Chronic Effects of Fluoride Exposure on Growth, Metamorphosis, and Skeleton Development in Bufo gargarizans Larvae

Bull Environ Contam Toxicol. 2017 Apr;98(4):496-501. doi: 10.1007/s00128-017-2036-3. Epub 2017 Feb 14.


Bufo gargarizans tadpoles were chronically exposed to waterborne fluoride at measured concentrations ranging from 0.4 to 61.2 mg F-/L for 70 days from Gosner stage 26 to completion of metamorphosis. The chronic exposure caused a concentration-dependent mortality in all tested fluoride concentrations. Total length, snout-to-vent length (SVL), body mass, and developmental stage of tadpoles were significantly inhibited at 42.6 mg F-/L. In addition, significant metamorphic delay and increase in size at completion of metamorphosis occurred after exposure to 19.8 mg F-/L. Moreover, 19.8 mg F-/L suppressed the bone mineralization of larvae at completion of metamorphosis. However, the bone mineralization could be enhanced by 4.1 mg F-/L. In conclusion, our results suggested that the presence of high concentrations of fluoride could increase mortality risk, delay metamorphosis, and suppress skeletal ossification in B. gargarizans larvae.

Keywords: Bufo gargarizans; Fluoride; Growth; Metamorphosis; Skeletal ossification.

MeSH terms

  • Animals
  • Bufonidae*
  • Calcification, Physiologic / drug effects*
  • Fluorides / toxicity*
  • Larva / growth & development*
  • Metamorphosis, Biological / drug effects*
  • Water Pollutants, Chemical / toxicity*


  • Water Pollutants, Chemical
  • Fluorides