Atrazine degradation patterns: the role of straw cover and herbicide application history

Abstract

In Brazil, atrazine (ATZ) is widely applied to maize (Zea mays L.) fields for weed control. The presence of ATZ and its metabolites in soil and water matrices has become a matter of some concern for governmental authorities as well as for society at large. This study evaluated the patterns of ATZ degradation (mineralization, extractable and non-extractable ATZ residues, and metabolite formation) in a Brazilian Typic Paleudult. Soil samples from a cultivated area under a no-tillage system with a history of ATZ application were incubated with 14 C-ATZ in both the presence and absence of straw cover on the soil surface, and the evolved 14 CO 2 was determined by liquid scintillation. Samples from an area with native vegetation, adjacent to the cultivated area, were also incubated as a control. A higher mineralization of ATZ was observed in the cultivated soil (> 85 %) in comparison with the native soil (10 %) after 85 days of incubation. In addition to the higher mineralization and hydroxyatrazine (HA) formation, a rapid decrease in the water-extractable residues was observed in the cultivated soil. When the cultivated soil was covered with straw, mineralization was reduced by up to 30 % although a small amount of remobilization to the soil occurred within the 85 days. Straw cover hindered the degradation of ATZ in cultivated soils; whereas an accelerated biodegradation was due to repeated applications of ATZ, which may have selected microbiota more skilled at biodegrading the herbicide.

Potential use of floating treatment wetlands established with Canna flaccida for removing organic contaminants from surface water

“…EPA (Environmental Protection Agency) 2007). Although the use of ATZ has been banned in the European Union since 2004, it is still used in many countries including the USA, Australia, and Brazil (Australian Pesticides and Veterinary Medicines Authority (APVMA) 2016; Leal et al 2019). Likewise, the pharmaceuticals acetaminophen (N-(4hydroxyphenyl)ethanamide; APAP) and carbamazepine (5Hdibenzo[b,f]azepine-5-carboxamide; CBZ) have been frequently detected in wastewater from domestic sewages (Kim et al 2007;Ekpeghere et al 2018), and may also be considered a CEC (Daniele et al 2017;Peng et al 2018).…”

Electrochemical degradation of aqueous alachlor and atrazine: products identification, lipophilicity, and ecotoxicity

“…Atrazine (1-chloro-3-ethylamino-5isopropylamino-2,4,6-triazine), as well as alachlor, is widely used in weed control in maize, sugarcane, and soybean crops. This herbicide belongs to the triazines group, and it is the most important chemical of this family as well as one of the most used herbicides in the world due to its high phytotoxic activity 11,12 . Among its main characteristics are: low vapor pressure, moderate solubility in water, slow hydrolysis, and the ability of leaching 13,14 .…”

The role of bacterial diversity on the antibiotic and herbicide biodegradation in agricultural soils

“…It contributed to slightly higher ATZ sorption to the CS due to its higher OC, even though sorption was low in both soils (Kd-app < 3 L kg -1 ). Several studies have already reported ATZ low sorption even in tropical soils, having high metal (oxy)hydroxide contents (Inoue et al, 2006;Leal et al, 2019), in which it may reach surface and subsurface water bodies (Barizon et al, 2020;. Land use and adopted agricultural management practices, such as pesticide, fertilizer, and corrective amendments to soils under no-till, also impacted soil bacterial community composition, structure, and bacterial diversity.…”

“…This is possibly due to the CS community has bacterial groups already adapted to the herbicide. Therefore, the impact of the herbicide on the microbial population would be more attenuated when compared to the GS (Poursat et al, 2019), which will probably also reflect on the higher capacity of the microbial population to biodegrade the pesticide (Leal et al, 2019;.…”

“…Atrazine [2-chloro-4-ethylamino-6-isopropylamino) -1,3,5-triazine] (ATZ) is the second most widely used herbicide in the world (~7 x 10 4 -9 x 10 4 tons of active ingredient is consumed per year) (Fan et al, 2020;Henn et al, 2020;Khatoon and Rai, 2020). It is often used to control pre-emergence and post-emergence of weeds in corn, millet, sugarcane, and sorghum (Aguiar et al, 2020;Leal et al, 2019). ATZ belongs to the chemical group of chlorinated S-triazines and is formed by an aromatic heterocyclic ring alternating carbon and nitrogen atoms, besides to the chlorine substituent (Henn et al, 2020;Pertile et al, 2021;.…”