The death of the fema­le polar bear “Frost” and her cub on Good Fri­day 2023 in Sas­senfjord had attrac­ted inter­na­tio­nal atten­ti­on (click here for fur­ther details). The polar bear fami­ly had come clo­se to an area with huts on Vin­dod­den and peo­p­le had scared the two bears away. Soon the­re­af­ter Frost was seen dead in the water not far from the shore. The poli­ce (Sys­sel­mes­ter) was invol­ved; they shot the young bear that had appeared to be aggres­si­ve and secu­red the bodies and other infor­ma­ti­on for inves­ti­ga­ti­ons.

Soon it beca­me known that Frost and her cub had been anes­the­ti­zed just two days befo­re their death by sci­en­tists from the Nor­we­gi­an Polar Insti­tu­te. This led to spe­cu­la­ti­ons that the anaes­the­tiza­ti­on might have been the cau­se of the death of the two bears which had appeared to be a bit of a mys­tery; usual­ly polar bears are excel­lent swim­mers and they cover gre­at distances in icy waters with ease.

Now the aut­ho­ri­ties have an auto­psy report; it is (so far) unpu­blished, but Sval­bard­pos­ten could read at least parts of it. The result: the anaes­the­tiza­ti­on was not the cau­se of death. Frost had serious inter­nal inju­ries inclu­ding bro­ken ribs, a punc­tu­red lung and inter­nal blee­ding. Accor­ding to the report, the­se inju­ries were the cau­se of Frost’s death.

It is not known how Frost recei­ved the­se inju­ries. A fall from a cliff appears as a reasonable sce­na­rio.

The anaes­the­tiza­ti­on had been done two days ear­lier in Tem­pel­fjord, six to seven kilo­me­t­res away from Vin­dod­den whe­re the two bears later died. After the anaes­the­tiza­ti­on, the sci­en­tists had obser­ved Frost and her cub for a while until their beha­viour appeared to be nor­mal again. A cau­sal con­nec­tion bet­ween the anaes­the­tiza­ti­on and Frost’s death is the­r­e­fo­re ruled out by the aut­ho­ri­ties.

Polar bear fami­ly in Isfjord. It is not known if this was Frost.

Every year seve­ral dozens or a three-digit num­ber of polar bears are anaes­the­ti­zed by sci­en­tists for inves­ti­ga­ti­ons. The polar bears are mark­ed and some of them equip­ped with trans­mit­ters, size and weight are recor­ded and various samples taken. Also Frost, known to sci­ent­sists as N23992, had been through that pro­ce­du­re a num­ber of times in her life. Polar bear bio­lo­gist Jon Aars of the Nor­we­gi­an Polar Insti­tu­te says that he and his col­le­agues have anaes­the­ti­zed about 1000 polar bears in 20 years. In 3 cases, polar bears are known to have died from the con­se­quen­ces; the­re might be at least a 4th case which is not pro­ven bey­ond a noti­ceable tem­po­ral con­nec­tion. In any case, the pro­ce­du­re invol­ves signi­fi­cant stress for the bears and it is thus cri­ti­ci­zed by ani­mal rights acti­vists.

The fema­le polar bear Frost had been seen by many, also becau­se she had a ten­den­cy to stay near huts and sett­le­ments. She had made it a habit to break into huts, an unfort­u­na­te habit which she appeared to have taught to her cubs. She beca­me a bit of a cele­bri­ty through media covera­ge inclu­ding the docu­men­ta­ry “Queen wit­hout land” made by Asge­ir Hel­ge­land (ori­gi­nal title: „Dron­ning uten Land“). Click here for more about Frost’s adven­tur­ous and part­ly tra­gic life.

Her ten­den­cy to stay near sett­le­ments and to break into huts was any­thing but popu­lar among­st locals, and the­re were many who took the infor­ma­ti­on about her death with reli­ef.

Radioc­ti­ve? Cae­si­um? Lost? That may rai­se more than an eye­brow or two.

So befo­re anyo­ne gets high blood pres­su­re: no need to. Not­hing and nobo­dy is end­an­ge­red and that won’t chan­ge.

Simi­lar case in Aus­tra­lia

The sto­ry reminds one of a case in Aus­tra­lia in Janu­ary 2023 when a very small cap­su­le of radio­ac­ti­ve cae­si­um was lost during road trans­port over 1400 kilo­me­t­res. If hand­led irre­spon­si­bly, cae­si­um can inde­ed be a very dan­ge­rous sub­s­tance. Hence, a major search was initia­ted and the cae­si­um cap­su­le was found only two days later.

Cae­si­um cap­su­le lost in 1984

A simi­lar cap­su­le was lost on the moun­tain Brein­osa near mine 7 east of Lon­gye­ar­by­en in Spits­ber­gen. The inci­dent hap­pen­ed in 1984, no less than 40 years ago. Now the sto­ry sur­faced again in a report in the con­text of pre­pa­ra­ti­ons to clo­se mine 7 in 2025, as Sval­bard­pos­ten recent­ly repor­ted.

The dif­fe­rence to the case in Aus­tra­lia: the cae­si­um cap­su­le in Spits­ber­gen is still whe­re it was lost in 1984. And it will stay the­re.

Mine 7 and the moun­tain Brein­osa: cae­si­um cap­su­le under 300 met­res of solid rock
(pho­to taken during a sche­du­led flight to Lon­gye­ar­by­en).

Radio­ac­ti­ve cae­si­um 137 in mining

So what hap­pen­ed? A source of radia­ti­on such as a cap­su­le of cae­si­um 137 is used for exam­p­le during pro­s­pec­ting mine­ral resour­ces: it can be appli­ed to get infor­ma­ti­on about the com­po­si­ti­on of rocks. The idea is that the inten­si­ty of radia­ti­on recei­ved by a mea­su­ring device from a source of known inten­si­ty and in a known distance yields infor­ma­ti­on aboutn the den­si­ty of the rocks bet­ween the source and the mea­su­ring device and this again tells geo­lo­gists some­thing about the poten­ti­al pre­sence (or absence) of mate­ri­als such as coal that have a dif­fe­rent den­si­ty than, say, sand­stone.

But it is not a good thing when someone drops the cae­si­um cap­su­le into a bore­hole more than 300 met­res deep. This is not to say that someone actual­ly drop­ped it manu­al­ly, a cae­si­um cap­su­le is not some­thing you just hold in your hand, obvious­ly. But any­way, somehow the cap­su­le dis­ap­peared into that 300 m deep, nar­row hole near mine 7 on the moun­tain Brein­osa during pro­s­pec­ting work.

The cae­si­um cap­su­le will stay whe­re it is

It is tech­ni­cal­ly not pos­si­ble to retrie­ve the cae­si­um cap­su­le from more than 300 m depth at the bot­tom of a nar­row bore­hole wit­hout crea­ting an enti­re­ly new way of access, some­thing that would obvious­ly invol­ve mas­si­ve effort. On the other hand, a rock cover of 300 m pro­vi­des a pret­ty safe place for a small amount of cae­si­um. Ground­wa­ter flow lea­king to the sur­face is ruled out by experts, and ero­si­on of more than 300 m of solid rock would requi­re more than one gla­cia­ti­on peri­od, rough­ly equi­va­lent to 100,000 years, and even lon­ger time in case the­re won’t be any future peri­ods of major gla­cia­ti­on. In other words, it can be ruled out that the cae­si­um cap­su­le will appear at the sur­face due to natu­ral pro­ces­ses for a very long time.

Ano­ther fac­tor of the risk assess­ment is the half life of cae­si­um 137 which is 30.1 years. This means that alre­a­dy now the acti­vi­ty of the cae­si­um is redu­ced by more than 50 %. After a total of 10 half life peri­ods, a good 300 years in total, the remai­ning radia­ti­on is under the the­shold of detec­tion thres­hold and far from levels that might be a risk for health of envi­ron­ment. Con­side­ring all this, aut­ho­ri­ties and mining com­pa­ny have deci­ded to let the cae­si­um cap­su­le rest in peace whe­re it is. The only mea­su­re taken is to docu­ment the inci­dent and the whe­re­a­bouts so it is known to future gene­ra­ti­on that it might be a bad idea to dig a deep hole in that very posi­ti­on.