The first signs of heavy metal contamination from human activity are found in Gorham Cave in Gibraltar, dating back more than 40,000 years , when it was inhabited by Neanderthals. This is collected by an international team of researchers, including several scientists from different Spanish institutions, in a study published in the journal Scientific Report s.
These experts indicate that although concentrations of these elements are usually found in caves caused by guano depositions, the analyzes carried out in Gorham, in the nearby Vanguard cave and in the Paleolithic site of El Pirulejo, in Córdoba, suggest that in These cases are due to the bonfires made in that environment and the products resulting from combustion , such as smoke and ash.
In El Pirulejo, in particular, much of the heavy metal remains discovered seems to be related to the use of galena, a compound of lead and sulfur that has been used as a pigment and in the manufacture of beads for thousands of years. The researchers believe that the presence of these polluting products did not pose a threat to the survival of the various populations that inhabited the enclaves where they were found , but could have influenced their tolerance to environmental pollution to some extent.
