Question:
I need to know the mercury concentration in mg/L or ng/L for the following:

-log M (Hg) = 8.5

where mw of Hg=200.59

(it's the negative sign in front of log that confuses me).

thanks
Brenda

Hi Brenda,

I am not sure what you are doing but I can interpret the negative sign in front of the log. It comes from the fact that log(a^b) = b log(a). In your case you have b = -1 so -log(a) = (-1) log(a) = log(a^-1) = log(1/a)

Cheers
Harley