Bill DoucetteUtah Water Research Laboratory

Utah State UniversityLogan, Utah USA

Plant uptake data forrisk assessments:

laboratory and fieldexperiments

Transfer of organic pollutants from soils to plantsUniversity of Reading25-26 September 2007

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

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

PhytoremediationTrichloroethylene (TCE)

UptakeVolatilizationMetabolism

Descriptors of uptake (passive)

= TSCFBCF =

Soil

Shoot Xylem

Aqueous phase

Chemical

Uptake (TSCF, BCF) vs. logKow

Briggs et al. 1982 Travis and Arms, 1988• Hsu et al., 1990• Burken & Schnoor, 1992• Sicbaldi et al, 1997• Ciucani et al, 2002

Using TSCF to predict uptake

Plant Uptake = (TSCF)(CC)(T)

TSCF = transpiration stream concentration factorCC = chemical concentration in GWT = Transpiration (200 - 1400 L/m2-yr)

TCE 1-10 mg/L1-10 mg/L

~50 cm/yr

~125 cm/yr

2.3 m~1.5 m

CCAS vs. HAFB

Root depth profiles different.Tree core concentrations 100 X greater at HAFB

Using TSCF to predict uptake

Plant Uptake = (TSCF)(CC)(T) ( f )

TSCF = transpiration stream concentration factorCC = chemical concentration in GWT = Transpiration (200 - 1400 L/m2-yr)f = fraction of GW used (≤ 1)

0

0.2

0.4

0.6

0.8

1

-1 0 1 2 3 4 5log Kow

Tra

nsp

irati

on

Str

eam

Co

ncen

trati

on

Facto

r Estimated

Orchard et al. 2000

Chard, 1999

Burken & Schnoor 1998

TSCF

Davis et al. 1998

Variability of TSCF for TCE

Davis et al. 1998

No “standard” method, variation in exposure system, duration, analysis

S

O

O

S= 1000 g/L, log Kow = -0.77

S= 870 g/L, log Kow = -0.86

pKa = 9.1

HN

OH

OH

H2N

OH

OH

+

DIPA

Sulfolane

Final plant concentrations(mg/kg dry weight)

DIPA

Roots

Sulfolane

Exposure (20 mg/L) /(40 mg/L)

46

48

143

5310

17

17.9

7.5

1.6

Plume Delineation

Treecoreconc.

GW conc.

Chlorinated SolventsBTEXSulfolane

Uptake andtransfer to fruits

(field)

US view

Northern Utah

HAFB

• Maintenance facility since the early 1940s• Solvents releases investigated since 1976• 6,670 acres on a plateau roughly 300 feet above

the valley floor.• Adjacent land use is residential and mixed

agricultural, commercial and residential.

Hill Air Force Base, Utah

27 km2

HAFB Operable UnitsN

Hill AFBOU2

• Climate– Semi-arid– Annual precipitation 50 cm

• Elevation– 1400-1500 m

Analysis:Headspace GC/MS

Sampling:Fruit & tree cores

Screening Level Risk Assessment: 15 ug/kg fresh wt

Year 1 Field Survey Results

28167Total1364Core15103Fruit

DetectsaboveMDLb

Totalsamples

collecteda

SampleType

a Replicates included. Headspace GC/ECD & MSb0.1 to 18 µg/kg fresh wtNote: no correlation between TCE tree core andfruit concentrations

Risk Assessment- HilltopTimes Headline

Summary of field survey results

934131031528167Total

93(0.4 to 204)

26410(0.6 to 62)

5813(0.4 to 7.5)

64Trunkcores

0149025715(0.4 to 17.9)

103Fruit

DetectsaboveMDL

Totalsamples(Year 3)

DetectsaboveMDL

Totalsamples(Year 2)

DetectsaboveMDLb

Totalsamplesa

(Year 1)

Sampletype

a17 locations in year 1, 31 in yr 2, and 5 in yr 3. Replicates included.b0.1 ug/kg fresh weight

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

Secondarycontainer

Soil watersampler

Secondarycontainer

[

Tensiometer

Activated carbon

Elevated Stand

[14C]TCE/H2OReservoir

Charcoaltrap

Watering line

Drip emitter

GreenhouseExposure System

Greenhouse fruit uptakephoto

C3B2

C1

A1

D2

B2

D1

A3

D3

B3

C2

A2

E1

F1

A: 5 µg/L appleB: 500 µg/L apple

E: Control appleF: Control peach

C: 5 µg/L peachD: 500 µg/L peach

G: Control apple (2)H: Control peach (2)

Apple & peach photo

Average [14C] data 2nd yrhigh/low (µg/kg fresh wt)

Comparing Peaches to Peaches

Fruit flesh44 / 0.6Leaves260 / 3.2

Branches560 / 8.4

Elevated Stand

Irrigationwater (µg/L)

690/ 5.3

Fruit peel

Fruit flesh

Branches

Leaves*

Irrigationwater

67

483

64

562

1210 259

626 606

*No statistical difference

Elevated Stand

171 days 14C [TCE]exposure

Elevated Stand

220 days 14C [TCE]exposure

TCE <0.1

TCE <0.1

TCE <0.1

TCE 690

Comparing Apples to Peachesaverage [14C] 2nd yr (µg/kg fresh wt)

23 44TCE <0.1

Early Stages of Fruit DevelopmentSimilar phloem contribution and xylem contribution(some backflow during high ET demands)

Later Stages of Fruit Development

Large phloem contributionSmall xylem contribution

(Lang, A. 1990. Xylem, phloem, and transpiration flowsin developing apple fruits. J. Exp. Bot. 41:645-651.)

Control apple trees(no sulfolane added)

Treatment apple trees (100 ppm sulfolane added)

Sulfolane in apple trees

Leaves: 3700 mg/kg

30-dayexposure:55 mg/L

Apple: 16 mg/kgS

O

O

Xylem

Volatilization(glycoside metabolite, trichloroethanol)

(TCE, sulfolane)

(TCE)

Tentative Hypothesis

Phloem

sulfolane

TCE

Summary• Trees take up, metabolize, and volatilize TCE if

utilizing contaminated groundwater.

• Field & lab data suggest TCE contamination offruit unlikely due to volatilization losses.

– Identity & fate of 14C metabolites not clear.

• Mature trees useful for identifying GW plumes.

Current focus

1leaf edges showed toxic response2fresh wet

110100Solution(mg/L)

896072400Leaves(mg/kg)

1.741140Ripe Fruit(mg/kg)

25 L25 L6 LWaterTranspired

424218Exposure(days)

0.710.550.79TSCF

SulfolaneSulfolaneSulfolane1

Results-Hydroponic Tomatoes

Log Kow = -0.77

1,4-dioxane, t-butylalcohol, trichloroethanol also found in fruit

Results Pressure Chamber

>TSCF

VolatilizationMetabolism

Faster, less costly,more reproducible?

Distribution

ConclusionsPressure chamber vs. intact plants

Xylem

Volatilization(glycoside metabolite, trichloroethanol)

(sulfolane, 1,4-dioxane, MTBE)

(MTBE)

Conclusions

Phloem

(sulfolane,1,4-dioxane)

TCE

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

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)

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

Chemical/Physical Properties

View TSCF Values

TSCF by Technique

Thank you

References• Doucette, WJ, Chard, JK, Fabrizius, H, Crouch, C, Petersen, M, Chard, B., Carlsen, T., Gorder, K.

2007. Trichloroethylene Uptake into Fruits and Vegetables: Three-Year Field Monitoring Study.Environ. Sci. Technol. 41(7):2505-2509.

• Dettenmaier E, Doucette WJ. 2007. Mineralization and Plant Uptake of 14C-Labeled Nonylphenol,Nonylphenol Tetraethoxylate, and Nonylphenol Nonylethoxylate In Biosolids/Soil Systems Planted withCrested Wheatgrass. Environ Toxicol Chem. 26(2):193-200.

• Henry, A.; Doucette, W.; Norton, J.; Bugbee, B., 2007. Changes in crested wheatgrass root exudationcaused by flood, drought, and nutrient stress. Journal of Environmental Quality, 36, 904-912.

• Chard, BK, Doucette, WJ, Chard, JK, Bugbee, B, Gorder, K. 2006. Trichloroethylene Uptake by Appleand Peach Trees and Transfer to Fruit. Environ. Sci. Technol. 40(15):4788-4793.

• Henry, A.; Doucette, W.; Norton, J.; Jones, S.; Chard, J.; Bugbee, B., 2006. An axenic plant culturesystem 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. 2005. Uptakeof Nonylphenol and Nonylphenol Ethoxylates by Crested Wheatgrass. Environ. Toxicol. Chem.24(11):2965-2972.

• Doucette, W.J., Chard, J.K., Moore, B.J., Staudt, W.J., and Headley, J.V. 2005. "Uptake Of SulfolaneAnd Diisopropanolamine (DIPA) By Cattails (Typha latifola)." Microchemical Journal. 81(1): 41-49.

• Doucette, W.J. B. Bugbee, S Hayhurst, C. Pajak, J. S. Ginn. 2003. Uptake, Metabolism, andPhytovolatilization of Trichloroethylene by Indigenous Vegetation: Impact of Precipitation inPhytoremediation. p. 561-588. Transformation and Control of Contaminants .S C. McCutcheon and J. L.Schnoor Eds. John Wiley and Sons, Inc. New York, NY.

Table3 TCE tree core conc

TCE in destructivelysampled trees

Nonylphenol ethoxylatesand nonylphenol

Land application of biosolids

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 0.013 (mg/kg day-1) wasused, and the target risk was 1x 10-6.

Hydroponic (TSCFs & distribution)

Soil column (BCFs)

Pressure Chamber

Results - pressure chamber

6234230Exposure(days)

100

175

8.8

6 L

1.42

0.15

TCEt

0.940.0005-0.27Log Kow

1fresh wet

100104.1Solution(mg/L)

<MDL<MDL3.8Leaves(mg/kg)

<MDL0.80.7Fruit(mg/kg)1

23 L25 L23.5 LWaterTranspired

<MDL0.010.016TSCF

MTBETBA1,4-Dioxane

Results-Hydroponics

0.82.13Benzene

1.0-0.271,4-Dioxane

0.82.01,2-Dichloroethene

0.91.981,2-DCP

0.82.091,2-DCE

0.72.491,1,1-trichloroethane

0.52.42Trichloroethylene

1.11.42Trichloroethanol

0.52.491,1,1-Trichloroethane

0.52.391,1,2,2-Tetrachloroethane

0.43.4Tetrachloroethylene

1.00.35TBA Labeled

1.3-0.77Sulfolane

0.61.25Methylene Chloride

0.91.24MTBE

0.61.981,2-Dichloropropane

0.52.091,2-Dichloroethylene

0.51.97Cholorform

0.52.83Carbon Tetrachloride

TSCFLogKow

CompoundTSCFLog

KowCompound

0.21.33TCAA

0.62.42TCE

1.0-0.77Sulfolane

0.04.88Pyrene

0.24.46Phenanthrene

0.33.0NPE9

0.23.1NPE4

0.24.2NP

0.8-0.07Caffeine

0.82.13Benzene

0.72.61Atrazine

0.8-0.07Caffeine

0.72.73Toluene

0.72.42TCE

0.53.4PERC

1.00.94MTBE

0.91.97Chloroform

0.62.83Carbon Tetrachloride