EAST LANSING, Mich. — A Michigan State University research team has received a $611,000 grant from the U.S. Department of Agriculture’s National Institute of Food and Agriculture to examine crop uptake of heavy metals, such as arsenic, cadmium and lead.
The project is led by Wei Zhang, associate professor and associate chair in the Department of Plant, Soil and Microbial Sciences.
In addition to Zhang, the team is composed of scientists representing four MSU departments, and each member is also supported by MSU AgBioResearch. They are:
- Zachary Hayden, assistant professor in the Department of Horticulture.
- Hui Li, professor in the Department of Plant, Soil and Microbial Sciences.
- Kurt Steinke, associate professor and MSU Extension specialist in the Department of Plant, Soil and Microbial Sciences.
- Felicia Wu, John A. Hannah Distinguished Professor in the departments of Food Science and Human Nutrition, and Agricultural, Food and Resource Economics.
In 2021, the U.S. Food and Drug Administration released an action plan called Closer to Zero geared toward reducing contaminant exposure from foods, especially those commonly consumed by infants and young children.
The initiative came on the heels of a 2021 congressional report on the neurological and developmental dangers of high levels of arsenic, cadmium, lead and mercury in store-bought baby foods.
Zhang said it is anticipated that over the coming years, the FDA will create guidelines on maximum allowable levels of these heavy metals in foods. This will have significant consequences for farmers and food processors.
“To ensure a safe food supply, it is crucial to understand what drives crop uptake of heavy metals, which is extremely complex and varies by crop species, soil type, field topography and climatic conditions,” Zhang said. “We recognize that solutions to this problem require stakeholder collaboration across entire food supply chains.”
The new USDA-funded project builds on ongoing research that includes various team members. Zhang, Hayden, Li and Steinke are testing the effectiveness of soil amendments on minimizing carrot uptake of multiple heavy metals, which is funded by a Specialty Crop Block Grant through the Michigan Department of Agriculture and Rural Development.
“Michigan carrot growers annually produce more than 52,000 tons of processing carrots, consistently striving to deliver a safe and wholesome ingredient to processors,” said Jamie Clover Adams, executive director of the Michigan Carrot Committee. “Our initial year of the Specialty Crop Block Grant has revealed that multiple factors influence the uptake of heavy metals in carrots. This research is a good start to helping growers better predict potential uptake risk at the time of field selection and manage uptake risk during carrot growth, but it’s only the beginning. The USDA funding represents the crucial subsequent phase that will equip Michigan carrot growers with the necessary information to provide an even safer product to consumers in the future.”
For another project through the Institute for the Advancement of Food and Nutrition Sciences, Zhang, Li and Wu are assessing cadmium exposure from rice, spinach and other crops as part of the Closer to Zero plan. Lastly, Zhang and Li are applying innovative machine learning techniques to predict crop uptake of contaminants more accurately. Machine learning is able to consider an array of climate and human activity factors, as well as complex interactions among heavy metals, plants and soils.
With the new USDA funding, the team will expand research on carrots and broaden the scope to include wheat. Carrots and wheat were chosen because they are common ingredients in baby foods and have large production regions in Michigan.
Intended to serve as a resource for growers, food industries and policymakers, the project has three overarching objectives aimed at uncovering the circumstances that lead to heavy metal uptake and what can be done to mitigate it.
For the first objective, Zhang and Li will examine soil samples taken from participating grower and commercial carrot and wheat fields in Michigan. The samples will be analyzed for arsenic, cadmium and lead, three of the heavy metals of highest concern for baby foods.
Using sensitive extraction methods, researchers will check for low contamination levels and measure that alongside crop uptake. Zhang said if heavy metal levels are high in crops at low soil contamination, it stands to reason that greater contamination could lead to more crop uptake.
Researchers will also grow carrots and wheat in MSU greenhouses to evaluate crop uptake at various growth stages and soil moisture levels. They hypothesize these different developmental and climatic conditions will be highly consequential.
The second objective will focus on applied research in Michigan carrot and wheat fields. Hayden and Steinke will take soil and plant samples across multiple years to investigate potential changes in crop uptake based on differing growth stages, soil properties and topography.
Samples will be taken at three points during the season — early, middle and end — but researchers will determine if additional samples are needed due to excessive wet or dry periods.
For the third objective, Zhang and Wu will use the climate, plant and soil data collected from the first two objectives to create machine learning-based risk models for heavy metal uptake. Using these models and other available data, researchers will generate an assessment of the feasibility and cost-effectiveness of mitigation strategies, which include soil amendments, crop rotation, fertilizer management and cultivar selection, among others.
The end goal of the project is to develop a management guide that offers cost-effective practices tailored to the conditions of individual farms, and resources for policymakers that help them make informed decisions.
“We need to be able to evaluate how beneficial interventions are that help to reduce heavy metals in food crops, in terms of how this will improve human health,” Wu said. “That would provide policymakers information about whether to adopt those interventions. Our research will ideally lead to actionable solutions that ensure a safer food supply for everyone.”