A wastewater sample contains two nitrogen species, namely ammonia and nitrate. Consider the atomic weight of $\text{N, H, and O}$ as $14\:g/mol$, $1\:g/mol$, and $16\:g/mol$, respectively. In this wastewater, the concentration of ammonia is $34\:mg\:NH_{3}/\text{liter}$ and that of nitrate is $6.2\:mg\:NO^{-}_{3} /\text{liter}$. The total nitrogen concentration in this wastewater is _____________   milligram nitrogen per liter. (round off to one decimal place)