A new report, which examined the soil, water, and production of urban farms and gardens in Baltimore, found low levels of lead and other metals that are not of concern at most growing sites. Researchers at the Johns Hopkins Sustainable Future Center at the Johns Hopkins Bloomberg School of Public Health found that 96 percent of soil samples and 95 percent of irrigation water samples taken from participating farms and gardens met criteria for metal contaminants.
The researchers say their findings should convince growers that farming and horticulture in Baltimore is generally safe.
Urban farms and gardens can benefit communities, but growing food in urban soils, especially in industrialized cities like Baltimore, has been a major concern due to possible residual pollutants, including heavy metals like lead and arsenic, which are harmful for human health.
To investigate the potential impact of metals on urban farms and community gardens in Baltimore, researchers at the Center for Sustainable Future have partnered with the Baltimore Farmers Alliance, the Parks and People Foundation, Baltimore City Sustainable Development and the University of Maryland in Baltimore. develop and implement a Safe Urban Harvest Study.
“Urban gardeners in Baltimore are deeply concerned about the health of their communities, and we have received many questions from them about the safety of urban soils and urban-grown produce,” said Rachel Santo, M.Sc., lead author of the report and senior research scientist. coordinator of the CLF research program. “The good news is it’s safe to grow food in Baltimore. We hope this report will help farmers and gardeners make the right choices about where and how to grow food in the city. ”
For their study, the researchers surveyed 104 farms and gardens in Baltimore during the 2017 growing season to learn about gardeners’ growing practices and took samples of their soil and irrigation water. They also collected fruits and vegetables from 69 participating farms and orchards. The researchers then tested samples of soil, water, fruits and vegetables in laboratories at Johns Hopkins University and the USDA for harmful metals, including arsenic, barium, cadmium, chromium, lead, and nickel.
The researchers emphasize that the presence of metals in everyday life is normal, and most soil, water and food contain small amounts of these pollutants. They note that there are currently no universal safety standards for metals in soil or irrigation water for urban farms and gardens, or acceptable limits for metals in products. To interpret the results of their metal tests, the research team developed a rigorous set of criteria that protect public health.
In cases where the research team found high levels of heavy metals on a farm or garden, they would identify the closest source of contamination and / or give growers specific advice on how to safely farm or garden.
To assess the metal content of foods, the research team collected and tested 248 fruit and vegetable samples from Baltimore city farms and orchards, as well as a comparison group of 405 conventional and USDA-certified organic fruits and vegetables from both grocery stores and farmer’s market vendors. Tests showed that the levels of these pollutants in foods grown in cities were similar to those in the same foods from grocery stores and farmers’ markets.
As a result, consumers may feel that it is as safe to buy produce from a farm or garden in Baltimore as it is from a farmer’s market or grocery store. The researchers emphasize that eating fruits and vegetables, regardless of their source, is an essential part of a healthy diet.
The report’s findings also highlight the role of urban agriculture in Baltimore’s local food system. The 104 farms and orchards surveyed cover over 24 acres of land, produce about 93,000 pounds each growing season and regularly attract about 2 percent of the city’s residents.
For growers unsure of their growing area or still concerned about soil safety, the report outlines simple and cost-effective measures that urban growers and consumers can take to reduce metal exposure.
To accompany the report, the researchers developed a series of videos and other resources to share their research findings and best practices for safe cultivation in urban soils. The results of this work will also be used to inform the Baltimore Sustainable Development Agency’s Soil Safety Policy update that will limit test requirements to specific metals and conditions found to be most likely to be of concern to Baltimore farms and gardens.
“The results of the Safe Crop in Cities study and this report are encouraging for farmers, gardeners and people who consume urban-grown food in Baltimore,” said report co-author Keev Nachman, Ph.D., director of the Center for Food for a Sustainable Future. Program in Manufacturing and Public Health and Associate Professor in the Department of Environmental Health and Engineering at Bloomberg School. “We are grateful to our research staff and the urban agriculture community in Baltimore for their support at every stage of the research process. While our findings apply to Baltimore, the evidence and recommendations from this study may apply to broader efforts to stimulate safer and more dynamic urban food systems. “
For more information, see these resources:
Video: Safe Urban Harvest Study: An Overview of Results
Video: Best Practices for Safe Urban Growing
A Study on Safe Urban Crops: An Assessment of Urban Farms and Community Gardens in Baltimore City was written by Rachel Santo, Sarah Lupolt, Brent Kim and Keev Nachman.
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