-1 radiation at dose rates of up to 200 µ Gy h . It was concluded that changes in nematode community structure at high dose rate sites are a result of either ongoing chronic radiation exposure or the long-term effects of the initial impacts of the accident on invertebrate communities .
Gy = Gray . The SI unit for absorbed dose .
For a person working with radiation one Gray would represent a large dose and therefore the milli Gray ( mGy = 0.001Gy ) and micro Gray (µ Gy = 0.000001Gy ) are often used .
Studies on other groups of invertebrates have also been conducted . One conducted in 2009 reported dramatic declines on the abundance of dragonflies , bees and butterflies at radiation dose rates as low as 1
-1 µ Gy h . Conversely , a study in 2011 that investigated the abundance and diversity of aquatic macroinvertebrate communities , in lakes exposed to radioactive fallout from Chernobyl , found no evidence that these communities were influenced by the Chernobyl accident . Indeed , the most contaminated lake contained the highest richness of aquatic invertebrates .
Researchers have also looked at the effects on mammals . A study in 2013 , which focused on larger mammals , reported significant declines in mammal abundance with higher radiation levels . However , a subsequent study in 2015 which covered a larger area found no relationship between increasing radiation dose and mammal abundance .
Conflicting results have also emerged from studies involving rodents . A series of studies ( 1996 – 2002 ) on rodents in highly
contaminated Ukrainian sites ( internal dose
-1
20 mGy d ) found no evidence of genetic changes but a study from 1995 in Belarus at lower dose rates ( total dose rate up to
-1
30 µ Gy d ) reported an increased frequency of chromosome aberrations .
CHAR Project – Goshawk
A number of radiation effects have been reported in birds including morphological abnormalities ( e . g . deformed wings and beaks ), increase in nonbreeding birds at contaminated sites , elevated frequency of cataracts and reduced abundance . It has been suggested that these negative impacts are caused by increased oxidated stress as a result of the production of free radicals in cells . However , this hypothesis is not supported by a study conducted in 2012 .
A separate study in 2015 investigated the impacts of radiation on cuckoos and concluded that cuckoos in areas subject to higher contamination had abnormal calls compared to those in areas of lower contamination . However , other studies have confirmed it is normal for cuckoos to produce calls of more than two syllables .
How has Chernobyl impacted our knowledge of radiation contamination ? The CEZ has provided a natural laboratory for researchers to understand the impacts on wildlife as opposed to studies conducted under laboratory conditions . Moreover , recolonisation by animal populations , even in areas subject to high levels of radiation , has been able to occur due to the absence of people . The CEZ is an ideal site for studying rewilding initiatives , the effects of humans on biodiversity and ecological succession .
12 Radiation Protection Today www . srp-rpt . uk