NMSU Student Studies Lead in Corn Harvested from the Animas Watershed

By Marcus Gay, NM WRRI Student Program Coordinator

The Animas River has historically received contamination from natural acid rock drainage, and for the last 160 years, from legacy mines throughout the river’s watershed. In August of 2015, the Gold King Mine wastewater spill raised concerns about the safety of food grown using Animas River water. A research team has been measuring the concentrations of several metalloids in the soil, water, and plants in the watershed since 2017 and found that only two elements have ever measured above EPA or NMED recommended levels. An elevated level of arsenic (As) has been measured in soil, and an elevated level of lead (Pb) has been measured in corn kernels. Previous research has shown that arsenic is not extractable in water and thus not likely available for plant uptake, but ongoing monitoring of lead concentrations in plants of the Animas River Watershed has shown sporadic high levels of lead in corn kernels. These findings warrant further research because corn is a staple crop in the region, especially in the Navajo Nation. NM WRRI has awarded a Student Water Research Grant to New Mexico State University (NMSU) student Bianca Wright to help determine if the corn grown on fields irrigated by the Animas and San Juan Rivers is safe for consumption.

The project entitled, Evaluating Soil Lead Bioavailability in Agricultural Fields across Animas Watershed, aims to measure the amount of lead in corn plants harvested from agricultural fields irrigated from the Animas and San Juan Rivers. Under the guidance of Wright’s faculty sponsor Dr. April Ulery, whole corn plant samples were collected, including roots, leaf tissue, husk, and kernels, as well as the soil around the roots. Plant and soil material was separated and processed in the NMSU Soil Chemistry Research Lab and analyzed for lead. The results of the analyses will be compared with WHO/FAO lead safety standards of 0.05 mg/kg. Using a variety of chemicals, sequential extraction of the soil was conducted to determine the bioavailability of the lead.

According to Wright, the results of the study will improve the community’s understanding of toxic metals found in the region. The research team working on this project has participated in 16 teach-ins at various Navajo Nation Chapter houses and three radio interviews from 2017-2020. The team continues to work with local farmers in the Aztec and Farmington areas to answer questions and address concerns. As Wright explains, “The farmers and growers across the Animas and San Juan watershed want to know about the safety of their produce following the Gold King Mine Spill of 2015. Our research will look closely at some corn-growing areas to answer some of these questions.”

Wright presented her work on this project at the 65th Annual New Mexico Water Conference. Originally from El Paso, Texas, Wright expects to graduate in December with a bachelor’s degree in Environmental Engineering. After graduation, Wright plans to work on landing her dream job at Los Alamos National Laboratory and continuing her education by earning a master’s degree in Environmental Engineering.