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Hayama SI, Nakanishi S, Tanaka A, Kato T, Watanabe C, Kikuchi N, Danjo R, Matsuda A, Mori W, Kawabata Y, Akiba H, Konno F, Kawamoto Y, Omi T. Decline in the Conception Rate of Wild Japanese Monkeys after the Fukushima Daiichi Nuclear Power Plant Accident. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2024; 86:325-334. [PMID: 38664243 PMCID: PMC11143026 DOI: 10.1007/s00244-024-01063-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 03/26/2024] [Indexed: 06/02/2024]
Abstract
We examined the conception rate of wild Japanese monkeys (Macaca fuscata) in Fukushima City that were exposed to radiation as a result of the Fukushima Daiichi Nuclear Power Plant accident in March 2011. The conception rate in the year of delivery from 2009 to 2022 was estimated by dissecting individuals that were euthanized by the government for population control as a countermeasure against crop damage. To evaluate the effects of exposure, the cumulative exposure dose for each individual was calculated using the concentration of radiocesium deposited in the soil at the capture site and the concentration of radiocesium in muscle estimated from the aggregated transfer factor. There were no significant differences in conception rates across all age classes over time. In terms of conception rates by age class, there was a significant decrease post-exposure compared with pre-exposure in the age class ≥ 8 years, but no significant differences in the age class 5-7 years. The non-ovulation rate did not significantly differ between the pre- and post-exposure periods for any age class. Body fat index, which can affect fertility, was compared between the pre- and post-exposure periods, and no significant differences were found in either age class. In contrast, the median total cumulative exposure (cumulative internal exposure + cumulative external exposure) was significantly higher in the age class ≥ 8 years compared with the age class 5-7 years. These results suggest that the total cumulative exposure dose may be one of the reasons for the lower conception rate in the post-exposure period among the age class ≥ 8 years.
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Affiliation(s)
- Shin-Ichi Hayama
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan.
| | - Setsuko Nakanishi
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan
| | - Aki Tanaka
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan
| | - Takuya Kato
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan
| | - Chinatsu Watanabe
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan
| | - Nobutaka Kikuchi
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan
| | - Risa Danjo
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan
| | - Ayano Matsuda
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan
| | - Wakako Mori
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan
| | - Yuki Kawabata
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan
| | - Hikari Akiba
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan
| | - Fumiharu Konno
- Tohoku Wildlife Management Center, Sendai, Miyagi, 989-3212, Japan
| | - Yoshi Kawamoto
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan
| | - Toshinori Omi
- School of Veterinary Nursing and Technology, Nippon Veterinary and Life Science University, Musashino, Tokyo, 180-8602, Japan
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Hayama SI, Nakanishi S, Tanaka A, Konno F, Kawamoto Y, Omi T. Influence of radiation exposure to delayed fetal growth in wild Japanese monkeys after the Fukushima accident. Front Vet Sci 2023; 10:1151361. [PMID: 37180055 PMCID: PMC10169707 DOI: 10.3389/fvets.2023.1151361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/13/2023] [Indexed: 05/15/2023] Open
Abstract
Wild Japanese monkeys (Macaca fuscata) were exposed to radiation after the Fukushima Daiichi nuclear accident in 2011. To clarify the biological effects of radiation exposure on their fetal growth, pregnant monkeys and their fetuses were analyzed. These animals were collected between 2008 and 2020 (before and after the accident in 2011) living in Fukushima City, approximately 70 km from the nuclear power plant. Multiple regression analyses were conducted with fetal body weight (FBW) and fetal head circumference (FHS) as objective variables, and maternal and fetal factors as explanatory variables. The maternal factors were relative exposure dose rate (REDR), age, body weight, body length, fat index, and parity. The fetal factors were crown ramp length (CRL) and sex. Multiple regression analyses showed that FBR and FHS growth were positively associated with CRL, maternal body length, and negatively associated with REDR. Since the relative growth of FBR and FHS to CRL decreased with increasing REDR, radiation exposure due to the nuclear accident may have contributed to the delayed fetal growth observed in Japanese monkeys.
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Affiliation(s)
- Shin-ichi Hayama
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, Japan
| | - Setsuko Nakanishi
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, Japan
| | - Aki Tanaka
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, Japan
| | - Fumiharu Konno
- Tohoku Wildlife Management Center, Sendai, Miyagi, Japan
| | - Yoshi Kawamoto
- School of Veterinary Medicine, Nippon Veterinary and Life Science University, Musashino, Tokyo, Japan
| | - Toshinori Omi
- School of Veterinary Nursing and Technology, Nippon Veterinary and Life Science University, Musashino, Tokyo, Japan
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