Vanadium Stable Isotopes in Biota of Terrestrial and Aquatic Food Chains

Vanadium, a potentially toxic metal, is enriched in the environment from anthropogenic releases, particularly during fossil fuel production and use and steel manufacturing. Metal stable isotopes are sophisticated tools to trace pollution; however, only recent analytical advances have allowed for the accurate and precise measurement of vanadium isotope ratios (δ51V). To examine its potential as a tracer in terrestrial and aquatic ecosystems, δ51V was measured in soil, plant, lichen, marten, and lake sediment from sites near vanadium emissions at oil sands mines (Alberta, Canada) and in the sediment and biota (algae, zooplankton, fish) from a remote subarctic lake (Northwest Territories, Canada). Samples from Alberta had distinct δ51V values with marten liver the lowest (−1.7 ± 0.3‰), followed by lichen (−0.9 ± 0.1‰), soil (−0.7 ± 0.1‰), sediment (−0.5 ± 0.2‰), and plant root (−0.3 ± 0.2‰). Average values were lower than Alberta bitumen and petroleum coke (−0.1 ± 0.1‰). Plant roots had systematically higher δ51V than the soil from which they grew (Δ51Vplant‑soil = 0.4 ± 0.1‰), while δ51V of lichen and aquatic biota were lower (0.1–0.3‰) than likely crustal sources. These δ51V measurements in terrestrial and aquatic biota demonstrate promise for tracer applications, although further study of its biological fractionation is needed.