Chlorotriazine herbicides (CTs) are widely used pest control chemicals. In contrast to groundwater contamination, little attention has been given to the circumstances of residue formation of parent compounds and transformation products in soils. Seventy-five cultivated floodplain topsoils in the Czech Republic were sampled in early spring of 2015, corresponding to a minimum of six months (current-use terbuthylazine, TBA) and a up to a decade (banned atrazine, AT and simazine, SIM) after the last herbicide application. Soil residues of parent compounds and nine transformation products were quantified via multiple residue analysis using liquid chromatography - tandem mass spectrometry of acetonitrile partitioning extracts (QuEChERS). Using principal component analysis (PCA), their relation to soil chemistry, crops and environmental parameters was determined. Of the parent compounds, only TBA was present in more than one sample. In contrast, at least one CT transformation product, particularly hydroxylated CTs, was detected in 89% of the sites, or 54% for banned triazines. Deethylated and bi-dealkylated SIM or AT residues were not detectable. PCA suggests the formation and/or retention of CT hydroxy-metabolite residues to be related to low soil pH, and a direct relation between TBA and soil organic carbon, and between deethyl-TBA and clay or Ca contents, respectively, the latter pointing towards distinct sorption mechanisms. The low historic application of simazine contrasted by the high abundance of its residues, and the co-occurrence with AT residues suggests the post-ban application of AT and SIM banned triazines as a permitted impurity of TBA formulations as a recent, secondary source. The present data indicate that topsoils do not contain abundant extractable residues of banned parent chlorotriazines, and are thus likely not the current source for related ground- and surface water contamination. In contrast, topsoils might pose a long-term source of TBA and CT transformation products for ground and surface water contamination.
- MeSH
- biodegradace MeSH
- herbicidy analýza metabolismus MeSH
- látky znečišťující půdu analýza metabolismus MeSH
- podzemní voda chemie MeSH
- půda chemie MeSH
- rezidua pesticidů analýza metabolismus MeSH
- triaziny analýza metabolismus MeSH
- zemědělství * MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
In this research, the adsorption of two herbicides, alachlor (ALA) and terbuthylazine (TBA), on granular activated carbon (GAC) in the presence of well-characterized peptide fraction of cellular organic matter (COM) produced by cyanobacterium Microcystis aeruginosa was studied. Two commercially available GACs were characterized using nitrogen gas adsorption and surface charge titrations. The COM peptides of molecular weight (MW) < 10 kDa were isolated and characterized using MW fractionation technique and high-performance size exclusion chromatography (HPSEC). The effect of surface charge on the adsorption of COM peptides was studied by means of equilibrium adsorption experiments at pH 5 and pH 8.5. Electrostatic interactions and hydrogen bonding proved to be important mechanisms of COM peptides adsorption. The adsorption of ALA and TBA on granular activated carbon preloaded with COM peptides was influenced by solution pH. The reduction in adsorption was significantly greater at pH 5 compared to pH 8.5, which corresponded to the increased adsorption of COM peptides at pH 5. The majority of the competition between COM peptides and both herbicides was attributed to low molecular weight COM peptides with MW of 700, 900, 1300 and 1700 Da.
- MeSH
- acetamidy analýza chemie MeSH
- adsorpce MeSH
- chemické látky znečišťující vodu analýza chemie MeSH
- dřevěné a živočišné uhlí chemie MeSH
- herbicidy analýza chemie MeSH
- kinetika MeSH
- Microcystis chemie MeSH
- odpad tekutý - odstraňování metody MeSH
- peptidy chemie MeSH
- povrchové vlastnosti MeSH
- triaziny analýza chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The use of fast semi-automated method employing direct analysis in real time (DART) ion source coupled to time-of-flight mass spectrometry (TOFMS) for analysis of melamine (MEL) and cyanuric acid (CYA) in milk powder and milk based products has been demonstrated in this study. Simple sample extraction procedure employing methanol-5% aqueous formic acid mixture, which enabled disruption of melamine-cyanurate complex, was followed by direct, high-throughput (30s per run) examination of sample extracts spread on a glass rod by mass spectrometry under ambient conditions, without any prior chromatographic separation. After optimization of instrument parameter settings, limits of detection (LODs) 170 and 450microgkg(-1) were achieved for MEL and CYA, respectively. In the final phase of study, the possibility of minimizing spectral interference, thus improving method performance characteristics through the use of ultrahigh resolving power offered by Orbitrap based mass analyzer is demonstrated.
- MeSH
- hmotnostní spektrometrie metody MeSH
- kontaminace potravin analýza MeSH
- limita detekce MeSH
- mléko chemie MeSH
- prášky, zásypy, pudry analýza MeSH
- skot MeSH
- triaziny analýza MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
- MeSH
- acetamidy * analýza krev MeSH
- chemické látky znečišťující vodu * MeSH
- chromatografie plynová * metody využití MeSH
- kapři MeSH
- rezidua pesticidů * metabolismus MeSH
- ryby MeSH
- triaziny * analýza krev MeSH
- věkové faktory MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
- MeSH
- antiinfekční látky klasifikace škodlivé účinky toxicita MeSH
- chemický průmysl MeSH
- chloraminy MeSH
- dezinficiencia * aplikace a dávkování škodlivé účinky toxicita MeSH
- lidé MeSH
- sloučeniny chloru * analýza chemie toxicita MeSH
- statistika jako téma MeSH
- triaziny analýza chemie toxicita MeSH
- výzkum MeSH
- Check Tag
- lidé MeSH
