Exploring chronic arsenic poisoning in pre-Columbian Chilean mummies

This paper explores to what extent arsenic poisoning affected pre-Columbian northern Chile populations living between Arica and Iquique cities. We hypothesize, the pre-Columbian inhabitants of this region, will show arseniasis according to modern geographic endemic levels. Continuous exposure to high levels of arsenic causes serious health problems. Today, in the Camarones valley, where many Chinchorro people lived, arsenic levels are 100 times above the 10 μg/L recommended by the World Health Organization (WHO). Using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) we determined arsenic levels in a single strand of hair of 45 Arica mummies coming from ten sites (Morro 1, Morro 1/5, Yungay 372, Camarones 8, 9, 15D, and 17 and Azapa 140, Sermenia and Patillos), ranging from Chinchorro (ca. 5000-2000 years B.C.) to the Late Intermediate Period (1000-1400 years A.D.). Each hair was cleaned using distilled ionized water and placed on double sided mounting tape and ablated using a 266 nm Nd-YAG UV laser. Hair samples were also investigated for potential diagenesis.Results indicate minimal diagenesis. Arsenic hair (AsH) concentrations in the mummies ranged from <0.8 to 262.2 μg/g. We noted AsH variability within burial sites as well as regional variation. The Morro mummies have the highest mean group value (58 ± 103.8 mg/g). Contrary to hypothetical expectations, some Arica Chinchorro mummies have high values, perhaps indicating inter site mobility related to exogamous marriage and mummification rites. Our study shows that ancient people of northern Chile were significantly affected by arsenic poisoning throughout generations. Finally, this study calls attention to naturally occurring eco-toxic contaminants and its impact on ancient Andean people.