The construction of Egypt’s famous Pyramids of Giza, one of the wonders of the ancient world, was a sacrifice, and workers working in the pyramids may have been exposed to large amounts of copper, perhaps the oldest known example of metal contamination.
The discovery of copper in ancient soil samples could have implications for when the area was first settled and what the living conditions were for ordinary Egyptians outside of royalty at the time. The presence of toxic copper also points to a thriving tool-making industry. Furthermore, the new study reveals that industrial pollution has a deeper history than is generally recognized.
In 2019, a team of geochemists from France’s University of Aix-Marseille excavated beneath the 4,500-year-old Port of Khufu, the oldest known port in history, near the site of the pyramids of Khufu, Khafre, and Menkaure. The port was located on a now-defunct tributary of the Nile. The scientists then examined the samples using a technique called plasmaless spectroscopy to measure concentrations of copper and other metals, including aluminum, iron, and titanium.
The same research team used carbon dating to GeologyThey estimate that copper contamination began around 3265 BC, meaning the area was inhabited by humans 200 years earlier than previously thought. Contamination peaked 750 years later, eventually disappearing around 1000 BC. Copper concentrations were “five to six times higher than in the natural environment,” study lead Professor Alain Véron of France’s Aix-Marseille University told Eos.
The presence of copper is likely evidence of a thriving tool-making industry, according to the researchers. The discovery of arsenic in the samples — a metalloid element historically used by metalworkers to strengthen other metals — suggests workers may have made tools such as blades, chisels and drills that would have been essential for the construction of the pyramid complex.
Copper contamination in the environment can have dire effects on both humans and animals. Small amounts of copper are essential for several biological functions in humans, such as producing energy and forming blood vessels, but excessive exposure can cause vomiting, diarrhea, nausea, and abdominal pain. Long-term exposure can have even more devastating effects, including kidney and liver damage. It is unclear how the contamination affected the ancient Egyptians, but the presence of this metal in soil samples provides greater insight into their lives.
The copper concentrations were so high that it’s likely there was heavy industrial activity in the area, Bellon said. It also suggests the area’s inhabitants were resilient. The period of contamination overlaps with around 2200 B.C., when the Nile reached its lowest level ever, shaking Egypt’s economy and social structure. But work continued at Giza and other projects.
“While much research has been done on the pyramids, including how they were built and how the pharaohs lived, the new study offers a glimpse into the daily lives of ancient Egyptians, who were dealing with turbulent political dynasties and a changing environment — all things that seem all too familiar to us,” Veron said. “The techniques used in this study can be adapted to other ancient Egyptian sites to tell us more about how the non-elites lived and worked, making the tools used to build some of the most enduring monuments in human history.”
