Question

Data Interpretation and Analysis 135. Public water systems often add fluoride to drinking water because, in the proper amounts, fluoride improves dental health and prevents cavities. Too much fluoride, however can cause fluorosis, which stains teeth. In 2015, the U.S. Public Health Service (PHS) revised its 1962 recommenda- tions for the amount of fluoride in public water systems. The 1962 recommendations depended on the average temperature for the region in question as shown here. 1962 Fluoride Recommendations Annual Average Recommended Fluoride Air Temperatures Lower Optimum Upper Maximum Allowable Fluoride Concentration of Maximum Daily Concentration (mg/L) (mg/L) (oc) 10.0-12.0 12.1-14.6 14.7-17.7 17.8-21.4 21.5-26.3 26.4-31.5 2.4 2.2 2.0 1.8 1.6 1.4 1.2 0.9 0.8 1.1 1.5 0.8 1.0 1.3 0.7 0.9 1.2 0.7 0.8 1.0 0.6 0.7 0.8 1.7 The new recommendation is simply for municipalities to fluoridate public water systems at a level of 0.7 mg/L Notice that this level is at the lower end of previous rec- ommendations. The recommended level was lowered Answers to Skillbuilder Exercises 5 32 x 1022 Au atoms

Answer 1