Why were mottled teeth common in donora?

Mottled teeth common in donora due to the following

Explanation:

1.One investigator found that mottled teeth, characteristic of fluoride poisoning, were common in Donora.All the gases from Donora's mills, its furnaces and stoves, were unable to rise above the hilltops and began to fill the homes and streets of the town with a blinding fog of coal, coke, and metal fumes.

2.Horror visited the US Steel company-town of Donora on Halloween night, 1948, when a temperature inversion descended on the town. Fumes from US Steel's smelting plants blanketed the town for four days, and crept murderously into the citizens' homes.

If the smog had lasted another evening "the casualty list would have been 1,000 instead of 20," said local doctor William Rongaus at the time. Later investigations by Rongaus and others indicated that one-third of the town's 14,000 residents were affected by the smog. Hundreds of residents were evacuated or hospitalized. A decade later, Donora's mortality rate remained significantly higher than neighboring areas.

3.A PHS report released in 1949 reported that "no single substance" was responsible for the Donora deaths and laid major blame for the tragedy on the temperature inversion. But according to industry consultant Philip Sadtler, in an interview taped shortly before his 1996 death, that report was a whitewash. "It was murder," said Sadtler about Donora. "The directors of US Steel should have gone to jail for killing people." Sadtler charged that the PHS report helped US Steel escape liability for the deaths and spared a host of fluoride- emitting industries the expense of having to control their toxic emissions. (A class-action lawsuit by Donora victims families was later settled out of court.)

b..

is the correct one

explanation:

covalent bonds form as valence electrons are shared between two atoms. lewis structures and structural formulas are common ways of showing the covalent bonding in organic molecules. formal charge describes the changes in the number of valence electrons as an atom becomes bonded into a molecule.

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