Roman metallurgy and early Anthropocene footprints in Kerala, South India: geochemical reflections from Muziris sediments

Abstract This study investigates early anthropogenic environmental impact at the Pattanam archaeological site in Kerala, South India, identified as the ancient port of Muziris, through geochemical analysis of heavy metals, particularly lead (Pb). Sediment samples collected from a 3-m trench were analyzed using XRF, and contamination was assessed using Enrichment Factor (EF), Geoaccumulation Index (Igeo), and Pollution Load Index (PLI). Results reveal significant Pb enrichment between 1.8- and 2.8-m depth, peaking at 2.6 m, aligning with the Early Historic period (200 BCE–400 CE), a time of active Indo-Roman trade. EF and Igeo values confirm that Pb contamination is of anthropogenic origin, likely stemming from local recycling of Roman materials, metallurgical activity, and the importation of goods. A marked decline in Pb levels in the overlying layers reflects the post-Roman decline of Muziris, possibly linked to the 1341 CE flood that reshaped regional trade patterns. This research not only connects South Indian archaeological layers to global Roman-era pollution signals but also contributes to ongoing debates on the onset of the Anthropocene by highlighting early human-induced environmental change.