Down by the river

It's 92 degrees. Your thighs are sticking together as you wait out your 90-minute un-air-conditioned lecture. Beads of sweat are oozing out of pores you didn't know existed.

But keep that perspiring chin up. The EPA just bumped the Charles River's D grade to a B+. Not bad, if you are willing to risk the remaining microbes and stormwater pollution still muddying the (in)famous waters.