The oldest evidence yet of atmospheric pollution caused by human activity has been discovered by a group of researchers working at the Laguna de Rio Seco lagoon in Sierra Nevada (Spain). That location, located at an altitude of 3,020 meters, shows clear evidence of the atmospheric pollution (lead primarily) caused by large-scale metallurgical activities beginning around 3,900 years ago, during the Early Bronze Age.
“Lead pollution increased gradually during the Late Bronze Age and Early Iron Age, coinciding with the development and expansion of metallurgy in southern Europe.”
In modern times, atmospheric heavy metal contamination is a severe problem, it has been linked to and implicated in many of the common diseases of modern times. As this research shows, though, this type of pollution has long accompanied human industry, even 4,000 years ago, the only thing that has really changed in modern times is the scale.
The new research “reveals the influence of human activity on the environment due to the beginnings of metallurgy at the end of the Holocene period in southern Europe. From the geochemical analyses carried out on the sediments deposited during the past 10,000 years in the Laguna de Rio Seco lagoon, a remote alpine lake in Sierra Nevada, at 3,020 meters above sea level, evidence has been found of atmospheric pollution from lead. This contamination is traced back to metallurgical activities from 3,900 years ago (Early Bronze Age), coinciding with an increase in forest fires and deforestation in southern Europe.”
University of Granada researcher, Jose Antonio Lozano Rodriguez, elaborates: “this data tells us of the great influence our ancestors had on the environment. Lead pollution gradually increased during the Late Bronze Age and the Early Iron Age, coinciding with the development and expansion of metallurgy in southern Europe.”
“The samples studied show a maximum contamination from lead about 2,900 years ago, which would imply an intense movement and manipulation of this metal in the area around Sierra Nevada.”
“In the samples studied by the scientists, there are also high levels of atmospheric contamination from lead during the Roman Empire, when large quantities of this metal were extracted in the south of the Iberian Peninsula, as well as during the past 300 years, coinciding with the Industrial Revolution and the reactivation of mining activity in southern Spain.”
It’s worth noting that the actions taken in recent decades to reduce lead emissions: lead-free gasoline, lead-free paint, etc, appear to have had some effect. Lozano concludes, this “suggests that the global measures taken to reduce lead emissions, such as the use of lead-free gasoline, have helped to reduce the levels of this metal in the atmosphere.”