Seasonal variation of polychlorinated biphenyl congeners in surficial sediment, trapped settling material, and suspended particulate material in Lake Michigan, USA.

A unique time series of surface sediment, trapped settling material, and suspended particulate material polychlorinated biphenyl (PCB) samples were collected at a 45-m deep site off Grand Haven (MI, USA) over a 14-month period. Both concentrations and congener distributions remained constant for the sediments, although there were seasonal and interannual variability in the other matrices. Trapped settling material and suspended particulate material PCB concentrations were substantially lower (~50%) in 1997 than in the samples from December 1997 through July 1998.

Comparing behavioral and chronic endpoints to evaluate the response of Lumbriculus variegatus to 3,4,3',4'-tetrachlorobiphenyl sediment exposures.

The response of Lumbriculus variegatus to 3,4,3',4'-tetrachlorobiphenyl (TCBP) was examined with feeding behavior and changes in carbon assimilation by using stable carbon isotopes at 22 and 10 degrees C. The classical measure of feeding behavior determined on a subset of sediment for which the biological burial rate was determined in a companion study allowed direct method comparison. This comparison helped address relationships between biological burial rate, feeding rate, and bioaccumulation.

Effect of 3,4,3',4'-tetrachlorobiphenyl on the reworking behavior of Lumbriculus variegatus exposed to contaminated sediment.

The reworking response (bioturbation) of the oligochaete Lumbriculus variegatus was measured by following the burial rate and spread of a 137Cs marker layer translating worm activity into a biological burial rate (Wb) and a biological diffusion rate constant (Db) for surficial sediment mixing. Reworking was measured at 10 and 22 degrees C in two sediments: a reference site sediment dosed with 3,4,3',4'-tetrachlorobiphenyl (TCBP) and a field-collected sediment from a polychlorinated biphenyl (PCB)-contaminated site in Dicks Creek (DCC, Middletown, OH, USA). The body residue associated with response to TCBP also was determined.

Episodic particle transport events controlling PAH and PCB cycling in Grand Traverse Bay, Lake Michigan.

To evaluate the influence of episodic events on particle and hydrophobic organic contaminant (HOC) cycling in the Great Lakes, we deployed sequencing sediment traps at two locations in the western arm of Grand Traverse Bay, Lake Michigan. The traps collected integrated samples of settling particles every 2 weeks from May 1997 to September 1999. The total polycyclic aromatic hydrocarbon (t-PAH) and total polychlorinated biphenyl (t-PCB) settling fluxes from the surface waters in the southern site were significantly greater than those from the northern site.