About this Research Topic
Mountain glaciers are sentinels of climate change, since they are highly sensitive to global warming. The most vulnerable are located in rapidly warming tropical regions, where they have undergone high rates of mass loss and retreat in the last decades. Attention to date has focused primarily on the quantity of water released from mountain glaciers, because of its impact on global sea levels and water security. However, the concurrent changes in water quality are much more poorly constrained, despite their paramount importance for agriculture, food security, hydropower and ecosystem functioning. The melting of snow and glaciers may be a source of a cocktail of persistent, toxic bioaccumulative substances deposited for decades, which are now being released into and mobilized across aquatic systems. In addition, some contaminants may be sourced from para-glacial water-rock processes occurring in catchments, such as meltwater and freshly exposed geology interactions. Among these substances, metals, dioxins, polychlorinated biphenyls, and organochlorine pesticides may exceed international protective standards, potentially threatening human health, aquatic life and the environment.
Glacial catchments are evolving along a trajectory from pristine conditions, where glacial runoff is an important nutrient source for downstream ecosystems, to those in which the same runoff is toxic to ecosystems and human health. This poses a novel challenge for water resource management in response to spatio-temporal changes in water quantity and quality. To understand the impacts of such evolution we require first to know how contaminants transport and accumulate in snow and glaciers, the paths they follow within glaciers, the chemical and physical interactions or changes they undergo, and the temporal dynamics of their release. This makes it necessary to expand measurements to a wider seasonal study of catchments in different regions along this evolutionary path. Unravelling the complex interplay between glaciation history, hydrological and geological processes, will deliver a step change in our ability to predict water quality evolution in deglaciating terrains, understand the effectiveness of downstream buffers and controls of toxicity shifts, identify key elements driving vulnerability of catchments, and develop effective solutions for toxic catchments. Thus, there is an imperative to move beyond diagnosing the toxicity problem towards developing the solution, so creating resilience in an unprecedented climate change scenario.
Although the topic is focused on contaminants deposited in ice and snow and their release in headwaters ecosystems, this is an excellent opportunity to bring interest into melting and hydrological processes interacting in a very dynamic way with geological formations around the globe. This may add complexity to understanding processes underpinning contaminant flux from glaciers and their environmental impacts in a variety of ecosystems. This Research Topic for the Geochemistry Section of Frontiers in Earth Science welcomes scientists to submit Original Research, Reviews and Perspective articles on the geology, geochemistry, climatology, hydrology, and ecotoxicology. We expect papers on specific topics such as:
• Processes driving deposition, accumulation and environmental fate of contaminants, including sources and sinks, transport pathways and transformation;
• Climatic and hydrological processes governing exposure of terrestrial and glacial surfaces and release and mobilization of contaminants through glacial catchments;
• Para-glacial water-rock processes occurring in catchments, such as meltwater interactions with freshly exposed geology and production of acid drainage;
• Adsorption-desorption processes and interaction of natural and anthropogenic contaminants that determine their dynamics in different geochemical and aquatic environments;
• Development of analytical methods for trace quantification of complex chemical mixtures in sediments from lakes, bogs and wetlands to determine temporal trends of release and deposition and their distribution along glacial catchments; and
• Modelling of geochemical and hydrological processes that control water quality evolution in deglaciating terrains, considering buffers of contaminants toxicity, and vulnerability of catchments.
Keywords: geochemistry, snow and glacial melting, earth surface processes, contaminant interactions, environmental impacts
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.