Clausen, Lauge Peter Westergaard

Gosewinkel Karlson, Ulrich

Trapp, Stefan

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Downloaded from orbit.dtu.dk on: Dec 20, 2017Phytotoxicity of Sodium Fluoride and Uptake of Fluoride to Willow TreesClausen, Lauge Peter Westergaard; Gosewinkel Karlson, Ulrich; Trapp, StefanPublication date:2014Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Clausen, L. P. W., Gosewinkel Karlson, U., & Trapp, S. (2014). Phytotoxicity of Sodium Fluoride and Uptake ofFluoride to Willow Trees. Poster session presented at 11th International conference of Phytotechnologies,Heraklion, Crete, Greece.Fluoride (F) is present in pristine air, soil and water. As exposure to F through food and beverages is unavoidable, the effects of F on human and mammalian health have been intensely investigated. Due to continued use of super phosphate fertilizers, F accumulates in agricultural soils. However, little is known about the phytotoxicity of sodium fluoride (NaF) and the uptake of F when exposed through roots. The aim of this study is to:1) Assess the phytotoxicity of NaF to willows when taken up through    the roots2) Determine the uptake of F to willows when taken up through roots3) Describe the uptake of F to willows with a non-linear mass balance model Intro and scope• NaF is phytotoxic at levels of EC10: 38.0±34.2; EC20: 59.6±40.7 and EC50: 128±51 (values in mg F L-1±95% confidence interval)• Uptake of F can be described by a non-linear mass balance model assuming enzymatic removal• At external concentrations above 210 mg F L-1 the willows can no longer pump out F from the plant cells and start to accumulate F• Enzymatic removal of F and Cl from plant cells is likely to be managed by the same “pump”-systemPhytotoxicity of Sodium Fluoride and Uptake of Fluoride to Willow TreesLauge Peter Westergaard Clausen*1, Ulrich Gosewinkel Karlson2 and Stefan Trapp11Department of Environmental Engineering, Technical University of Denmark  2Department of Environmental Science, Aarhus University*Email: lpwc@env.dtu.dkExperimental setup – the willow tree tox testPhytotoxicity results Model description and outputConclusionsModel parameterization • 40 cm willow sticks (Salix viminalis) were pre-grown and transferred to Erlenmeyer flasks• Trees were exposed to solutions of various NaF concentrations• Test duration: 96 h• Normalized Relative Transpiration (NRT) used as test parameter:• Toxic effects observed within 48 h for conc. >100 mg F L-1• Clear dose-response relationship• No statistically significant difference between toxicity of 50 mg F L-1 and 100 mg F L-1• Wilting of the trees exposed to 400 mg F L-1• Maximal enzymatic removal rate, vmax: 9 g F kg-1 d-1• Breakthrough point (BTP): 210 mg F L-1 – On a molar basis the same as obtained by Trapp et al. (2008)* for chloride (Cl) • Uptake slope approx. 1 for C > BTP – unhindered transport with water The model assumes:• Steady state• Passive uptake of F with the transpiration stream • Enzymatic removal described by Michaelis-Menten kineticsRRRRRMRWRRRWRRMRRWRWM CvCkCkKKMQCKMQCKMCQCMQCKmax220 −−−−−+=Enzymatic removalUptake by transp. GrowthTranslocationKM) Half saturation constant;               Q) Transpiration; CW) Conc. in external solution; MR) Mass of roots; CR) Conc. in roots; KRW) Conc. ratio root/water;      kR) Root growth rate and vmax) Max. enzymatic removal rate see Trapp et al (2008)* where,100)0,0(/),0(1)0,(/),(1(%)),(11×=∑∑==mj jjni iiTtTmCTtCTntCNRTC) Conc.; t) Time period; T) Abs. transpiration; i and j) Replicate no.; n) No. of replicates; m) No. of controls see Trapp et al (2008)Where,Parameter Value Unit OriginConc. In solution, CW 0-400 mg L-1 MeasuredRoot mass, mR 0.001 Kg EstimatedTranspiration stream, Q 0.04 L d-1 Measured ave.Half-saturation constant, KM 2 g L-1 FittedMax. Enzymatic removal rate, vmax 8.992 g kg-1 d-1 FittedRoot growth rate, kR 0 d-1 EstimatedEquation Valid conc. R2 n PRegression 1 y = 0.128x – 5.186 C < 209.5 0.764 16 << 0.001Regression 2 y = 1.005x – 210.5 C > 209.5 0.790 8 < 0.005For more details, see: Lauge PW Clausen, Ulrich G Karlson and Stefan Trapp, 2014, Phytotoxicity of Sodium Fluoride and Uptake of Fluoride to Willow Trees, International Journal of Phytoremediation (In press)* Trapp S, Feificova D, Rasmussen N F, Bauer-Gottwein P, 2008, Plant uptake of NaCl in relation to enzyme kinetics and toxic effects, Environ. Exp. Bot., 64, 1-7

Phytotoxicity of Sodium Fluoride and Uptake of Fluoride to Willow Trees

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Phytotoxicity of Sodium Fluoride and Uptake of Fluoride to Willow Trees

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