Current situation regarding lead exposure in birds in Japan (2015–2018); leadexposure is still occurring

摘要

Birds of a number of species have died as a result of lead (Pb) poisoning, including manySteller’s sea eagles ( ) and white-tailed sea eagles( ) in Hokkaido, the northernmost island of Japan.To address this issue, the use of any type of Pb ammunition for hunting of large animalswas prohibited in Hokkaido in 2004. However, Pb poisoning is still being reported in thisarea, and there are few regulations regarding the use of Pb ammunition in other parts ofJapan, where it has been reported that eagles and water birds have been exposed to Pb.This study was performed to accurately determine the current level of Pb exposure of birdsfound dead in the field or dead in the wild bird centers in Japan (June 2015–May 2018) andto identify the sources of Pb. Pb exposure was found to still be occurring in raptors andwater birds in various parts of Japan. Twenty-six point five % and 5.9% of the recordeddeaths of Steller’s sea eagles and white-tailed sea eagles, respectively, were found tohave been poisoned by Pb. In addition, Pb isotope ratio analysis showed that both Pb riflebullets and Pb shot pellets cause Pb exposure in birds, and these endangered eagles arealso exposed to Pb in Hokkaido due to the illegal use of Pb ammunition. Changing toPb-free ammunition, such as copper (Cu) rifle bullets, steel shot pellets, or bismuth shotpellets, will be essential for the conservation of avian species in Japan.