Roman Empire's lead pollution harmed European intelligence for 180 years

The ancient Roman Empire, which spanned much of the Mediterranean region, saw a significant rise in lead pollution from mining and smelting operations, particularly after 15 BC. This pollution continued to increase until the end of the Pax Romana around AD 180, creating a toxic environment that negatively affected the cognitive abilities of its population. A recent study published in the Proceedings of the National Academy of Sciences provides evidence that this exposure led to a decrease in average intelligence quotients (IQ) by 2.5 to 3 points across the population, a decline that persisted throughout the nearly 180 years of peace and prosperity. Researchers studying chemical compositions in Greenland's ice cores were able to quantify atmospheric lead levels and link them to the Roman era. This groundbreaking research demonstrated that human activities, particularly industrial emissions from mining and metalworking, have had far-reaching and long-lasting impacts on public health, turning focus on how ancient civilizations managed their resources. Lead, widely used in the Empire for coinage and other applications, fused with dust particles in the atmosphere, spreading the toxic metal across Europe. The results of this study are striking when considering the extent of environmental health issues the Roman populace may have faced. It raises questions about the potential link between lead exposure and the decline of Roman civilization. Other sources of lead pollution, such as residential plumbing and kitchenware, further aggravated the situation, underlining how deeply ingrained toxic materials were in daily life. While correlations between lead exposure and societal decline have been debated for years, this study offers quantitative support for broader discussions regarding health and environmental factors in historical contexts. This new evidence illuminates the longstanding effects of human-generated pollution on cognitive development and public health. As the understanding of past pollution expands, researchers are left to contemplate the implications it may have had on history, with lead exposure posing considerable health risks that were long overlooked. While the study primarily focused on air pollution, it underscores the need for a more comprehensive perspective on ancient lifestyles and their consequences for both health and civilization as a whole.