Anaerobic Biodegradation of Pesticides
With the exception of those used in paddy rice, pesticides are typically applied to oxic environments but may be transported to anoxic environments through leaching, surface runoff, or eroded sediments. Pesticides are often applied to sites subject to tra
- PDF / 594,960 Bytes
- 22 Pages / 439.37 x 666.142 pts Page_size
- 119 Downloads / 285 Views
Anaerobic Biodegradation of Pesticides Gerald K. Sims and Ramdas Gopinath Kanissery
Abstract With the exception of those used in paddy rice, pesticides are typically applied to oxic environments but may be transported to anoxic environments through leaching, surface runoff, or eroded sediments. Pesticides are often applied to sites subject to transient flooding, eventually causing soil to become anoxic as oxygen consumptions rates exceed supply rates. This is largely due to decreased gas diffusion as pore space becomes saturated. Pesticide degradation occurs in each of the major anaerobic redox regimes, including aerobic, nitrate-reducing, iron-reducing, sulfate-reducing, and methanogenic environments. The ecology of microorganisms involved in anaerobic degradation of pesticides was poorly described until recently. Pesticide degraders (especially anaerobes) can be difficult to isolate; however, molecular biology tools allow examination of microorganisms involved in pesticide degradation without the need for isolation. In some cases, pesticide biodegradation has proved more rapid in aerobic environments, while certain substances are more labile under anaerobic conditions. Keywords Anaerobic degradation · Biodegradation · Biotransformation · Pesticides
G. K. Sims (*) Department of Entomology, Plant Pathology and Weed Science, New Mexico State University, Las Cruces, NM, USA e-mail: [email protected] R. G. Kanissery Southwest Florida Research & Education Center, University of Florida, Immokalee, FL, USA e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2019 P. K. Arora (ed.), Microbial Metabolism of Xenobiotic Compounds, Microorganisms for Sustainability 10, https://doi.org/10.1007/978-981-13-7462-3_2
33
34
G. K. Sims and R. G. Kanissery
2.1 Introduction Pesticides differ from many organic contaminants in their intentional release into the environment to manage pests. Evaluation of pesticides for registration thus involves studies primarily focused on the consequences of intended usage over a large area (dispersed or non-point sources). However, it is also possible for pesticides to enter the environment unintentionally, typically at a point source such as a spill (Shaffer et al. 2010) or legacy sites where mixing and loading of pesticides have occurred over time. Pesticides undergo many environmental fate processes, including sorption (reversible and irreversible), hydrolysis, volatilization, transport, and degradation (biological or abiotic). Certain properties of pesticides are predictors of particular behaviors. For example, it has been shown that for a given pesticide, empirical sorption and degradation measurements may be strongly correlated among a wide range of soil types (Lehmann et al. 1993; Mervosh et al. 1995a, b; O’Loughlin et al. 2000; Sims et al. 2009). Environmental fate processes can be linked, with each component process responding differently to environmental conditions; thus, outcomes may be difficult to predict (Sims and Cupples 1999). The flow of pesticides into one envir
Data Loading...
