Understanding Pb contamination in wild mammals and birds and examining the potential contamination related to ammunition in Japan.

This study investigates lead (Pb) contamination in wild animals in Japan. Pb is a known environmental toxin that can cause several issues in wildlife. Pb is still used in human society, and among Pb products, ammunition is reported to harm human and animal health. In Japan, few instances of Pb contamination in wild animals have been reported outside Hokkaido. Possible reasons for this include the absence of Pb contamination and insufficient investigation. This study aimed to understand the current state of Pb contamination in Japan and clarify the extent of Pb contamination related to ammunition. Blood lead concentrations (BLLs) were measured in wild birds and mammals from 25 municipalities, and an analysis was conducted based on ammunition-related factors. More than half of the avian and mammalian taxonomic groups were found to exhibit Pb contamination from environmental sources. Overall, this study suggests that Pb contamination is also present in wild birds and mammals living outside Hokkaido, Japan, and highlights the risks of mass mortality during infectious disease outbreaks as well as the potential health hazards of Pb exposure upon their consumption by humans. The results of this study highlight the importance of monitoring Pb contamination, particularly in hunting areas of Japan. Further, it indicates the need to reconsider the use of Pb-based ammunition for protecting the health and welfare of both humans and wildlife.