Nohoch Mul pyramid at the Maya city of Cobá, Yucatán Peninsula. Photo: Bernard DUPONT / Wikimedia Commons, CC BY-SA 2.0
6 Nov 2026 · Lago Cobá and Cenote Xcach, Yucatán Peninsula, Mexico
Toxic mercury in Maya lakes coincided with food-web collapse
Matthew Waters, Mark Brenner and colleagues dated sediment cores from two lakes beside ancient Maya settlements in the northern Yucatán. Mercury, linked to the Maya use of cinnabar (red pigment) and elemental mercury, exceeded modern sediment toxicity thresholds for centuries between about 40 and 820 CE, peaking around 720 CE at Cenote Xcach. In the same layers, markers for algae, cyanobacteria, ostracods, snails and midge larvae declined or vanished, and recovered when mercury fell.
Why it matters: It adds mercury poisoning of water and aquatic food to drought, deforestation and soil erosion as stressors on Classic Maya cities, a live question in the debate over why many lowland Maya centres were abandoned.
Mainstream view: The authors present mercury as one additional environmental stressor during the Classic Period, not a single cause of the Maya decline; effects on human health are inferred, not measured.
Jianbo Guo, Ruochen Ge, Lu Yang and colleagues studied textile residues on objects from the Sanxingdui sacrificial pits K2–K8, the site of the famous bronze heads and gold masks of the ancient Shu culture. They found silk on 101 objects, 94 of them bronzes, dating to the Late Shang period (1300–1046 BCE). Microscopy and infrared tests identify mulberry silk, mostly plain weave, some coloured with hematite or an organic red dye, and some cloths as finely woven as Shang silks from the Central Plains.
Genomes from early farming villages including Çatalhöyük shed light on household and kinship structure. The research highlights women’s lines in some communities.
