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Recycled tire mulch is a common material found in playgrounds and landscaping. Exposures to varying temperatures, UV radiation, and acid rain may release toxicants into soil and surface waters. Exposure to these chemicals may contribute to declining amphibian populations. Xenopus laevis is highly sensitive to environmental toxicants during early developmental stages. Xenopus laevis embryos were placed in an isotonic saline solution or varying concentrations of tire mulch leachate. To create the leachate, shredded tire mulch was suspended in pH 5.6 isotonic saline and shaken at 200 rpm and 27oC for 48 hours. The final leachate solution was created by filtering out remaining particulates and bringing the solution’s pH to 7.7. The tadpoles were observed daily for 96 hours and data regarding malformations and mortality were recorded. We found that tadpoles exposed to increasing leachate concentrations had greater malformation and mortality numbers than those exposed to an isotonic solution. Further, leachate made from tire mulch weathered outdoors for one week caused notably increased larval mortality and malformation rates. Using mass spectroscopy, Triethyl Phosphate and 2-(3H)-benzothiazolone were isolated from the tire mulch residue. Further experiments will determine whether these chemicals are the primary leachate toxicants, and at what concentration they can be tolerated.


This is a metadata-only record.



  • Event location
    • Open 3rd Floor

  • Event date
    • 4 April 2013

  • Date submitted

    18 July 2022

  • Additional information
    • Acknowledgements:

      Dr. Nancy Eufemia Dalman