Trends of Halogenated Flame Retardants in Herring Gull across Canada from 2008 - 2019
Halogenated flame retardants (HFRs) are chemicals that are used to reduce the flammability of objects and are of international concern due to their negative effects on the environment and human health. Some HFRs have been regulated under the Stockholm Convention on Persistent Organic Pollutants that aims to protect human health and the environment. To address whether such international regulations are reducing concentrations of HFRs, temporal trends of polybromodiphenyl ethers (PBDEs), hexabromocyclododecane (HBCDD), and dechlorane plus (DP) were examined in herring gull (Larus argentatus smithsonianus) eggs. Eggs were sampled from 18 Canadian colonies located in the Laurentian Great Lakes, Niagara River, St. Lawrence River, the Atlantic, and the Arctic. One egg was sampled from each of 10-15 individual nests from each colony for 5-12 years and pooled within colonies and years on an equal wet weight basis. Egg pools were analyzed using gas chromatography-mass spectrometry for 14 PBDE congeners, total-a-HBCDD, and syn- and anti-DP. Generalized linear models and breakpoint analysis was used to determine if, and when, changes in concentrations occurred and the direction of these changes. I found few significant declines of flame retardant concentrations over time in herring gull eggs, and therefore, there was little support for the hypotheses that either 1) the nomination of a flame retardant or 2) the listing of a flame retardant reduces its concentrations in herring gull eggs. These results support that flame retardants are still emitted to the environment due to stockpiles, discarded products, or re-release of environmental reservoirs after their regulation. These results show that in only a few cases management due to the Stockholm Convention reduced concentrations of HFRs in Canadian herring gull eggs, but that overall concentrations had not begun to decrease between 2008 and 2019 in response to regulation. However, declines in HFR concentrations may not have occurred during this study period since a longer time frame may be required before significant declines concentrations due to SC management are seen. Additionally, the SC’s importance may be the framework it provides to signatory parties for generating their own national regulations.