The abundance of health-associated bacteria is altered in PAH polluted soils—Implications for health in urban areas?

Abstract

Long-term exposure to polyaromatic hydrocarbons (PAHs) has been connected to chronic human health disorders. It is also well-known that i) PAH contamination alters soil bacterial communities, ii) human microbiome is associated with environmental microbiome, and iii) alteration in the abundance of members in several bacterial phyla is associated with adverse or beneficial human health effects. We hypothesized that soil pollution by PAHs altered soil bacterial communities that had known associations with human health. The rationale behind our study was to increase understanding and potentially facilitate reconsidering factors that lead to health disorders in areas characterized by PAH contamination. Large containers filled with either spruce forest soil, pine forest soil, peat, or glacial sand were left to incubate or contaminated with creosote. Biological degradation of PAHs was monitored using GC-MS, and the bacterial community composition was analyzed using 454 pyrosequencing. Proteobacteria had higher and Actinobacteria and Bacteroidetes had lower relative abundance in creosote contaminated soils than in non-contaminated soils. Earlier studies have demonstrated that an increase in the abundance of Proteobacteria and decreased abundance of the phyla Actinobacteria and Bacteroidetes are particularly associated with adverse health outcomes and immunological disorders. Therefore, we propose that pollution-induced shifts in natural soil bacterial community, like in PAH-polluted areas, can contribute to the prevalence of chronic diseases. We encourage studies that simultaneously address the classic “adverse toxin effect” paradigm and our novel “altered environmental microbiome” hypothesis.

Urbanization Reduces Transfer of Diverse Environmental Microbiota Indoors

“…Our results thus indicated that urban inhabitants were exposed to less diverse environmental microbiota and to potentially pathogenic bacteria at the same time. Moreover, as reported in our previous study (Parajuli et al, 2017 ), environmental pollutants such as polyaromatic hydrocarbons (PAH) can change bacterial communities in an urban context. Therefore, our findings suggest that anthropogenic disturbances are responsible for the difference in microbial community composition between rural and urban settings.…”

Molecular Biology-Based Analysis of the Interactive Effect of Nickel and Xanthates on Soil Bacterial Community Diversity and Structure

“…It comprises the majority of Gram-negative bacteria, morphologically, physiologically and metabolically largely diversified [57,58], including phototrophs, heterotrophs, and chemolithotrophs, as well as numerous pathogens for humans, animals, and plants [59]. Its dominance was reported in soil contaminated by polyaromatic hydrocarbons (PAHs) [60,61] and oil [59]. In this study, its low abundance (15.06%) was observed in Ni-treated samples.…”

Short‐term direct contact with soil and plant materials leads to an immediate increase in diversity of skin microbiota

“…Soils including composted gardening materials host especially diverse microbial communities (Yu et al, 2015) and thus increasing contact with such soils for urban citizens could provide a means for increasing the diversity of their microbiota and further decrease the prevalence of asthma and atopies (von Hertzen & Haahtela, 2006). This is especially significant in the light of our earlier findings, which suggest that urbanization and pollution could lead to changes in soil microbiota and urbanization reduces microbial transfer indoors (Parajuli et al, 2017(Parajuli et al, , 2018.…”