Tf. Rozan et G. Benoit, Mass balance of heavy metals in New Haven Harbor, Connecticut: Predominance of nonpoint sources, LIMN OCEAN, 46(8), 2001, pp. 2032-2049
A mass balance A as constructed quantifying all known sources and sinks for
the metals Ag, Cd, Cu, and Pb in New Ha en Harbor. Connecticut, USA. Sourc
es included direct atmospheric deposition, rivers, treated sewage effluent.
combined sewer overflows, and permitted industrial discharge. Sinks were b
urial in sediments, tidal exchange with Long Island Sound, removal in salt
marshes, and dredging. All of these fluxes were measured directly, rather t
han estimated, and uncertainties were quantified. The mass balance closed s
uccessfully within the uncertainty of the measurements. Riverine inputs acc
ount for most of the total yearly metal flux. Metal concentrations in the r
iver can he approximated is a simple linear function of discharge. Salt mar
shes remove an amount of metal equivalent to 20%-30% of the flux from the r
iver before it reaches the harbor. Burial in sediments is the major sink fo
r all metals examined, but dredging acts as a substantial short-circuit of
this sink. Tidal exchange appears to be a relatively small term: however, i
t is also the least well quantified. Sewage treatment plant (STP) effluent
and combined sewer overflow discharge are minor contributors to the overall
metal balance. except in the case of Ag. Metal concentrations in STP efflu
ent are a linear function of discharge. Atmospheric deposition is of minor
importance but is comparable to sewage effluent. Lakes can he used as natur
al collectors and indicators of atmospherically deposited metals.