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Temporal trends (1987-2002) of persistent, bioaccumulative and toxic (PBT) chemicals in beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary, Canada.
- Source :
-
The Science of the total environment [Sci Total Environ] 2007 Sep 20; Vol. 383 (1-3), pp. 216-31. Date of Electronic Publication: 2007 Jun 08. - Publication Year :
- 2007
-
Abstract
- Temporal trends of persistent, bioaccumulative and toxic (PBT) chemicals were examined in beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary (SLE), Canada. Blubber samples of 86 adult belugas were collected from animals stranded on the shore of the SLE between 1987 and 2002 and analyzed for several regulated PBTs, including polychlorinated biphenyls (PCBs), p,p'dichlorodiphenyltrichloroethane (DDT) and its metabolites, chlordane (CHL) and related compounds, hexachlorocyclohexane (HCH) isomers, hexachlorobenzene (HCB) and Mirex. In addition, time trends of tris(4-chlorophenyl)methane (TCPMe) and tris(4-chlorophenyl)methanol (TCPMOH), two compounds that may origin from DDT formulations, were also examined. Concentrations of most of the PBTs examined had exponentially decreased by at least a factor of two (half-life time (t(1/2))<15 years) in beluga between 1987 and 2002 while no increasing trends were observed for any of the PBTs measured. The decreasing trends of PBT concentrations in SLE beluga may be due to a decline in contamination of its diet following North American and international regulations on the use and production of these compounds or by a change in its diet itself or by a combination of both. Some PBTs did not exhibit any significant trends in beluga possibly because the most intense elimination phase subsequent to legislative regulations occurred prior to the 1987-2002 time period. Other chemicals, such gamma-HCH, did not significantly decrease likely because they are still currently used in some restricted applications. Conversely, alpha-HCH showed a significant decreasing trend indicating that SigmaHCHs is not representative of all HCHs. Both TCPMe and TCPMOH exhibited no trends in beluga during the time period examined. The metabolic capacity of SLE beluga has apparently accelerated the depletion of at least one PBT, namely CB-28/31. A significant relationship between the half-life of PBTs in beluga and log Kow was observed for most of the chemicals examined. Several factors are expected to have influenced the temporal changes of PBT concentrations in beluga which limit the usefulness of this species as a bioindicator of changes in PBT contamination in the SLE ecosystem.
- Subjects :
- Adipose Tissue chemistry
Animals
Environmental Monitoring
Female
History, 20th Century
History, 21st Century
Hydrocarbons, Chlorinated history
Male
Quebec
Rivers
Trityl Compounds history
Water Pollutants, Chemical history
Beluga Whale metabolism
Hydrocarbons, Chlorinated metabolism
Trityl Compounds metabolism
Water Pollutants, Chemical metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0048-9697
- Volume :
- 383
- Issue :
- 1-3
- Database :
- MEDLINE
- Journal :
- The Science of the total environment
- Publication Type :
- Academic Journal
- Accession number :
- 17560630
- Full Text :
- https://doi.org/10.1016/j.scitotenv.2007.04.026