Routes of Entry, Degradation, and Persistence of Emerging Contaminants of Concern in Agroecosystems

The presence of emerging contaminants in organic wastes and derived products (compost or digestate) is one of the main concerns for agricultural ecosystems due to their use in the soil-plant system to recycle their nutrients and organic matter.Emerging contaminants of concern include pharmaceutical drugs and personal care products, including plasticizers (used in cosmetics, shampoo, hair spray and gel) (PPCPs), and veterinary products (hormones, antibiotics, etc.). They can cause the appearance of antibiotic resistance genes (ARGs) and the alteration of soil microbial diversity. Antibiotics and other drugs are extensively taken by humans and are given to livestock. Once absorbed by the organism, they undergo metabolic reactions, producing metabolites which can be more harmful than the original compound, finally entering manure or wastewater treatment plants. The low removal efficiency of the different treatment technologies for sewage sludge or animal manure processing means that they end up in the resulting materials. In fact, sewage treatment and wastewater treatment plants are the primary pathway that introduces PPCPs in the environment. Also, the use of manures for soil fertilisation is considered a relevant route for introducing antibiotics and ARGs in the environment. At the same time, there is still limited understanding of how these emerging contaminants degrade during composting and anaerobic digestion. In addition, the main factors affecting plant uptake have been identified as: the biological characteristics of the plants, physiochemical properties of the compounds and soil conditions, affecting their bioavailability.Pollution by plastic impacts Earth system processes due to their long persistence in the environment. They can break down into smaller particles of different sizes, from macro- to meso- to micro- to nanoplastics. Plastics and microplastics remain in the organic fraction of municipal solid wastes and persist in the derived compost, due to inadequate source separation and poor degradation.Despite this, little is known about the degradation pathways of these emerging contaminants in composting and in anaerobic digestion. Their low biodegradability makes compost and digestate an entry route into the soil and the wider environment. Although some studies have been reported, in general there is a lack of information on their effects on plant growth and performance. Even though the use of bio-based and biodegradable plastics is now widespread, the risk of contamination by plastics and microplastics still exists.This Research Topic accepts manuscripts in the following subjects, but is not limited to them:• Emerging contaminants of concern in organic wastes and derived products, affecting agronomic quality and food safety;• Degradation pathways of the emerging contaminants in composting, anaerobic digestion and in the soil system;• Implication of the emerging contaminants of concern in the development of antibiotic resistance genes and the alteration of microbial diversity in agroecosystems;• Effects of emerging contaminants in the soil-plant agroecosystems: plant uptake and toxicity, bioavailability in soils affecting functionality;• Microplastics in compost and effects on the composting process: organic matter decomposition and humification process, alteration of nitrogen conversion, plant phytotoxicity, lowering of compost quality.• Mobility of the emerging contaminants in the soil-plant-animal system. Topic editors: Paula Alvarenga, Isabel Martínez-Alcalá, Airton Kunz, Silvia Silvestri Source: https://www.frontiersin.org/research-topics/76954/routes-of-entry-degradation-and-persistence-of-emerging-contaminants-of-concern-in-agroecosystems