Aging by pollutants: introducing the aging dose (AD)50

The global scale of environmental pollution and the accumulation of pollutants in environmental sinks such as soil and surface water sediments call for long-term investigation of relevant target organisms. Consistently, age-resolved toxicology in the nematode roundworm C. elegans revealed that effective concentrations of pollutants such as heavy metals and nanomaterials accelerate a variety of age-related phenotypes from reduced locomotion to amyloid protein aggregation and neurodegeneration. We suggest the definition of this acceleration by introduction of the aging dose (AD)50 that provides a new metric to characterize adverse effects of pollutants. AD50 represents any concentration of a pollutant that significantly accelerates an age-related defect in 50% of the exposed individuals. Comparison of pollutant-exposed with unexposed specimen concerning their age when 50% individuals display a specific aging phenotype indicates the time-frame of this acceleration and defines the corresponding reduction of health span. Application of AD50 is invented in the short-lived nematode C. elegans, however, provides for a research platform to better understand the role of pollutants in aging across different taxa. Toxicology that addresses the entire life span impacts both, environmental protection of wild fauna as well as health protection in the human population.