PHAGOCYTIC AND METABOLIC-ACTIVITIES OF MACROPHAGES FROM MUMMICHOG NATURALLY EXPOSED TO PULP-MILL EFFLUENTS IN THE MIRAMICHI RIVER

Chemicals present in bleached kraft pulp mill effluents (BKMES) can mo dulate the immune response of fish. This work was conducted to determi ne if mummichogs living downstream from a bleached kraft pulp mill (BK M) had an impaired immune response. Head kidney phagocytes from males and females were tested for their phagocytic and metabolic activities. Mummichogs were captured 4 km (S2) and 39 km (S1) downstream from a B KM in the Miramichi estuary (New Brunswick, Canada) and at two sites l ocated upstream (S3) and 20 km downstream (S4) in a reference estuary, the Bouctouche. Both male and female mummichogs captured at S2 in the Miramichi estuary had a lower phagocytic activity, whereas only femal es from the same site had a decreased oxidative burst response, indica ting a difference between sexes in the susceptibility to pollutants pr esent in the Miramichi. Therefore, the results indicate that mummichog s exposed to BKMES have an impaired immune response and that females a re more sensitive than males to the chemicals present in BKMES. (C) 19 98 Academic Press.