Caffeine in Boston Harbor past and present, assessing its utility as a tracer of wastewater contamination in an urban estuary.

Sites throughout Boston Harbor were analyzed for caffeine to assess its utility as a tracer in identifying sources of sanitary wastewater. Caffeine ranged from 15ng/L in the outer harbor to a high of 185ng/L in the inner harbor. Inner harbor concentrations were a result of combined sewage overflow (CSO) events as well as illicit discharge of sanitary sewage into municipal storm drains.