The sustainability of cobalt is an important emerging issue because this critical base metal is an essential component of lithium-ion batteries for electric vehicles. More than half the world’s cobalt mine production comes from the Katanga Copperbelt in DR Congo, with a substantial proportion (estimated at 15-20%) being extracted by artisanal miners. Here we show, in a case study performed in the town of Kolwezi, that people living in a neighbourhood that had been transformed into an artisanal cobalt mine, had much higher levels of cobalt in urine and blood than people living in a nearby control area. The differences were most pronounced for children, in whom we also found evidence of exposure-related oxidative DNA damage. It was already known that industrial mining and processing of metals have led to severe environmental pollution in the region. This field study provides novel and robust empirical evidence that the artisanal extraction of cobalt that prevails in the DR Congo may cause toxic harm to vulnerable communities. This strengthens the conclusion that the currently existing cobalt supply chain is not sustainable.

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Cores recovered from periglacial Lake Le Bourget deep basin (northwestern Alps) were investigated to examine the influence of the 'Little Ice Age' (LIA) on terrigenous lacustrine sedimentation. Growing glaciers in the regional watershed induced catastrophic Rhone river floods and major underflow deposits in the deep basin during the early fifteenth, the sixteenth and the mid-eighteenth centuries. The LIA is characterized by a decrease in deposition from interflows from AD -1550 to 1740 and an increase in deposition from underflows from AD -1550 to 1800. On one hand, spectral analyses of the laminations in interflow deposits reveal 4-5 years cyclicities from AD -1440 to 1550, as well as 7-8 and 13-14 years cyclicities from AD -1740 to 1870; on the other hand, spectral analyses of a clay mineral ratio reflecting underflow deposits highlight 45-50 years cyclicities from AD -1550 to 1800. These pluriannual, decadal and pluridecadal periods are typical of the North Atlantic Oscillation (NAO). A NAO-like period in our data would be a consequence of periodical variations in rainfall and snow accumulation during late autumn and winter over Lake Le Bourget's watershed.

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