|
| Chemical speciation and bioaccessibility of arsenate in soil as influenced by humic acids |
| Received:January 10, 2017 |
| View Full Text View/Add Comment Download reader |
| KeyWord:humic acids;bioaccessibility;arsenic;species;humic acid;fulvic acid |
| Author Name | Affiliation | E-mail | | WANG Jun | College of Resources and Environment, Southwest University, Chongqing 400716, China
Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, China
Key Laboratory of the Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing 400716, China | | | WANG Qing-qing | College of Resources and Environment, Southwest University, Chongqing 400716, China
Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, China
Key Laboratory of the Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing 400716, China | | | WEI Shi-qiang | College of Resources and Environment, Southwest University, Chongqing 400716, China
Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, China
Key Laboratory of the Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing 400716, China | sqwei@swu.edu.cn |
|
| Hits: 2361 |
| Download times: 2683 |
| Abstract: |
| The speciation and bioaccessibility of heavy metals in soil are influenced by humic acids(HAs), which exist widely in the environment. An in vitro experiment was carried out to elucidate the effects of the two active components of HAs(fulvic acid, FA; and humic acid, HA) and the HA/FA ratio on the speciation and bioaccessibility of arsenate(As) in soils. The relationship between the bioaccessibility and transformation of As in soils, as influenced by HAs, was analyzed. The results showed that HAs could increase the allocation proportion of Ex-As in soil at an application dosage of ≤1%(as carbon, C, basis). FA could observably promote the transformation of soil As from Al-As and Fe-As forms to Res-As species, and the effects were enhanced with an increase in the FA dosage. However, HA showed a weaker or even reversed role in affecting such a transformation process at the highest usage of 5% C. FA and HA at 3% C usage could increase the bioaccessibility of soil As in the gastric phase. The bioaccessibility of soil As in the small intestinal phase was always enhanced by HA and FA regardless of their usage levels. HAs with different HA/FA ratios always enhanced the bioaccessibility of soil As in both gastric and small intestinal phases at a constant usage of 1% C; the degree of the effect was related to the HA/FA ratio, with a maximum bioaccessibility of soil As in the gastric phase and a minimum bioaccessibility of soil As in the small intestinal phase at HA/FA ratios of 5/5 and 7/3, respectively. The bioaccessibility of soil As was strongly linked to As speciation in soil as influenced by HAs. Ex-As and Ca-As forms were found to have significantly positive contributions to the bioaccessible As in the gastric phase, with Ex-As being greater than Ca-As per unit, and only Ca-As showed a significant positive contribution to the bioaccessibility of soil As in the small intestinal phase. |
|
|
|
