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. 2022 Nov 16;12(11):1900.
doi: 10.3390/life12111900.

Arsenic Pollution and Anaerobic Arsenic Metabolizing Bacteria in Lake Van, the World's Largest Soda Lake

Esra Ersoy Omeroglu  1 , Mert Sudagidan  2 , Erdal Ogun  3
Affiliations

Arsenic Pollution and Anaerobic Arsenic Metabolizing Bacteria in Lake Van, the World's Largest Soda Lake

Esra Ersoy Omeroglu et al. Life (Basel). .

Abstract

Arsenic is responsible for water pollution in many places around the world and presents a serious health risk for people. Lake Van is the world's largest soda lake, and there are no studies on seasonal arsenic pollution and arsenic-resistant bacteria. We aimed to determine the amount of arsenic in the lake water and sediment, to isolate arsenic-metabolizing anaerobic bacteria and their identification, and determination of arsenic metabolism. Sampling was done from 7.5 m to represent the four seasons. Metal contents were determined by using ICP-MS. Pure cultures were obtained using the Hungate technique. Growth characteristics of the strains were determined at different conditions as well as at arsenate and arsenite concentrations. Molecular studies were also carried out for various resistance genes. Our results showed that Lake Van's total arsenic amount changes seasonally. As a result of 16S rRNA sequencing, it was determined that the isolates were members of 8 genera with arsC resistance genes. In conclusion, to sustain water resources, it is necessary to prevent chemical and microorganism-based pollution. It is thought that the arsenic-resistant bacteria obtained as a result of this study will contribute to the solution of environmental arsenic pollution problems, as they are the first data and provide the necessary basic data for the bioremediation studies of arsenic from contaminated environmental habitats. At the same time, the first data that will contribute to the creation of the seasonal arsenic map of Lake Van are obtained.

Keywords: Lake Van; anaerobic bacteria; arsenate; arsenic pollution; arsenite.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure A1
Figure A1
Pressure and salt resistant ladle (A–C) and sampling (D–K).
Figure A1
Figure A1
Pressure and salt resistant ladle (A–C) and sampling (D–K).
Figure A2
Figure A2
Isolation of anaerobic and alkalifilic arsenate-reducing and arsenite-oxidizing bacteria. Preparation of media with Hungate technique (A–E), Bacterial growth in Balch and Hungate tubes (F–I), Obtaining pure culture using anaerobic chamber (J–M), Different types of colonies formed on agar media (N–R).
Figure A2
Figure A2
Isolation of anaerobic and alkalifilic arsenate-reducing and arsenite-oxidizing bacteria. Preparation of media with Hungate technique (A–E), Bacterial growth in Balch and Hungate tubes (F–I), Obtaining pure culture using anaerobic chamber (J–M), Different types of colonies formed on agar media (N–R).
Figure A2
Figure A2
Isolation of anaerobic and alkalifilic arsenate-reducing and arsenite-oxidizing bacteria. Preparation of media with Hungate technique (A–E), Bacterial growth in Balch and Hungate tubes (F–I), Obtaining pure culture using anaerobic chamber (J–M), Different types of colonies formed on agar media (N–R).
Figure A3
Figure A3
Comparison of arsenic amounts of Lake Van samples.
Figure 1
Figure 1
Satellite image of the sampling area.
Figure 2
Figure 2
Effect of some physicochemical parameters and different concentrations of As(V) and As(III) on bacterial growth. (A) Temperature, (B) pH, (C) NaCl, (D) As(V), (E) As(III).
Figure 2
Figure 2
Effect of some physicochemical parameters and different concentrations of As(V) and As(III) on bacterial growth. (A) Temperature, (B) pH, (C) NaCl, (D) As(V), (E) As(III).
See this image and copyright information in PMC

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