High Fe and Ca contents contribute to geologically-high As but bioaccessibly-low As in karstic residential soils
Karstic soils are often naturally-high in As contents, primarily due to the secondary enrichment during soil weathering from carbonate rocks. However, the As risk via soil exposure for residents in karst areas remains unclear. In this study, we collected 32 residential soils from rural karst area in...
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Elsevier
2025-04-01
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| Series: | Soil & Environmental Health |
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| author | Yuanchen Zhang Guobing Lin Chenjing Liu Zhongfang Yang Lena Q. Ma |
| author_facet | Yuanchen Zhang Guobing Lin Chenjing Liu Zhongfang Yang Lena Q. Ma |
| author_sort | Yuanchen Zhang |
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| description | Karstic soils are often naturally-high in As contents, primarily due to the secondary enrichment during soil weathering from carbonate rocks. However, the As risk via soil exposure for residents in karst areas remains unclear. In this study, we collected 32 residential soils from rural karst area in Guangxi and measured their total As, Fe, Ca and organic C contents. To assess their health risk, we determined and compared bioaccessible As, Fe, and Ca using three in vitro assays (solubility bioaccessibility research consortium-SBRC, physiologically based extraction test-PBET, and in vitro gastrointestinal methods-IVG). The karstic soils showed high As contents at 8.09–256 mg kg−1, averaging 58.2 mg kg−1, but low bioaccessible As at 0.386–0.977 mg kg−1, averaging 0.783 mg kg−1. The As bioaccessibility was low at 1.14–3.34%, averaging 1.97%, suggesting a low health risk to humans via incidental oral ingestion. The high Fe content averaging 74.8 g kg−1 may have contributed to As enrichment in karstic soils, with a positive correlation of R2 = 0.623. Further, the low Fe bioaccessibility at 0.28% in the gastric phase of SBRC indicated that Fe was poorly soluble in simulated gastrointestinal solution, which may have contributed to low bioaccessible As (R2 = 0.360). Besides, bioaccessible Ca and soil organic C may also play a role with R2 = 0.404−0.449. This study sheds light on the high total As contents but low bioaccessible As in residential soils, indicating the low health risks via incidental oral ingestion in karst areas. |
| format | Article |
| id | doaj-art-3cbf9adf49f343dfaf7f2e25f15bd0d3 |
| institution | Kabale University |
| issn | 2949-9194 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Soil & Environmental Health |
| spelling | doaj-art-3cbf9adf49f343dfaf7f2e25f15bd0d32025-08-20T03:52:06ZengElsevierSoil & Environmental Health2949-91942025-04-013210014210.1016/j.seh.2025.100142High Fe and Ca contents contribute to geologically-high As but bioaccessibly-low As in karstic residential soilsYuanchen Zhang0Guobing Lin1Chenjing Liu2Zhongfang Yang3Lena Q. Ma4Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, ChinaZhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, ChinaZhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, ChinaSchool of Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, ChinaZhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Corresponding author.Karstic soils are often naturally-high in As contents, primarily due to the secondary enrichment during soil weathering from carbonate rocks. However, the As risk via soil exposure for residents in karst areas remains unclear. In this study, we collected 32 residential soils from rural karst area in Guangxi and measured their total As, Fe, Ca and organic C contents. To assess their health risk, we determined and compared bioaccessible As, Fe, and Ca using three in vitro assays (solubility bioaccessibility research consortium-SBRC, physiologically based extraction test-PBET, and in vitro gastrointestinal methods-IVG). The karstic soils showed high As contents at 8.09–256 mg kg−1, averaging 58.2 mg kg−1, but low bioaccessible As at 0.386–0.977 mg kg−1, averaging 0.783 mg kg−1. The As bioaccessibility was low at 1.14–3.34%, averaging 1.97%, suggesting a low health risk to humans via incidental oral ingestion. The high Fe content averaging 74.8 g kg−1 may have contributed to As enrichment in karstic soils, with a positive correlation of R2 = 0.623. Further, the low Fe bioaccessibility at 0.28% in the gastric phase of SBRC indicated that Fe was poorly soluble in simulated gastrointestinal solution, which may have contributed to low bioaccessible As (R2 = 0.360). Besides, bioaccessible Ca and soil organic C may also play a role with R2 = 0.404−0.449. This study sheds light on the high total As contents but low bioaccessible As in residential soils, indicating the low health risks via incidental oral ingestion in karst areas.http://www.sciencedirect.com/science/article/pii/S2949919425000159Health riskIn vitro assaysCarbonate rockSecondary enrichmentIncidental oral ingestionGeochemical background |
| spellingShingle | Yuanchen Zhang Guobing Lin Chenjing Liu Zhongfang Yang Lena Q. Ma High Fe and Ca contents contribute to geologically-high As but bioaccessibly-low As in karstic residential soils Soil & Environmental Health Health risk In vitro assays Carbonate rock Secondary enrichment Incidental oral ingestion Geochemical background |
| title | High Fe and Ca contents contribute to geologically-high As but bioaccessibly-low As in karstic residential soils |
| title_full | High Fe and Ca contents contribute to geologically-high As but bioaccessibly-low As in karstic residential soils |
| title_fullStr | High Fe and Ca contents contribute to geologically-high As but bioaccessibly-low As in karstic residential soils |
| title_full_unstemmed | High Fe and Ca contents contribute to geologically-high As but bioaccessibly-low As in karstic residential soils |
| title_short | High Fe and Ca contents contribute to geologically-high As but bioaccessibly-low As in karstic residential soils |
| title_sort | high fe and ca contents contribute to geologically high as but bioaccessibly low as in karstic residential soils |
| topic | Health risk In vitro assays Carbonate rock Secondary enrichment Incidental oral ingestion Geochemical background |
| url | http://www.sciencedirect.com/science/article/pii/S2949919425000159 |
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