Legacy contaminants in beluga Marie Noël, Lisa L. Loseto, Gary Stern

1. Legacy persistent organic pollutants (POPs) biomagnify (i.e., increase in concentration) in food webs and lead to relatively high concentrations in predators, like beluga whales.

2. We assessed temporal trends (1989–2015) of POPs including polychlorinated biphenyls (PCBs) and 14 different pesticides in eastern Beaufort Sea beluga blubber collected during traditional harvests in the Mackenzie estuary area, Northwest Territories.

3. The majority of POPs analyzed showed no significant changes during the study period, therefore not reflecting regulations put into place over the past few decades to reduce release of POPs into the environment.

4. Continuous monitoring is necessary with climate change potentially affecting the transport of legacy POPs to the Arctic via the melting of sea ice or permafrost and release of POPs that have been trapped inside.

For close to 30 years, the beluga monitoring program based out of Hendrickson Island, Northwest Territories, has provided samples that are used to measure concentrations of different types of contaminants.

Nationally and internationally, it is the best available data on long-term contaminant trends. The program allows us to monitor changes in contaminant concentrations that may reflect changes in the 1) usage of a particular chemical, 2) transport from lower latitudes to the Arctic, and/or 3) beluga food web which in turn would affect how contaminants are being transferred up the food chain.

This paper focuses on persistent organic pollutants (POPs) that are still widely found in the marine environment today even though they were banned several decades ago due to their potential for causing harm to humans and the environment.

These pollutants have the potential to accumulate in the fatty tissues of living organisms and are found at higher concentrations in predators at the top of the food chain, including beluga whales.

Most of the POPs that we measured in beluga whale blubber surprisingly showed no significant changes or a very slow decline in concentrations between 1989 and 2015, possibly suggesting that most of the decline happened before 1989, after environmental regulations were put into place (late 1970s). While regulations have had a positive impact on the marine environment by preventing concentrations of POPs from increasing, the lack of continuing decline in concentrations further demonstrates the persistence of these chemicals.

The lack of continuing decline also suggests that POPs from latitudes below the Arctic are still being delivered to the Arctic via atmospheric and ocean currents. Other factors may have also contributed to the observed trends, such as changes in beluga diet over time and climate change, which can directly or indirectly impact the transport and availability of contaminants to Arctic food webs. It is therefore important to keep such monitoring programs in place given that the Arctic environment is changing now more than ever.

Read the full paper in Arctic ScienceLegacy contaminants in the eastern Beaufort Sea beluga whales (Delphinapterus leucas): are temporal trends reflecting regulations?

Corresponding author: Marie Noël, marie.noel@ocean.org

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