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RECENT DECLINES IN PAH, PCB, AND TOXAPHENE LEVELS IN THE NORTHERN GREAT LAKES AS DETERMINED FROM HIGH RESOLUTION SEDIMENT CORES. (R825151)
Citation:
Schneider, A. R., H. M. Stapleton, J. Cornwell, AND J. E. Baker. RECENT DECLINES IN PAH, PCB, AND TOXAPHENE LEVELS IN THE NORTHERN GREAT LAKES AS DETERMINED FROM HIGH RESOLUTION SEDIMENT CORES. (R825151). ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 35(19):3809-3815, (2001).
Description:
Sediment cores were collected from two sites in Grand Traverse Bay, Lake
Michigan in May 1998, dated using 210Pb geochronology, and analyzed
for polychlorinated biphenyl (PCB) congeners, polycyclic aromatic hydrocarbons
(PAHs), and toxaphene. The extraordinarily high sediment focusing and
accumulation rates in these cores relative to other Great Lakes sediments
allowed quantification of high-resolution temporal trends in the burial of
hydrophobic organic contaminants. The focus-corrected accumulation rate of total
PCBs (sum of 105 congeners) in 1998 was 0.50 ng/cm2-year at both
sites. Toxaphene and total PAH (t-PAH; sum of 33 compounds) surficial
accumulations varied at each site and ranged from 0.08 to 0.41
ng/cm2-year for toxaphene and 25 to 52 ng/cm2-yr for
t-PAHs at the two sites. The maximum t-PAH accumulation rate was
in sediment dated from 1942, and PAH accumulation decreased from 1942 to 1980
with a first-order rate of decline 0.017 yr-1. Both
toxaphene and t-PCB accumulations peaked in sediment deposited in 1972,
after which their accumulations decreased with nearly identical rates of decline
(0.027 yr-1 and 0.028 yr-1,
respectively).