Fate of Land Applied Emerging Organic Contaminants in Waste Materials

Abstract

In this review, we describe recent research on: (1) the occurrence of antibiotic resistant genes (ARGs) in waste materials and in soils receiving land application of ARG-contaminated waste materials; (2) the environmental behavior of ARGs in soils; (3) approaches to waste material management in terms of the elimination and reduction of ARGs. Land application of organic waste materials provides valuable nutrients to plant growth, but it can also introduce emerging organic contaminants, for example, antibiotics, into the environment. The widespread use of antibiotics and their entry into the environment are believed to result in the development and proliferation of antibiotic-resistant bacteria and ARGs in humans and animals, as well as in the environment. For this reason, ARGs are classified as emerging organic contaminants. Land application of manure, biosolids from wastewater treatment plants, and wastewater can potentially load elevated levels of antibiotics, antibiotic-resistant bacteria, and ARGs into soils. A host of environmental and biological factors may influence the environmental behavior of ARGs, including persistence and mobility, as well as their transmission among microorganisms in soil matrixes. Traditional on-site waste material management approaches may not be able to completely remove ARGs from the waste material before it is applied to the soils. However, recent research has suggested certain waste material land application management approaches may be able to further reduce the input of ARGs and mobility in the environment. Knowledge of the environmental behavior of ARGs is essential for better understanding and predicting the development and spread of antibiotic resistance in the environment. Information on the ecological consequences of ARG contamination and the possible entry of ARGs into the human food chain is also needed for better risk assessment of land application of ARG-contaminated waste materials. There is an urgent need to develop effective management and land application approaches to minimize/eliminate the input and mobility of ARGs in the soil environment.