Hard to belie­ve, but the­re are good news for polar bears: bio­lo­gists from the uni­ver­si­ty of Trond­heim (Nor­way) have done rese­arch on tis­sue samples coll­ec­ted from fema­le polar bears. Their results show that poly­chlo­r­a­ted biphe­nyls (PCB) have drop­ped signi­fi­cant­ly bet­ween 1998 and 2008. The values for young bears are 59 % lower and tho­se of adult fema­les have decreased by 55 %. The actu­al con­cen­tra­ti­ons are still well capa­ble of doing harm to a bear’s repro­duc­ti­ve and immu­ne sys­tem, but the trend is wit­hout doubt good news.

PCBs have been used world­wi­de for mul­ti­ple tech­ni­cal pro­ces­ses, inclu­ding coo­ling agents and elec­tric parts. Sin­ce 2004, the­re is a ban on PCB pro­duc­tion within the Stock­holm con­ven­ti­on sys­tem that has been signed by most major count­ries, with a few excep­ti­ons, noti­ce­ab­ly the USA.

Source: Uni­ver­si­tät Trond­heim