Legacy organochlorine pollutants in glacial watersheds: a review

Northern Hemisphere alpine glaciers have been identified as a point of concentration and reemergence of legacy organochlorine pollutants (OCPs). In this review, we compile a selection of published literature combining long-range, global atmospheric transport and distribution-based compartmental environmental flux models, as well as data from glacial meltwater, ice core, crevasse and proglacial lake sediment studies. Regional studies of ice and meltwater in alpine glaciers of the northern latitudes show similarities in sample deposition profiles and concentration due to chemical atmospheric residence time, precipitation type and glacier flow rates. In glaciated locations near areas of extensive OCPs use, such as the Swiss and Italian Alps, glacier sample concentrations are higher, while in areas more distant from use, including Arctic nations, OCPs concentrations in glaciers are significantly lower. Our review identifies alpine glaciers co-located with regions characterized by OCPs use as a significant organochlorine pollutant distribution source, secondary in timing and location to direct deposition, with subsequent bioaccumulation and potential human risk impacts.