Melting Himalayan glaciers contaminated by legacy atmospheric depositions are important sources of PCBs and high-molecular-weight PAHs for the Ganges floodplain during dry periods

Sharma, Brij Mohan; Nizzetto, Luca; Bharat, Girija K.; Tayal, Shresth; Melymuk, Lisa; Sáňka, Ondřej; Příbylová, Petra; Audy, Ondřej; Larssen, Thorjørn

doi:10.1016/j.envpol.2015.08.012

Cited by 49 publications

(22 citation statements)

References 37 publications

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“…D and Supporting Information Table S5). These results were attributable, at least partly, to the high sewage and runoff inputs in the river and high usage of aromatic compounds, heavy metals and antibiotics in India (Kotwani and Holloway, ; Wats and Sohal, ; Singh and Pandey, ; Sharma et al ., ), and were consistent with the phylogenetic diversity patterns described above.…”

Section: Discussionsupporting

confidence: 89%

Intensive allochthonous inputs along the Ganges River and their effect on microbial community composition and dynamics

Zhang

Tsementzi

Hatt

et al. 2018

Environmental Microbiology

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Summary Little is known about microbial communities in the Ganges River, India and how they respond to intensive anthropogenic inputs. Here we applied shotgun metagenomics sequencing to study microbial community dynamics and function in planktonic samples collected along an approximately 700 km river transect, including urban cities and rural settings in upstream waters, before and after the monsoon rainy season. Our results showed that 11%–32% of the microbes represented terrestrial, sewage and human inputs (allochthonous). Sewage inputs significantly contributed to the higher abundance, by 13‐fold of human gut microbiome (HG) associated sequences and 2‐fold of antibiotic resistance genes (ARGs) in the Ganges relative to other riverine ecosystems in Europe, North and South America. Metagenome‐assembled genome sequences (MAGs) representing allochthonous populations were detectable and tractable across the river after 1–2 days of (downstream) transport (> 200 km apart). Only approximately 8% of these MAGs were abundant in U.S. freshwater ecosystems, revealing distinct biodiversity for the Ganges. Microbial communities in the rainy season exhibited increased alpha‐diversity and spatial heterogeneity and showed significantly weaker distance‐decay patterns compared with the dry season. These results advance our understanding of the Ganges microbial communities and how they respond to anthropogenic pollution.

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Section: Discussionsupporting

confidence: 89%

Intensive allochthonous inputs along the Ganges River and their effect on microbial community composition and dynamics

Zhang

Tsementzi

Hatt

et al. 2018

Environmental Microbiology

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“…Due to relatively low air temperatures, which favor persistent POP deposition, the Arctic has so far been a global sink for POPs released at lower latitudes. Glacierized regions are now poised to become a POP source; however, as rapid warming there remobilizes POPs that have been stored in the cryosphere [ Grannas et al , ; Sharma et al , ]. While substantial PCB remediation efforts have been undertaken at the majority of 63 former Distant Early Warning (DEW) bases built along the Arctic Circle in the 1960s [ Poland et al , ], Camp Century is only one of five abandoned and unremediated ice sheet bases in the vicinity of Thule AB [ Lufkin and Tobiasson , ].…”

Section: Abandoned Wastesmentioning

confidence: 99%

“…PCBs could therefore be remobilized from Camp Century by englacial water flow decades before surface runoff is observed at the site [ Pavlova et al , ]. Such hydrologic remobilization, primarily via dispersion, and subsequent englacial flow would transport these toxins down hydraulic gradient from Camp Century, deeper into the ice, before eventually reaching proglacial regions [ Sharma et al , ].…”

Section: Climatic Projectionsmentioning

confidence: 99%

The abandoned ice sheet base at Camp Century, Greenland, in a warming climate

Colgan

Machguth

MacFerrin

et al. 2016

Geophysical Research Letters

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In 1959 the U.S. Army Corps of Engineers built Camp Century beneath the surface of the northwestern Greenland Ice Sheet. There they studied the feasibility of deploying ballistic missiles within the ice sheet. The base and its wastes were abandoned with minimal decommissioning in 1967, under the assumption they would be preserved for eternity by perpetually accumulating snowfall. Here we show that a transition in ice sheet surface mass balance at Camp Century from net accumulation to net ablation is plausible within the next 75 years, under a business‐as‐usual anthropogenic emissions scenario (Representative Concentration Pathway 8.5). Net ablation would guarantee the eventual remobilization of physical, chemical, biological, and radiological wastes abandoned at the site. While Camp Century and four other contemporaneous ice sheet bases were legally established under a Danish‐U.S. treaty, the potential remobilization of their abandoned wastes, previously regarded as sequestered, represents an entirely new pathway of political dispute resulting from climate change.

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“…Regardless of whether organic material is autochthonous or allochthonous, glacier-derived dissolved organic material has been shown to be significant sources to downstream ecosystems; studies in Alaska have shown that glaciers are a source of ancient and labile organic material to ocean ecosystems (Hood & Berner, 2009). Other recent work in the Himalayas has traced the contribution in glacier meltwater of sources of contamination once deposited from the atmosphere; hence, climate change induced glacier mass loss is enhancing pollution exposure levels over large and already heavily impacted regions of Northern India (Sharma et al, 2015). Whereas different hypotheses have been postulated as to the source of this material, high resolution spectrographic analyses of the age of this material suggests that the aerosols come from fossil fuel burning (Stubbins et al, 2012).…”

Section: Biogeochemical Processesmentioning

confidence: 99%

“…Whereas different hypotheses have been postulated as to the source of this material, high resolution spectrographic analyses of the age of this material suggests that the aerosols come from fossil fuel burning (Stubbins et al, 2012). Other recent work in the Himalayas has traced the contribution in glacier meltwater of sources of contamination once deposited from the atmosphere; hence, climate change induced glacier mass loss is enhancing pollution exposure levels over large and already heavily impacted regions of Northern India (Sharma et al, 2015). (Thompson, Mosley-Thompson, Davis, & Brecher, 2011) but we may also witness a transformation in the hydrological and biogeochemical cycles that geographers are uniquely poised to appreciate from a truly integrated perspective, using the many tools of observation and methods of tracing over many different scales.…”

Section: Biogeochemical Processesmentioning

confidence: 99%

The significance of mountain glaciers as sentinels of climate and environmental change

Mark

Fernández

2017

Geography Compass

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Mountain glaciers are transient hydrologic reservoirs persisting at the habitable extremes of Earth that both document and respond to climate change. They withhold water in solid phase from other reservoirs and ultimately impact sea levels. Moreover, they are valued resources with economic and cultural significance for human societies living below them. They also preserve histories of past climates. Yet, when climate change forces glaciers to lose mass, the water and suspended matter flow downstream with various impacts. Profoundly, current glacier and environmental changes are now accelerating and being propelled by human activity. Diverse consequences of these changes are emerging, and many are negative for society. Nevertheless, these changes coincide with a time in human history during which science is able to observe changes with unprecedented detail. Geography has a key role to play in analyzing the patterns and impacts of mountain glacier changes over multiple spatial and temporal scales and involving an integrated approach that draws on different disciplines and innovative technology to account for interactions between multiple spheres of the Earth System.

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Melting Himalayan glaciers contaminated by legacy atmospheric depositions are important sources of PCBs and high-molecular-weight PAHs for the Ganges floodplain during dry periods

Cited by 49 publications

References 37 publications

Intensive allochthonous inputs along the Ganges River and their effect on microbial community composition and dynamics

Intensive allochthonous inputs along the Ganges River and their effect on microbial community composition and dynamics

The abandoned ice sheet base at Camp Century, Greenland, in a warming climate

The significance of mountain glaciers as sentinels of climate and environmental change

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