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a b s t r a c tVegetation changes in the Maya Lowlands during the Holocene are a result of changing climate conditions, solely anthropogenic activities, or interactions of both factors. As a consequence, it is difficult to assess how tropical ecosystems will cope with projected changes in precipitation and land-use intensification over the next decades. We investigated the role of fire during the Holocene by combining macroscopic charcoal and the molecular fire proxies levoglucosan, mannosan and galactosan. Combining these two different fire proxies allows a more robust understanding of the complex history of fire regimes at different spatial scales during the Holocene. In order to infer changes in past biomass burning, we analysed a lake sediment core from Lake Pet en Itz a, Guatemala, and compared our results with millennial-scale vegetation and climate change available in the area. We detected three periods of high fire activity during the Holocene: 9500e6000 cal yr BP, 3700 cal yr BP and 2700 cal yr BP. We attribute the first maximum mostly to climate conditions and the last maximum to human activities. The rapid change between burned vegetation types at the 3700 cal yr BP fire maximum may result from human activity.

a b s t r a c tThe occurrence and temporal variation of 18 perfluoroalkyl substances (PFASs) and 8 polybrominated diphenyl ethers (PBDEs) in the European Alps was investigated in a 10 m shallow firn core from Colle Gnifetti in the Monte Rosa Massif (4455 m above sea level). The firn core encompasses the years 1997e2007. Firn core sections were analyzed by liquid chromatographyetandem mass spectrometry (PFASs) and gas chromatographyemass spectrometry (PBDEs). We detected 12 PFASs and 8 PBDEs in the firn samples. Perfluorobutanoic acid (PFBA; 0.3e1.8 ng L À1 ) and perfluorooctanoic acid (PFOA; 0.2e0.6 ng L À1 ) were the major PFASs while BDE 99 (