AD  - TOXEN, Universite du Quebec a Montreal, Canada.
TA  - Environ Health Perspect
LR  - 20041117
DCOM- 19951102
PST - ppublish
AB  - A small isolated population of beluga whales (Delphinapterus leucas) that are highly contaminated by pollutants, mostly of industrial origin, resides in the St. Lawrence estuary, Quebec, Canada. Overhunting in the first half of the century was the probable cause for this population to dwindle from several thousand animals to the current estimate of 500. The failure of the population to recover might be due to contamination by organochlorine compounds, which are known to lead to reproductive failure and immunosuppression in domestic and laboratory animals and seals. Functional and morphological changes have been demonstrated in thyroid gland and adrenal cortex in many species exposed to organochlorinated compounds, including seals. Morphological lesions, although different, were also found in belugas. Functional evaluation of thyroid and adrenal glands of contaminated (St. Lawrence) versus much less contaminated (Arctic) belugas is currently under way. Necropsy of St. Lawrence belugas showed numerous severe and disseminated infections with rather mildly pathogenic bacteria, which suggests immunosuppression. Organochlorine compounds and other contaminants found in beluga whales cause immunosuppression in a variety of animal species including seals. Thirty-seven percent of all the tumors reported in cetaceans were observed in St. Lawrence beluga whales. This could be explained by two different mechanisms: high exposure to environmental carcinogens and suppression of immunosurveillance against tumors. Overall, St. Lawrence belugas might well represent the risk associated with long-term exposure to pollutants present in their environment and might be a good model to predict health problems that could emerge in highly exposed human populations over time.
STAT- MEDLINE
RN  - 0 (Environmental Pollutants)
RN  - 0 (Polychlorinated Biphenyls)
LA  - eng
PG  - 73-7
SB  - IM
DA  - 19951102
EDAT- 1995/05/01
AU  - De Guise S
AU  - Martineau D
AU  - Beland P
AU  - Fournier M
JID - 0330411
OWN - NLM
MHDA- 1995/05/01 00:01
PMID- 7556028
SO  - Environ Health Perspect 1995 May;103 Suppl 4:73-7.
DP  - 1995 May
RF  - 78
IS  - 0091-6765
TI  - Possible mechanisms of action of environmental contaminants on St. Lawrence beluga whales (Delphinapterus leucas).
FAU - De Guise, S
FAU - Martineau, D
FAU - Beland, P
FAU - Fournier, M
MH  - Adrenal Cortex/drug effects/physiology
MH  - Animals
MH  - Environmental Pollutants/*adverse effects
MH  - Fresh Water
MH  - Immune System/drug effects/physiology
MH  - Immunosuppression
MH  - Neoplasms/chemically induced/epidemiology/veterinary
MH  - Polychlorinated Biphenyls/adverse effects/pharmacology
MH  - Quebec/epidemiology
MH  - Reproduction/drug effects/physiology
MH  - Research Support, Non-U.S. Gov't
MH  - Thyroid Gland/drug effects/physiology
MH  - Time Factors
MH  - Whales/*physiology
PL  - UNITED STATES
VI  - 103 Suppl 4
PT  - Journal Article
PT  - Review
PT  - Review, Tutorial