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.
| Original language | English |
|---|---|
| Pages (from-to) | 65-75 |
| Number of pages | 11 |
| Journal | Chemosphere |
| Volume | 202 |
| DOIs | |
| Publication status | Published - 2018 Jul 1 |
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Keywords
- Apatite
- Atoll
- Fixation
- Foraminifera
- Heavy metal
- X-ray absorption near edge structure
ASJC Scopus subject areas
- Chemistry(all)
- Environmental Chemistry
Cite this
Origin and migration of trace elements in the surface sediments of Majuro Atoll, Marshall Islands. / Ito, Lisa; Omori, Takayuki; Yoneda, Minoru; Yamaguchi, Toru; Kobayashi, Ryuta; Takahashi, Yoshio.
In: Chemosphere, Vol. 202, 01.07.2018, p. 65-75.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Origin and migration of trace elements in the surface sediments of Majuro Atoll, Marshall Islands
AU - Ito, Lisa
AU - Omori, Takayuki
AU - Yoneda, Minoru
AU - Yamaguchi, Toru
AU - Kobayashi, Ryuta
AU - Takahashi, Yoshio
PY - 2018/7/1
Y1 - 2018/7/1
N2 - 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.
AB - 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.
KW - Apatite
KW - Atoll
KW - Fixation
KW - Foraminifera
KW - Heavy metal
KW - X-ray absorption near edge structure
UR - http://www.scopus.com/inward/record.url?scp=85043773655&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85043773655&partnerID=8YFLogxK
U2 - 10.1016/j.chemosphere.2018.03.083
DO - 10.1016/j.chemosphere.2018.03.083
M3 - Article
C2 - 29554509
AN - SCOPUS:85043773655
VL - 202
SP - 65
EP - 75
JO - Chemosphere
JF - Chemosphere
SN - 0045-6535
ER -