Employee volunteering, knowledge integration, and career sustainability: the moderating role of competitive orientation.

Fluoride is a naturally occurring mineral in rocks, soils, and water. Globally, 2.5 billion people rely on groundwater for daily needs. The WHO recommended 1 ppm of fluoride in drinking water as optimal for preventing dental caries. However, in tropical regions like India, where water intake and natural fluoride levels are higher, concentrations below 1.0 ppm are considered safe. While fluoride is crucial for dental health, its excessive consumption is linked to severe health issues. These include skeletal and dental fluorosis, conditions that can also impair a child's cognitive development. The neurotoxic potential of excess fluoride exposure is well-documented, and there are studies showing that high levels may reduce intelligence quotient because of the effects of fluoride on the developing brain. As fluoride can readily cross the placental and blood–brain barriers, fetuses are particularly vulnerable to its effects, which can lead to disturbed brain development resulting in postbirth cognitive impairments. At higher concentrations, fluoride inhibits the enzymatic process, disturbing metabolism and physiological processes, which may have direct consequences on the nervous system and neurodevelopment. Fluorosis represents a severe public-health challenge in India, mainly in its rural settings, where the major source of drinking water comes from groundwater. Dental fluorosis represents an acute problem in the state of Tamil Nadu, while high prevalence was documented in districts such as Dharmapuri, Salem, Namakkal, and Krishnagiri. The effects of fluoride exposure are exacerbated by poor sanitation and hygiene practices, as well as malnutrition. The wide range of fluoride exposure in this region creates a unique opportunity to investigate the direct relationship between fluoride intake and children's intelligence quotient (IQ) scores. The current study aims to apply Raven's Colored Progressive Matrices (RCPM), a nonverbal test designed for children aged 5 through 11 years, to measure cognitive abilities and provide insights into the public health implications of fluoride exposure in this region. The study focuses on Salem District, where groundwater fluoride content varies widely, to investigate the potential relationship between fluoride exposure and IQ in children.