Department of Civil and Environmental Engineering, University of Maine, 5711 Boardman Hall, Orono, ME, 04469, USA.
Environ Res. 2021 Mar;194:110635. doi: 10.1016/j.envres.2020.110635. Epub 2020 Dec 31.
A circular food system is one in which food waste is processed to recover plant nutrients and returned to the soil to enable the production of more food, rather than being diverted to landfill or incineration. The approach may be used to reduce energy and water use in food production and contribute to the sustainability of the system. Anaerobic digestion and composting are common food waste treatment technologies used to stabilize waste and produce residual materials that can replenish the soil, thus contributing to a circular food system. This approach can only be deemed safe and feasible, however, if food waste is uncontaminated or any contaminants are destroyed during treatment. This review brings together information on several contaminant classes at different stages of the food supply chain, their possible sources, and their fates during composting and digestion. The main aim is to identify factors that could impede the transition towards a safe, reliable and efficient circular food system. We investigated heavy metals, halogenated organic compounds, foodborne pathogens and antibiotic resistance genes (ARGs) in the food system and their fates during digestion and composting. Production and processing stages were identified as major entry points for these classes of contaminants. Heavy metals and foodborne pathogens pose less risk in a circular system than halogenated organics or antibiotic resistance. Given the diversity of properties among halogenated organic compounds, there is conflicting evidence about their fate during treatment. There are relatively few studies on the fate of ARGs during treatment, and these have produced variable results, indicating a need for more research to clarify their fate in the final products. Repeated land application of contaminated food waste residuals can increase the risk of accumulation and jeopardize the safety of a circular food system. Thus, careful management of the system and research into the fate of the contaminants during treatment is needed.
循环食物系统是指将食物垃圾进行处理以回收植物养分，并将其返还到土壤中，以促进更多的食物生产，而不是将其转移到垃圾填埋场或焚烧。这种方法可用于减少食物生产中的能源和水的使用，并有助于系统的可持续性。厌氧消化和堆肥是常见的食物垃圾处理技术，用于稳定废物并产生可以补充土壤的剩余物质，从而促进循环食物系统的发展。但是，只有当食物垃圾未被污染或任何污染物在处理过程中被破坏时，这种方法才能被认为是安全和可行的。本综述汇集了有关不同食物供应链阶段的几种污染物类别的信息，包括它们的可能来源以及在堆肥和消化过程中的命运。主要目的是确定可能阻碍向安全、可靠和高效的循环食物系统过渡的因素。我们研究了食物系统中的重金属、卤代有机化合物、食源性致病菌和抗生素抗性基因（ARGs）及其在消化和堆肥过程中的命运。发现生产和加工阶段是这些污染物类别的主要进入点。与卤代有机物或抗生素抗性相比，重金属和食源性致病菌在循环系统中造成的风险较小。鉴于卤代有机化合物性质多样，关于它们在处理过程中的命运存在相互矛盾的证据。关于 ARGs 在处理过程中的命运的研究相对较少，并且产生的结果各不相同，这表明需要进行更多的研究来阐明它们在最终产品中的命运。反复将受污染的食物垃圾残留物施用于土地会增加积累的风险，并危及循环食物系统的安全性。因此，需要仔细管理系统并研究处理过程中污染物的命运。
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