title: Aerobic versus Anaerobic Microbial Degradation of Clothianidin under Simulated California Rice Field Conditions.
abstract: Microbial degradation of clothianidin was characterized under aerobic and anaerobic California rice field conditions. Rate constants (k) and half-lives (DT50) were determined for aerobic and anaerobic microcosms, and an enrichment experiment was performed at various nutrient conditions and pesticide concentrations. Temperature effects on anaerobic degradation rates were determined at 22 ± 2 and 35 ± 2 °C. Microbial growth was assessed in the presence of various pesticide concentrations, and distinct colonies were isolated and identified. Slow aerobic degradation was observed, but anaerobic degradation occurred rapidly at both 25 and 35 °C. Transformation rates and DT50 values in flooded soil at 35 ± 2 °C (k = -7.16 × 10(-2) ± 3.08 × 10(-3) day(-1), DT50 = 9.7 days) were significantly faster than in 25 ± 2 °C microcosms (k= -2.45 × 10(-2) ± 1.59 × 10(-3) day(-1), DT50 = 28.3 days). At the field scale, biodegradation of clothianidin will vary with extent of oxygenation.
authors: Department of Environmental Toxicology, College of Agricultural and Environmental Sciences, University of California , One Shields Avenue, Davis, California 95616-8588, United States.
authors: Rebecca A
authors: RA
authors: Mulligan
authors: Patrick L
authors: PL
authors: Tomco
authors: Megan W
authors: MW
authors: Howard
authors: Department of Chemistry and Biochemistry, California State University , 400 West First Street, Chico, California 95929-0210, United States.
authors: Tabitha T
authors: TT
authors: Schempp
authors: Davis J
authors: DJ
authors: Stewart
authors: Phillip M
authors: PM
authors: Stacey
authors: Department of Chemistry and Biochemistry, California State University , 400 West First Street, Chico, California 95929-0210, United States.
authors: David B
authors: DB
authors: Ball
authors: Department of Environmental Toxicology, College of Agricultural and Environmental Sciences, University of California , One Shields Avenue, Davis, California 95616-8588, United States.
authors: Ronald S
authors: RS
authors: Tjeerdema
mesh_terms: D001420:Bacteria, Aerobic / Q000378:metabolism; D001421:Bacteria, Anaerobic / Q000378:metabolism; D001673:Biodegradation, Environmental; D002140:California; D015169:Colony Count, Microbial; D018556:Crops, Agricultural / Q000382:microbiology; D006146:Guanidines / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007306:Insecticides / Q000737:chemistry*; D000073943:Neonicotinoids; D012275:Oryza / Q000382:microbiology*; D010802:Phylogeny; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000737:chemistry*; D013696:Temperature; D013844:Thiazoles / Q000737:chemistry*
chemical_list: D006146:Guanidines; D007306:Insecticides; D000073943:Neonicotinoids; D012987:Soil; D012989:Soil Pollutants; D013844:Thiazoles; C480342:clothianidin
keywords: aerobic; anaerobic; clothianidin; rice; rice water weevil