puits (1) temps (durée) (1) risque (1) nitrate (1) matériau (1) santé humaine (1) histoire (1) analyse (1) émission (1) dégradation (1) conservation (1) comparaison (1) chimie (1) cellulose (1) taux (1) Color (1) Preservation (1) Conservation (1) Comparison (1) History (1) Chemical warfare (1) Additives (1) Identification (1) Zinc oxide (1) Time (1) Threats (1) Synchrotrons (1) Stability (1) Risk (1) Reason (1)