Johanna Diaz, D.V.M.


Education: Bachelor of Science in biology (May 2012)

Doctor of Veterinary Medicine from the Kansas State University

McNair Project: Roadside Plants as Metal Contaminant Indicators (2011)

Mentor: Deon Van der Merwe, Ph.D.

The use of plants to indicate environmental contaminants is a potential alternative to the use of chemical or physical tests. Typha spp., more commonly known as cattails, are of interest due to their tolerance of heavy metals, and their abundance in areas that are likely to become contaminated with elements that are washed from road surfaces, such as roadside ditches where runoff water accumulates and stagnates. To test the hypothesis that cattail stands grow in roadside areas that are more contaminated (as suggested by higher element concentrations) than other roadside areas, surface soil of 15 roadside cattail stands were compared to 43 control surface soil samples from roadsides without cattail stands. Samples were collected from roadside ditches next to paved roadways in Riley and Pottawatomie Counties, Kansas, USA. After nitric acid extraction, soil samples were analyzed for beryllium, magnesium, aluminum, potassium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, selenium, molybdenum, silver, cadmium, antimony, barium, thallium, and lead, using inductively coupled plasma mass spectrometry. Also, total organic contents were estimated gravimetrically following sample ashing. Four element concentrations differed significantly between cattail and control soils. Vanadium and magnesium were higher in cattail soil versus control soil. Barium and silver concentrations were higher in control soils. All other tested elements, and total organic contents, were not significantly different between cattail and control soil samples. The results did not support the hypothesis that cattails indicate roadside areas of increased elemental contaminant concentrations.