Sediment biomarker, bacterial community characterization of high arsenic aquifers in Jianghan Plain, China

Abstract

Representative biomarkers (e.g., n-alkanes), diversity and microbial community in the aquifers contaminated by high concentration of arsenic (As) in different sediment depth (0–30 m) in Jianghan Plain, Hubei, China, were analyzed to investigate the potential mechanism of As enrichment in groundwater. The concentration of As was abundant in top soil and sand, but not in clay. The analysis of the distribution of n-alkanes, CPI values, and wax to total n-alkane ratio (Wax(n)%) indicated that the organic matter (OM) from fresh terrestrial plants were abundant in the shallow sediment. However, n-alkanes have suffered from significant biodegradation from the depth of 16 m to 30 m. The deposition of fresh terrestrial derived organic matters may facilitate the release of As from sediment to groundwater in the sediment of 0–16 m. However, the petroleum derived organic matters may do the favor to the release of As in the deeper section of borehole (16 m to 30 m). The 16S rRNA gene sequences identification indicated that Acidobacteria, Actinomycetes and Hydrogenophaga are abundant in the sediments with high arsenic. Therefore, microbes and organic matters from different sources may play important roles in arsenic mobilization in the aquifers of the study area.

Effect of the natural arsenic gradient on the diversity and arsenic resistance of bacterial communities of the sediments of Camarones River (Atacama Desert, Chile)

“…The increase in diversity along the course of the river from east (M1) to west (M3) was associated with an increase in TOC and a decrease in As concentration. Concordantly, other authors described that moderately disturbed conditions, as a higher arsenic concentration in groundwater and sediment samples, often result in low diversity of microbial communities [ 56 , 59 ], like those occurring at the origin of Camarones river (site M1). Gu et al [ 60 ] reported that the structure of a bacterial community varied depending on the levels of arsenic contamination, showing an increase in the diversity of arsenic functional genes and 16S RNA genes as arsenic levels increased.…”

“…Metal-contaminated sediments are inhabited by extremely complex and well-adapted microbial communities, which play a fundamental role in degrading organic matter and in biogeochemical cycles [ 54 – 56 ]. Microbial diversity, here investigated by a massive parallel sequencing (Illumina), revealed a great diversity of bacterial communities, detecting also bacteria occurring at very low abundance (≤0.01%), that would have been masked by dominant populations if techniques with lower resolution had been applied.…”

“…The increase in bacterial diversity in sediment samples was associated with an increase in TOC and a decrease in As concentration. As generally accepted, moderately disturbed conditions, as lowering arsenic concentration on groundwater and sediments sample, often result in higher diversity of microbial communities [ 54 – 56 ], like those occurring at the mouth of Camarones river (site M3). Although adaptation of a community can take a long time (years), microorganisms present in metal contaminated soils may be selected in short periods of time (weeks or months) and after a period of time, microorganisms autochthonous of contaminated areas will be adapted to predominant conditions [ 57 – 58 ].…”

“…High abundances of Acidobacteria and particularly those of GP6, retrieved across all samples, and of GP2, the most abundant in M2 site, may be related to their high metal resistance capability [ 56 ]. Sequences related to the genus Caldimicrobium ( Thermodesulfobacteria ), grouping extremely thermophilic, strictly anaerobic, sulphur-oxidizing bacteria, widely distributed in other hot environments [ 31 ], were dominant in the upper sites (M1 and M2) of Camarones river.…”

Reconstructing Draft Genomes Using Genome Resolved Metagenomics Reveal Arsenic Metabolizing Genes and Secondary Metabolites in Fresh Water Lake in Eastern India

“…15 Therefore the possible occurrence of resistance genes related to arsenic (As) contamination in lake microbes can be investigated with genome resolved metagenomics approach. [75][76][77][78] Importantly, arsenic (As) resistant and metabolism-related genes were found to be present in the recovered genome bins of the lake sample (Figure 5 and Supplementary Table S6); This is an indication that the mechanism to stabilize the Arsenic toxicity is already active in the lake microbes. The predominant forms of As in environment are inorganic arsenate (As [V]) and arsenite (As [III]).…”