American oyster (Crassostrea virginica) as a biosentinel for radium: influence of age on radium-226 levels in shell and soft tissues.

Age-related variations in 226 Ra concentrations differ between oyster shells and soft tissues, with shells showing increases and tissues showing decreases as oysters age.

• Why it matters: Understanding how biological factors like age influence contaminant levels is crucial for accurate environmental monitoring and site discrimination using oysters as biosentinels.
• What they did: The study analyzed 1650 Crassostrea virginica oysters from five sites, measuring 226 Ra in shells and soft tissues, and used PCA and ANOVA to evaluate age and site effects, including elemental ratios.
• The result: Normalization of 226 Ra with barium significantly reduced age-related variability and enhanced spatial discrimination, supporting elemental normalization as a useful approach in oyster-based biomonitoring.