Behaviour of birds and worms at Chernobyl

Date:18/10/2007 URL: http://www.thehindu.com/thehindu/seta/2007/10/18/stories/
2007101850081500.htm
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Sci Tech



Behaviour of birds and worms at Chernobyl
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Lot of variation among species and within species
Strong correlation between internal dose, radiation level
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Recent studies of birds at Chernobyl revealed some strange behaviour of certain species. Anders Moller at Pierre and Marie University in Paris and Tim Mousseau at the University of South Carolina found that the bird species, pied flycatcher and the great tit (Parus major), generally avoided nesting boxes kept at high levels of background radiation. Pied flycatcher exhibited stronger effect. Radiation levels at some nest sites were as much as 2,000 times the natural levels elsewhere in the world (New Scientist, March, 28, 2007).
Nest site choice
“Inter specific differences in effects of radiation on nest-site choice suggest that species respond in a species-specific manner to radiation,” they claimed (Proc. Roy.Soc. Biology, March 27, 2007).
Their claim may not be valid as they did not consider internal doses which were substantial. “We cannot agree more that internal dose is most important. We have…measured dose rate of over 300 birds around Chernobyl. There is a very strong correlation between internal dose and radiation level at the site of capture,” the authors responded. Ukrainian scientists coordinated the study of internal body burden estimates.
“… the preliminary results suggest considerable variation among species and individuals within species, even those living in the same general area. We hope to fully explore these data once our colleagues have finished with the primary publication,” Dr Mousseau clarified.
Once Time magazine noted that yellow legged mud-dauber wasps at the Oak Ridge National Laboratory use mud containing radioactivity to build their nests whereas pipe-organ mud-daubers use only non-radioactive mud, though the same source of nest materials was available to both ( http://www.time.com/time/printout/0,8816,897250,00.html).
Dr Mousseu had seen mud-dauber tubes at the Savannah River site. “I will investigate the possibility of measuring activity in the mud,” he promised in an e-mail message. He noted that barn swallows, the bird species studied extensively at Chernobyl also build their nest in the area!
Three species studied
Certain species of worms in the lakes in Chernobyl behaved strangely! Scientists studied three species contaminated by radioactivity from the Chernobyl accident; greater proportions of two species of worms started seeking partners for sex, switching from asexual to sexual reproduction. Ukrainian scientists believe that they did it to increase their chance of survival (EurekAlert, April 9, 2003).
The third species showed double the rate for asexual reproduction in the polluted lake (Journal of Env. Radioactivity, 2003).
Background radiation in certain areas of Kerala and Tamil Nadu is above normal (far too less than that in Chernobyl).
I asked Dr Mousseau whether the study of insects and other invertebrates in such high background radiation areas (HBRA) is of any interest.
“It would seem to me that this region would likely reveal some very interesting adaptations to radiation that might not have had time to evolve in other regions”, he conceded. “…it would be important to focus on a few key species that occur in this area and examine survival and reproduction with control sites.
Similarly, it would be valuable to examine the community of organisms, especially insects, to determine if species composition changes in a predictable way.
Either way, I suspect that this region would be an excellent target for further investigation and my suspicion is that one would be very likely to generate many exciting discoveries of organismal responses to this environmental effect”, he asserted.
No scientific basis
Learned national academies and international agencies should support a dedicated research project to study the flora and fauna in the HBRA.
Radiation biologists, geneticists, biotechnologists and radiation physicists must carry it out.
The International Commission on Radiological Protection has realised that its old concept that if man is protected, other organisms will be protected has no scientific basis.
K. S. PARTHASARATHY
FORMER SECRETARY, AERB
( ksparth@yahoo.co.uk)
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