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Microbially mediated reduction of FeIII and AsV in Cambodian sediments amended with 13C-labelled hexadecane and kerogen

Athanasios Rizoulis A , Wafa M. Al Lawati A B , Richard D. Pancost C , David A. Polya A , Bart E. van Dongen A and Jonathan R. Lloyd A D
+ Author Affiliations
- Author Affiliations

A School of Earth, Atmospheric and Environmental Sciences and Williamson Research Centre for Molecular Environmental Science, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.

B Higher College of Technology, Ministry of Manpower, Al Janubyyah Street, 133, Muscat, Sultanate of Oman.

C Organic Geochemistry Unit, The Cabot Institute, School of Chemistry, Cantock’s Close, Bristol University, Bristol, BS8 1TS, UK.

D Corresponding author. Email: jon.lloyd@manchester.ac.uk

Environmental Chemistry 11(5) 538-546 https://doi.org/10.1071/EN13238
Submitted: 22 December 2013  Accepted: 5 June 2014   Published: 25 September 2014

Journal Compilation © CSIRO Publishing 2014 Open Access CC BY-NC-ND

Environmental context. The use of groundwater with elevated concentrations of arsenic for drinking, cooking or irrigation has resulted in the worst mass poisoning in human history. This study shows that organic compounds that can be found in arsenic rich subsurface sediments may be used by indigenous microorganisms, contributing to the release of arsenic from the sediments into the groundwater. This study increases our understanding of the range of organic substrates (and their sources) that can potentially stimulate arsenic mobilisation into groundwaters.

Abstract. Microbial activity is generally accepted to play a critical role, with the aid of suitable organic carbon substrates, in the mobilisation of arsenic from sediments into shallow reducing groundwaters. The nature of the organic matter in natural aquifers driving the reduction of AsV to AsIII is of particular importance but is poorly understood. In this study, sediments from an arsenic rich aquifer in Cambodia were amended with two 13C-labelled organic substrates. 13C-hexadecane was used as a model for potentially bioavailable long chain n-alkanes and a 13C-kerogen analogue as a proxy for non-extractable organic matter. During anaerobic incubation for 8 weeks, significant FeIII reduction and AsIII mobilisation were observed in the biotic microcosms only, suggesting that these processes were microbially driven. Microcosms amended with 13C-hexadecane exhibited a similar extent of FeIII reduction to the non-amended microcosms, but marginally higher AsIII release. Moreover, gas chromatography–mass spectrometry analysis showed that 65 % of the added 13C-hexadecane was degraded during the 8-week incubation. The degradation of 13C-hexadecane was microbially driven, as confirmed by DNA stable isotope probing (DNA-SIP). Amendment with 13C-kerogen did not enhance FeIII reduction or AsIII mobilisation, and microbial degradation of kerogen could not be confirmed conclusively by DNA-SIP fractionation or 13C incorporation in the phospholipid fatty acids. These data are, therefore, consistent with the utilisation of long chain n-alkanes (but not kerogen) as electron donors for anaerobic processes, potentially including FeIII and AsV reduction in the subsurface.


References

[1]  A. H. Smith, E. O. Lingas, M. Rahman, Contamination of drinking-water by arsenic in Bangladesh: a public health emergency. Bull. World Health Organ. 2000, 78, 1093.
| 1:STN:280:DC%2BD3cvmsFSqtA%3D%3D&md5=ceb53fb427645e3595643e4f259bbf06CAS | 11019458PubMed |

[2]  M. Berg, C. Stengel, P. T. K. Trang, P. H. Viet, M. L. Sampson, M. Leng, S. Samreth, D. Fredericks, Magnitude of arsenic pollution in the Mekong and Red River Deltas – Cambodia and Vietnam. Sci. Total Environ. 2007, 372, 413.
Magnitude of arsenic pollution in the Mekong and Red River Deltas – Cambodia and Vietnam.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXitl2msw%3D%3D&md5=9b6b78e337e931a57e98ec3224d079e1CAS | 17081593PubMed |

[3]  L. Charlet, D. A. Polya, Arsenic in shallow, reducing groundwaters in southern Asia: an environmental health disaster. Elements. 2006, 2, 91.
Arsenic in shallow, reducing groundwaters in southern Asia: an environmental health disaster.Crossref | GoogleScholarGoogle Scholar |

[4]  D. A. Polya, A. G. Gault, N. J. Bourne, P. R. Lythgoe, D. A. Cooke, Coupled HPLC-ICP-MS analysis indicates highly hazardous concentrations of dissolved arsenic species in Cambodian groundwaters, in Plasma Source Mass Spectrometry: Applications and Emerging Technologies (Eds J. G. Holland, S. D. Tanner) 2003, pp. 127–140 (The Royal Society of Chemistry: Cambridge, UK).

[5]  D. A. Polya, A. G. Gault, N. Diebe, P. Feldman, J. W. Rosenboom, E. Gilligan, D. Fredericks, A. H. Milton, M. Sampson, H. A. L. Rowland, P. R. Lythgoe, J. C. Jones, C. Middleton, D. A. Cooke, Arsenic hazard in shallow Cambodian groundwaters. Mineral. Mag. 2005, 69, 807.
Arsenic hazard in shallow Cambodian groundwaters.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XjsFCltrY%3D&md5=22a8558b2c89375f87b82a3c8187e61eCAS |

[6]  M. Berg, H. C. Tran, T. C. Nguyen, H. V. Pham, R. Schertenleib, W. Giger, Arsenic contamination of groundwater and drinking water in Vietnam: a human health threat. Environ. Sci. Technol. 2001, 35, 2621.
Arsenic contamination of groundwater and drinking water in Vietnam: a human health threat.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXks1ems74%3D&md5=700b9d2037e997612e900c070f73b9efCAS | 11452583PubMed |

[7]  H. M. Guo, Y. X. Wang, G. M. Shpeizer, S. L. Yan, Natural occurrence of arsenic in shallow groundwater, Shanyin, Datong Basin, China. J. Environ. Sci. Health Part A Tox. Hazard. Subst. Environ. Eng. 2003, 38, 2565.
Natural occurrence of arsenic in shallow groundwater, Shanyin, Datong Basin, China.Crossref | GoogleScholarGoogle Scholar |

[8]  A. M. Sancha, M. O’Ryan, Managing hazardous pollutants in Chile: arsenic, in Reviews of Environmental Contamination and Toxicology, Vol 196 (Ed. D. M. Whitacre) 2008, pp. 123–146 (Springer Science+Business Media, LLC: New York).

[9]  J. D. Ayotte, D. L. Montgomery, S. M. Flanagan, K. W. Robinson, Arsenic in groundwater in eastern New England: occurrence, controls, and human health implications. Environ. Sci. Technol. 2003, 37, 2075.
Arsenic in groundwater in eastern New England: occurrence, controls, and human health implications.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXislSitLc%3D&md5=9bad7a9db1e138fe70d4a38a51b3f13dCAS | 12785510PubMed |

[10]  A. L. Lindberg, W. Goessler, E. Gurzau, K. Koppova, P. Rudnai, R. Kumar, T. Fletcher, G. Leonardi, K. Slotova, E. Gheorghiuc, M. Vahter, Arsenic exposure in Hungary, Romania and Slovakia. J. Environ. Monit. 2006, 8, 203.
Arsenic exposure in Hungary, Romania and Slovakia.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28Xht1WktQ%3D%3D&md5=dbf86c82904e41b3d4ce4e68633d9da1CAS | 16395480PubMed |

[11]  C. F. Harvey, C. H. Swartz, A. B. M. Badruzzaman, N. Keon-Blute, W. Yu, M. A. Ali, J. Jay, R. Beckie, V. Niedan, D. Brabander, P. M. Oates, K. N. Ashfaque, S. Islam, H. F. Hemond, M. F. Ahmed, Arsenic mobility and groundwater extraction in Bangladesh. Science 2002, 298, 1602.
Arsenic mobility and groundwater extraction in Bangladesh.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xosl2ktb0%3D&md5=15bf4a1b66c8fa3cada9b42a1c6cdd03CAS | 12446905PubMed |

[12]  M. L. Polizzotto, B. D. Kocar, S. G. Benner, M. Sampson, S. Fendorf, Near-surface wetland sediments as a source of arsenic release to ground water in Asia. Nature 2008, 454, 505.
Near-surface wetland sediments as a source of arsenic release to ground water in Asia.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXovV2mtLs%3D&md5=c6b5cb4d41410848c3e8658837b86453CAS | 18650922PubMed |

[13]  J. M. McArthur, P. Ravenscroft, D. M. Banerjee, J. Milsom, K. A. Hudson-Edwards, S. Sengupta, C. Bristow, A. Sarkar, S. Tonkin, R. Purohit, How paleosols influence groundwater flow and arsenic pollution: a model from the Bengal Basin and its worldwide implication. Water Resour. Res. 2008, 44, W11411.
How paleosols influence groundwater flow and arsenic pollution: a model from the Bengal Basin and its worldwide implication.Crossref | GoogleScholarGoogle Scholar |

[14]  D. Postma, F. Larsen, N. T. M. Hue, M. T. Duc, P. H. Viet, P. Q. Nhan, S. Jessen, Arsenic in groundwater of the Red River floodplain, Vietnam: controlling geochemical processes and reactive transport modeling. Geochim. Cosmochim. Acta 2007, 71, 5054.
Arsenic in groundwater of the Red River floodplain, Vietnam: controlling geochemical processes and reactive transport modeling.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXht1Gis7jP&md5=7e79166c6904be3bbb81f824e1d7d794CAS |

[15]  A. van Geen, J. Rose, S. Thoral, J. M. Garnier, Y. Zheng, J. Y. Bottero, Decoupling of As and Fe release to Bangladesh groundwater under reducing conditions. Part II. Evidence from sediment incubations. Geochim. Cosmochim. Acta 2004, 68, 3475.
Decoupling of As and Fe release to Bangladesh groundwater under reducing conditions. Part II. Evidence from sediment incubations.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXmvVGju7g%3D&md5=5de40bed5a77cc31766be46e01774db0CAS |

[16]  M. Lawson, D. A. Polya, A. J. Boyce, C. Bryant, D. Mondal, A. Shantz, C. J. Ballentine, Pond-derived organic carbon driving changes in arsenic hazard found in Asian groundwaters. Environ. Sci. Technol. 2013, 47, 7085.
| 1:CAS:528:DC%2BC3sXptFeisb0%3D&md5=e8b44f76eb273f56a777dd117cd1be0eCAS | 23755892PubMed |

[17]  B. J. Mailloux, E. Trembath-Reichert, J. Cheung, M. Watson, M. Stute, G. A. Freyer, A. S. Ferguson, K. M. Ahmed, M. J. Alam, B. A. Buchholz, J. Thomas, A. C. Layton, Y. Zheng, B. C. Bostick, A. van Geen, Advection of surface-derived organic carbon fuels microbial reduction in Bangladesh groundwater. Proc. Natl. Acad. Sci. USA 2013, 110, 5331.
Advection of surface-derived organic carbon fuels microbial reduction in Bangladesh groundwater.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXntVehtbw%3D&md5=f62d70f6a2ffd857a9becb10c041d5c2CAS | 23487743PubMed |

[18]  D. A. Polya, L. Charlet, Rising arsenic risk? Nat. Geosci. 2009, 2, 383.
Rising arsenic risk?Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXms1Ortbc%3D&md5=d91435bc2e0064ee363a05645439a394CAS |

[19]  M. Héry, B. E. van Dongen, F. Gill, D. Mondal, D. J. Vaughan, R. D. Pancost, D. A. Polya, J. R. Lloyd, Arsenic release and attenuation in low organic carbon aquifer sediments from West Bengal. Geobiology 2010, 8, 155.
Arsenic release and attenuation in low organic carbon aquifer sediments from West Bengal.Crossref | GoogleScholarGoogle Scholar | 20156294PubMed |

[20]  F. S. Islam, A. G. Gault, C. Boothman, D. A. Polya, J. M. Charnock, D. Chatterjee, J. R. Lloyd, Role of metal-reducing bacteria in arsenic release from Bengal delta sediments. Nature 2004, 430, 68.
Role of metal-reducing bacteria in arsenic release from Bengal delta sediments.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXlt1Cqt7c%3D&md5=07a3ade80cca1d42f0e375dd9a62d0aaCAS | 15229598PubMed |

[21]  J. Akai, K. Izumi, H. Fukuhara, H. Masuda, S. Nakano, T. Yoshimura, H. Ohfuji, H. M. Anawar, K. Akai, Mineralogical and geomicrobiological investigations on groundwater arsenic enrichment in Bangladesh. Appl. Geochem. 2004, 19, 215.
Mineralogical and geomicrobiological investigations on groundwater arsenic enrichment in Bangladesh.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXisFKntg%3D%3D&md5=c1250b47e608cf04a319bb5774241b88CAS |

[22]  H. A. L. Rowland, R. L. Pederick, D. A. Polya, R. D. Pancost, B. E. Van Dongen, A. G. Gault, D. J. Vaughan, C. Bryant, B. Anderson, J. R. Lloyd, The control of organic matter on microbially mediated iron reduction and arsenic release in shallow alluvial aquifers, Cambodia. Geobiology 2007, 5, 281.
The control of organic matter on microbially mediated iron reduction and arsenic release in shallow alluvial aquifers, Cambodia.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtFCgurfN&md5=42d0f2ef51b32b8f089e7d50d1435518CAS |

[23]  R. S. Oremland, J. F. Stolz, Arsenic, microbes and contaminated aquifers. Trends Microbiol. 2005, 13, 45.
Arsenic, microbes and contaminated aquifers.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXoslaltg%3D%3D&md5=31936b4578ef8ddb033476629e7a763cCAS | 15680760PubMed |

[24]  R. S. Oremland, J. F. Stolz, The ecology of arsenic. Science 2003, 300, 939.
The ecology of arsenic.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXjsVyjsLs%3D&md5=840e38f53bf5d9201af72c47691ceb50CAS | 12738852PubMed |

[25]  G. Lear, B. Song, A. G. Gault, D. A. Polya, J. R. Lloyd, Molecular analysis of arsenate-reducing bacteria within Cambodian sediments following amendment with acetate. Appl. Environ. Microbiol. 2007, 73, 1041.
Molecular analysis of arsenate-reducing bacteria within Cambodian sediments following amendment with acetate.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXitlyqsrg%3D&md5=ad2324dfc0f226db2f4a3d7a899583f4CAS | 17114326PubMed |

[26]  M. Héry, A. Rizoulis, H. Sanguin, D. A. Cooke, R. D. Pancost, D. A. Polya, J. R. Lloyd, Microbial ecology of arsenic-mobilizing Cambodian sediments: lithological controls uncovered by stable-isotope probing. Environ. Microbiol. 2014, [Published online early 5 March 2014]
Microbial ecology of arsenic-mobilizing Cambodian sediments: lithological controls uncovered by stable-isotope probing.Crossref | GoogleScholarGoogle Scholar | 24467551PubMed |

[27]  H. A. L. Rowland, C. Boothman, R. Pancost, A. G. Gault, D. A. Polya, J. R. Lloyd, The role of indigenous microorganisms in the biodegradation of naturally occurring petroleum, the reduction of iron, and the mobilization of arsenite from West Bengal aquifer sediments. J. Environ. Qual. 2009, 38, 1598.
The role of indigenous microorganisms in the biodegradation of naturally occurring petroleum, the reduction of iron, and the mobilization of arsenite from West Bengal aquifer sediments.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXosFKqsbk%3D&md5=95d68e3a8c14c35ea7e70dfe2f90dffeCAS |

[28]  M. Héry, A. G. Gault, H. A. L. Rowland, G. Lear, D. A. Polya, J. R. Lloyd, Molecular and cultivation-dependent analysis of metal-reducing bacteria implicated in arsenic mobilisation in south-east asian aquifers. Appl. Geochem. 2008, 23, 3215.
Molecular and cultivation-dependent analysis of metal-reducing bacteria implicated in arsenic mobilisation in south-east asian aquifers.Crossref | GoogleScholarGoogle Scholar |

[29]  D. C. White, W. M. Davis, J. S. Nickels, J. D. King, R. J. Bobbie, Determination of the sedimentary microbial biomass by extractable lipid phosphate. Oecologia 1979, 40, 51.
Determination of the sedimentary microbial biomass by extractable lipid phosphate.Crossref | GoogleScholarGoogle Scholar |

[30]  R. P. Evershed, Z. M. Crossman, I. D. Bull, H. Mottram, J. A. J. Dungait, P. J. Maxfield, E. L. Brennand, 13C-Labelling of lipids to investigate microbial communities in the environment. Curr. Opin. Biotechnol. 2006, 17, 72.
13C-Labelling of lipids to investigate microbial communities in the environment.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XhtlKlu7c%3D&md5=0dbeba5a75f2958ee9a270fc86f4b6c4CAS | 16423522PubMed |

[31]  M. P. Waldrop, M. K. Firestone, Microbial community utilization of recalcitrant and simple carbon compounds: impact of oak-woodland plant communities. Oecologia 2004, 138, 275.
Microbial community utilization of recalcitrant and simple carbon compounds: impact of oak-woodland plant communities.Crossref | GoogleScholarGoogle Scholar | 14614618PubMed |

[32]  L. Zelles, Fatty acid patterns of phospholipids and lipopolysaccharides in the characterisation of microbial communities in soil: a review. Biol. Fertil. Soils 1999, 29, 111.
Fatty acid patterns of phospholipids and lipopolysaccharides in the characterisation of microbial communities in soil: a review.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXisleks7c%3D&md5=07e3bc408db5504979762b493a6a4997CAS |

[33]  A. G. Gault, F. S. Islam, D. A. Polya, J. M. Charnock, C. Boothman, D. Chatterjee, J. R. Lloyd, Microcosm depth profiles of arsenic release in a shallow aquifer, West Bengal. Mineral. Mag. 2005, 69, 855.
Microcosm depth profiles of arsenic release in a shallow aquifer, West Bengal.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XjsFClt78%3D&md5=d876c66e7ab2ab252cc4c3cdfb79993bCAS |

[34]  J. M. McArthur, D. M. Banerjee, K. A. Hudson-Edwards, R. Mishra, R. Purohit, P. Ravenscroft, A. Cronin, R. J. Howarth, A. Chatterjee, T. Talukder, D. Lowry, S. Houghton, D. K. Chadha, Natural organic matter in sedimentary basins and its relation to arsenic in anoxic ground water: the example of West Bengal and its worldwide implications. Appl. Geochem. 2004, 19, 1255.
Natural organic matter in sedimentary basins and its relation to arsenic in anoxic ground water: the example of West Bengal and its worldwide implications.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXkt1WksL0%3D&md5=1c30e71d154a3c6b92091a7ffa71db05CAS |

[35]  Y. Zheng, A. van Geen, M. Stute, R. Dhar, Z. Mo, Z. Cheng, A. Horneman, I. Gavrieli, H. J. Simpson, R. Versteeg, M. Steckler, A. Grazioli-Venier, S. Goodbred, M. Shahnewaz, M. Shamsudduha, M. A. Hoque, K. M. Ahmed, Geochemical and hydrogeological contrasts between shallow and deeper aquifers in two villages of Araihazar, Bangladesh: implications for deeper aquifers as drinking water sources. Geochim. Cosmochim. Acta 2005, 69, 5203.
Geochemical and hydrogeological contrasts between shallow and deeper aquifers in two villages of Araihazar, Bangladesh: implications for deeper aquifers as drinking water sources.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXhtlerurrM&md5=877b7154ab06b5dc9171d54ded6e2075CAS |

[36]  H. A. L. Rowland, D. A. Polya, J. R. Lloyd, R. D. Pancost, Characterisation of organic matter in a shallow, reducing, arsenic-rich aquifer, West Bengal. Org. Geochem. 2006, 37, 1101.
Characterisation of organic matter in a shallow, reducing, arsenic-rich aquifer, West Bengal.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XptVSisr4%3D&md5=f3d8e8fb5433e776817f0b3cb2ded92fCAS |

[37]  B. E. van Dongen, H. A. L. Rowland, A. G. Gault, D. A. Polya, C. Bryant, R. D. Pancost, Hopane, sterane and n-alkane distributions in shallow sediments hosting high arsenic groundwaters in Cambodia. Appl. Geochem. 2008, 23, 3047.
Hopane, sterane and n-alkane distributions in shallow sediments hosting high arsenic groundwaters in Cambodia.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXhtlWkur3M&md5=d1b0c8c06d078cda317c8f10916207e1CAS |

[38]  W. M. Al Lawati, J.-S. Jean, T. R. Kulp, M.-K. Lee, D. A. Polya, C.-C. Liu, B. E. van Dongen, Characterisation of organic matter associated with groundwater arsenic in reducing aquifers of southwestern Taiwan. J. Hazard. Mater. 2013, 262, 970.
Characterisation of organic matter associated with groundwater arsenic in reducing aquifers of southwestern Taiwan.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhsl2gt7bM&md5=834c6f23b079893ef8f91c8d4ac80ffaCAS | 22964390PubMed |

[39]  C. De Pasquale, E. Palazzolo, L. Lo Piccolo, P. Quatrini, Degradation of long-chain n-alkanes in soil microcosms by two actinobacteria. J. Environ. Sci. Health Part A Tox. Hazard. Subst. Environ. Eng. 2012, 47, 374.
Degradation of long-chain n-alkanes in soil microcosms by two actinobacteria.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XitVCgtro%3D&md5=7d8c312804ce04b7d1cc4fa9bc27c42dCAS |

[40]  A. V. Callaghan, M. Tierney, C. D. Phelps, L. Y. Young, Anaerobic biodegradation of n-hexadecane by a nitrate-reducing consortium. Appl. Environ. Microbiol. 2009, 75, 1339.
Anaerobic biodegradation of n-hexadecane by a nitrate-reducing consortium.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXjtVyqs7s%3D&md5=7be964c2b67d8bece64d4b0442b14ccbCAS | 19114507PubMed |

[41]  V. Grossi, C. Cravo-Laureau, R. Guyoneaud, A. Ranchou-Peyruse, A. Hirschler-Réa, Metabolism of n-alkanes and n-alkenes by anaerobic bacteria: a summary. Org. Geochem. 2008, 39, 1197.
Metabolism of n-alkanes and n-alkenes by anaerobic bacteria: a summary.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXovFOltr0%3D&md5=59c085860003019db7b1b27d0c40945bCAS |

[42]  A. Wentzel, T. E. Ellingsen, H. K. Kotlar, S. B. Zotchev, M. Throne-Holst, Bacterial metabolism of long-chain n-alkanes. Appl. Microbiol. Biotechnol. 2007, 76, 1209.
Bacterial metabolism of long-chain n-alkanes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtVGmt7%2FN&md5=536601b309eb6149c1d023e2eae63862CAS | 17673997PubMed |

[43]  B. Durant, Sedimentary organic matter and kerogen. Definition and quantitative importance of kerogen, in Kerogen-Insoluble Organic Matter from Sedimentary Rocks (Ed. B. Durand) 1980, pp 13–34 (Editions Technip: Paris).

[44]  S. T. Petsch, R. A. Berner, T. I. Eglinton, A field study of the chemical weathering of ancient sedimentary organic matter. Org. Geochem. 2000, 31, 475.
A field study of the chemical weathering of ancient sedimentary organic matter.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXktFartLw%3D&md5=992d5d001873461435876b21521ca383CAS |

[45]  S. T. Petsch, T. I. Eglinton, K. J. Edwards, 14C-Dead living biomass: evidence for microbial assimilation of ancient organic carbon during shale weathering. Science 2001, 292, 1127.
14C-Dead living biomass: evidence for microbial assimilation of ancient organic carbon during shale weathering.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXjs1Churs%3D&md5=de08c72424686517dba7f0a0c6fbfa30CAS | 11283356PubMed |

[46]  J. Buschmann, M. Berg, C. Stengel, M. L. Sampson, Arsenic and manganese contamination of drinking water resources in Cambodia: coincidence of risk areas with low relief topography. Environ. Sci. Technol. 2007, 41, 2146.
Arsenic and manganese contamination of drinking water resources in Cambodia: coincidence of risk areas with low relief topography.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhs1SqtLs%3D&md5=a16a604437615f9276b03b299b805685CAS | 17438755PubMed |

[47]  H. A. L. Rowland, A. G. Gault, P. Lythgoe, D. A. Polya, Geochemistry of aquifer sediments and arsenic-rich groundwaters from Kandal Province, Cambodia. Appl. Geochem. 2008, 23, 3029.
Geochemistry of aquifer sediments and arsenic-rich groundwaters from Kandal Province, Cambodia.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXhtlWkurzF&md5=7bdec4825396a5ae958e5b2ad04acee9CAS |

[48]  H. A. L. Rowland, A. G. Gault, J. M. Charnock, D. A. Polya, Preservation and XANES determination of the oxidation state of solid-phase arsenic in shallow sedimentary aquifers in Bengal and Cambodia. Mineral. Mag. 2005, 69, 825.
Preservation and XANES determination of the oxidation state of solid-phase arsenic in shallow sedimentary aquifers in Bengal and Cambodia.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XjsFCltrc%3D&md5=257eac8535e53d023dbbbb9d5b7bc321CAS |

[49]  W. M. Al Lawati, The Role Of Organics In The Mobilization Of Arsenic In Shallow Aquifers 2012, Ph.D. Thesis, The University of Manchester.

[50]  D. R. Lovley, E. J. P. Phillips, Availability of ferric iron for microbial reduction in bottom sediments of the freshwater tidal Potomac River. Appl. Environ. Microbiol. 1986, 52, 751.
| 1:CAS:528:DyaL28XmtFekur4%3D&md5=e53b1035bbf215729fa3f202e24d08aaCAS | 16347168PubMed |

[51]  A. G. Gault, J. Jana, S. Chakraborty, P. Mukherjee, M. Sarkar, B. Nath, D. A. Polya, D. Chatterjee, Preservation strategies for inorganic arsenic species in high iron, low-Eh groundwater from West Bengal, India. Anal. Bioanal. Chem. 2005, 381, 347.
Preservation strategies for inorganic arsenic species in high iron, low-Eh groundwater from West Bengal, India.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXht1KrtLc%3D&md5=48d105b47414a5daa8c0e93952c2cee7CAS | 15558247PubMed |

[52]  J. G. Caporaso, J. Kuczynski, J. Stombaugh, K. Bittinger, F. D. Bushman, E. K. Costello, N. Fierer, A. G. Peña, J. K. Goodrich, J. I. Gordon, G. A. Huttley, S. T. Kelley, D. Knights, J. E. Koenig, R. E. Ley, C. A. Lozupone, D. McDonald, B. D. Muegge, M. Pirrung, J. Reeder, J. R. Sevinsky, P. J. Tumbaugh, W. A. Walters, J. Widmann, T. Yatsunenko, J. Zaneveld, R. Knight, QIIME allows analysis of high-throughput community sequencing data. Nat. Methods 2010, 7, 335.
QIIME allows analysis of high-throughput community sequencing data.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXksFalurg%3D&md5=8e8440f7b29c9f97830e90daed0dbef0CAS | 20383131PubMed |

[53]  J. D. Neufeld, J. Vohra, M. G. Dumont, T. Lueders, M. Manefield, M. W. Friedrich, J. C. Murrell, DNA stable-isotope probing. Nat. Protoc. 2007, 2, 860.
DNA stable-isotope probing.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtFGnur7E&md5=37219e41e5b2c1d87e6c3237d973a071CAS | 17446886PubMed |

[54]  D. R. Elliott, J. D. Scholes, S. F. Thornton, A. Rizoulis, S. A. Banwart, S. A. Rolfe, Dynamic changes in microbial community structure and function in phenol-degrading microcosms inoculated with cells from a contaminated aquifer. FEMS Microbiol. Ecol. 2010, 71, 247.
Dynamic changes in microbial community structure and function in phenol-degrading microcosms inoculated with cells from a contaminated aquifer.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXnvVOmsA%3D%3D&md5=a4fd8823abf5724fe1f5f5349e8a45f5CAS | 19930459PubMed |

[55]  Å. Frostegård, A. Tunlid, E. Bååth, Microbial biomass measured as total lipid phosphate in soils of different organic content. J. Microbiol. Methods 1991, 14, 151.
Microbial biomass measured as total lipid phosphate in soils of different organic content.Crossref | GoogleScholarGoogle Scholar |

[56]  K. P. Nevin, D. E. Holmes, T. L. Woodard, E. S. Hinlein, D. W. Ostendorf, D. R. Lovley, Geobacter bemidjiensis sp. nov. and Geobacter psychrophilus sp. nov., two novel Fe(III)-reducing subsurface isolates. Int. J. Syst. Evol. Microbiol. 2005, 55, 1667.
Geobacter bemidjiensis sp. nov. and Geobacter psychrophilus sp. nov., two novel Fe(III)-reducing subsurface isolates.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXovV2nt7Y%3D&md5=4589c39d665e22b4aab94cb3011d470eCAS | 16014499PubMed |

[57]  S. Viulu, K. Nakamura, Y. Okada, S. Saitou, K. Takamizawa, Geobacter luticola sp. nov., an Fe(III)-reducing bacterium isolated from lotus field mud. Int. J. Syst. Evol. Microbiol. 2013, 63, 442.
Geobacter luticola sp. nov., an Fe(III)-reducing bacterium isolated from lotus field mud.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXmtlWrtL8%3D&md5=e1209b578ce95cb6c16dfe988bb37819CAS | 22493170PubMed |

[58]  J. Sikorski, A. Lapidus, A. Copeland, T. G. Del Rio, M. Nolan, S. Lucas, F. Chen, H. Tice, J.-F. Cheng, E. Saunders, D. Bruce, L. Goodwin, S. Pitluck, G. Ovchinnikova, A. Pati, N. Ivanova, K. Mavromatis, A. Chen, K. Palaniappan, P. Chain, M. Land, L. Hauser, Y.-J. Chang, C. D. Jeffries, T. Brettin, J. C. Detter, C. Han, M. Rohde, E. Lang, S. Spring, M. Göker, J. Bristow, J. A. Eisen, V. Markowitz, P. Hugenholtz, N. C. Kyrpides, H.-P. Klenk, Complete genome sequence of Sulfurospirillum deleyianum type strain (5175T). Stand. Genomic Sci. 2010, 2, 149.
Complete genome sequence of Sulfurospirillum deleyianum type strain (5175T).Crossref | GoogleScholarGoogle Scholar | 21304697PubMed |

[59]  D. J. Lonergan, H. L. Jenter, J. D. Coates, E. J. P. Phillips, T. M. Schmidt, D. R. Lovley, Phylogenetic analysis of dissimilatory Fe(III)-reducing bacteria. J. Bacteriol. 1996, 178, 2402.
| 1:CAS:528:DyaK28Xit1Ors7s%3D&md5=c6332f7bc5031958f6dc47d7ebbe8983CAS | 8636045PubMed |

[60]  H. Wilkes, R. Rabus, T. Fischer, A. Armstroff, A. Behrends, F. Widdel, Anaerobic degradation of n-hexane in a denitrifying bacterium: further degradation of the initial intermediate (1-methylpentyl)succinate via C-skeleton rearrangement. Arch. Microbiol. 2002, 177, 235.
Anaerobic degradation of n-hexane in a denitrifying bacterium: further degradation of the initial intermediate (1-methylpentyl)succinate via C-skeleton rearrangement.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xitl2itLg%3D&md5=2b1c7f285893f4c86140383be68568f6CAS | 11907679PubMed |

[61]  C. Cravo-Laureau, V. Grossi, D. Raphel, R. Matheron, A. Hirschler-Rea, Anaerobic n-alkane metabolism by a sulfate-reducing bacterium, Desulfatibacillum aliphaticivorans strain CV2803. Appl. Environ. Microbiol. 2005, 71, 3458.
Anaerobic n-alkane metabolism by a sulfate-reducing bacterium, Desulfatibacillum aliphaticivorans strain CV2803.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXmt1ylsLs%3D&md5=6d65493ed551283aa771ad16fbff8186CAS | 16000749PubMed |

[62]  I. A. Davidova, K. E. Duncan, O. K. Choi, J. M. Suflita, Desulfoglaeba alkanexedens gen. nov., sp nov., an n-alkane-degrading, sulfate-reducing bacterium. Int. J. Syst. Evol. Microbiol. 2006, 56, 2737.
Desulfoglaeba alkanexedens gen. nov., sp nov., an n-alkane-degrading, sulfate-reducing bacterium.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtVWmsLk%3D&md5=5331f998d5b6f9fb3d60451fdb7d2370CAS | 17158970PubMed |

[63]  J. R. Lloyd, A. G. Gault, M. Héry, J. D. MacRae, Microbial transformations of arsenic in the subsurface, in Microbial Metal and Metalloid Metabolism: Advances and Applications (Eds J. F. Stolz, R. S. Oremland) 2011, pp. 77–90 (ASM Press: Washington, DC).

[64]  P. Doumenq, E. Aries, L. Asia, M. Acquaviva, J. Artaud, M. Gilewicz, G. Mille, J. C. Bertrand, Influence of n-alkanes and petroleum on fatty acid composition of a hydrocarbonoclastic bacterium: Marinobacter hydrocarbonoclasticus strain 617. Chemosphere 2001, 44, 519.
Influence of n-alkanes and petroleum on fatty acid composition of a hydrocarbonoclastic bacterium: Marinobacter hydrocarbonoclasticus strain 617.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXkvVehsbo%3D&md5=70fc969f6f6ac73bb904f83e5a480023CAS | 11482638PubMed |

[65]  F. Aeckersberg, F. A. Rainey, F. Widdel, Growth, natural relationships, cellular fatty acids and metabolic adaptation of sulfate-reducing bacteria that utilize long-chain alkanes under anoxic conditions. Arch. Microbiol. 1998, 170, 361.
Growth, natural relationships, cellular fatty acids and metabolic adaptation of sulfate-reducing bacteria that utilize long-chain alkanes under anoxic conditions.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXntleltbY%3D&md5=ff765c143960487f82ef6349d81137dbCAS | 9818355PubMed |

[66]  M. Hasinger, K. E. Scherr, T. Lundaa, L. Bräuer, C. Zach, A. P. Loibner, Changes in iso- and n-alkane distribution during biodegradation of crude oil under nitrate and sulphate reducing conditions. J. Biotechnol. 2012, 157, 490.
Changes in iso- and n-alkane distribution during biodegradation of crude oil under nitrate and sulphate reducing conditions.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XjtF2gtLw%3D&md5=3fa2e8c40f96120776b8b32b1e5671c5CAS | 22001845PubMed |

[67]  D. Postma, F. Larsen, T. Nguyen Thi, T. Pham Thi Kim, R. Jakobsen, N. Pham Quy, L. Tran Vu, V. Pham Hung, A. S. Murray, Groundwater arsenic concentrations in Vietnam controlled by sediment age. Nat. Geosci. 2012, 5, 656.
Groundwater arsenic concentrations in Vietnam controlled by sediment age.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XhtFCgs7jP&md5=915a0d7d1be7a1bfebf707119fc9c80bCAS |