Question

One water sample form a home in Flint had lead levels of 13,200 ppb (part per billion) (See Chemical & Engineering News; February 11, 2016; vol. 97; issues 7; pp 26-29). All samples from the same home had more than 300 ppb, even after flushing. The average of several samples that were taken from the home was 2,000 ppb. If ppm is equivalent to micrograms/liter, then how many grams of lead were in each liter of water? Why is it a problem when too much lead is in drinking water?

Answer 1

Ans. Note: 1 ppb = ug/ L               ; 1 ppm = 1 mg/ L

# Given, average lead concertation = 2000 ppb

                                                            = 2000 ug / L                                    ; [1 ug = 10^-6 g]

                                                            = 2000 x 10^-6 g/ L

                                                            = 2.0 x 10^-3 g/ L

                                                            = 0.002 g/ L

Therefore, average mass of Pb in 1.0 L water sample = 0.002 g

# Lead ay exert following toxicities –

I. May cause impaired neurological development in young children.

II. Lead is able to cross placenta. Once reaching the fetal circulation, it may cause poor fetal development, premature parturition, etc.

III. Impairs fertility in both males and females.

IV. May cause cancers upon prolonged exposure.