Potential for Abiotic Reduction of Pesticides in Prairie Pothole Porewaters

Abstract

Prairie pothole lakes (PPLs) are critical hydrological and ecological components of central North America and represent one of the largest inland wetland systems on Earth. These lakes are located within an agricultural region, and many of them are subject to nonpoint-source pesticide pollution. Limited attention, however, has been paid to understanding the impact of PPL water chemistry on the fate and persistence of pesticides. In this study, the abiotic reductive transformation of seven dinitroaniline pesticides was investigated in PPL sediment porewaters containing naturally abundant levels of reduced sulfur species (i.e., bisulfide (HS(-)) and polysulfides (S(n)(2-))) and dissolved organic matter (DOM). Target dinitroanilines underwent rapid degradation in PPL porewaters and were transformed into corresponding amine products. While the largest fraction of the transformation could be attributed to reduced sulfur species, experimental evidence suggested that other reactive entities in PPL porewaters, such as DOM and mineral phases, might also affect the reaction rates of dinitroanilines. Results from this study highlight the importance of reductive transformation as an abiotic natural attenuation pathway for pesticides entering the PPL sedimentary environment.

Residues and potential ecological risks of veterinary antibiotics in manures and composts associated with protected vegetable farming

“…Abiotic transformation of the antibiotics might contribute a great to the degradation during composting. Research has demonstrated that high-organic soils/sediments tend to produce elevated levels of reduced sulfur compounds (e.g., bisulfide and polysulfides) and iron(II) species, which typically possess strong reducing capacity that may degrade veterinary antibiotics faster than microorganisms (Zeng et al 2011(Zeng et al , 2012Mohatt et al 2011). Similar to the manures, the SAs concentrations in the composts are lower than other TCs and FQs generally; however, SDZ in the soybean meal compost (SMC) and SCX in the rice husk compost (RHC) are prominent due to their significant higher level in the two composts.…”

“…Thus, some degradation of antibiotics is likely to occur during the composting, especially during the exothermic stage (Kim et al 2012). Meanwhile, abiotic reaction with reduced sulfur species could remove the antibiotics from the fresh manures during composting (Zeng et al 2011(Zeng et al , 2012. The objectives of the present study were therefore to identify veterinary antibiotic residues in animal manures and different types of compost and to evaluate the ecological risks associated with the application of organic fertilizers in the protected vegetable farming based on the observed concentrations of antibiotics.…”

Biochar‐mediated reductive transformation of nitro herbicides and explosives

“…No reduction product of pendimethalin was identified by hexane extraction and GC-MS analysis. Pendimethalin was presumably transformed through reduction of the nitro groups [29,31], which would have produced the more polar and less extractable amino compounds. Extraction using a solvent with a hydrogendonating property may be necessary to recover the amino products.…”

“…Finally, biochar may play a role in the natural attenuation of redox-labile contaminants in reducing environments, in a manner similar to other types of BC [23]. Indeed, BC has recently been implicated in the abiotic reduction of pesticides in sediment porewaters in the Prairie Pothole Region [31]. Biochar-mediated reduction of herbicides and explosives Environ.…”

Dissipation kinetics and leaching of cyazofamid fungicide in texturally different agricultural soils

“…The behavior of pesticides in soil, therefore, depends on the characteristics and overall function of the ecosystem as well as physicochemical properties of active ingredients and of its formulated products (Flury 1996;Kerle et al 2007). In addition to adsorption and biodegradation, it has been recently shown that reduced sulfur species and dissolved organic matter present in soil/sediment are capable of promoting the in situ transformation of otherwise recalcitrant pesticides (Zeng et al 2011(Zeng et al , 2012.…”