Factors Affecting Cadmium Accumulation and Mitigation: A Literature Review to Inform Spinach and Carrot Producers

Cadmium (Cd), a nonessential element with potential adverse health consequences, enters the human food system predominantly through plant uptake from soils. In the United States, some regions that are known to have elevated levels of Cd are otherwise ideal for the production of fresh produce, including spinach ( Spinacia oleracea L.) and carrots ( Daucus carota L.). Given the considerable nutritional benefits of these commodities, they are often incorporated into the diets of infants and young children, either as processed ingredients or as those eaten whole. To reduce levels of dietary Cd and support the US Food and Drug Administration’s Closer to Zero initiative, it is important to understand factors that affect the Cd uptake by crops (i.e., phytoavailability) and the ability of Cd to be absorbed by the human body (i.e., bioavailability) from crops such as carrots and spinach. The state of knowledge of factors that affect the phytoavailability of Cd in these two crops and potential mitigation strategies to benefit growers as they consider their individual soils, crops, and circumstances are summarized. These include amending soil (with organic amendments, such as manures, composts, or biosolids, chloride, or elements such as zinc), the potential use of cultivars with lower rates of uptake, and the use of novel methods such as phytoextraction. The impact of some of these mitigations on microbial food safety efforts is also noted.