An Examination of Radiation Workers at Chornobyl and Residents of Slavutych, Ukraine for Effects of Exposure to Chornobyl Fallout

Brenda E. Rodgers1,2 and Laura K. Baker2 1Department of Biological Sciences Texas Tech University, 2Department of Family Medicine Texas Tech University Health Sciences Center, Lubbock, TX, 79409, USA

 

 

ABSTRACT

 

In October of 1999, a study was conducted on the following four groups: 1) liquidators of the Chornobyl accident (directly involved in the accident cleanup), 2) Ukrainian scientists that have carried out research in the 30km Exclusion Zone, 3) U.S. scientists, who have worked in the Exclusion zone, and 4) residents of Slavutych, Ukraine, with no occupational exposure to the Chornobyl fallout. Documented radiation doses ranged from 25 to 280 mSv in the Liquidator group and 0.21 to 1.75 mSv in the U.S. research group. Each subject was given a complete physical exam and a whole body count of gamma radiation levels. Each participant answered detailed health and radiation exposure history questionnaires. Blood and urine samples were obtained for chemical analyses. Blood smears were examined for differential lymphocyte and micronucleus counts. Analysis of blood samples indicates no evidence of thyroid disease in any group. In Ukrainian subjects, white blood cell counts were lower and mean corpuscular volumes were higher than in the U.S. researchers, but there was no significant difference among groups. Micronucleus (MN) frequencies were significantly elevated (c 2, p<0.005) in all experimental groups when compared to the reference group from Slavutych. From this preliminary study, we cannot unambiguously determine whether the observed increase in MN erythrocytes were the direct result of exposure to radiation, some unknown confounding factor, or a synergistic interaction between these. Further study of a larger cohort is needed to determine if these chromosomal aberrations are stable and truly indicative of any long-term health risk of exposure to the fallout from Chornobyl.

 

Blood samples analyzed

32 hematological variables, thyroid function, blood chemistry, MN assay

Results

Normal leukocyte counts and morphology Normal TSH levels

MN counts significantly elevated in all exposed groups

 

 

Physical exam

Blood pressure/pulse

Eyes(cataracts)

Thyroid

Heart/Lungs

Abdomen/extremities

Weinberg et al., 1995. JAMA 274(5):408-412

 

Results

No enlarged thyroids

No cataracts

No evidence of tumors

No chronic disease states

 

Conclusions

Highest counts were observed in those recently exposed to the exclusion zone OR those with the highest magnitude of exposure.

Data suggest a linear relationship between time since first exposure and magnitude of exposure.

Due to the limitations of this pilot study (small sample size and a single sample) we cannot conclude from these data whether the observed increases in MN are the direct result of exposure to radiation. However, no correlation was observed between MN frequency and confounders analyzed (age, diet, smoking, etc.)

We were able to determine the feasibility of conducting such research in Ukraine and future research projects will include an expanded, long- term study of this cohort

Mean percent micronuclei (MN). 10,000 erythrocytes per individual were examined . The reference group is comprised of residents of Slavutych, Ukraine. The study groups have been occupationally exposed to Chornobyl radiation.

R= reference population (N=11), UR = Ukrainian research group (N=10), L = Liquidators (N=10), US = U.S. research group (N=7).

 

Subjects Recruited by International Radioecology Laboratory:

Matched in age, gender and smoking habits

Health history questionnaire

Exposure history questionnaire

Dosimetry records

Whole body count at CNPP

Study Groups

 

Residents of Slavutych, Ukraine – no occupational exposure (N=11)

Liquidators – each with > 25mSv occupational exposure (N=10)

Ukrainian Researchers – conducting research within the Exclusion Zone (N=10)

U.S. Researchers – conducting research within the Exclusion Zone (N=7)

Group

X Age

Occupational Exposure

Whole Body Count

Acknowledgments

Dr. Robert Baker (TTU)

Dr. Ronald Chesser (TTU)

Dr. Mikhail Bondarkov (IRL)

Dr. Anatoly Nosovsky (SLRT)

Dr. O.A. Martynova

T. Dyma (Ukrainian nurse pictured)

A.S. Veremetsky (ChNPP)

N.G. Povernova (ChNPP)

N.I. Drapey (ChNPP)

Texas GAP Analysis Program (TTU)

Slavutich 42 none (32-42 µCi; N=4)
Liquidators 44 (25-280 mSv) (46 µCi; N=1)
Ukrainian 44 no records available (21-156 µCi; N=5)
U.S. 46 (0.02-1.75 mSv) ~

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