Sorption of Pesticides to Dissolved Organic Matter Originated from Treated Wastewater and its Effect on Pesticides Mobility

Transcription

1 Sorption of Pesticides to Dissolved Organic Matter Originated from Treated Wastewater and its Effect on Pesticides Mobility Talli Ilani and Benny Chefetz Department of Soil and Water Sciences Faculty of Agricultural, Food and Environmental Quality Sciences The Hebrew University of Jerusalem,

2 Background Wastewater dissolved organic matter (DOM) is highly heterogeneous in size and chemical composition : MW(< 500 to >5000 Da), and it is comprised of a mixture of compounds (humics, polysaccharides, proteins, lipids, and etc.)

3 Objectives To study the mechanism governing the binding of s-triazine herbicides and polycyclic aromatic hydrocarbons (PAHs) to structural fractions of wastewater DOM.

4 Sampling sites Activated sludge Netanya Oxidation ponds Lachish

5 Selected properties of the studied treated wastewater BOD (mg/l) COD (mg/l) TSS (mg/l) ph EC (ds/m) N total (mg/l) Netanya Lachish

6 Fractionation of treated wastewater DOM bulk Treated DOM waste water bulk DOM >1000 Acidify to ph 2 NaOH 0.1N HoN Soxhlet extraction with MeOH HoN>1000 XAD-8 Na + -HoA H + -Cation exchange resin Hydrophilic fraction H + -HoA HoA>1000

7 Carbon mass balance of the DOM fractions (% of DOM) Fraction Netanya Lachish DOM ( 12 mg/l) (23 mg/l) Hydrophilic Hydrophobic: HoA HoN

8 C, N and H contents, atomic rations and total acidity of the DOM fractions sample C H % N H/C Atomic ratio Total acidity meq/g HoA Netanya HoN Netanya HoA Lachish HoN Lachish

9 FTIR spectra of DOM fractions (Netanya) HoA>1000 HoA HoN>1000 HoN Absorbance wavenumber (cm -1 ) wavenumber (cm -1 )

10 Characterization summary The HoN fractions exhibited more aliphatic nature than the HoA fractions. The >1000 Da fractions contained more polar groups than corresponding bulk fractions (HoA and HoN). The fractions from Lachish WW exhibited higher aliphaticity character than the fractions from Netanya WW.

11 Selected properties of the sorbates Compound Structure Formula Log K OW Aqueous solubility (mg/l) pka Cl Atrazine N N CH 3 C 8 H 14 ClN C H 3 NH N NH CH 3 Ametryn N S CH 3 N CH 3 C 9 H 17 N 5 S C H 3 NH N NH CH 3 Phenanthrene C 14 H Fluoranthene C 16 H Pyrene C 16 H

12 Atrazine binding isotherms by the DOM Netanya Lachish Free חופשי atrazine אטרזין (mg/l) Free חופשי atrazine אטרזין (mg/l) (mg/l) Sorbed ספוח atrazine אטרזין (mg/kgdoc) DOC) Sorbed ספוח atrazine אטרזין (mg/kgdoc) DOC) Compost water extract bulk DOM HoA HoN Free atrazine אטרזין חופשי (mg/l) Sorbed ספוח atrazine אטרזין (mg/kgdoc) DOC)

13 Sorption coefficients of atrazine DOM fraction bulk DOM > 1000 Da Netanya HoA >1000 Da Netanya HoN >1000 Da Netanya bulk DOM > 1000 Da Lachish HoA >1000 Da Lachish HoN >1000 Da Lachish bulk DOM > 1000 Da compost HoA >1000 Da compost HoN >1000 Da compost K DOC (L/kg DOC) 690±31 175±4 710±31 373±11 321±8 846±38 40±1 120±6 568±20

14 Sorption coefficients of PAHs Phenanthrene K DOC (L/kg DOC) Fluoranthene Pyrene HoA Netanya 790±35 1,980±190 4,360±170 HoN Netanya 9,375±430 23,425±2,150 22,800±1,290 HoA Lachish 2,020±50 4,070 ±65 5,415 ±650 HoN Lachish 8,020 ±200 18,870 ±2,660 37,120 ±2,510 HoA compost 880 ±130 1,770 ±360 2,820 ±310 HoN compost 2,790 ±535 25,710 ±1,560 44,635 ±7,325

15 10000 Sorption coefficients of PAHs (HoA and HoA>1000 Da fractions) phenanthrene flouranthene pyrene HoA>1000 Da HoA 8000 K DOC (L/kg DOC) K DOC (L/kgDOC) Lachish לכיש 0 לכיש A נתניה נתניה 0 Netanya Lachish Netanya Lachish Netanya לכיש 0 לכיש A נתניה נתניה 0 לכיש 0 לכיש A נתניה נתניה

16 Summary K DOC values : HoN > HoA K DOC values of the HoA fractions: Lachish > Netanya > compost water extract K DOC values of the HoN fractions: Lachish Netanya > compost water extract. The fractions from the compost water extract have a more polar character than the fractions from wastewater.

17 Transport of atrazine in soil (Bazra sandy soil, 3 mg/kg atrazin) Atrazine (mg/l) Netanya treated wastewater Fresh water Effluent volume (ml)

18 Transport of atrazine in soil (Bazra sandy soil, 3 mg/kg atrazin) Atrazine (mg/l) HoA after fresh water Netanya treated wastewater HoA after treated wastewater Fresh water Effluent volume (ml)

19 Transport of atrazine in soil (Bazra sandy soil, 3 mg/kg atrazin) HoN after treated wastewater Atrazine (mg/l) Netanya treated wastewater HoA after treated wastewater HoA after fresh water Fresh water Effluent volume (ml)

20 Conclusions The HoN fraction has major effect on the overall sorption capability of the DOM; although it comprises less than 10% of the total WW DOC. The HoN fraction can enhance the transport of weakly polar and apolar organic compounds in soils irrigated with wastewater. The overall sorption capability of the DOM is governed by the level of hydrophobic fractions (HoA + HoN)! Netanya > Lachish

21 Pro Frac. mass CHN FTIR sum1 sorb atra atra PAH big sum2 move Poll. NMR amet SPME Relt Ilani, T., E. Schulz and B. Chefetz Interactions of Organic Compounds with Wastewater Dissolved Organic Matter: Role of the Hydrophobic Fractions. Journal of Environmental Quality. 34:

22 Background effluent High quality water Depth (cm) Depth (cm) [ 3] [ 5] [ 27] [ 13] [ 40] [ 20] [ 25] [ 1] [ 15] [21] Atrazine (µg/kg) After Graber et al., 1995 Atrazine (µg/kg)

23 PAHs and pesticides concentrations in the treated wastewater (ng/l; ppt) Napthalene Acenaphthylene Acenaphthene Fluorene Phenanthrene Antracene Fluoranthene Pyrene Beno[a]anthracen Chrysene Atrazine Terbutylazine Alachlor Diazinon Netanya Lachish

24 FTIR bands of dissolved organic matter Wavenumber (cm -1 ) Peak assignment H-bonds, OH groups Aromatic C-H stretch Symmetric and asymmetric aliphatic C-H stretch (CH 2, CH 3 ) OH stretch of H-bonds in COOH C=O stretch of COOH C=O stretch of aromatic COOH C=C-C of aromatic rings Symmetric stretch in COO -, N-H or C=N stretch in amide II -CH deformation of CH 3 and CH bending of CH 2 -C-H deformation of C-CH 3 groups -C-O stretch and OH deformation of carboxyl and phenols C-H of aromatic ring C-O-C stretch of ethers bonds -C-O stretch of polysaccharides

25 FTIR spectra of DOM fractions (Lachish) HoA>1000 HoA HoN>1000 HoN Absorbance wavenumber (cm -1 ) wavenumber (cm -1 )

26 13 C NMR characterization of the DOM fractions (>1000 Da) Chemical shift (ppm) C-containing groups paraffinic methoxyl C-O, C-N aromatic phenolic carboxyl HoN Lachish % of total C in the sample HoA Lachish HoA Netanya

27 Sorption exp. using SPME Free analyte DOM-Analyte GC/MS

28 Sorption exp. using SPME K DOC calculations: K DOC n 1,n 2 C DOC K DOC = n n C DOC = experimental sorption coefficient, determined by using SPME. = Extracted amount of analyte (fiber uptakes) from a DOM containing sample and from DOM-free solution sample, respectively. = Concentration of dissolved organic carbon (kg/l).

29 Relative K DOC K DOC % from DOM Relative K DOC HoA Netanya Phenantrene HoN Netanya HoA Lachish 9,374 2, HoN Lachish 8, Relative K DOC = K DOC f C( DOC)