Human beings have been contaminating the environment with mercury earlier than previously thought. An international study with the participation of the CSIC and published in the journal Science Advances says so. Anthropic emissions of toxic metal began at least during the Bronze Age, about 4,000 years ago. Mercury has contaminated our world for 4,000 years.
Data were taken from an ice core over 1,200 meters (m) from Greenland. It covers the entire Holocene, from 11,700 years ago to the present. First, it was meticulously cut into smaller pieces, equivalent to five-year periods. It was cleaned to avoid cross contamination. The ice chunks were then melted in the laboratory for analysis.
old pollution
Mercury emissions in the past were large. He left his mark on the Greenland ice. «We usually think that humans have only been polluting the planet for a couple of centuries. But they are millennia,” they explain.
The sources of these early emissions could have been the refining of copper and tin ores or the use of cinnabar. It is a mineral rich in mercury, highly appreciated as a red pigment and as a medicine. There are high levels of mercury in human bones from funerary sites on the Iberian Peninsula. Cinnabar was widely used in that period.
It is an early indication that mercury emissions were very high. Ice core data show that contamination has only worsened over time. The accumulation of mercury in Greenland multiplied by 2.7 since the 13th century and by 7.4 from 1840, coinciding with the industrial revolution.
This study could help determine when human emissions began. It is a fact that would not only settle an open debate in the scientific community. It would allow compliance with international agreements on the use of this toxic metal to be monitored more precisely.
Reevaluating
Mercury has been polluting for 4000 years. This provides new evidence that humans began altering mercury levels in the environment earlier than previously thought. It will force a reassessment of the amount of human-derived mercury present today. "We hope that this will help improve current mercury emissions models and thereby be able to monitor and limit its use," they conclude.
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