentrations of arsenic and uranium in public drinking water.
According to the study published in the journal Science, a significant global positive spatial autocorrelation was observed for both metals, meaning that concentrations tend to cluster geographically.
Using local indicators of spatial association (LISA), specific areas where the spatial autocorrelation was significant were identified. High clusters (areas with high arsenic and uranium concentrations) were found in the midwestern and southwestern United States, such as Nevada, California, Arizona, New Mexico, Texas, Kansas, and Nebraska. These areas have higher levels of arsenic and uranium in groundwater.
On the other hand, low clusters (areas with low concentrations) of arsenic were identified in the southeast and mid-Atlantic, including Alabama, Arkansas, North and South Carolina, Virginia, and Kentucky. Low uranium clusters were also found in similar geographic areas, although with more limited spatial coverage in the eastern United States.
In addition to arsenic and uranium, significant positive spatial autocorrelation was also observed for barium and selenium.
How is contaminated water distributed by ethnic and racial composition?
In the study, different racial/ethnic groups were analyzed for arsenic and uranium concentrations in drinking water at a county level. To avoid positivity violations, the analysis was restricted to counties with at least 100 residents of each racial/ethnic group. Results showed that the number of counties included in each analysis varied.
Nationally, the median percentage of residents belonging to each racial/ethnic group was found to be 7% for non-Hispanic Blacks, 2% for American Indian/Alaska Natives, 9% for Hispanics/Latinos, and 80% for non-Hispanic whites.
Counties analyzed for non-Hispanic Black residents had lower mean concentrations of arsenic and uranium in drinking water, as well as a lower percentage of water systems relying on groundwater sources and a lower proportion of rural population. On the other hand, the counties included in the analysis for American Indian/Alaska Native residents had a higher population size and density, as well as the lowest percentage of population living in rural areas. For Hispanic/Latino residents, the counties analyzed had higher average uranium concentrations in drinking water.
For non-Hispanic white residents, no counties were excluded due to having fewer than 100 residents, so these counties are the same as those included in any analysis.
Are there protection measures?
In March, the US Environmental Protection Agency (EPA) proposed the first federal limits for six forms of PFASs. However, companies that use these chemicals have not yet been banned from discharging them into public wastewater systems.
Laboratory animal studies have found possible links between PFASs and various cancers, high blood pressure and low birth weight.
The presence of PFASs was detected in most of the faucets tested, and samples were taken between 2016 and 2021 in a variety of locations, from protected areas to urban centers with industries known to generate these chemicals.