Spatial Distribution of Mercury and Organochlorine Contaminants in Great Lakes Sea Lamprey ( Petromyzon marinus)

Abstract

Adult sea lamprey ( Petromyzon marinus) were collected during their spawning migration in streams entering each of the Great Lakes, except Lake Michigan. Skinless muscle tissue samples were analyzed for a range of organochlorine contaminants including p,p’-DDE, total PCB, toxaphene, and mercury. Concentrations of p,p’-DDE and PCBs were above the detection limit of 0.002 μg/g in all samples. Levels of total toxaphene in some individuals from Lake Superior were above recent Health Canada consumption advisory limits of 0.2 μg/g for fish. PCBs and ΣDDT concentrations in some lamprey tissue samples from the Lake Ontario basin exceeded limits for unrestricted human consumption. Mercury concentrations were highest in lamprey from the Lake Superior basin. Mercury levels were above the 0.5 μg/g Canada Health Protection Guideline for consumption in 75% of all the lamprey muscle tissue samples analyzed. Comparison of organic contaminant levels for lamprey muscle tissue samples and whole lake trout ( Salvelinus namaycush) collected from the same lakes showed patterns of contaminant accumulation that were similar within each lake for both species. Mercury concentrations were up to 10 times higher in lamprey muscle tissue samples than whole lake trout sampled from the same lake. Lamprey display a differential ability to accumulate mercury versus organochlorines. By understanding these relationships for different classes of contaminants, it may be possible to utilize lamprey as a future alternate to lake trout as an indicator species to track spatial and temporal contaminant trends in the Great Lakes.