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. (November 2015)

• Record Type: Journal Article
• Authors: Sharma, Brij Mohan; Nizzetto, Luca; Bharat, Girija K.; Tayal, Shresth; Melymuk, Lisa; Sáňka, Ondřej; Přibylová, Petra; Audy, Ondřej; Larssen, Thorjørn
• Is Part Of: Environmental pollution. Volume 206(2015)
• Page Start: 588
• Page End: 596
• Publication Date: 2015-11
• Subjects: PCBs -- PAHs -- DDT -- Glacier -- India; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2015.08.012
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Melting glaciers are natural redistributors of legacy airborne pollutants, affecting exposure of pristine proglacial environments. Our data shows that melting Himalayan glaciers can be major contributors of polychlorinated biphenyls (PCBs) and high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) for surface water in the Gangetic Plain during the dry season. Glacial emissions can exceed in some cases inputs from diffuse sources within the catchment. We analyzed air, deposition and river water in several sections along the Ganges River and its major headwaters. The predominant glacial origin of these contaminants in the Himalayan reach was demonstrated using air–water fugacity ratios and mass balance analysis. The proportion of meltwater emissions compared to pollutant discharge at downstream sections in the central part of the Gangetic Plain was between 2 and 200%. By remobilizing legacy pollutants from melting glaciers, climate change can enhance exposure levels over large and already heavily impacted regions of Northern India. Highlights: Glacial meltwater as main source of PCBs and some PAHs for the high Ganges reach. Glacial stream water was a source of PCBs for the atmosphere. Elevated emissions of PAHs were consistent with reported levels in ice core. Glacial emissions were 2–200% of contaminant discharges in the mid Ganges reach. Abstract : During dry periods, glacial meltwater discharge of some PCBs and high-molecular-weight PAHs is comparable to their total discharge at river sections in the central Gangetic plain.