@article{d0db403f7c774db1933ce2849b93eaf6,
title = "Origin and migration of trace elements in the surface sediments of Majuro Atoll, Marshall Islands",
abstract = "The sediments of Majuro Atoll, Marshall Islands, consist of bioclastic materials, including foraminifera and coral debris. The sedimentary depth profiles of elements showed that various elements including zinc (Zn) and copper (Cu) were enriched in the upper layers of the islands of Majuro Atoll. Carbon-14 dating revealed that the sedimentation of the upper layer was completed before 1670 and 542 cal BP in Laura and Calalen, respectively. The enriched elements could be categorized by their origins: (a) terrestrial elements transported as dust (aluminum (Al) and rare earth elements (REEs)); (b) anthropogenic elements (Zn and Cu); and (c) elements supplied by seabirds (phosphorus (P)). From the results of the total amount of Al supplied to sediments for ca. 2000 years, Al in Majuro Atoll was suggested to be airborne origin. The enrichment factors of the elements normalized to Al concentration of continental crust showed that REEs were also transported as dust, while Zn and Cu were mainly of anthropogenic origin. The speciation analysis by X-ray absorption near-edge structure (XANES) showed the presence of Zn–Cu alloys originated from industrial products. It was also revealed that Zn was enriched in the surface due to anthropogenic emission after urbanization on Majuro Atoll and fixed by carbonate and phosphate at the upper layer, which inhibits migration of Zn into the deeper layer and its release to the groundwater and costal water. Hence, the fixation of heavy metals at the surface prevents their exposure to aquatic organisms and residents via fresh groundwater in the island.",
keywords = "Apatite, Atoll, Fixation, Foraminifera, Heavy metal, X-ray absorption near edge structure",
author = "Lisa Ito and Takayuki Omori and Minoru Yoneda and Toru Yamaguchi and Ryuta Kobayashi and Yoshio Takahashi",
note = "Funding Information: This study was supported by Grants-in-Aid for scientific research from the Ministry of Education, Culture, Sports, Science and Technology of Japan (15H02149, 16H04073, and 16K12627). This work has been performed with the approval of KEK (Proposal Nos. 2015G664 and No. 2016G632) and SPring-8 (Proposal Nos. 2015A0126, 2015B0126, 2015A1809, and 2016A1642). The authors would like to thank Dr. K. Shimoda in Keio University, S. Muto in the University of Tokyo for sampling and H. Yoshida in the University of Tokyo, Dr. K. Sakata in National Institute for Environmental Studies for assistant of analysis. Funding Information: This study was supported by Grants-in-Aid for scientific research from the Ministry of Education, Culture, Sports, Science and Technology of Japan ( 15H02149 , 16H04073 , and 16K12627 ). This work has been performed with the approval of KEK (Proposal Nos. 2015G664 and No. 2016G632) and SPring-8 (Proposal Nos. 2015A0126, 2015B0126, 2015A1809, and 2016A1642). The authors would like to thank Dr. K. Shimoda in Keio University, S. Muto in the University of Tokyo for sampling and H. Yoshida in the University of Tokyo, Dr. K. Sakata in National Institute for Environmental Studies for assistant of analysis. Appendix A Publisher Copyright: {\textcopyright} 2018 Elsevier Ltd",
year = "2018",
month = jul,
doi = "10.1016/j.chemosphere.2018.03.083",
language = "English",
volume = "202",
pages = "65--75",
journal = "Chemosphere",
issn = "0045-6535",
publisher = "Elsevier Limited",
}