title: Fatty Acid Methyl Ester (FAME) Succession in Different Substrates as Affected by the Co-Application of Three Pesticides.
abstract: BACKGROUND
  In intensive agriculture areas the use of pesticides can alter soil properties and microbial community structure with the risk of reducing soil quality.
  
  
  METHODS
  In this study the fatty acid methyl esters (FAMEs) evolution has been studied in a factorial lab experiment combining five substrates (a soil, two aged composts and their mixtures) treated with a co-application of three pesticides (azoxystrobin, chlorotoluron and epoxiconazole), with two extraction methods, and two incubation times (0 and 58 days). FAMEs extraction followed the microbial identification system (MIDI) and ester-linked method (EL).
  
  
  CONCLUSIONS
  The pesticides showed high persistence, as revealed by half-life (t1/2) values ranging from 168 to 298 days, which confirms their recalcitrance to degradation. However, t1/2 values were affected by substrate and compost age down to 8 days for chlorotoluron in S and up to 453 days for epoxiconazole in 12M. Fifty-six FAMEs were detected. Analysis of variance (ANOVA) showed that the EL method detected a higher number of FAMEs and unique FAMEs than the MIDI one, whereas principal component analysis (PCA) highlighted that the monosaturated 18:1ω9c and cyclopropane 19:0ω10c/19ω6 were the most significant FAMEs grouping by extraction method. The cyclopropyl to monoenoic acids ratio evidenced higher stress conditions when pesticides were applied to compost and compost+soil than solely soil, as well as with final time.
  
  
  CONCLUSIONS
  Overall, FAMEs profiles showed the importance of the extraction method for both substrate and incubation time, the t1/2 values highlighted the effectiveness of solely soil and the less mature compost in reducing the persistence of pesticides.
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment, DAFNAE, University of Padua, Viale dell'Università, 16-35020 Legnaro (PD), Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Cardinali
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment, DAFNAE, University of Padua, Viale dell'Università, 16-35020 Legnaro (PD), Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Pizzeghello
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment, DAFNAE, University of Padua, Viale dell'Università, 16-35020 Legnaro (PD), Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zanin
mesh_terms: D004784:Environmental Monitoring; D004852:Epoxy Compounds / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis*; D006207:Half-Life; D008689:Methacrylates / Q000032:analysis; D010575:Pesticides / Q000032:analysis*; D010671:Phenylurea Compounds / Q000032:analysis; D011743:Pyrimidines / Q000032:analysis; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D000073739:Strobilurins; D013997:Time Factors; D014230:Triazoles / Q000032:analysis
chemical_list: D004852:Epoxy Compounds; D005227:Fatty Acids; D008689:Methacrylates; D010575:Pesticides; D010671:Phenylurea Compounds; D011743:Pyrimidines; D012987:Soil; D000073739:Strobilurins; D014230:Triazoles; C087670:azoxystrobin; C007033:chlortoluron; C109476:epoxiconazole