Selective transfer of persistent organic pollutants and their metabolites in grey seals during lactation

Abstract

a b s t r a c t a r t i c l e i n f oTwenty grey seal (Halichoerus grypus) mother-pup pairs from the colony of the Isle of May (Scotland) were sampled at early and late lactation in order to study the transfer of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and their metabolites (HO-PCBs and HO-PBDEs) as well as organochlorine pesticides (OCPs), such as DDT and metabolites (DDXs) and hexachlorobenzene (HCB). The transfer of the naturally produced MeO-PBDEs was also investigated. Generally, concentrations (on a lipid weight basis) of the sum of PCBs, PBDEs and DDXs tended to be higher in all tissues at late lactation (for maternal outer blubber ΣPCBs = 3860 ± 2091 ng/g, ΣPBDEs = 120 ± 74 ng/g and ΣDDXs = 559 ± 207 ng/g; for maternal inner blubber ΣPCBs = 4229 ± 3274 ng/g, ΣPBDEs = 148 ± 118 ng/g and ΣDDXs = 704 ± 353 ng/g; for maternal serum ΣPCBs = 1271 ± 796 ng/g, ΣPBDEs = 27 ± 16 ng/g and ΣDDXs = 242 ± 125 ng/g; for milk ΣPCBs = 1190 ± 747 ng/g, ΣPBDEs = 55 ± 36 ng/g and ΣDDXs = 357 ± 160 ng/g; for pup serum ΣPCBs = 1451 ± 901 ng/g, ΣPBDEs = 48 ± 31 ng/g and ΣDDXs = 395 ± 201 ng/g). In all tissues, ΣMeO-PBDEs were found at very low levels or even undetected and their concentrations appeared to increase at late lactation only in maternal inner blubber (2.7 ± 1.3 to 5.3 ± 2.9 ng/g for early and late lactation, respectively) and milk (0.6 ± 0.3 to 1.1 ± 0.5 ng/g for early and late lactation, respectively). The transfer from inner blubber to maternal serum was selective and strongly depended on the log K ow value of the compounds, with less lipophilic compounds being more efficiently released. Only a limited amount of HO-PCBs was transferred during lactation as 4-HO-CB-107 was the only metabolite detected in milk (29 to 40 pg/g lw). On the contrary, most of HO-PCB metabolites found in maternal serum were also detected in pup serum. These findings suggest not only a transplacental transfer of HO-PCBs from mothers to pups but also the possibility of endogenous biotransformation in suckling pups or accumulation of undetectable low amounts from milk.

Maternal transfer of organohalogenated compounds in sharks and stingrays

“…Compared to the two ova/mother pairs (litters 2 and 3), the ratios of BDE 47 for the female and male embryo/ mother pairs (litter 1, Table 2) dropped considerably from 8 (litter 2) and 1 (litter 3) to 0.1 and 0.01. In serum of grey seals, there was a selective transfer of POPs, but transfer ratios of BDE 47 from maternal serum to milk were not particularly low compared to the ratios for HCB, DDXs, other PBDE congeners or tetra to nona-PCBs (Vanden Berghe et al, 2012). For the Atlantic stingrays however, partitioning of BDE 47 into the histotroph seems less efficient compared to all other compounds investigated.…”

“…This aspect of pollutant transfer has received comparatively less attention than biomagnification, although there have been a considerable number of studies regarding mammalian species (e.g. humans, marine mammals) dealing with body burdens of POPs in offspring (Soechitram et al, 2004;Greig et al, 2007;Vanden Berghe et al, 2012;Wang et al, 2012;Mori et al, 2014). Results for several contaminant classes have suggested a difference between prenatal maternal transfer (i.e.…”

Effects of polychlorobiphenyls, polybromodiphenylethers, organochlorine pesticides and their metabolites on vitamin A status in lactating grey seals

“…Vitamin A was also positively associated to serum levels of SHOPCBs and 4-OH-CB107, the major HO metabolite detected in serum (Vanden Berghe et al, 2012).…”

“…Details concerning POP levels and profiles, as well as lipid contents in maternal blubber and serum can be found elsewhere (Vanden Berghe et al, 2012).…”

“…Details on the lipid determination as well as the blubber and serum sample preparation, extraction, clean-up, quality assurance and chromatography analyses are described elsewhere (Vanden Berghe et al, 2012). In all samples, 35 PCB congeners , six PBDEs (IUPAC numbers: BDE-28, -47, -99, -100, -153 and -154), six DDXs (o,p 0 -DDD, o,p 0 -DDT, o,p 0 -DDE, p,p 0 -DDD, p,p 0 -DDE, and p,p 0 -DDT), HCB and two MeO-PBDEs (2 0 -MeO-BDE-68 and 6-MeO-BDE 47) were measured.…”