MIT sleuths on trail of missing benzene  Call it "The Case of
the Missing Benzene."  The scene of the "crime" is the Halls
Brook Storage Area, a lake in the Aberjona watershed near
Boston. At a January 12 IAP talk, Ford Professor of Engineering
Philip Gschwend explained how during World War I, the production
of explosives near the lake also polluted the area -- and
eventually the lake -- with benzene, a component of the
explosives and a known carcinogen.  But when Professor Gschwend
and colleagues in the Department of Civil and Environmental
Engineering (CEE) began studying the benzene in the lake, they
made a surprising discovery: although benzene flows into the
lake every day via groundwater, the total amount present was
less than expected. Only small quantities of the chemical flow
out of the lake or go into the atmosphere, Professor Gschwend
said, so where is the missing benzene?  The researchers may have
solved the mystery. It appears that bacteria present in the lake
could be gobbling up the chemical. T