Submitted to: Environmental Toxicology and Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 14, 2005
Publication Date: July 1, 2005
Citation: Chernyak, S.M., Rice, C., Quintal, R.T., Begnoche, L.J., Hickey, J.P., Vinyard, B.T. 2004. Time trends (1983-1999) for organochlorines and PBDEs in rainbow smelt (Osmerus mordax) from lakes Huron and Superior in Michigan. Environmental Toxicology and Chemistry. 24(7):1632-1641.
Interpretive Summary: Certain industrial and agricultural pollutants have a long history of accumulating in larger and fattier fish residing in the Great Lakes. This feature has become such a problem that the joint governments of the US and Canada have identified several "Contaminants of Concern" and have established cooperative cleanup and management policies to reduce their levels. The effectiveness of these programs is best assessed through monitoring for time trends in suitable indicator fish. Heretofore, lake trout has been the preferred indicator species. It is shown in this paper that smaller fish might provide more responsive information. To obtain the fish samples, archived composite of the rainbow smelt were analyzed. The compiled data indicated that all of the older established contaminants, PCBs, and organochlorine pesticides were declining similarly to trend data reported for lake trout by other researchers; however, an emerging problem contaminant, polybrominated biphenyl ether, was shown to be increasing and at rates faster than reported in lake trout from similar collection points. This faster increase suggests that these smaller fish may be better indicators of pollution trends, although they do have lower overall concentration levels which can hinder detection of low level residues.
The USGS Great Lakes Science Center has archived rainbow smelt (Osmerus mordax) collected from the early 1980s to the present. These fish were collected to provide time- and site-dependent contaminant residue data needed by researchers and managers to fill critical data gaps for trends and behavior of persistent organic contaminants in the Great Lakes ecosystem. In this study, data are presented on concentrations of several organochlorine (OC) contaminants in the archived smelt including DDTs, PCBs, toxaphene, and chlordanes in Lakes Michigan, Huron and Superior. The trend for all the OCs was found to be declining over the sampled time series (83/85 - 93/99) with the exception of toxaphene in lake Superior and PCBs at the Charlevoix/Little Traverse Bay site in Lake Michigan. Concentration of the emerging issue contaminant, polybrominated diphenyl ethers (PBDEs), was also traced from its apparent entry into this ecosystem from about 1980 until 1999. Time trends for the PBDEs were increasing exponentially at all of the sites, with concentration doubling times varying from 1.58 to 2.94 years.