1 / 21

Dissipation of Polar Xenobiotics from Pharmaceutical POCIS - N. Mazzella

Study on dissipation of polar xenobiotics from pharmaceutical POCIS, proposing a performance reference compound. Analytical techniques, herbicides analysis, microcosm experiments, calibration, and results discussed.

chrisp
Download Presentation

Dissipation of Polar Xenobiotics from Pharmaceutical POCIS - N. Mazzella

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Unité de recherche REBX Bordeaux, FRANCE Dissipation of polar xenobiotics from pharmaceutical POCIS and suggestion of a performance reference compound N. Mazzella, T. Debenest, J. Grange, C. Madigou, F. Delmas

  2. Introduction 2 Evaluation of the water quality and its consequences on river biological organisms (WFD) Effects of pesticides and metabolites on diatom communities • Time-weighted average concentration estimates : • Classical grab sampling  Representative ? • Automated/extensive sampling  Time-consuming and expensive • Passive sampling  Validity of quantitative results ?

  3. CPOCIS (1-e-ket) Cwater Cf (t) = = Equilibrium regime ku ku ke ke Cf = = Ksw Linear uptake regime ku >> ke Cf (t) = ku x t time Introduction 3 Assumption of linear isotherms and isotropic exchanges

  4. Aim and objectives 4 • Methodologies • Analytical techniques and analyte recoveries • Calibration of pharmaceutical POCIS • Determination of ku and Rs • Study of analyte elimination rates • Suggestion of a potential PRC

  5. Compression holder washers Polyethersulfone membranes Sorbent Methodologies 5 Analyte recoveries Columns packed with sorbents Elution with MeOH

  6. Herbicides analyzed Large polarity range: -1.7 (Nicosulfuron) ≤ Log Kow ≤ 5.07 (trifluraline) Different classes :Triazines, Phenylureas, Sulfonylureas, Diphenyl ethers,Chloroacetanilides, Dinitroanilines, Benzonitriles, Triketones Triazines and Phenylureas metabolites Analytical method 2 multiresidue methods : HPLC-DAD technique Reverse phase (ODS 2) and weakly anion-exchanger (polyamine) columns Methodologies 6

  7. Methodologies 7 Analysis with an ODS 2 column Separation of 16 neutral or basic herbicides

  8. Methodologies 8 Analysis with a polyamine column Acidic herbicides Log Kow ≤ 0 for Mesotrione Sulcotrione Nicosulfuron

  9. Methodologies 9 Microcosm experimental design Constant temperature (17±1° C) and obscurity Large volume (80 L) Turbulent conditions: constant flow velocity 2-3 cm.s-1

  10. Microcosm experiment Constant temperature and flow velocity, obscurity Tap water Constant concentrations over 21 days of exposure Duplicate analyses CPOCIS 1. Linearity and kinetic regimes 2. Sampling rates Rs Cwater t Calibration of POCIS 10

  11. Calibration of POCIS 11 Cf (L.g-1) 0.974 r 0.998 Days

  12. log KOW -1.7 3.03 5.18 Pendimethalin Calibration of POCIS 12 Sampling rates over 21 days

  13. Calibration of POCIS 13 Cf (L.g-1) r=0.326 r=0.786 r=0.985 Days Sorbent saturation or isotropic exchanges ?

  14. Calibration of POCIS 14 Partial conclusion Linear uptakes of 16 herbicides for 21 days Curvilinear uptakes of DIA and 3 other polar herbicides : • Assumption of isotropic exchanges for DIA • Estimation of the elimination rate constant • Use of DIA as PRC ?

  15. Performance Reference Compound kePRC=ln(CPRC0/CPRC)/t ku KSW = ke CPRC/CPRC0 Rsin situ= (kein situ/kecal) x Rscal t Suggestion of a PRC 15 Rs depends on : Temperature Turbulence Biofouling CPOCIS x MPOCIS Cw = Rs x t

  16. Suggestion of a PRC 16 Dissipation of DIA and simazine from pharmaceutical POCIS C/C0 Simazine DIA Days Elimination rate constant estimates : ke= 0.047± 0.005 d-1 (dissipation) and ke= 0.08± 0.02 d-1 (uptake) Isotropic exchanges might exist for DIA

  17. Suggestion of a PRC 17 Microcosm experiment Turbulent flow (20-50 cm.s-1) River water (biofouling effects) 9-day exposure Correction of TWA concentrations (PRC)

  18. µg.L-1 µg.L-1 3 6 9 Days POCIS POCIS (PRC) « Peak » concentration 3 6 9 Days Suggestion of a PRC 18 Terbuthylazine + 25 % Average concentration + 30 % The « peak » concentration was integrated during 9 days

  19. µg.L-1 µg.L-1 POCIS 3 6 9 Days POCIS (PRC) « Peak » concentration 3 6 9 Days Suggestion of a PRC 19 Deethylterbuthylazine + 11 % Average concentration + 25 % DET (log Kow=1.98) Terbuthylazine (log Kow=3.21)

  20. Conclusions and further studies 20 Isotropic exchanges for DIA (first-order monophasic kinetic) « Peak » concentrations are integrated for the 2 test chemicals Correction of TWA concentration estimates for 9 days Desorption of DIA and other herbicides for 28 days (biphasic kinetics) Correction of TWA concentrations for 21-28 days In situ validation with one or several PRCs

  21. Unité de recherche REBX Bordeaux, FRANCE Thank you for your attention !

More Related