sergey gashchak – ecology of the chernobyl zone

Ecology of the Chernobyl Zone: Nuclear desert or wildlife paradise?

Sergey Gashchak (Slavutych, Ukraine)

International Radioecology Laboratory

P.O. Box 151, 77th Gvardeiskaya Diviziya St. 7/1, Slavutych, Kiev Region, Ukraine 07100

Who I am: Introduction •  Education – biology (biology and ecology of

Vertebrates), 1984

•  Ph.D. – radioecology, countermeasures for agricultural animals production, 1996

•  Specialization – radioecology, radiation impact on wildlife, generic ecology of Chernobyl natural complexes, biodiversity and conservation

•  Skills – spectrometry, radiochemistry, lab and field research of Vertebrates

•  Professional preference – biodiversity, bats, birds

•  Current position (since 2000) – Deputy Director, International Radioecology Laboratory (Slavutych)

First meeting with Chernobyl •  July-September 1986

•  Officer of Soviet Army

•  Cleaning up the cars in 3 km area around the destroyed reactor

•  Since July 1990 – up to now, lab assistant – up to Deputy Director

•  Radioecology of agricultural animals, countermeasures, effects of radiation impact.

•  Radioecology of wild boar and roe deer, Murines and shrews, small birds, bats, amphibians, reptilians.

•  Generic ecology of zoological complexes, biodiversity, census of birds, bats, small mammals.

•  Effects of radiation impact in populations of wild animals

•  Radiation ecology of urbo landscape.

•  Migration and distribution of radionuclides in terrestrial ecosystems

•  Tens International research projects with scientists from U.S.A., U.K., Sweden, France

•  Long-term experience as an IAEA expert (urbo radioecology and biota dosimetry)

•  More 70 articles

•  Tens reports at the scientific conferences

Chernobyl Exclusion

Zone

Russia

Belarus

Ukraine

Poland

France

Germany

Italy

Romania

Chernobyl zone: Location

Kiev

Slavutych ChNPP

50 km from Slavutych and Ivankov 100 km from Kiev (capital)

Ivankov

Chernobyl zone: Shape

2600 km2

Chernobyl zone: Contamination

Chernobyl zone: Contamination

241Am 154Eu

238Pu 241Pu

Chernobyl zone: Status

•  Secure territorial object with own administration

•  Strictly restricted access

•  Restricted set of activities

•  Restricted and controlled movement

•  A lot of lows defining rules of behavior and being there

•  Almost no resident population (only near 200 people)

•  Mostly staff of different enterprises, service and research organizations (now near 5000).

Chernobyl zone: Mission •  Protect regular population from

the radioactive contamination

•  Control and restrict movement of the radioactive depositions

•  Maintain ecosystems of the region in stable and safe state

•  Controlled elimination of the accident’s consequences

•  Promote the natural process of auto rehabilitation of the lands

Modern landscapes and biocenoses were created 10000-30000 years ago during Glacial periods

Now – near 60-70% of the territory under forests and new wood growth up

Vegetation – boreal on poor organic soils and overwetted low-lands (pine forests and mixed pine & deciduous forests, swamps)

Near 1500 lichens, moss and higher plants

•  Fuel, fission and activation products – evaporated, finely dispersed and distributed on very vast area (1017-1018 Bq).

•  A lot of “hot particles”.

•  Most of radioactive matters in very mobile state (aerosols, dust, gases) in air and surfaces.

•  Tens radioactive isotopes in different chemical and physical forms.

•  External dose rates ranged from 0.1 up to 1000 mGy/hr (it is 1000-10000000 times higher the natural level)

•  Coniferous woods died around the ChNPP (“Red Forest”) – up to 400-500 ha (near 1000 ha more – heavy affections).

•  Vertebrates likely died also if stayed long time close ChNPP or in radioactive spots (there are few evidences).

•  Even Invertebrates suffered (disappearance of number soil species)

•  A lot of health troubles, injures, violations in reproduction and development (both flora and fauna). Evidence of radiation effects in cells, tissues, populations, biocenosis.

But! •  Most of these effects took place on very limited areas

around ChNPP, in spots of considerable fallouts, and along tracks of the radioactive clouds.

•  Following decay of the short and medium-lived isotopes the radiation situation changed fast and became soon softer.

•  Wild animals were not restricted for movement, and constantly visited (occupied) even the most contaminated sites. It was not a nuclear desert!

•  Degradation of coniferous forest ecosystem;

•  Increased mortality of number organism (flora, fauna);

•  Inhibition of reproduction and development (flora and fauna);

•  Abnormalities (morphosises, teratogenesis, numerous evidences of epigenetic effects);

•  Changes of species composition and population structures.

There were no “monsters” or “mutants”!!!

•  Cytogenetic •  Genetic •  Histologic •  Biochemical •  Physiological •  Immunological •  Etc.

•  Dose dependant •  Species dependant •  Sex-age dependant •  Physiological state

•  No “visible” radio-determined effects

•  Hardly distinguishing “invisible” effects

•  Absolute and total predominance of secondary ecological effects, i.e.:

•  Degradation of human-dependant ecosystems

•  Reverse development to wild autochthonic (native) type (succession)

•  Gradual recovery of the lost wildlife abundance and diversity

•  Growing abundance and diversity of wildlife

•  Reduction of “invisible” effects of radiation impact

•  Gradual recovery: “Red Forest” to “Green Forest”

Wildlife appeared to be thriving!!!

•  Total resettlement of human population

•  The largest technogenic catastrophe with Global negative effects

•  Extreme high and very dangerous radiation conditions

Explanation 1: Radiation is a norm of the

Universe

•  Radioactive isotopes and all kind of radiation were always and everywhere, and much before appearance of the biological objects.

•  All live appeared under permanent action of the radiation (external and internal)

•  The biological matter had to elaborate means and ways for the radioresistance.

Explanation: Radioresistance

Explanation 2: Dose - Effect Certainly radiation is a negative destructive factor. But the effect depends on:

•  Total value of the absorbed dose from external and internal sources.

•  Rate of the exposure to radiation.

•  History and circumstances of the irradiation.

•  Genetically determined radioresistance.

•  Ecological, biological and behavior features of the given individual organism.

Explanation 3: Unevenness of the spatial contamination

•  Less contaminated areas predominate

•  Actively moving animals with large home range relatively rarer visit the ‘hot’ spots – “pure math”

•  Migrants regularly leave the radioactive areas

•  Considerable part of animal populations have opportunity to reduce the affect and to recover

Explanation 4: Metabolism of the radionuclides

•  137Cs is both accumulated fast and rather quickly excreted from the animal organism

•  Heavy isotopes (Pu, Am, U) have extremely negligible factor of accumulation in biota

•  Among present long-lived isotopes only 90Sr is excreted slow, but it is mostly accumulated in skeletons

137Cs 90Sr

Explanation 5: Considerable decrease of radiation

(From Wikipedia)

•  Almost complete decay of short lived isotopes during first 5 years

•  Considerable decay of medium-lived isotopes

•  102-103-decrease of external dose rate

•  Now the most radiologically important: 137Cs, 90Sr, 241Am.

• Due to decay of radionuclides the area with extremely high radiation is permanently reducing.

0.2 mGy/hr - 1996

• The main pool of depositions transferred into dipper layers of soil (3-10 cm). Decrease of availability and screening radiation.

• Binding 137Cs with soil mineral and organic complexes.

Even soil-dwelling animals are not much contaminated on the body surface

Explanation 8: No men – the more opportunities for wildlife

•  No hunting and fishing, no disturbance

•  No forestry, agricultural and industrial activities; no chemical impact

•  90% of the territory – absolutely abandoned (de facto regime of natural reserve)

•  Recovery or almost recovery of natural state of the former agricultural lands, and degradation of the drainage systems, recovery of swamped lands

•  Increase of mature and ill woodstands, favorable for tree-dwelling animals (bats, owls, eagles, etc)

•  Before the accident it was mostly “natural” ecosystems (forests 40%, meadows, marshes) and semi-natural (agricultural lands)

1986 р.

•  There were number natural reserves in 50-150 km vicinities.

•  Large European rivers Dnieper and Pripyat

•  Crossroad of great season migrations of the birds

Chernobyl natural complexes: 25 yrs after

•  High radioactive contamination of biota (up to 104-105 Bq g-1) and high absorbed doses (up to 1-50 mSv d-1) are still possible in the most contaminated sites.

•  Numerous effects of negative influence of radiation are still observed in the most contaminated sites.

•  On 99% of the territory radiation effects are not observed, or radiation determination is impossible to prove.

•  On 99% of the territory relation “Dose-Effect” does not work.

•  Generic ecological factors, intra-population processes and interspecies interactions, gradual development of the abandoned ecosystems – absolutely predominate and can explain most of the effects.

Chernobyl natural complexes: 25 yrs after

1. 260 000 ha of Ukraine + 215 000 ha of Belarus in the middle of Europe, where Man almost does not disturb wildlife during last 25 years, and at least 10-20 years more further

Chernobyl natural complexes: 25 yrs after

2. Conditions appeared for recovery

•  biocenosis relationships and interactions, which existed there 1000 years ago

•  Animals which need vast individual territories

•  Animals sensitive to disturbance and persecution

•  Species, which need old and untreated woodlands and marshes

Chernobyl natural complexes: 25 yrs after

Chernobyl natural complexes: 25 yrs after

Net of protected natural territories (red), and lands proposed for nature conservation activity

Nuclear desert or wildlife paradise? •  This is not the Desert

•  This is still not complete Paradise

•  This is a beginning of Real Life without people

•  This is an example of what adventures the wildlife can get if no people

•  This is a test for people maturity, how wise our decisions can be

•  People as a rule consider non-human biota anthopomorphically: emphasizing individual risks (threats) and underestimate population and biocenosis capabilities to maintain total “homeostasis” formed during millions years

•  Direct transfer of the “lab effects” on natural systems

•  Ignoring importance of non-radiation factors and natural history of the objects studied

After word •  A lot of people know the words “CHERNOBYL” and

“RADIATION”, but FEW have basic knowledge of radiation and radiation impact on biological objects. IT HAS TO BELIEVE those who pose themselves as specialists in these fields.

•  At that the public as usual does not examine quality of judgments and conclusions of the “RESEARCHERS” and “SPECIALISTS”.

•  At the global reduction of the science support it threatens not only with misunderstanding, stupid ideas and extra fears, it makes more serious effects: high risks of new accidents, ungrounded expenses, and inability to arrange safe, comfortable and nature-friendly life.

Science must be strong and wise! Science need real support and respect!

Thank you for the attention!