Current-use and legacy pesticide history in the Austfonna Ice Cap, Svalbard, Norway.

The Svalbard archipelago in arctic Norway receives considerable semivolatile organic contaminant (SOC) inputs from the atmosphere. To measure the history of net SOC accumulation there, we analyzed the upper 40 m of an ice core from Austfonna, the largest ice cap in Eurasia, for several legacy organochlorine (OC) compounds and current-use pesticides (CUPs) including organophosphorus (OP), triazine, dinitroaniline, and chloroacetamide compounds. Five OP compounds (chlorpyrifos, terbufos, diazinon, methyl parathion, and fenitrothion), two OCs (methoxychlor and dieldrin), and metolachlor--an herbicide--had historical profiles in the core. The highest OC concentration observed was aldrin (69.0 ng L(-1)) in the surface sample (1992-1998). The most concentrated OP was dimethoate (87.0 ng L(-1)) between 1986 and 1992. The surface sample also had highest concentrations of pendimethalin (herbicide, 18.6 ng L(-1)) and flutriafol, the lone observed fungicide (9.6 ng L(-1)). The apparent atmospheric persistence of CUPs likely results from little or no oxidation by OH* during the dark polar winter and in spring. Long-range atmospheric pesticide transport to Svalbard from Eurasia is influenced by the positive state of the North Atlantic Oscillation Index since 1980 and also by occasional fast-moving summer air masses from northern Eurasian croplands.