Is Bone Mineral Composition Disrupted by Organochlorines in East Greenland Polar Bears ( Ursus maritimus )?

Abstract

We analyzed bone mineral density (BMD) in skulls of polar bears (Ursus maritimus) (n = 139) from East Greenland sampled during 1892–2002. Our primary goal was to detect possible changes in bone mineral content (osteopenia) due to elevated exposure to organochlorine [polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane (DDT) and its metabolites, chlordanes (CHLs), dieldrin, hexacyclohexanes, hexachlorobenzene] and polybrominated diphenyl ether (PBDE) compounds. To ensure that the BMD value in skull represented the mineral status of the skeletal system in general, we compared BMD values in femur and three lumbar vertebrae with skull in a subsample. We detected highly significant correlations between BMD in skull and femur (r = 0.99; p < 0.001; n = 13) and skull and vertebrae (r = 0.97; p < 0.001; n = 8). BMD in skulls sampled in the supposed pre-organochlorine/PBDE period (1892–1932) was significantly higher than that in skulls sampled in the supposed pollution period (1966–2002) for subadult females, subadult males, and adult males (all, p < 0.05) but not adult females (p = 0.94). We found a negative correlation between organochlorines and skull BMD for the sum of PCBs (∑PCB; p < 0.04) and ∑CHL (p < 0.03) in subadults and for dieldrin (p < 0.002) and ∑DDT (p < 0.02) in adult males; indications for ∑PBDE in subadults were also found (p = 0.06). In conclusion, the strong correlative relationships suggest that disruption of the bone mineral composition in East Greenland polar bears may have been caused by organochlorine exposure.

High accumulation of PCDD, PCDF, and PCB congeners in marine mammals from Brazil: A serious PCB problem

“…This organochlorine compound (OC) accumulation pattern, in which extremely high concentrations are found in only a few individuals, has been reported for marine mammals (Hall, 2002). Actually, extremely wide concentration ranges could be found for organohalogen compounds in marine mammals Hall, 2002;Sonne et al, 2008Sonne et al, , 2004Sonne et al, , 2006bSonne et al, , 2005Sonne et al, , 2006c, even reaching a 70-fold variation (Sonne, 2010).…”

Exposure to pastures fertilised with sewage sludge disrupts bone tissue homeostasis in sheep

“…Since sludge contains a large number of EDCs of different classes and with different mechanisms of action, it is not possible to identify the agent(s) responsible for the observed effects on bone tissues. However, previous studies have shown that bone tissue homeostasis can be perturbed by exposure to either mixtures of EDCs in wildlife species (Fox et al, 2008;Lind et al, 2003;Lind et al, 2004;Sonne et al, 2004) or humans (Alveblom et al, 2003;Glynn et al, 2000;Hodgson et al, 2008) or single compound studies in laboratory (Hermsen et al, 2008;Jamsa et al, 2001;Lind et al, 1999;Lind et al, 2000a) or domestic animals (Lundberg et al, 2006).…”

“…Most of these studies concern exposure to abnormally high concentrations of the chemicals concerned. Studies of wildlife species (Fox et al, 2008;Lind et al, 2003;Lind et al, 2004;Sonne et al, 2004) and of humans (Alveblom et al, 2003;Glynn et al, 2000;Hodgson et al, 2008) based on observational data show effects of exposure but, owing to the fact that the populations studied have been exposed to a mixture of pollutants, cannot identify the causal agents.…”

Effect of In Ovo Exposure to PCBs and Hg on Clapper Rail Bone Mineral Chemistry from a Contaminated Salt Marsh in Coastal Georgia

“…In this case, PCB exposure reversed the effects expressed by estrogen deficiency after ovariectomy (i.e., decreased bone density). In other studies, exposure to PCBs showed the opposite effects and produced a decreased bone mineral density and other bone pathologies (e.g., tooth loss) (6,9,13,15).…”