Normal water fluoride level in mg/L:
Ans: (0.5 - 0.8) Ref: Textbook of preventive and social medicine, K. Park, 22nd edition page no 579Explanation:Normal flouride level is 0.5 to 0.8 mg/1.Increased level causes dental and skeletal flurosisModerate amounts lead to dental effectsLong-term ingestion of large amounts can lead to potentially severe skeletal problemsLow levels of fluoride intake help to prevent dental cariesThe dental effects of fluorosis develop much earlier than the skeletal effects in people exposed to large amounts of fluoride (See Following tables) Gold standard disease positiveGold standard disease negative Test positiveA (true positive)B (false post five)Total test positiveTest negativeC (false negative)D (true negative)Total test negative Total diseased (a+c)Total normal (B+D)Total population (A+B+C+D) Dental flurosisSkeletal flurosisWater Level of fluorineHigh >2mg/lVery high (3-6mg/l or more)DurationEarlyLateOnset of symptomsDuring early age for 1-2 yearsFor lifetime exposureTimingwhen the teeth are forming under the gums (<8 years age) SymptomsStaining and pitting of the teeth, enamel damageStiffness and pain in the joints, bone structure may change and ligaments may calcify, impairment in muscle activity and painAcute high-level exposure to fluoride causes immediate effects of abdominal pain, excessive saliva, nausea and vomiting. Seizures and muscle spasms may also occur.Control:Removal of excessive fluoride from drinking- water is difficult and expensive.The preferred option is to find a supply of safe drinking-water with safe fluoride levels.Where access to safe water is already limited, de-fluoridation is the solutionDifferent de-fluoridation techniques: Use of bone charcoal, contact precipitation, use of Nalgonda (aluminum sulfate used) or activated alumina.Only water for drinking and cooking purposes should be treated as all methods produce sludge with very high concentration of fluoride.
0.5-0.8
1.5-2.0
0.05-0.08
8-May
Environment and Health