Abstract
The present study examined the adverse effects of fluoride exposure on embryos and larvae of Rana chensinensis. Survival, morphological abnormalities, growth and development, time to metamorphosis and size at metamorphic climax of R. chensinensis were examined. Our results showed that embryos malformation occurred in all fluoride treatments. Morphological abnormalities of embryos are characterized by axial flexures, the extrusion of fin axis, edema, and ruffled dorsal and ventral fin. Additionally, 4.1mg F–/L and above could significantly inhibit embryos growth and development. On day 15, total length and weight of tadpole were significantly lower in 19.6 and 42.4mg F–/L treatments compared to control. However, significant reductions in total length and weight were observed only at 42.4mg F–/L on day 30. Moreover, significant metamorphic delay and decrease in the size at metamorphic climax were found in larvae exposed to 42.4mg F–/L. Taken together, embryos of R. chensinensis are more vulnerable to fluoride exposure than their tadpoles. Our results suggested that the presence of high concentrations fluoride might increase mortality risk and a reduction in juvenile recruitment in the field by increasing embryos malformation, delaying metamorphosis and decreasing size at metamorphosis.
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Impact of subchronic exposure to triclosan and/or fluoride on estrogenic activity in immature female rats: The expression pattern of calbindin-D9k and estrogen receptor a genes.
This study explored the influence of triclosan (TCS) in the absence and presence of sodium fluoride (NaF) on estrogenic activity and thyroid function of adolescent female rats. The results indicated that the individual exposure to TCS evoked a significant decline in T3 and T4 but the levels of estradiol, FSH,
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Fluoride in Drinking Water: A Scientific Review of EPA’s Standards.
Excerpts: Summary Under the Safe Drinking Water Act, the U.S. Environmental Protection Agency (EPA) is required to establish exposure standards for contaminants in public drinking-water systems that might cause any adverse effects on human health. These standards include the maximum contaminant level goal (MCLG), the maximum contaminant level (MCL), and the secondary
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Effect of fluoride on endocrine tissues and their secretory functions - review.
Highlights Fluoride induce e.g. oxidative stress, apoptosis and inflammation in endocrine tissues. Fluoride causes changes in the level of hormones released from endocrine tissues. Fluoride causes changes in the morphology of endocrine tissues. Abstract The effects of fluoride on endocrine tissues has not been sufficiently explored to date. The current body of
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Fluoride toxicity in the male reproductive system
This review covers the current scientific understanding of the links between environmental exposure to fluoride (F) and its known or potential effects on human male fertility. The most important consequences of these F exposures are: changes in the structure and functional behavior of spermatozoa, disruption of spermatogenesis, and disturbances of
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Necessity to Pay Attention to the Effects of Low Fluoride on Human Health: an Overview of Skeletal and Non-skeletal Damages in Epidemiologic Investigations and Laboratory Studies.
Due to the implementation of water improvement and fluoride reduction plans supported by central and local governments in recent years, areas with high fluoride exposure are being gradually decreased. Therefore, it is of practical importance to study the effect of low fluoride on human health. Epidemiologic investigations and in vivo
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Fluoride, Water Hardness, and Endemic Goitre
Variations in goitre prevalence were found to correlate closely with the fluoride content (p=0-74; P<0-01) and with the hardness (p=0.77; P<0-01) of the water in each village. The effects of fluoride and water hardness seem to be independent.
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Fluoride's Effect on Male Reproductive System: Animal Studies
Over 60 studies on animals (including rats, mice, roosters, and rabbits) have found that fluoride adversely impacts the male reproductive system. These studies have repeatedly found the following effects: (1) decreases in testosterone levels; (2) reduced sperm motility; (3) altered sperm morphology; (4) reduced sperm quantity; (5) increased oxidative stress; (6) and reduced capacity to breed.
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Fluoride's Effect on Male Reproductive System - Human Studies
Consistent with in vitro and animal research, studies of human populations have reported associations between fluoride exposure and damage to the male reproductive system. Most notably, a scientist at the Food & Drug Administration reported in 1994 that populations in the United States with more than 3 ppm fluoride in their water had lower "total fertility rates" than populations with lower fluoride levels.
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Fluoride's Effect on the Male Reproductive System -- In Vitro Studies
Carefully controlled in vitro studies have found that direct exposure of fluoride to the testes or semen inhibits testosterone production and damages sperm. While researchers have known since the 1930s that mega concentrations of fluoride can completely (but reversibly) immobilize sperm, it was not until the 1970s and 1980s that researchers found that relatively modest concentrations of fluoride could cause damage prior to complete immobilization.
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Fluoride's Effect on Male Reproductive System -- The "Sprando/Collins" Anomaly
In contrast to the findings of over 60 animal studies from other research teams, a series of studies by FDA researchers Sprando & Collins reported virtually no evidence of reproductive toxicity among animals treated with very high levels of fluoride exposure. The reasons for this discrepancy remains unclear. Excerpts from Sprando/Collins' Studies: "This study
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