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Zn Ecotoxicological Endpoints in Metal Contaminated Soils. Gary Pierzynski, Arline Novak, and Walter Fick Kansas State University. Objectives. Assess the potential for Zn phytotoxicity in the Tri-State Mining region through field and greenhouse studies
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Zn Ecotoxicological Endpoints in Metal Contaminated Soils Gary Pierzynski, Arline Novak, and Walter Fick Kansas State University
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
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 m2 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
Methods – Greenhouse • Sand/nutrient cultures • Zn sources: ZnSO4, 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(NO3)2 extraction
Chat - Pigweed ZnSO4 -Pigweed
Chat – Big bluestem ZnSO4 – Big bluestem
Chat – Big bluestem Chat - Switchgrass
ZnSO4 – Big bluestem - P ZnSO4 – Big bluestem - Fe
Chat – Big bluestem - P Chat – Big bluestem - Fe
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