Plant uptake data for risk assessments: laboratory and field experiments

Transcription

1 Plant uptake data for risk assessments: laboratory and field experiments Bill Doucette Utah Water Research Laboratory Utah State University Logan, Utah USA Transfer of organic pollutants from soils to plants University of Reading September 2007

2 Acknowledgements Crop Physiology Laboratory Bruce Bugbee, Julie Chard Utah Water Research Laboratory (UWRL) E Dettenmaier, R Winters, B Chard M Petersen, C Crouch, H Fabrizius, T Carlsen Funding Agencies Hill Air Force Base Air Force Center for Environmental Excellence National Water Research Institute, Canada UWRL

3 Outline Introduction Plant uptake perspective Uptake of TCE and transfer to fruit Field Study Laboratory study Generation of BCF and TSCF data Laboratory studies Lessons learned

4 Phytoremediation Trichloroethylene (TCE) Uptake Volatilization Metabolism

5 Descriptors of uptake (passive) Shoot Xylem BCF = = TSCF Soil Aqueous phase Chemical

6 Uptake (TSCF, BCF) vs. log Kow Briggs et al Travis and Arms, 1988 Hsu et al., 1990 Burken & Schnoor, 1992 Sicbaldi et al, 1997 Ciucani et al, 2002

7 Using TSCF to predict uptake Plant Uptake = (TSCF)(C C )(T) TSCF = transpiration stream concentration factor C C = chemical concentration in GW T = Transpiration ( L/m 2 -yr)

8 CCAS vs. HAFB ~50 cm/yr ~125 cm/yr ~1.5 m 2.3 m 1-10 mg/l TCE 1-10 mg/l Root depth profiles different. Tree core concentrations 100 X greater at HAFB

9 Using TSCF to predict uptake Plant Uptake = (TSCF)(C C )(T) ( f ) TSCF = transpiration stream concentration factor C C = chemical concentration in GW T = Transpiration ( L/m 2 -yr) f = fraction of GW used ( 1)

10 Variability of TSCF for TCE TSCF Factor log K ow Davis et al Burken & Schnoor 1998 Estimated Chard, 1999 Davis et al Orchard et al No standard method, variation in exposure system, duration, analysis

11 DIPA OH OH + H N H 2 N OH pk a = 9.1 OH S= 870 g/l, log K ow = Sulfolane O S O S= 1000 g/l, log K ow = -0.77

12 Final plant concentrations (mg/kg dry weight) DIPA Roots Sulfolane Exposure (20 mg/l) /(40 mg/l)

13 Plume Delineation Chlorinated Solvents BTEX Sulfolane Tree core conc. GW conc.

14 Uptake and transfer to fruits (field)

15 US view

16 Northern Utah HAFB

17 Hill Air Force Base, Utah Maintenance facility since the early 1940s Solvents releases investigated since ,670 acres on a plateau roughly 300 feet above the valley floor. Adjacent land use is residential and mixed agricultural, commercial and residential. 27 km 2

18 HAFB Operable UnitsN

19 Climate Semi-arid Annual precipitation 50 cm Elevation m Hill AFB OU2

20 Sampling: Fruit & tree cores Analysis: Headspace GC/MS Screening Level Risk Assessment: 15 ug/kg fresh wt

21 Year 1 Field Survey Results Sample Type Fruit Core Total Total samples collected a Detects above MDL b a Replicates included. Headspace GC/ECD & MS b 0.1 to 18 µg/kg fresh wt Note: no correlation between TCE tree core and fruit concentrations

22 Risk Assessment- Hilltop Times Headline

23 Summary of field survey results Sample type Total samples a (Year 1) Detects above MDL b Total samples (Year 2) Detects above MDL Total samples (Year 3) Detects above MDL Fruit (0.4 to 17.9) Trunk cores (0.4 to 7.5) (0.6 to 62) (0.4 to 204) Total a 17 locations in year 1, 31 in yr 2, and 5 in yr 3. Replicates included. b 0.1 ug/kg fresh weight

24 Summary Only fruit detects above MDL in Year 1 Environmental conditions? Tree age, irrigation patterns? Analysis method? Year 3 focus 5 locations, biweekly sampling Mature trees (20+ yrs) likely using GW Year 3 results No fruit detects Core TCE proportional to groundwater Core concentrations uniform to 6 m

25 Greenhouse Exposure System Watering line Tensiometer Soil water sampler Activated carbon [ 14 C]TCE/H 2 O Reservoir Charcoal trap Secondary container Secondary container Drip emitter [ Elevated Stand

26 Greenhouse D1fruit uptake C3 B2 photo A3 D3 F1 C1 A1 B3 C2 E1 D2 A2 B2 A: 5 µg/l apple B: 500 µg/l apple C: 5 µg/l peach D: 500 µg/l peach E: Control apple F: Control peach G: Control apple (2) H: Control peach (2)

27 Apple & peach photo

28 Comparing Peaches to Peaches Average [ 14 C] data 2 nd yr high/low (µg/kg fresh wt) Fruit flesh 44 / 0.6 Leaves 260 / 3.2 Branches 560 / 8.4 Irrigation water (µg/l) 690/ 5.3 Elevated Stand

29 Comparing Apples to Peaches average [ 14 C] 2 nd yr (µg/kg fresh wt) Elevated Stand 171 days 14 C [TCE] exposure 67 Fruit peel 23 Fruit flesh TCE <0.1 TCE <0.1 Branches TCE < Leaves* 259 TCE <0.1 Irrigation water TCE 690 *No statistical difference Elevated Stand 220 days 14 C [TCE] exposure

30 Early Stages of Fruit Development Similar phloem contribution and xylem contribution (some backflow during high ET demands) Later Stages of Fruit Development Large phloem contribution Small xylem contribution (Lang, A Xylem, phloem, and transpiration flows in developing apple fruits. J. Exp. Bot. 41: )

31 Control apple trees (no sulfolane added) Sulfolane in apple trees Leaves: 3700 mg/kg Apple: 16 mg/kg O S Treatment apple trees (100 ppm sulfolane added) O 30-day exposure: 55 mg/l

32 Tentative Hypothesis TCE (glycoside metabolite, trichloroethanol) Phloem Volatilization (TCE) sulfolane Xylem (TCE, sulfolane)

33 Summary Trees take up, metabolize, and volatilize TCE if utilizing contaminated groundwater. Field & lab data suggest TCE contamination of fruit unlikely due to volatilization losses. Identity & fate of 14 C metabolites not clear. Mature trees useful for identifying GW plumes.

34 Current focus

35 Results-Hydroponic Tomatoes Sulfolane 1 Sulfolane Sulfolane TSCF Exposure (days) Water Transpired 18 6 L L L Log K ow = Ripe Fruit (mg/kg) Leaves (mg/kg) Solution (mg/l) leaf edges showed toxic response 2 fresh wet 1,4-dioxane, t-butylalcohol, trichloroethanol also found in fruit

36 Results Pressure Chamber

37 Conclusions Pressure chamber vs. intact plants TSCF > Volatilization Metabolism Faster, less costly, more reproducible? Distribution

38 Conclusions TCE (glycoside metabolite, trichloroethanol) Phloem Volatilization (MTBE) Xylem (sulfolane, 1,4-dioxane) (sulfolane, 1,4-dioxane, MTBE)

39 Overall lessons learned Extrapolate lab to field? Artifacts associated with experimental setup, plant age, or exposure period Water source critical for uptake in field trees Combination of lab and field data More phytovolatilization & metabolism data Standard methods Work with plant people Uptake decreases with increasing log Kow Consider use of probe chemicals

40 UWRL Plant Uptake Database Microsoft Access Database View/Input/Edit functionality Data Types Physical Properties, 2D & 3D Structures Uptake Data (TSCF, BCF, RCF, Tissue Conc.) Literature/References (PDF) Plant Lipid Content (Values) Images (jpeg) Methods (Word Documents) Calculations (Excel)

41 Current Database Counts Item Count Compounds 246 TSCF Values 179 BCF Values 233 RCF Values 189 Tissue Conc. 479 Edible Tissue Conc. 51

42 Chemical/Physical Properties

43 View TSCF Values

44 TSCF by Technique

45 Thank you

46

47 References Doucette, WJ, Chard, JK, Fabrizius, H, Crouch, C, Petersen, M, Chard, B., Carlsen, T., Gorder, K Trichloroethylene Uptake into Fruits and Vegetables: Three-Year Field Monitoring Study. Environ. Sci. Technol. 41(7): Dettenmaier E, Doucette WJ Mineralization and Plant Uptake of 14C-Labeled Nonylphenol, Nonylphenol Tetraethoxylate, and Nonylphenol Nonylethoxylate In Biosolids/Soil Systems Planted with Crested Wheatgrass. Environ Toxicol Chem. 26(2): Henry, A.; Doucette, W.; Norton, J.; Bugbee, B., Changes in crested wheatgrass root exudation caused by flood, drought, and nutrient stress. Journal of Environmental Quality, 36, Chard, BK, Doucette, WJ, Chard, JK, Bugbee, B, Gorder, K Trichloroethylene Uptake by Apple and Peach Trees and Transfer to Fruit. Environ. Sci. Technol. 40(15): Henry, A.; Doucette, W.; Norton, J.; Jones, S.; Chard, J.; Bugbee, B., An axenic plant culture system for optimal growth in long-term studies. Journal of Environ Quality, 35, 590. Doucette, WJ, Wheeler, BR, Chard, JK, Bugbee, B, Naylor, CG, Carbone, JC, Sims, RC Uptake of Nonylphenol and Nonylphenol Ethoxylates by Crested Wheatgrass. Environ. Toxicol. Chem. 24(11): Doucette, W.J., Chard, J.K., Moore, B.J., Staudt, W.J., and Headley, J.V "Uptake Of Sulfolane And Diisopropanolamine (DIPA) By Cattails (Typha latifola)." Microchemical Journal. 81(1): Doucette, W.J. B. Bugbee, S Hayhurst, C. Pajak, J. S. Ginn Uptake, Metabolism, and Phytovolatilization of Trichloroethylene by Indigenous Vegetation: Impact of Precipitation in Phytoremediation. p Transformation and Control of Contaminants.S C. McCutcheon and J. L. Schnoor Eds. John Wiley and Sons, Inc. New York, NY.

48 Table3 TCE tree core conc

49 TCE in destructively sampled trees

50 Land application of biosolids Nonylphenol ethoxylates and nonylphenol

51 Screening-level risk assessment Concentrations above 15 ug/kg fresh weight raise regulatory concerns (carcinogenic effects) Exposure assumptions: Duration: 30 years (24 as an adult, 6 as a child), Body weight: 70 kg (adult) and 15 kg (child), Ingestion rate for fruit: 500 g/day Frequency: 350 days/year Averaging time of 70 years The California EPA oral slope factor of (mg/kg day -1 ) was used, and the target risk was 1x 10-6.

52 Hydroponic (TSCFs & distribution)

53 Soil column (BCFs)

54 Pressure Chamber

55 Results - pressure chamber

56 Results-Hydroponics 1,4-Dioxane TBA MTBE TCEt TSCF <MDL 0.15 Log Kow Exposure (days) Water Transpired 23.5 L 25 L 23 L 6 L Fruit <MDL 8.8 (mg/kg) 1 Leaves (mg/kg) 3.8 <MDL <MDL 175 Solution (mg/l) fresh wet

57 Benzene ,4-Dioxane ,2-Dichloroethene ,2-DCP ,2-DCE ,1,1-trichloroethane Trichloroethylene Trichloroethanol ,1,1-Trichloroethane ,1,2,2-Tetrachloroethane Tetrachloroethylene TBA Labeled Sulfolane Methylene Chloride MTBE ,2-Dichloropropane ,2-Dichloroethylene Cholorform Carbon Tetrachloride TSCF Log Kow Compound TSCF Log Kow Compound TCAA TCE Sulfolane Pyrene Phenanthrene NPE NPE NP Caffeine Benzene Atrazine Caffeine Toluene TCE PERC MTBE Chloroform Carbon Tetrachloride