Using historical herbarium specimens to track heavy metal pollution in the eastern United States

Plant specimens stored in herbaria are being used to explore important ecological questions. Researchers have now shown the effectiveness of herbarium specimens of herbaceous plants to track changes in heavy metal concentrations over time. The study compares concentrations of copper, lead, and zinc in specimens collected around Providence, RI, from 1846 to 1916, and compares these levels to plants collected from the same areas in 2015.