A study explores the biogeochemical cycle of vanadium. Human activities contribute a significant amount of the element vanadium to the environment, and high vanadium concentrations have poorly documented but potentially negative consequences for human health. William Schlesinger and colleagues estimated the annual global flux of vanadium between the Earth’s crust, rivers, oceans, and the atmosphere from both natural and anthropogenic processes. Extraction of fossil fuels released an estimated 320-600 billion grams of vanadium per year from the Earth’s crust, whereas mining of vanadium-bearing ores released an additional 130 billion grams per year. Human activities increased the annual flux of dissolved vanadium into oceans by approximately 15%, primarily via disposal of coal combustion residues. The dissolved vanadium budget in the oceans was remarkably well balanced, with a mean residence time for dissolved vanadium in seawater of about 130,000 years with respect to inputs from rivers. Anthropogenic vanadium emissions to the atmosphere, most of which came from petroleum combustion, were estimated to exceed natural emissions by a factor of up to 1.7, which exceeded the human impact on atmospheric lead and mercury. According to the authors, atmospheric vanadium emissions are likely to increase in the near future with increasing use of vanadium-rich petroleum products, such as heavy oils, bitumen, and petroleum coke.