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The Effect of Chromium on Algal Populations

Investigating the effects of chromium runoff on aquatic life using Euglena as an experimental model. Results indicate significant impact on growth due to potassium chromate exposure.

carrollroberts
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The Effect of Chromium on Algal Populations

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  1. The Effect of Chromium on Algal Populations Peter Chekan Central Catholic High School Pittsburgh

  2. Surface Runoff • Flow of water from rain or snow melting • Soil's saturation level is filled to capacity • Water goes into rivers and lakes • Water picks up dangerous chemicals • Pesticide, insecticides, and chromium

  3. Chromium Runoff • Because of its solubility, it poses a threat to aquatic life. • It is often used in paints, dyes, and chrome plating.

  4. Chromium • 24th element in the periodic table. • Heavy metal • Soluble in water • Breaks up into ions • Hexaaquachromium or [Cr(H2O)6]3+. • Potassium Chromate

  5. Potassium Chromate • K2CrO4 • Yellow • Powder form • Soluble in water • Used as a solution in experiment

  6. Euglena • Protist • Single celled algae • Lives in fresh water • Oval shaped • Between 20-300μm long • Bottom of the food chain • Used as an experimental algal model

  7. Materials • Spectrophotometer • Test Tubes • Test Tube Rack • Potassium Chromate • Euglenasp. • Macro Pipettes • Micro Pipettes • Pipette tips • Spring Water

  8. Purpose Determine if chromium inhibits the growth of aquatic life To estimate the minimum concentration of potassium chromate detrimental to euglena

  9. Hypothesis • The potassium chromate concentrations will not significantly affect euglena population growth

  10. Procedure • The following experimental tubes were created

  11. Procedure Continued • The test tubes were placed in a dark room with a controlled source of light for 12 hours • All tubes were mixed by inversion prior to spectrophotometry • The absorbance of algae was measured everyday by a spectrophotometer using a wavelength of 430nm • Absorbance was recorded everyday for 20 days

  12. P=0.02227 P=.0067 P=.00676 P=.0068 P=.0052 P=.0041

  13. Conclusion • The Statistical analyses allow a rejection of the null hypothesis, indicating that potassium chromate can significantly effect euglenas population growth • All tested potassium chromate concentrations resulted in significant changes in the euglena populations

  14. Limitations/Extensions • Use lower concentrations of chromium • Use larger sample sizes • Test different types of algae • Test natural aquatic systems

  15. References • http://en.wikipedia.org/wiki/Euglena • http://en.wikipedia.org/wiki/Chromium • http://topsoil.nserl.purdue.edu/nserlweb/weppmain/overview/runoff.html • http://en.wikipedia.org/wiki/Surface_runoff • http://www.chemguide.co.uk/inorganic/transition/chromium.html • http://en.wikipedia.org/wiki/Potassium_chromate • http://www.jtbaker.com/msds/englishhtml/p5642.htm

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