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Zn Ecotoxicological Endpoints in Metal Contaminated Soils Gary Pierzynski, Arline Novak, and Walter Fick Kansas State University.

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Presentation on theme: "Zn Ecotoxicological Endpoints in Metal Contaminated Soils Gary Pierzynski, Arline Novak, and Walter Fick Kansas State University."— Presentation transcript:

1 Zn Ecotoxicological Endpoints in Metal Contaminated Soils Gary Pierzynski, Arline Novak, and Walter Fick Kansas State University

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5 Objectives Assess the potential for Zn phytotoxicity in the Tri-State Mining region through field and greenhouse studies Evaluate the use of diffusive gradients in thin film (DGT) for the assessment of Zn bioavailability to plants

6 Methods – Field Study Eight 100 m transects laid out in areas impacted by mine wastes Plant community structure was assessed every 5 m in 0.5 m 2 frames in June 2002 –Species identification –Relative abundance of each species –Soil samples collected from 0-5 and 5-10 cm around perimeter of each frame Biomass production determined every 10 m in October 2002

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13 Total ZnNo. SpeciesBiomass Dominant Species - mg/kg --- kg/ha -- >20003.3a973aC. Ragweed <20006.2b1328bB. Bluestem >10003.9a978aC. Ragweed <10007.2b1436bB. Bluestem >5004.0a1000aC. Ragweed <5007.6b1532bB. Bluestem

14 SamplenNo. SpeciesDominant Species Chat,>2000653.5aC. ragweed, moss Chat,<200054.8aS. sumac, G. goldenrod Soil, >2000434.7aC. ragweed, moss Soil, <2000476.3bB. bluestem, L. bluestem

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18 Methods – Greenhouse Sand/nutrient cultures –Zn sources: ZnSO 4, chat, smelter slag –Zn sources mixed with sand to provide a wide range of Zn concentrations –Big bluestem, pigweed, switchgrass –Zn bioavailability assessed with DGT and 0.1 M Ca(NO 3 ) 2 extraction

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22 ZnSO 4 -Pigweed Chat - Pigweed

23 ZnSO 4 – Big bluestem Chat – Big bluestem

24 Chat - Switchgrass Chat – Big bluestem

25 ZnSO 4 – Big bluestem - Fe ZnSO 4 – Big bluestem - P

26 Chat – Big bluestem - Fe Chat – Big bluestem - P

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29 Critical values for 75% of control yield – Big bluestem --------------- critical value ------------- Zn SourceTotal ZnDGT ZnCa(NO 3 ) 2 Shoot Zn - mg/kg --umol/L------- mg/kg ------ Chat5547a1592a195a352ab Dearing6901a600b163a185b ZnSO 4 61b1292a81b600a

30 Critical values for 75% of control yield – Pigweed --------------- critical value ------------- Zn SourceTotal ZnDGT ZnCa(NO 3 ) 2 Shoot Zn - mg/kg --umol/L------- mg/kg ------ Chat4127b1438a174b1210a Dearing10062a583b213a1237a ZnSO 4 44b1204a55c1607a

31 Critical values for 75% of control yield – Switchgrass --------------- critical value ------------- Zn SourceTotal ZnDGT ZnCa(NO 3 ) 2 Shoot Zn - mg/kg --umol/L------- mg/kg ------ Chat2216a700a121a220a Dearing3360a379a103a208a ZnSO 4 23b558a24a244a

32 Conclusions Field data suggest that Zn may play a role in species richness, species present, and biomass production. Greenhouse data indicate Zn phytotoxicity can be induced with mine wastes. DGT was superior to batch extractions Further evaluation of DGT for assessment of ecotoxicologial endpoints is warranted


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