Chronic exposure to gamma radiation of wild populations of meadow voles (Microtus pennsylvanicus)

Mihok, Steve

doi:10.1016/j.jenvrad.2004.01.001

Cited by 22 publications

(28 citation statements)

References 55 publications

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“…Plasma was not available from the medium dose‐rate experiment (experiment 1, in 1981–1982) because samples had already been used for genetic studies [24]. Mean ambient background in the region varies from about 0.05 to 0.11 μGy/h across years [21]. In the low dose–rate experiment (experiment 2, November 1982–October 1983), voles on the irradiated area (grid 4) lived in a gamma field of about 200 × background (22.6 ± 2.6 μGy/h) versus a dosage for controls of 0.19 to 0.42 μGy/h.…”

Section: Methodsmentioning

confidence: 99%

“…Cumulative doses from first capture sampled for the 254 voles in this study were 5.0 ± 0.1 mGy for the low group and 1,505 ± 20 mGy for the high group. Doses from conception were estimated at about 1.9X these measured values [21]. Controls received negligible doses, mostly indistinguishable from background, as estimated by the animal dosimetry system used (Harshaw TLD‐100 chips on collars exposed for about 2–4 weeks [21]; Harshaw‐Bicron, Newbury, OH, USA).…”

Section: Methodsmentioning

confidence: 99%

“…This study was designed to test the hormetic hypothesis using samples from a radioecological study of free‐living meadow vole ( Microtus pennsylvanicus ) populations at the Zoological Environment Under Stress (ZEUS) facility in Manitoba, Canada [21]. Specifically, the glucocorticoid stress response was studied in free‐ranging populations exposed in the field with a gamma irradiator for yearlong periods to contrast the impact of low and high chronic doses of gamma radiation.…”

Section: Introductionmentioning

confidence: 99%

“…It is a seasonally reproducing small mammal with breeding concentrated in spring through autumn and little or no reproduction occurring in winter. In Manitoba, the ground is snow‐covered from November to late April and the breeding season typically begins in May and ends in September [21]. These voles have a high reproductive rate, with females becoming pregnant at 25 d of age, having a gestation of 21 d and five to six young per litter, and engaging in postpartum estrus.…”

Section: Introductionmentioning

confidence: 99%

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Hormetic effects of gamma radiation on the stress axis of natural populations of meadow voles (Microtus pennsylvanicus)

Boonstra

Manzon

Mihok

et al. 2005

Environmental Toxicology and Chemistry

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We tested the hypothesis that low doses of gamma radiation have beneficial, hormetic effects on the stress axis (the hypothalamic-pituitary-adrenocortical axis) of free-ranging meadow vole populations (Microtus pennsylvanicus). Voles were exposed to chronic gamma radiation from a 137Cs field irradiator. In isolated populations, voles received one of three treatments over a four-year period: Controls (0.19-0.42 microGy/h--levels that were 2-5x above background levels [0.1 microGy/h] and live-trapped in all years--1982--1985), low doses (22.6 microGy/h--50-200x background, live-trapped from November 1982--April 1985), or high doses (3,840 microGy/h--40,000x background, live-trapped from November 1983--April 1985). Voles exposed to a low dose had levels of free and total corticosterone that were significantly higher than those in the control or high-dose groups. Differences in response to radiation between the sexes were apparent for maximum corticosterone-binding capacity, with females exposed to low doses having higher binding capacity than control or high-dose females, whereas males exposed to low doses had lower binding capacity than control or high-dose males. Low-dose voles had higher counts of neutrophils than either the controls or high-dose voles; hematocrit was greater in the controls than in irradiated voles. These results indicate that voles display a hormetic response to radiation, wherein low doses of an otherwise harmful agent produce a beneficial effect. The stimulation of the stress axis resulting in the increased secretion of glucocorticoids, which may protect against the excessive actions of the immune and inflammatory responses, may be a key mechanism producing this effect.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hormetic effects of gamma radiation on the stress axis of natural populations of meadow voles (Microtus pennsylvanicus)

Boonstra

Manzon

Mihok

et al. 2005

Environmental Toxicology and Chemistry

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“…According results of long-term ZEUS experiments (zoological environment under stress), conducted by Mihok et al [6,7], no effects on population characteristics were detected up in a gradient of gamma radiation (chronic external exposure rate 10-100 mGy/d) of red-backed voles (Clethrionomys gapperi) and meadow voles (Microtus pennsilvanicus). These levels of exposures to low-LET external radiation are insufficient to cause population effects (numbers, reproduction, survival, growth and demography structure of voles), even if some effects on individuals occur.…”

Section: Numbersmentioning

confidence: 99%

East urals radioactive trace: Adaptive strategy of rodents’ population

Grigorkina

Olenev

2011

Radioprotection

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Abstract. Population of small rodents in radiocontaminated environment is compelled to include more energy-intensive way of maintenance its ability to live -increasing of the proportion of mature young of the year (first pathway of ontogeny). Their reproductive characteristics -actual fecundity was higher, whereas embryonic mortality and the proportion of females with embryonic losses were significantly lower compared with neighboring areas. Abundance of mice in the impact zone was higher, age cross was revealed, which improves the adaptive possibility of the population. Preconditions for acceleration of evolutionary transformations of a population are created, but this process is restrained by both the local configuration of the polluted territory and migration of murine rodents. As a consequence, the population decreases the probability that certain changes will be fixed and inherited in a series of generations. Chronic low-dose radiation (stress) can be considered as the mechanism of switching of life history of cyclomorphic mammals. Thus, ontogenetic multiversality of small mammals is an important mechanism of protection strategy of population and decreasing the damaging action on biota in radiocontaminated environment. Functional approach makes it possible to reduce errors in assessing the radiological consequences and hence, can provide a reliable methodological basis for organization of biological monitoring.

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Ecological mechanisms can modify radiation effects in a key forest mammal of Chernobyl

et al. 2019

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Nuclear accidents underpin the need to quantify the ecological mechanisms which determine injury to ecosystems from chronic low‐dose radiation. Here, we tested the hypothesis that ecological mechanisms interact with ionizing radiation to affect natural populations in unexpected ways. We used large‐scale replicated experiments and food manipulations in wild populations of the rodent, Myodes glareolus, inhabiting the region near the site of the Chernobyl disaster of 1986. We show linear decreases in breeding success with increasing ambient radiation levels with no evidence of any threshold below which effects are not seen. Food supplementation of experimental populations resulted in increased abundances but only in locations where radioactive contamination was low (i.e., below ≈ 1 μSv/h). In areas with higher contamination, food supplementation showed no detectable effects. These findings suggest that chronic low‐dose‐rate irradiation can decrease the stability of populations of key forest species, and these effects could potentially scale to broader community changes with concomitant consequences for the ecosystem functioning of forests impacted by nuclear accidents.

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Chronic exposure to gamma radiation of wild populations of meadow voles (Microtus pennsylvanicus)

Cited by 22 publications

References 55 publications

Hormetic effects of gamma radiation on the stress axis of natural populations of meadow voles (Microtus pennsylvanicus)

Hormetic effects of gamma radiation on the stress axis of natural populations of meadow voles (Microtus pennsylvanicus)

East urals radioactive trace: Adaptive strategy of rodents’ population

Ecological mechanisms can modify radiation effects in a key forest mammal of Chernobyl

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