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A review of the literature published in 2019 on topics associated with the fate of environmental pollutants is presented. Environmental pollutants covered include pharmaceuticals, antibiotic-resistant bacteria and genes, pesticides and veterinary medicines, personal care products and emerging pollutants, PFAS, microplastics, nanomaterials, heavy metals and radionuclides, nutrients, pathogens and indicator organisms, and oil and hydrocarbons. For each pollutant, the occurrence in the environment and/or their fate in engineered as well as natural systems in matrices including water, soil, wastewater, stormwater, runoff, and/or manure is presented based on the published literature. The review includes current developments in understanding pollutants in natural and engineered systems, and relevant physico-chemical processes, as well as biological processes.

Understanding methane (CH4) fluxes from rice (Oryza sativa L.) at the field scale is paramount to reducing environmental impacts while ensuring global food security. Greenhouse gas (GHG) measurements at the plot scale using static flux chambers (SFC) have long informed the understanding of flux dynamics and have largely been the basis of global flux estimates. However, in many parts of the world, the landscapes where agricultural fluxes are generated come from larger fields. Eddy covariance (EC) can measure trace gases on larger fields, but there are few studies available quantifying CH4 emissions under typical practices at a field scale. Furthermore, few of these studies are from the U.S. Midsouth, the largest producer of U.S. rice. This study compares and quantifies field‐scale SFC and EC flux measurements on a large commercial system in northeastern Arkansas during the 2015 and 2016 growing seasons, following typical producer practices. Daily measured SFC CH4 fluxes did not differ from EC‐daily CH4 fluxes (p = .108). Total season CH4 emissions, calculated as the sum of daily fluxes ranged from 50 to 156 kg CH4 ha−1 season−1, with SFC reporting greater emissions than EC. Although SFC and EC‐daily flux measurements were similar early (p = .382) and late (p = .543) in the season, they differed mid‐season (p

Flooding rice fields in the US mid-south during the fallow season (November–March) for migratory waterfowl habitats provides revenue from hunting-related activities and helps with soil retention and water quality. However, flooding has the potential to increase greenhouse gas (GHG) emissions. Research on GHG emissions in US mid-south during the fallow season has been limited. Eddy covariance (EC) systems measuring CO2 and CH4 fluxes were installed during the 2015–2016, 2016–2017, and 2017–2018 fallow seasons at paired production-sized fields in NE Arkansas. Rice residue was burned after harvest at both field locations. The paired fields were separated by an access road and consisted of one field flooded (F) with precipitation by installing barriers to prevent drainage and the other field allowed to drain or non-flooded field (NF). Flooding did not influence CO2 emissions during the fallow season significantly. However, F fields emitted 45 ± 2% more CH4 than NF fields. The three-year fallow season average was 1408 ± 185 kg CO2-C ha−1 season-1 and 12.5 ± 2.0 kg CH4-C ha−1 season-1 in F fields and 1355 ± 132 kg CO2-C ha−1 season-1 and 8.6 ± 1.4 kg CH4-C ha−1 season-1 in NF fields. Methane contributed 5 to 10% global warming potential (GWP), reported as CO2 equivalents from CO2 and CH4 measurements. The three-year fallow season average GWP was not different by treatment. Increases in fallow season GWP were noted to increase after rice cultivation. These findings will improve our overall understanding and modeling of GHG emissions from agricultural fields during an understudied but important period of the year.