Challenges of the
Chornobyl Radioactive Vertebrate Collection:
Are You Willing to Sacrifice?

 

INTRODUCTION

The Chornobyl Research Project at Texas Tech University in collaboration with the International Radioecology Laboratory in Ukraine is currently in its 10th year.  To date, intensive field surveys in the Chornobyl nuclear disaster site have brought significant advances in our understanding of ecological and genetic impacts of radiation upon wildlife populations (Matson et al., 2000).  In addition, a large number of valuable specimens and samples corroborating those studies have been generated.  Most of the specimens were collected within a thirty-kilometer ring around the nuclear power plant known as the Exclusion Zone.  Animals obtained from this region have been severely exposed to radiation externally and internally due to a large quantity of radioactive fallout remaining in their habitats.

 

RADIOISOTOPES

As a consequence of the meltdown of the Chornobyl Reactor IV in April 1986, various radioactive substances were dispersed into the environment in large quantities including iodine-131 and other volatile elements, most of which having a half-life of less than a year.  Sixteen years after the accident, however, longer-lived nuclides such as cesium-137 and strontium-90 (Chesser et al., 1999) still being detected from the Chernobyl samples are regarded as major sources of radiation that could potentially cause adverse effects on humans.  Theoretically, ¹³⁷Cs has a half-life of 30.0 years and emits beta and gamma radiations in the process of its radioactive decay, whereas ⁹⁰Sr generates beta rays with its half-life of 28.8 years.

 

COLLECTION OVERVIEW

At present, cataloging and installation of the voucher specimens are under way at the Natural Science Research Laboratory (NSRL), Museum of Texas Tech University.  Nearly 3000 of these vouchers comprise the Chornobyl Radioactive Vertebrate Collection, a highly unique natural history collection in the world.  In particular, rodents (Apodemus, Microtus, Clethrionomys, etc.) account for over 80 percent of those specimens, and they are housed as either study skins, flat skins, skeletons, or fluid specimens.  The collection also contains radioactive frozen tissue and blood samples.  Some tissues are preserved in lysis buffer solution.

The Radioactive Collection room.	Study skins of rodents stored in a specimen case in the Radioactive Collection room.

 

COLLECTION STORAGE

All radioactive specimens and samples except for frozen tissues are housed in the dedicated Radioactive Collection room (ca. 18.5 m²) in the NSRL.  Study skins, flat skins, and osteological specimens are installed in four metal specimen cases with metal drawers.  Fluid specimens in glass jars and blood samples in plastic centrifuge tubes are both stored on the open metal shelving.  An ultracold freezer (–80°C) maintaining radioactive frozen tissues and a conventional freezer (–20°C) for processing those samples are currently located in the main tissue collection room of the NSRL, but access to these freezers is strictly restricted to license holders.  All the facilities and equipment dedicated for radioactive samples storage as well as supplies used in the Chornobyl Collection room are clearly labeled as ‘RADIOACTIVE’ by a sticker or adhesive tape showing a standard sign of radiation on it.

Fluid specimens and blood samples stored on the open shelving.	Freezers dedicated for radioactive frozen tissues.

 

HUMAN AND ENVIRONMENTAL SAFETY

Every effort has been made to minimize the potential health and environmental safety risks associated with work involving radioactive specimens.  Appropriate safety and security measures have been incorporated to fulfill the mission under ‘As Low As Reasonably Achievable’ level of occupational exposure to radiation.  Only licensees who completed a special safety training course administered by the Radiation Safety Services of the University are permitted to work in the Radioactive Collection room.  Every worker in the room is required to wear a laboratory gown and globes as well as a film badge while on duty.  An acrylic shield is equipped on a work desk to mitigate the external exposure to radiation coming from specimens.  Besides quick contamination checks by survey meters after every use of the facility, we also meet a legal obligation to conduct monthly inspections by swipe tests of several points in the working area.

A work desk in the Radioactive Collection room.	A radiation safety and monitoring kit.

 

MANAGEMENT OF A DERMESTID COLONY

Limited resources in terms of work space require optimal use of the Chornobyl Collection room.  This room is used not only as collection storage but also for all curatorial and collection management activities including osteological preparation.  A dermestid colony for defleshing skeletal material is located adjacent to where study skins are housed in the same room.  In order to prevent potential biohazard spread by beetles, the colony housed in a small aquarium is exterminated as each cycle of the cleaning process has been completed.  Osteological material is further hand-cleaned with the greatest caution.  Moreover, all the specimen cases are currently treated with naphthalene to reduce the high risk of infestation by accidentally freed beetles.  Although today’s museum profession does not recommend its use in normal natural history collections storage, it is merited under these circumstances.

 

RADIOACTIVE WASTE

Collection management practices dealing with the Chornobyl Collection inevitably produce radioactive waste over time.  The disposal of hazardous material is executed strictly following federal and state regulations.  Efforts have been made to keep the amount of waste to the minimum.  The radioactive waste is classified into solid and liquid material.  The solid waste includes laboratory supplies comprised primarily of paper and plastic products such as used surgical gloves.  These constitute a major proportion of the total mass of waste.  Additionally, dirt and fluff generated from specimens, frass, cast-off skins, and carcasses of bugs in the dermestid colony are also treated as solid waste.  Meanwhile, the liquid waste contains aqueous buffer solutions spent for biochemical preparation purposes.  There is no sewage system equipped in the room, and thus the liquid is kept in an airtight container until picked up by the Radiation Safety Services staff.

Radioactive waste storage.

 

CONCLUSION

The in-perpetuity preservation of the unparalleled Chornobyl Radioactive Vertebrate Collection is our responsibility to society.  At the same time, human and environmental safety must be given the highest priority.  It is very important to make informed judgments based on scientific knowledge of radiation, regular monitoring of the work environment, and proactive thinking with regards to the long-term influence of every action to be taken upon health, safety, and the collection itself.  Improved preventive approaches will be made to ensure proper specific risk management.  This is required to fulfill our responsibility.  One such strategy is the formulation of an emergency preparedness plan for an unforeseen radiation accident as well as the standards for management of the Radioactive Collection.

 

LITERATURE CITED

Matson, C. W., B. E. Rodgers, R. K. Chesser, and R. J. Baker.  2000.  Genetic diversity of Clethrionomys glareolus populations from highly contaminated sites in the Chornobyl region, Ukraine.  Environmental Toxicology and Chemistry.  19: 2130-2135.

Chesser, R. K., D. W. Sugg, M. D. Lomakin, R. A. Van Den Bussche, J. A. Dewoody, C. H. Jagoe, C. E. Dallas, F. W. Whicker, M. H. Smith, S. P. Gaschak, I. V. Chizhevsky, V. V. Lyabik, E. G. Buntova, K. Holloman, and R. J. Baker.  1999.  Concentrations and dose rate estimates of ^{134, 137}cesium and ⁹⁰strontium in small mammals at Chornobyl, Ukraine.  Environmental Toxicology and Chemistry.  19: 305-312.

 

ACKNOWLEGMENTS

We are thankful to the Radiation Safety Services, Texas Tech University Health Sciences Center for providing us with technical advice regarding radiation safety.