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Characteristics and compound-specific carbon isotope compositions of sedimentary lipids in high arsenic aquifers in the Hetao basin, Inner Mongolia.
Environ Pollut 2018; 241:85-95EP

Abstract

Organic matter, as an electron donor, plays a vital role in As mobilization mediated by microorganisms during reductive dissolution of Fe/Mn oxides in shallow aquifers. However, the specific types and sources of organic matter involved in biogeochemical processes accelerating As mobilization are still controversial. Both sediment and groundwater samples were collected at different depths from aquifers of the Hetao Basin, a typical inland basin hosting high As groundwater. Sedimentary lipids and their compound-specific carbon isotope ratios were analyzed to evaluate characteristics and sources of organic matter. Results show that sedimentary As were well correlated with Fe and Mn oxides, suggesting that As exist as Fe/Mn oxide bound forms. Groundwater As far exceeded the drinking water guide value of 10 μg/L. Moreover, As concentrations in shallow groundwater were relatively higher. Lipids in clay were mainly originated from terrestrial higher plants, while that in fine sand samples were derived from terrestrial higher plants, microorganism and petroleum. Shallow fine sand samples were also characterized by evident in-situ biodegradation. Compound-specific carbon isotope compositions of sedimentary lipids showed that short-chain n-alkanes and n-alkanoic acids had more positive δ13C values compared to long-chain compounds, especially in shallow fine sand samples. δ13CTOC were also low in shallow fine sand samples. These results jointly indicate that these lipids in shallow fine sand samples acted as carbon source for indigenous microorganism and the short-chain components were particularly more vulnerable to biodegradation, which may contribute to high As concentrations in shallow groundwater. The new findings provide the first evidence that short chain length n-alkyl compounds afforded a source of potential electron donors for microbially mediated As mobilization process in the shallow aquifers.

Authors+Show Affiliations

State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing 100083, PR China.State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing 100083, PR China; MOE Key Laboratory of Groundwater Circulation & Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, PR China. Electronic address: hmguo@cugb.edu.cn.State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing 100083, PR China.MOE Key Laboratory of Groundwater Circulation & Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, PR China.Laboratory of Critical Zone Evolution, School of Earth Science, China University of Geosciences (Wuhan), Wuhan 430074, PR China.State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing 100083, PR China; MOE Key Laboratory of Groundwater Circulation & Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, PR China.MOE Key Laboratory of Groundwater Circulation & Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, PR China.MOE Key Laboratory of Groundwater Circulation & Environment Evolution & School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, PR China.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

29803028

Citation

Mao, Ruoyu, et al. "Characteristics and Compound-specific Carbon Isotope Compositions of Sedimentary Lipids in High Arsenic Aquifers in the Hetao Basin, Inner Mongolia." Environmental Pollution (Barking, Essex : 1987), vol. 241, 2018, pp. 85-95.
Mao R, Guo H, Xiu W, et al. Characteristics and compound-specific carbon isotope compositions of sedimentary lipids in high arsenic aquifers in the Hetao basin, Inner Mongolia. Environ Pollut. 2018;241:85-95.
Mao, R., Guo, H., Xiu, W., Yang, Y., Huang, X., Zhou, Y., ... Jin, J. (2018). Characteristics and compound-specific carbon isotope compositions of sedimentary lipids in high arsenic aquifers in the Hetao basin, Inner Mongolia. Environmental Pollution (Barking, Essex : 1987), 241, pp. 85-95. doi:10.1016/j.envpol.2018.05.021.
Mao R, et al. Characteristics and Compound-specific Carbon Isotope Compositions of Sedimentary Lipids in High Arsenic Aquifers in the Hetao Basin, Inner Mongolia. Environ Pollut. 2018;241:85-95. PubMed PMID: 29803028.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characteristics and compound-specific carbon isotope compositions of sedimentary lipids in high arsenic aquifers in the Hetao basin, Inner Mongolia. AU - Mao,Ruoyu, AU - Guo,Huaming, AU - Xiu,Wei, AU - Yang,Yuance, AU - Huang,Xianyu, AU - Zhou,Yinzhu, AU - Li,Xiaomeng, AU - Jin,Jianyi, Y1 - 2018/05/23/ PY - 2018/02/02/received PY - 2018/04/19/revised PY - 2018/05/04/accepted PY - 2018/5/29/pubmed PY - 2018/9/27/medline PY - 2018/5/27/entrez KW - Arsenic KW - Biomarker KW - GC-IRMS KW - Groundwater KW - Organic matter SP - 85 EP - 95 JF - Environmental pollution (Barking, Essex : 1987) JO - Environ. Pollut. VL - 241 N2 - Organic matter, as an electron donor, plays a vital role in As mobilization mediated by microorganisms during reductive dissolution of Fe/Mn oxides in shallow aquifers. However, the specific types and sources of organic matter involved in biogeochemical processes accelerating As mobilization are still controversial. Both sediment and groundwater samples were collected at different depths from aquifers of the Hetao Basin, a typical inland basin hosting high As groundwater. Sedimentary lipids and their compound-specific carbon isotope ratios were analyzed to evaluate characteristics and sources of organic matter. Results show that sedimentary As were well correlated with Fe and Mn oxides, suggesting that As exist as Fe/Mn oxide bound forms. Groundwater As far exceeded the drinking water guide value of 10 μg/L. Moreover, As concentrations in shallow groundwater were relatively higher. Lipids in clay were mainly originated from terrestrial higher plants, while that in fine sand samples were derived from terrestrial higher plants, microorganism and petroleum. Shallow fine sand samples were also characterized by evident in-situ biodegradation. Compound-specific carbon isotope compositions of sedimentary lipids showed that short-chain n-alkanes and n-alkanoic acids had more positive δ13C values compared to long-chain compounds, especially in shallow fine sand samples. δ13CTOC were also low in shallow fine sand samples. These results jointly indicate that these lipids in shallow fine sand samples acted as carbon source for indigenous microorganism and the short-chain components were particularly more vulnerable to biodegradation, which may contribute to high As concentrations in shallow groundwater. The new findings provide the first evidence that short chain length n-alkyl compounds afforded a source of potential electron donors for microbially mediated As mobilization process in the shallow aquifers. SN - 1873-6424 UR - https://www.unboundmedicine.com/medline/citation/29803028/Characteristics_and_compound_specific_carbon_isotope_compositions_of_sedimentary_lipids_in_high_arsenic_aquifers_in_the_Hetao_basin_Inner_Mongolia_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0269-7491(18)30488-3 DB - PRIME DP - Unbound Medicine ER -