Occurrence of polybrominated dibenzo-p-dioxins, dibenzofurans (PBDD/Fs) and polybrominated diphenyl ethers (PBDEs) in pilot whales (Globicephala melas) caught around the Faroe Islands

Investigating decadal changes in persistent organic pollutants in Scottish grey seal pups

“…The BDE profiles from 2015-17 are similar to those found in the same population of grey seals from the late 1990s and in 2008 (Kalantzi, Hall, Thomas, & Jones, 2005;Vanden Berghe et al, 2012), found in the blubber from grey seals elsewhere (Ikonomou & Addison, 2008), and reported in recent studies on other marine mammals (Bjurlid, Dam, et al, 2018;Ochiai et al, 2017;Ramu, Kajiwara, Tanabe, Lam, & Jefferson, 2005;Rigét et al, 2006;Ross et al, 2013;Weijs, Dirtu, et al, 2009) of BDEs (Airaksinen et al, 2014;Bjurlid, Dam, et al, 2018;Bjurlid, Roos, et al, 2018;Houde et al, 2017;Rigét et al, 2006Rigét et al, , 2019Ross et al, 2013;Sanganyado, Rajput, & Liu, 2018;Shunthirasingham et al, 2018), and may have stabilized recently in some regions (Brown, MacDonald, Muir, & Letcher, 2018;Fernandes et al, 2018;Houde et al, 2017;Rigét et al, 2016Rigét et al, , 2019. In combination with the technical disparities discussed below, the BDE data here do not provide a sufficient recent time series to determine whether the bans have been effective at reducing BDEs in grey seal blubber, but provide a starting point for future studies or comparisons to investigate the efficacy of the ban and its impact on levels in top predators.…”

“…The BDE profiles from 2015-17 are similar to those found in the same population of grey seals from the late 1990s and in 2008 (Kalantzi, Hall, Thomas, & Jones, 2005;Vanden Berghe et al, 2012), found in the blubber from grey seals elsewhere (Ikonomou & Addison, 2008), and reported in recent studies on other marine mammals (Bjurlid, Dam, et al, 2018;Ochiai et al, 2017;Ramu, Kajiwara, Tanabe, Lam, & Jefferson, 2005;Rigét et al, 2006;Ross et al, 2013;Weijs, Dirtu, et al, 2009). BDE 47 was always the most abundant congener, and accounted for 12.5-88.1% (median 80.9%) of the BDEs detected.…”

“…Recent BDE values here are 10-20-fold lower than the levels reported in adult harbour seals from the North Sea from 1999 to 2004 (Weijs, Dirtu, et al, 2009), and are an order of magnitude lower than values reported in UK grey seal pup blubber from 1998 to 2000 (Kalantzi et al, 2005), and in Salish Sea harbour seal pup blubber from 1984 to 2009 (Ross et al, 2013). Findings from other studies in the marine environment globally suggest that BDE levels peaked in the early 2000s and then fell, as a result of the ban on penta-and tetra-mixes of BDEs (Airaksinen et al, 2014;Bjurlid, Dam, et al, 2018;Bjurlid, Roos, et al, 2018;Houde et al, 2017;Rigét et al, 2006Rigét et al, , 2019Ross et al, 2013;Sanganyado, Rajput, & Liu, 2018;Shunthirasingham et al, 2018), and may have stabilized recently in some regions (Brown, MacDonald, Muir, & Letcher, 2018;Fernandes et al, 2018;Houde et al, 2017;Rigét et al, 2016Rigét et al, , 2019. In combination with the technical disparities discussed below, the BDE data here do not provide a sufficient recent time series to determine whether the bans have been effective at reducing BDEs in grey seal blubber, but provide a starting point for future studies or comparisons to investigate the efficacy of the ban and its impact on levels in top predators.…”

“…Marine mammal species typically show high individual variability in POP concentrations (Bjurlid, Dam, Hoydal, & Hagberg, 2018;Pomeroy et al, 1996) As the distribution of POP concentrations was positively skewed, a generalized linear model (GLM) with a gamma distribution and a log link function was used to investigate: (i) the relationship between POP concentrations and sex, mass, and days post-weaning (Debier et al, 2006;Louis et al, 2014;Louis, Covaci, Crocker, & Debier, 2016), as potential confounding factors; and (ii) the relationship between POP concentrations and time of sampling (year group), taking into account the effect of the confounding factors if necessary. Marine mammal species typically show high individual variability in POP concentrations (Bjurlid, Dam, Hoydal, & Hagberg, 2018;Pomeroy et al, 1996) As the distribution of POP concentrations was positively skewed, a generalized linear model (GLM) with a gamma distribution and a log link function was used to investigate: (i) the relationship between POP concentrations and sex, mass, and days post-weaning (Debier et al, 2006;Louis et al, 2014;Louis, Covaci, Crocker, & Debier, 2016), as potential confounding factors; and (ii) the relationship between POP concentrations and time of sampling (year group), taking into account the effect of the confounding factors if necessary.…”

“…All statistical analyses were performed using R 3.4.1 (R Development Core Team, 2012). Marine mammal species typically show high individual variability in POP concentrations (Bjurlid, Dam, Hoydal, & Hagberg, 2018;Pomeroy et al, 1996) As the distribution of POP concentrations was positively skewed, a generalized linear model (GLM) with a gamma distribution and a log link function was used to investigate: (i) the relationship between POP concentrations and sex, mass, and days post-weaning (Debier et al, 2006;Louis et al, 2014;Louis, Covaci, Crocker, & Debier, 2016), as potential confounding factors; and (ii) the relationship between POP concentrations and time of sampling (year group), taking into account the effect of the confounding factors if necessary. Model fits to the data were assessed using residual analysis, and outliers were identified from quantile-quantile plots (QQ plots) using Cook's distance.…”