Solid-phase microextraction coupled with gas chromatography-mass spectrometry (SPME-GC-MS) was used to analyze two triazine (atrazine and simazine) and three chloroacetamide herbicides (acetochlor, alachlor, and metolachlor) in water samples from a midwest US agricultural drainage ditch for two growing seasons. The effects of salt concentration, sample volume, extraction time, and injection time on extraction efficiency using a 100-mum polydimethylsiloxane-coated fiber were investigated. By optimizing these parameters, ditch water detection limits of 0.5 microgL(-1) simazine and 0.25 microgL(-1) atrazine, acetochlor, alachlor, and metolachlor were achieved. The optimum salt concentration was found to be 83% NaCl, while sample volume (10 or 20 mL) negligibly affected analyte peak areas. The optimum extraction time was 40 min, and the optimum injection time was 15 min. Results indicated that atrazine levels in the ditch water exceeded the US maximum contaminant level for drinking water 12% of the time, and atrazine was the most frequently detected among studied analytes.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.envpol.2007.04.029 | DOI Listing |
Huan Jing Ke Xue
January 2025
Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China.
The carbon emissions of three typical processes (AAO, MSBR, and oxidation ditch) were systematically analyzed from the perspective of the whole wastewater treatment process based on the annual data of eleven urban small and medium-scale WWTPs in the year 2022, and the effects of different influent characteristics (TP, TN, BOD, COD, influent volume, and COD/TN) on the carbon emissions were studied by using the partial least squares structural equation modeling (PLS-SEM) method. The results showed that indirect carbon emissions dominated the total carbon emissions of small and medium-scale WWTPs (69.5%), and carbon emissions from electricity consumption were the largest source (43.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Department of Ecology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, the Netherlands.
Recent studies indicate that greenhouse gas (GHG) emissions from agricultural drainage ditches can be significant on a per-unit area basis, but spatiotemporal investigations are still limited. Additionally, the impact of dredging - a common management in such environments - on ditch GHG emissions is largely unknown. This study presents year-round GHG emissions from nine ditches on a dairy farm in the center of the Netherlands, where each year, approximately half of the ditches are dredged in alternating cycles.
View Article and Find Full Text PDFJ Infect Chemother
December 2024
Division of General Internal Medicine, Department of Internal Medicine, Tokyo Medical University Ibaraki Medical Center, Japan.
Edwardsiella tarda is a Gram-negative intracellular pathogen within the Enterobacterales order, recognized as a causative agent of hemorrhagic septicemia in fish but also pathogenic to humans. However, the clinical course and prognostic factors of E. tarda bacteremia are not fully understood.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Department of Crop Sciences, University of Illinois at Urbana-Champaign, AW-101 Turner Hall, 1103 South Goodwin Avenue, Urbana, IL, USA. Electronic address:
Pumping surface water from a ditch into a denitrifying woodchip bioreactor could improve nitrate-nitrogen (N) removal by minimizing flow variabilities such as early flow cessation at a given subsurface drainage outlet and flashy drainage hydrographs. Few field-scale subsurface drainage bioreactors with pumping configurations have been assessed. Such evaluations would help better bound reasonable expectations of the benefits and drawbacks at these more advanced bioreactors.
View Article and Find Full Text PDFWater Res
December 2024
School of Environment, Nanjing Normal University, Jiangsu Province Engineering Research Center of Environmental Risk Prevention and Emergency Response Technology, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Wenyuan Road 1, Nanjing 210023, PR China. Electronic address:
Coupling of iron-carbon can form a mixotrophic denitrification and is regarded as a promising solution for purifying nitrate-rich agricultural runoff. However, its prevalence and efficacy of the synergistic augmentation of nitrogen elimination and net NO sinks remain crucial knowledge gaps in ecological ditches (eco-ditches). Here, we investigated the underlying variability mechanisms by implementing sponge iron (sFe)-coupled Iris hexagonus (IH)- or Myriophyllum aquaticum (MA)-derived biochar produced via microwave-assisted (MW) pyrolysis and conventional pyrolysis.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!