Radiation causing cataracts in birds of Chernobyl and Fukushima

the key factor determining the presence of the disease was the intensity of local radiation, with cataract scores of over one proving to be far more common in areas that were above ten microseiverts per hour

Birds live with cataracts in Chernobyl The Economist, Sep 7th 2013 CATARACTS are relatively common in people who live to a ripe old age. They are sometimes seen in animals that live in zoos as well, but in the wild they are almost unheard of. The reason is simple. Losing eyesight is in effect a death sentence for a wild animal that must find its own food and, should that animal live long enough to develop the disease, starvation or predation would quickly follow|cataracts unrelated to age are surprisingly common in birds living near the site of the Chernobyl nuclear disaster in 1986.

This is revealed in a new study by a pair of ornithologists, Timothy Mousseau of the University of South Carolina and Anders Moller of the University of Paris-Sud, which is published in the Public Library of Science. That cataracts and ionising radiation are related is well known. As high energy ions, usually produced by the sun’s rays, slam into the water found next to the lenses of the eyes, free radicals are created that damage DNA and cause errors to develop in the formation of proteins that make up the lenses, resulting in cataracts.

This led the researchers to suspect that cataracts in birds might be common in areas where there are high levels of ionising radiation, and they turned to Chernobyl as a study area. Working with nets in the mornings and evenings, the researchers collected a total of 1,111 birds in the greater Chernobyl area and examined their eyes. Cataract scores were given to each bird, ranging from zero (for total eye clarity and no cataract presence) to four (for an eye that was entirely opaque and probably blind with cataracts). The researchers also noted the sex of the birds and whether they were juveniles or adults.

In total, eight locations in the greater Chernobyl area were used in the study and the radiation levels in each were measured with a Geiger counter. The different sites showed readings from a very low radiation level of 0.02 microseiverts per hour to an average of almost 60 microseiverts per hour in one of the forests that was heavily contaminated by the meltdown.

In all, 391 of the birds the researchers caught had cataract scores of one or more, and were thus suffering some level of visual impairment. However, contrary to the way cataracts work in the rest of the world, those in the eyes of birds living near Chernobyl appeared regardless of whether they were young or old. When Dr Mousseau and Dr Moller examined their radiation measurements, they found that the key factor determining the presence of the disease was the intensity of local radiation, with cataract scores of over one proving to be far more common in areas that were above ten microseiverts per hour….. http://www.economist.com/news/science-and-technology/21584963-birds-live-cataracts-chernobyl-not-so-blindingly-obviou

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