Source assessment of atmospheric lead measured at Ny-Ã lesund, Svalbard

- Atmospheric lead reaching Ny-Ålesund is mainly anthropogenic.
- Lead concentrations are significantly higher in spring than in summer.
- There is a significant seasonal shift in the lead isotopic ratios.
- Eastern Eurasia is the main source area of atmospheric lead during spring.
- Northern America is the major source of atmospheric lead during summer.

Size-segregated (PM10) aerosol samples were collected at Ny-Ålesund (Svalbard Islands, Norwegian Arctic) from April to September 2012 and analysed for lead content and isotopic composition (207Pb/206Pb and 208Pb/206Pb), along with other chemical tracers, such as aluminium (crustal marker) and non-sea-salt sulphates (anthropogenic and marine biogenic marker). It was found that most of lead reaching Ny-Ålesund is anthropogenic, with a marked seasonality of both the concentration and isotopic signature. Particularly, average lead concentration in summer was significantly lower than in spring (p = 0.003), whereas 208Pb/206Pb decreased from 2.107 ± 0.002 to 2.090 ± 0.005 (mean ± 95%-confidence level, p = 6.0 10−6). A comparison of the measured isotopic ratios to literature data suggests that the atmospheric lead reaching the Arctic during spring can be mainly related to inputs from eastern Eurasia, whereas North America appeared to be the major source during the summer. Experimental results and sampling strategy also indicate that local inputs of crustal and anthropogenic lead play a minor role. The source-receptor relationship was confirmed by a back-trajectory cluster analysis of air-masses reaching the sampling site.

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