Maternal Transfer of Flame Retardants in Sharks from the Western North Atlantic Ocean

Abstract

The present work represents a comprehensive study of in utero maternal transfer of legacy and emerging flame retardants (FRs) in marine predators. We analyzed liver tissues from pregnant sharks of five viviparous species, including blacknose shark ( Carcharhinus acronotus; n = 12), blacktip shark ( Carcharhinus limbatus; n = 2), bonnethead ( Sphyrna tiburo; n = 2), Atlantic sharpnose shark ( Rhizoprionodon terraenovae; n = 2), and spinner shark ( Carcharhinus brevipinna; n = 2), as well as their embryos ( n = 84 in total from five species), collected from the western North Atlantic Ocean. Concentrations of frequently detected emerging FRs in adult female blacknose sharks were determined to be 6.1-83.3 ng/g lipid weight (lw) for dechlorane analogues, 2.5-29.8 ng/g lw for tetrabromo- o-chlorotoluene, and nondetection -32.6 ng/g lw for hexabromobenzene. These concentrations were 1-2 orders of magnitude lower than those of legacy polybrominated diphenyl ether flame retardants (85.7-398 ng/g lw). Similar contamination profiles were also found in the other four species, although FR concentrations varied in different species. A total of 21 FRs were commonly found in developing embryos of female sharks from five species, demonstrating maternal transfer in utero. The maternal transfer ratio (i.e., ratio of the mean litter concentration to their mother's concentration) determined in blacknose shark mother/embryo groups for each FR chemical was negatively associated with its octanol-water partition coefficient. Our work lays a solid foundation for future investigation of the underlying mechanisms of in utero transfer and additional physical or chemical factors that affect maternal transfer.

High Levels of Legacy and Emerging Contaminants in Killer Whales (Orcinus orca) from Norway, 2015 to 2017

“…). Hexabromobenzene has also shown to be transferred maternally in sharks (Marler et al 2018). Given that the neonate killer whale in the present study had similar levels of PBT and HBB to the subadult and adult individuals (Table 2), it is likely that a substantial amount of contaminants is transferred maternally.…”

“…There have previously been indications that emerging BFRs can be transferred maternally in humans, birds, and sharks, with PBT and HBB found in human milk in Europe, including Norway (Cechova et al 2017), and in glaucous gull eggs in the Norwegian Arctic (Verreault et al 2007). Hexabromobenzene has also shown to be transferred maternally in sharks (Marler et al 2018). Given that the neonate killer whale in the present study had similar levels of PBT and HBB to the subadult and adult individuals (Table 2), it is likely that a substantial amount of contaminants is transferred maternally.…”

Water Analysis: Emerging Contaminants and Current Issues

“…While this Water Analysis review is focused on water, a recent wildlife exposure study is worth noting. Marler et al measured maternal transfer of legacy and emerging flame retardants in sharks from the Western North Atlantic Ocean . α-Hexabromocyclododecane (HBCDD) diastereomers were measured using LC–MS/MS; other flame retardants, 35 non-PBDE flame retardants and 20 PBDE congeners, were measured using GC–MS.…”

Novel Dechlorane Analogues and Possible Sources in Peregrine Falcon Eggs and Shark Livers from the Western North Atlantic Regions

“…Other dechlorane analogues were quantitatively determined in the samples based on their respective reference standards and characteristic ions for quantification (summarized in Table S1). 20 Quality Assurance/Control and Data Analysis. The analytical precision and accuracy values for U1 and U2 were assessed through spiking experiments using other dechlorane analogues (i.e., Dec601, Dec602, Dec603, Dec604, Dec604CB, anti-Cl 11 -DP, anti-Cl 10 -DP, Cplus, and syn-and anti-DP) as alternatives, given that the reference standards of U1 and U2 are not available.…”

“…The limit of quantification (LOQ), estimated as an analyte response ten times the standard deviation of the noise during GC-ECNIqMS analysis, ranged from 0.4 to 0.8 ng/g lipid weight (lw) for major dechlorane analogues of interest (Table S1). 20 The LOQ for Dec603 (i.e., 0.6 ng/g lw) was used to represent that for U1 or U2, assuming they have similar ECNI response factors. Spearman's correlation analyses were employed to determine concentration correlations between dechlorane analogues (PASW Statistics 18.0, IBM Inc.).…”