What is the concentration of the LD50 in ppm? ?

Question

Orally it is toxic in excess; the LD50 is around 2500 milligram/kg (meaning that a person weighing 75 kg (165 lb) would have to consume about 190 g (6.7 ounces); regular salt is about as toxic). Intravenously this is reduced to just over 100 mg/kg but of more concern are its severe effects on cardiac muscles; high doses can cause cardiac arrest and rapid death.

Answer 1

What is ppm?  The LD50 for salt is 3000.

Answer 2

ppm stands for parts per million.

1 kilogram is 1000 grams, 1 gram is 1000 milligrams, so 1 kilogram is one million milligrams.

Therefore, by mass, if you have an LD50 in mg/kg, that same number is the LD50 in ppm -- 2500 mg in 1 million mg = 2500 ppm.