read the following information prepare any two question.
pharmaceutical and personal care products including medications lation and soap are being found in increasing concertration in lakes and rivers causing water pollution hazardous substance like fluorine mixed in ground water cause dangerous diseases called fluorosis
Answers
Fluorine is a univalent gaseous halogen, pale yellow-green in color and most chemically reactive electronegative of all other elements [1]. In aqueous solution fluorine is commonly found as fluoride (F-). Fluorine is the world's 13th most abundant element and constitutes 0.08% of the earth crustand the lightest member of the halogen group. Soil contains approximately 330 ppm of fluorine. Small amount of fluorine is naturally present in the water, air, plants and animals. As a result humans are exposed to fluorine through food, drinking water and breathing air. Fluorine is essential for the maintenance and solidification of our bones and prevents dental decay. However, if it is absorbed too frequently, it may act in reverse way causing teeth decay, osteoporosis and harm to kidney, bone, nerve and muscle also. According to WHO Guidelines for Drinking-water Quality, the optimal value of fluoride in drinking water is 1.5 mg l–1. Fluorine being the most electronegative of all the elements, possess a strong tendency to acquire a negative charge and in solution forms F– ions. Fluoride ions have the same charge and nearly the same radius as hydroxide ions and may replace each other in mineral structures [2]. Fluoride is one of the very few that has been shown to cause significant effects in population through many ways viz. drinking water, air, dental products, food, beverages and salts. It has beneficial effects on teeth & bones when it is present at low concentration in drinking water, but excessive exposure to fluoride in drinking-water, or in combination with other sources, can give rise to a number of adverse effects. The adverse effects range from mild dental fluorosis to crippling skeletal fluorosis as the level and period of exposure increases. Crippling skeletal fluorosis is a significant cause of morbidity in a number of regions of the world. From several studies, it was observed that the average daily dietary intake of fluoride by children residing in fluoridated (1 ppm) communities is 0.05 mg/kg/day; in communities without optimally fluoridated water, average intakes for children are about 50% lower. Dietary fluoride intake by adults in fluoridated (1 ppm) areas averages 1.4-3.4 mg/day while in non-fluoridated areas it averages 0.3-1.0 mg/day [3]. Fluorosis affects nearly one in every four Americans aged 6 to 49 years. It is the most prevalent in the ages between 12 to 15 years. A major cause of fluorosis is the inappropriate use of fluoridecontaining dental products such as toothpaste and mouth rinses [4]. Our concern while writing this review remains with how we can get the beneficial effects of fluoride without being exposed to the adverse consequences of using excess of it in the modern day.
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