Effects of multiple effluents on resident fish from Junction Creek, Sudbury, Ontario

Junction Creek in Sudbury, Ontario, Canada receives effluent from three metal mining effluents (MMEs), as well as urban run-off and municipal sewage treatment plant (STP) discharges. The present study examined organismal and sub-organismal end-points in prespawning fathead minnow (FHM; Pimephales promelas) and creek chub (CC; Semotilus atromaculatus) collected in May 2004 from Junction Creek. Metal body burdens of Cd, Cu, Rb, Se, and Sr increased in a gradient down Junction Creek in both species. In general, male fish had lower body weights downstream of effluents, while females were unchanged or larger compared to reference fish. Livers were larger in FHM of both sexes downstream of STP and in CC downstream of two MMEs compared to reference fish, while gonad weight was unchanged. The most consistent finding was delayed development, increased cell death and increased eosinophilia in FHM testes collected downstream of all effluents, while female FHM and both sexes of CC gonads were relatively unaffected. In conclusion, the results of the current study in Junction Creek suggest that male FHM reproduction may be sensitive to multiple effluents, but failed to clearly establish whether MME or STP effluents were causative agents over urban inputs or historical contamination.