Grantee Research Project Results

1999 Progress Report: Trophic Transfer of Atmospheric and Sedimentary Contaminants Into the Great Lakes Fisheries Controls on the Ecosystem Scale Response Times

EPA Grant Number: R825151
Title: Trophic Transfer of Atmospheric and Sedimentary Contaminants Into the Great Lakes Fisheries Controls on the Ecosystem Scale Response Times
Investigators: Baker, Joel E. , Ostrom, Nathaniel E. , Eadie, Brian , Hall, Don , Ostrom, Peggy , Coon, Tom
Institution: University of Maryland - College Park , Michigan State University , NOAA / GLERL
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1996 through September 30, 1999
Project Period Covered by this Report: October 1, 1998 through September 30, 1999
Project Amount: $617,254
RFA: Ecological Assessment (1996) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Aquatic Ecosystems

Objective:

During the past two decades, inventories of persistent, bioaccumulative organic contaminants have decreased dramatically in the Great Lakes ecosystem, clearly demonstrating the effectiveness of regulatory decisions about the production and use of certain classes of industrial and agricultural chemicals. For example, concentrations of polychlorinated biphenyls (PCBs) decreased in Great Lakes surface waters, surficial sediments, and fish during the 1970s and early 1980s in response to a restriction on PCB production in 1971. Initial rates of decline of PCBs in the Great Lakes were rapid during the 1970s and early 1980s, with pseudo first order rate constants of 0.2 year-1 for Lake Superior surface waters and ranging from 0.058 to 0.47 year-1 for fish. Clearly, the Great Lakes ecosystem responded favorably and, in retrospect, predictably to decreased loadings of PCBs. Unfortunately, the rate of decline in PCB levels in the Great Lakes ecosystem apparently has slowed during the second half of the 1980s, and the most recent data show little or no change in PCB levels in the Great Lakes fishery. This apparent stabilization of PCB levels near the Food and Drug Administration (FDA) advisory level (2 µg/g-wet tissue) is problematic for Great Lakes water quality managers. On one hand, the persistence of PCBs in Great Lakes fish has led to the call for additional regulations, as embodied in the Great Lakes Water Quality Guidance. Others have argued that the decrease in the rate of recovery of PCBs in the Great Lakes is a natural consequence of internal recycling and continental-scale atmospheric exchange, and that further regulations are neither cost effective or warranted.

The purpose of this study is to quantify the absolute and relative magnitudes of PCB transfers into the Great Lakes fisheries from three exposure routes: (1) atmospheric deposition transferred through the pelagic food web; (2) atmospheric deposition transferred, via rapidly settling particles, through the benthic food web; and (3) transfer from historically contaminated, in-place sediments through the benthic food web. This is being accomplished by using stable isotopes and PCBs as tracers of carbon and bioaccumulative contaminants, respectively, through the water column and food web of Grand Traverse Bay, an embayment of Lake Michigan. We hypothesize that each of these three routes differ both in their efficiencies of contaminant transfer and in their characteristic response times. This study will result in a quantitative, process-driven model of contaminant transfers in the Great Lakes food webs that distinguishes between new (i.e., regional atmospheric deposition) and in-place (i.e., recycling from contaminated sediments) sources of contaminants that support the slowly changing contaminant inventories in the highest trophic levels of the Great Lakes.

Progress Summary:

Intensive field work began in Grand Traverse Bay, Lake Michigan, in spring 1997, and is scheduled to be completed in August 1999. During both 1997 and 1998, cruises were conducted approximately monthly during the ice-free periods to collect surface water (dissolved and particulate chemical contaminants, seston), representative members of the food web (plankton, mysid, amphipods, sculpin, alewife, bloater, lake trout), air (gaseous and aerosol-bound chemical contaminants), settling particles (via sequencing sediment traps), and intact sediment cores. Sampling objectives were met in both years, with sufficient samples collected to quantify the seasonal dynamics of PCB transport and accumulation in the food web. Sequencing sediment traps have been deployed at two depths (just below the thermocline and 5 m above the bottom) at two locations in Grand Traverse Bay. These traps are programmed to collect sequential 2-week integrated settling particle samples.

To date, all water, air, and biota samples have been analyzed for PCB congeners. Stable isotope analysis of seston and food web members is nearly complete, as is the stomach analysis of the collected fish. Two sediment cores collected in 1998 have been radiodated using 210Pb and have been analyzed for PCB and polycyclic aromatic hydrocarbon (PAH) accumulation rates. Sediment traps have been retrieved through September 1998, with additional deployments continuing until late August 1999. All sediment traps samples have been split and analyzed for dry mass. Analysis of sediment trap material for PCBs, carbon, and isotopes is ongoing.

Although considerable data analysis is yet to be completed, results to date indicate the following:

PCB levels in forage fish undergo seasonal variations that are apparently driven by different processes. For alewife, PCB levels in tissue follow the seasonal dynamics of lipid production, storage, and consumption, with lowest body burdens observed in the late summer months. Bloater shift their diets from strictly Mysis relicta in the spring to a large proportion of amphipods and other prey species later in the summer. This shift maintains PCB levels nearly constant in bloater despite decreasing PCB levels in Mysis relicta during the summer. PCB levels in sculpin, a long-lived epibenthic fish, are constant throughout the year. Interestingly, PCB inventories in benthic amphipods increase in late fall, which may be a delayed response to settling of carbon- and PCB-rich particles during periods of maximum primary productivity in surface waters (pending stable isotope and algal pigment analysis will be used to test this explanation).

PCB and PAH levels and net accumulation rates in the sediments of Grand Traverse Bay have decreased during the past two decades, as determined by the high resolution geochronologies resulting from the sediment cores collected in the depositional basins of Grand Traverse Bay. The ecosystem-level rate of decrease of PCBs evidenced in these cores is slower than that observed in the water column, consistent with the hypothesis of intense PCB recycling and continual atmospheric inputs to the northern Great Lakes. (3) Seasonal 15N values in seston were high in the spring and declined through August. These 15N values reflect a balance between fractionation during assimilation of ammonium or nitrate and degradative processses.

Future Activities:

Work continues to complete laboratory analysis of the samples collected in this study. Although all biota analysis is nearly complete, considerable work remains to analyze the sediment trap samples (we extended the length of the sequencing sediment trap deployment through August 1999 so that the sampling record could extend over three summers). Data synthesis and integration continues, including preparing the manuscripts listed above. A no-cost extension has been requested to allow completion of these analyses.

Journal Articles on this Report : 5 Displayed | Download in RIS Format

Publications Views
Other project views:	All 34 publications	5 publications in selected types	All 5 journal articles

Publications
Type	Citation	Project	Document Sources
Journal Article	Feuerstein TP, Ostrom PH, Ostrom NE. Isotopic biogeochemistry of dissolved organic nitrogen: a new technique and application. Organic Geochemistry 1997;27(7-8):363-370.	R825151 (1999)	Full-text: ScienceDirect-Full Text HTML Exit Other: ScienceDirect-PDF Exit
Journal Article	McCusker EM, Ostrom PH, Ostrom NE, Jeremaison JD, Baker JE. Seasonal variation in the biogeochemical cycling of seston in Grand Traverse Bay, Lake Michigan. Organic Geochemistry 1999;30(12):1543-1557.	R825151 (1999)	Full-text: Science-Direct-Full Text HTML Exit Other: ScienceDirect-PDF Exit
Journal Article	Schneider AR, Stapleton HM, Cornwell J, Baker JE. Recent declines in PAH, PCB, and toxaphene levels in the northern Great Lakes as determined from high resolution sediment cores. Environmental Science & Technology 2001;35(19):3809-3815.	R825151 (1999)	Abstract from PubMed Abstract: ACS-Abstract Exit
Journal Article	Stapleton HM, Masterson C, Skubinna J, Ostrom P, Ostrom NE, Baker JE. Accumulation of atmospheric and sedimentary PCBs and toxaphene in a Lake Michigan food web. Environmental Science & Technology 2001;35(16):3287-3293.	R825151 (1999)	Abstract from PubMed Abstract: ACS-Abstract Exit
Journal Article	Stapleton HM, Skubinna J, Baker JE. Seasonal dynamics of PCB and toxaphene bioaccumulation within a Lake Michigan food web. Journal of Great Lakes Research 2001;28(1):52-64.	R825151 (1999)	Full-text: ScienceDirect-PDF Exit Abstract: ScienceDirect-Abstract Exit

Supplemental Keywords:

PCBs, PAHs, sediment traps, sediment cores, Great Lakes, Grand Traverse Bay, Lake Michigan, MI, Michigan., RFA, Scientific Discipline, Water, Waste, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Nutrients, Environmental Chemistry, Contaminated Sediments, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, Chemical Mixtures - Environmental Exposure & Risk, Ecological Effects - Environmental Exposure & Risk, Environmental Monitoring, Air Deposition, Ecological Effects - Human Health, Ecology and Ecosystems, Atmospheric Sciences, Ecological Risk Assessment, Ecological Indicators, Great Lakes, aquatic ecosystem, fate and transport, hydrological stability, ecological exposure, fate, carbon cycling, ecosystem assessment, sediment contaminant effects, trophic transfer, response times, contaminated sediment, organic contaminant transfers, benthic food web, chemical contaminants, atmospheric nitrogen deposits, biological integrity, nutrient stress, ecological assessment, polychlorinated biphenyls, regional scale, ecosystem stress, fish , atmospheric contaminants, Lake Michigan, benthic nutrients, bioaccumulation, atmospheric deposition

Progress and Final Reports:

Original Abstract

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.