Homo species were exposed to a new biogeochemical environment when they began to occupy caves. Here we report the first evidence of palaeopollution through geochemical analyses of heavy metals in four renowned archaeological caves of the Iberian Peninsula spanning the last million years of human evolution. Heavy metal contents reached high values due to natural (guano deposition) and anthropogenic factors (e.g. combustion) in restricted cave environments. The earliest anthropogenic pollution evidence is related to Neanderthal hearths from Gorham's Cave (Gibraltar), being one of the first milestones in the so-called “Anthropocene”. According to its heavy metal concentration, these sediments meet the present-day standards of “contaminated soil”. Together with the former, the Gibraltar Vanguard Cave, shows Zn and Cu pollution ubiquitous across highly anthropic levels pointing to these elements as potential proxies for human activities. Pb concentrations in Magdalenian and Bronze age levels at El Pirulejo site can be similarly interpreted. Despite these high pollution levels, the contaminated soils might not have posed a major threat to Homo populations. Altogether, the data presented here indicate a long-term exposure of Homo to these elements, via fires, fumes and their ashes, which could have played certain role in environmental-pollution tolerance, a hitherto neglected influence.
A multidisciplinary analysis of Holocene sediments from Saltés Island (Tinto-Odiel estuary, SW Spain) has allowed to differentiate eigth sedimentary facies, according to their textural characteristics, internal structure, paleontology and archaeological content. Its interpretation and the chronological datings carried out reconstruct a transition from a sandy tidal plain to a final occupation by a Roman salting (cetaria) between the 1st century BC to 5th century A. This evolution includes the deposit of washover fans derived from high-energy events between the 1st century BC to 3th century AD. The integration of these new data with others from previous research has allowed partially complete the palaeoenviromental reconstruction of the marine domain of the Tinto-Odiel estuary.
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