Widespread Risks of Dental Fluorosis in Cotton Rats (Sigmodon hispidus) Residing on Petrochemical Waste Sites

Abstract

Fluoride has been identified as a ubiquitous contaminant of soils where petrochemical wastes have been disposed. The purpose of this study was to assess how widespread toxicity risks are to resident vertebrates from chronic exposure to fluoride in the soil of petrochemical-contaminated waste sites. In total, 573 wild cotton rats (Sigmodon hispidus) were examined. The rats that were seasonally collected from 12 contaminated and 12 ecologically matched reference sites across Oklahoma over a 3-yr period. The risks of cotton rats exposed to fluoride were analyzed by means of gross examination, histopathology, and scanning electron microscopy of rat incisors. Cotton rats from reference sites showed no pathologic changes in incisors (98%). In comparison, 46% of cotton rats from contaminated sites had various degrees of dental lesions. The prevalence and severity of dental lesions in cotton rats from contaminated sites were significantly influenced by season. There was a 45% increase in prevalence and a 65% increase in severity of dental lesions from summer to winter. This study demonstrated that cotton rats are very sensitive biomonitors for assessing toxicity risks from soils contaminated with fluoride and that such assessments should consider seasonal influences.

Spatial distribution and temporal variation of high fluoride contents in groundwater and prevalence of fluorosis in humans in Yuanmou County, Southwest China

“…caries prevention) and bone growth [1][2][3][4], long-term excessive absorption of fluoride can lead to fluorosis of teeth and bones, and to a multitude of other health problems including negative impacts on the intellectual development of children [5][6][7][8]. High fluoride levels in humans result from exposure to numerous sources such as fluoride-emitting industries, burning of coal, volcanic ash, excessive fluoride in brick tea (tea compressed into block form), and fluoride contaminated drinking water [9][10][11][12]. Fluorosis is becoming a global environmental toxicological problem in a number of parts of the world [13], and is most commonly found in water-stressed regions [14,15].…”

Adsorptive Removal of Fluoride from Water Using Nanomaterials of Ferrihydrite, Apatite, and Brucite: Batch and Column Studies

“…However, because fluoride does not biodegrade, it accumulates in the soil and can leach out having detrimental impacts on the nearby terrestrial and aquatic ecosystems. Studies on fluoride exposures from the byproducts of petroleum refineries disclosed significant toxicological effects on sensitive keystone species such as the native Oklahoman, Cotton Rat (Propst et al, 1999;Kim et al, 2001;Schroder et al, 2003;Wake, 2005). Petrochemical byproduct disposal and other fluoride containing industrial wastes continues to threaten the environment.…”