Persistent organic pollutants (POPs) are long-range transported to the Arctic via atmospheric and oceanic currents, where they biomagnify to high concentrations in the tissues of apex predators such as polar bears (Ursus maritimus). A major concern of POP exposure is their physiological effects on vital organ-tissues posing a threat to the health and survival of polar bears. Here we examined the relationship between selected POPs and baculum bone mineral density (BMD) in the East Greenland and seven Canadian subpopulations of polar bears. BMD was examined in 471 bacula collected between years 1996–2015 while POP concentrations in adipose tissue were determined in 67–192 of these individuals collected from 1999 to -2015. A geographical comparison showed that baculum BMD was significantly lowest in polar bears from East Greenland (EG) when compared to Gulf of Boothia (GB), Southern Hudson (SH) and Western Hudson (WH) Bay subpopulations (all p < 0.05). The calculation of a T-score osteoporosis index for the EG subpopulation using WH bears as a reference group gave a T-score of −1.44 which indicate risk of osteopenia. Concentrations of ΣPCB₇₄ (polychlorinated biphenyls), ΣDDT₃ (dichlorodiphenyltrichloroethanes), p,p′-DDE (dichlorodiphenyldichloroethylene), ΣHCH₃ (hexachlorohexane) and α-HCH was significantly highest in EG bears while ΣPBDE (polybrominated diphenyl ethers), BDE-47 and BDE-153 was significantly highest in SH bears (all p < 0.04). Statistical analyses of individual baculum BMD vs. POP concentrations showed that BMD was positively correlated with ΣPCB₇₄, CB-153, HCB (hexachlorobenzene), ΣHCH, β-HCH, ClBz (chlorobenzene), ΣPBDE and BDE-153 (all p < 0.03). In conclusion, baculum density was significantly lowest in East Greenland polar bears despite the positive statistical correlations of BMD vs. POPs. Other important factors such as nutritional status, body mass and body condition was not available for the statistical modelling. Since on-going environmental changes are known to affect these, future studies need to incorporate nutritional, endocrine and genetic parameters to further understand how POP exposure may disrupt bone homeostasis and affect baculum BMD across polar bear subpopulations.

持久性有机污染物（POPs）通过大气和洋流远程运输到北极，在那里它们被生物放大到顶点捕食者如北极熊（Ursus maritimus）组织中的高浓度。）。持久性有机污染物暴露的一个主要问题是它们对重要器官组织的生理影响，这对北极熊的健康和生存构成了威胁。在这里，我们研究了东格陵兰岛和七个加拿大北极熊亚种中选定的POPs与杆状骨矿物质密度（BMD）之间的关系。在1996年至2015年间收集的471个细菌中检查了BMD，而在1999年至-2015年收集的这些人中，有67至192人测定了脂肪组织中的POP浓度。一个地域比较显示相比，布西亚湾（GB），南方哈德森（SH）和Western哈德森（WH）湾亚群（全时阴茎骨骨密度显著最低从东格陵兰（EG）北极熊p <0.05）。使用WH熊作为参考组，对EG亚群的T分数骨质疏松指数的计算得出的T分数为-1.44，表明存在骨质减少的风险。ΣPCB的浓度₇₄（多氯联苯），ΣDDT ₃（dichlorodiphenyltrichloroethanes），P，P' -DDE（二氯二苯二氯乙烯），ΣHCH ₃（hexachlorohexane）和α-HCH是显著最高在EG承载而ΣPBDE（多溴二苯醚），BDE- 47和BDE-153在SH熊中显着最高（所有p  <0.04）。个别阴茎骨BMD与POP浓度的统计分析表明，BMD呈正相关ΣPCB ₇₄，CB-153，HCB（六氯苯），ΣHCH，β-HCH，ClBz（氯苯），ΣPBDE和BDE-153（均p  <0.03）。总之，尽管BMD与POPs呈正相关，但东格陵兰北极熊的杆状杆菌密度显着最低。其他重要因素，例如营养状况，体重和身体状况，无法用于统计建模。由于已知持续的环境变化会影响这些因素，因此未来的研究需要纳入营养，内分泌和遗传参数，以进一步了解POP暴露如何破坏骨骼稳态并影响北极熊亚群的杆状BMD。