C2H2 EAGER: Gadolinium Contamination in the Middle Rio Grande Valley: Understanding Environmental Fate and Human Exposure

The escalating impacts of climate change pose unprecedented challenges to freshwater supplies globally, particularly in areas already experiencing water stress, such as New Mexico. This proposal addresses a pressing concern related to the contamination of water resources by medical waste, specifically gadolinium (Gd), a toxic element that is an important component of contrast agents used in magnetic resonance imaging. This research focuses on the analysis of river, stream, and groundwater of the Middle Rio Grande Valley in New Mexico to investigate the fate of anthropogenic Gadolinium in surface and subsurface water resources of understudied arid to semiarid areas and its impact on ecologocal and human health. The research involves field observations and sampling of river and groundwaters and laboratory experimental work. A focus will be to examine and trace the sources of Gd in natural waters and determine its distribution in the environment. The impact of Gadolinium, released to water treatment facilities and ultimately to the environment via the urine of those who have under gone MRI, will be studied and its impact on human health will be determined through exposure and toxicological studies of human digestive/gastric fluids. Broader impacts of the reserach include improved understanding the consequences of medical waste on water quality and public health. The work will provide much needed data for mitigation plans and serve the national interest in promoting environmental sustainability and public welfare. It will also engage local high school students, many from Native American tribes in the area, in water projects to foster interest and to increase understanding of water issues in a region already experiencing significant water stress. The proposed research will address critical research questions regarding the fate, distribution, and toxicity of Gd contamination stemming from medical waste from contrast enhancing magnetic resonance imaging (MRI) fluids containing the element Gadolinium (Gd), a toxic element to humans. In MRI fluids, Gd is chelated into a compound that renders it harmless to humans. However, this fluid is excreted from the body in urine, post imaging, and enters surface and groundwater systems through sewars and sweage treatment plants. Gd aqueous species are then released into the natural environment where they experience interactions with natural materials and processes that can change the speciation allowing it to become bioavailable. This resaerch provides a study of the Gd distribution and speciation in New Mexico Rio Grande Valley surface and ground waters and addresses analytical challenges of speciating natural samples with low-concentrations of Gd. It includes investigation into the effects of gastrointestinal fluids on speciation of Gadolinium and its toxicity. Key outcomes include (1) characterizing the concentrations and species of Gd in natural waters (surface water and groundwater) and sediments along the Rio Grande between Albuquerque and Elephant Butte, (2) an assessment of human exposure pathways and potential health risks associated with Gd ingestion through drinking water sources, and (3) improved understanding of the toxicological implications of Gd exposure focusing on the gastrointestinal tract and its effects on human health. The work will contribute significantly to our understanding of the risks posed by Gd medical waste in the environment. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.