Identification of New Biomarker Indicates Kidney Damage from Uranium in Water

A recent investigation conducted by scientists at Columbia University's Mailman School of Public Health has unveiled a potential biomarker that can indicate the accumulation of uranium in the kidneys, which may lead to significant damage. This research highlights the environmental health risks posed by uranium present in drinking water, even at minimal exposure levels.

The findings, published in the journal Environmental Science & Technology, suggest that the isotopic composition of uranium can be utilized as a noninvasive biomarker to assess kidney accumulation. With over two-thirds of U.S. community water systems showing detectable levels of uranium, this discovery aims to provide critical insights into an often-overlooked public health issue.

According to research, uranium can enter the body through contaminated drinking water, where it is filtered by the kidneys. Senior researchers have indicated that some portion of this uranium can be retained, potentially causing harm over time. This new biomarker could serve as an early warning system for kidney damage linked to uranium exposure.

Federal data reveals that approximately 320 million individuals are served by community water systems with detectable levels of uranium, with about 2% of these systems exceeding the Environmental Protection Agency's (EPA) maximum contaminant level (MCL) of 30 micrograms per liter. Furthermore, around 4% of private wells, which supply water to 15% of the population, also exceed this contaminant level.

Although uranium is primarily recognized for its radioactive properties, its chemical toxicity, particularly regarding kidney health, poses a greater risk at environmental exposure levels. Research indicates that even low concentrations of uranium, below the EPA's MCL, could impair kidney function.

Specific communities, particularly in the Great Plains and Colorado Plateau regions, are at heightened risk due to natural uranium deposits and historical mining activities that have contaminated groundwater. This presents a significant concern for many Native American populations residing in these areas.

Upon ingestion, roughly 80% of uranium is expelled through urine within days; however, the remaining amount can accumulate in the kidneys. This accumulation often occurs in the outer layer of the kidneys, where uranium binds to cells, causing injury and disrupting essential functions. Over an extended period, this damage can lead to chronic kidney disease.

Current methodologies for measuring uranium levels in the body fall short as they do not provide insights into the specific accumulation within the kidneys, which hampers efforts to comprehend and mitigate long-term kidney damage resulting from uranium exposure. Research involving animal models has demonstrated uranium accumulation in both the kidneys and bones, where distinct isotopic signatures were observed after exposure to contaminated water over short periods.

Because the isotopic signature of uranium can be detected in urine, the new biomarker offers a promising avenue for cost-effective and noninvasive monitoring of kidney uranium levels, especially in communities that are at a higher risk for exposure. This research lays the groundwork for advanced models that can trace how uranium travels through the body, from ingestion to accumulation and eventual excretion.

These findings signify a substantial step forward in environmental health surveillance, paving the way for the development of efficient tools to monitor metal exposures among vulnerable populations. Future research is planned to explore longer exposure periods and lower uranium doses to further understand the long-term consequences of such exposure.