Envi­ron­men­tal toxins lead to thin­ner eggs­hells for Ivory gulls

Envi­ron­men­tal toxins lead to thin­ner eggs­hells for Ivory gulls. This is one key result of a recent stu­dy made by sci­en­tists from the Nor­we­gi­an Polar Insti­tu­te (NPI), the Rus­si­an Ant­arc­tic Rese­arch Insti­tu­te (AARI) in St. Peters­burg and others. Sam­ples were taken in Sval­bard and arc­tic Rus­sia in 2007. Com­pa­red with data from the ear­ly 20th cen­tu­ry, eggs­hells from Spits­ber­gen and the Rus­si­an arc­tic are up to 17 % thin­ner.

Ivory gulls are on top of the food chain, and long-lived envi­ron­men­tal toxins such as PCBs and DDT are accu­mu­la­ting towards the top of the food chain. The thin­ned eggs­hells are shown to have high con­cen­tra­ti­ons espe­cial­ly of DDT.

DDT was gra­du­al­ly ban­ned in many coun­tries from the ear­ly 1970s onwards and is now used legal­ly only in rela­tively small quan­ti­ties to fight dise­a­ses such as mala­ria. After an ban on DDT in Nor­way, eggs­hell thic­kness of sea­b­irds and birds of prey reco­ve­r­ed again back to natu­ral values.

Source: Nor­we­gi­an Polar Insti­tu­te

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