The long-distance transport potential of toxic lead (Pb) by plastic marine debris was examined by pure water leaching experiments using plastic fishery floats containing high level of additive-Pb such as 5100 ± 74.3 mg kg− 1. The leaching of Pb ended after sequential 480-h leaching experiments, and the total leaching amount is equivalent to approximately 0.1% of total Pb in a float. But it recovered when the float was scratched using sandpaper. We propose that a “low-Pb layer,” in which Pb concentration is negligibly small, be generated on the float surface by the initial leaching process. Thickness of the layer is estimated at 2.5 ± 1.2 μm, much shallower than flaws on floats scratched by sandpaper and floats littering beaches. The result suggests that the low-Pb layer is broken by physical abrasion when floats are washed ashore, and that Pb inside the floats can thereafter leach into beaches.
Etsuko Nakashima, Atsuhiko Isobe, Shin’ichiro Kako, Takaaki Itai, Shin Takahashi, Xinyu Guo, Marine Pollution Bulletin, Volume 107, Issue 1, 15 June 2016, Pages 333–339