Global biogeochemical cycle of vanadium

Abstract

Synthesizing published data, we provide a quantitative summary of the global biogeochemical cycle of vanadium (V), including both human-derived and natural fluxes. Through mining of V ores (130 × 10 9 g V/y) and extraction and combustion of fossil fuels (600 × 10 9 g V/y), humans are the predominant force in the geochemical cycle of V at Earth's surface. Human emissions of V to the atmosphere are now likely to exceed background emissions by as much as a factor of 1.7, and, presumably, we have altered the deposition of V from the atmosphere by a similar amount. Excessive V in air and water has potential, but poorly documented, consequences for human health. Much of the atmospheric flux probably derives from emissions from the combustion of fossil fuels, but the magnitude of this flux depends on the type of fuel, with relatively low emissions from coal and higher contributions from heavy crude oils, tar sands bitumen, and petroleum coke. Increasing interest in petroleum derived from unconventional deposits is likely to lead to greater emissions of V to the atmosphere in the near future. Our analysis further suggests that the flux of V in rivers has been incremented by about 15% from human activities. Overall, the budget of dissolved V in the oceans is remarkably well balanced-with about 40 × 10 9 g V/y to 50 × 10 9 g V/y inputs and outputs, and a mean residence time for dissolved V in seawater of about 130,000 y with respect to inputs from rivers.vanadium | petroleum | geochemical cycle | aerosols | rock weathering V anadium (V) occurs in a wide range of earth materials and is a relatively abundant trace metal, with an average concentration in the upper continental crust (97 mg/kg) more than double those of nickel (Ni) and copper (Cu) (1). In modern society, the majority of V is used to improve the strength and corrosion resistance of steel; it is also of increasing strategic and technological interest as a specialty metal in electronics and batteries. V is an essential trace element in prokaryotic biochemistry, where it is found as an alternative to molybdenum in the molecular structure of nitrogenase, the enzyme of N fixation (2-4). It also appears in the structure of enzymes in the marine algae responsible for the formation of bromoform (5) and methyl bromide (6), which contributes to the depletion of stratospheric ozone. Whether V is an essential trace element in higher plants and animals is unknown (7), with some evidence favoring an essential role in at least some higher organisms (e.g., refs. 8 and 9). Higher plants accumulate about 1 mg/kg in their tissues (10).The mean concentration of V in the continental crust is about 97 mg/kg (1, 11), and ∼20 × 10 9 g V/y enters biogeochemical cycles at Earth's surface through chemical weathering (12). V, which can exist in three common oxidation states, is largely found as the vanadate ion (H 2 VO 4 − ) in natural oxidized waters of near-neutral pH. The dissolved concentration in river water is about 0.7 μg/L, less than half of the concentration of ∼1.8 μg/L in seawa...

Airborne survey of trace gases and aerosols over the Southern Baltic Sea: from clean marine boundary layer to shipping corridor effect

“…Despite the low particle fraction below 1%, Fe/V-containing particles showed an increase with extinction. Similar to EC2 particle type, vanadium containing particles are good tracers for anthropogenic emissions, in particular oil and coal combustion and production (Schlesinger et al, 2017). Particularly interesting for marine environments, earlier studies showed the presence of the Fe/V particle type to be associated with ship emission (Agrawal et al, 2008;Ault et al, 2010;Coggon et al, 2012).…”

“…The increase of the EC2 type indicates the rather aged character of the plume, and Fe/V might suggest the influence of ship fuel combustion (Agrawal et al, 2008;Ault et al, 2010). Nevertheless, vanadium containing particles are emitted by other industrial activities (Schlesinger et al, 2017) and due to the limited understanding of the chemical speciation of vanadium in primary aerosol sources (Shafer et al, 2012), the direct influence of shipping on this particular extinction event cannot be confirmed.…”

The evolving redox chemistry and bioavailability of vanadium in deep time

“…Recent studies indicate that the exposure of continental land above sea level is very limited until the middle of the Archean with lower elevation than that of the present-day plateaus (Bada & Korenaga, 2018;Flament, Coltice, & Rey, 2013;Korenaga, Planavsky, & Evans, 2017), thus possibly constraining the input of continental weathering of vanadium to the shallow ocean. Additionally, pervasive hydrothermal flux of Fe (Kump & Seyfried, 2005) and massive precipitation of iron (hydr)oxides as banded iron formations (BIFs; Klein, 2005) further limited the availability of vanadium in early seawater as surface adsorption or coprecipitation of vanadium along with iron (hydr)oxides and clay minerals are major sinks of the modern vanadium cycle (Breit & Wanty, 1991;Huang et al, 2015;Schlesinger, Klein, & Vengosh, 2017), and presumably in the Archean. Therefore, before the prominent occurrence and elevation of continental lands in the mid-Archean, limited weathering supply and large adsorption/coprecipitation sinks would have resulted in low concentrations of vanadium in the oceans, as evidenced by low V concentrations in early Archean BIFs (Aoki, Kabashima, Kato, Hirata, & Komiya, 2018).…”

Chemicals are contaminants too: Teaching appreciation and critique of science in the era of Next Generation Science Standards (NGSS)

“…These piles were stored outdoors in a densely populated community of color that has experienced a long history of environmental racism, including an ongoing concern with heavy metal contamination from steel mills (Hawthorne, ). Unconventional fossil fuels, like petcoke, are substantial contributors to heavy metal contamination (Schlesinger, Klein, & Vengosh, ). In the clarification statement of HS‐ESS3‐2, and in the “nature of science” appendix, the NGSS argue that “Science knowledge indicates what can happen in natural systems—not what should happen.” But this statement artificially disentangles natural, social, and political systems within the HS‐ESS3‐2 context of mining for minerals in ways that are contradicted by the standards’ own suggestions to engage students with neoliberal framings of gold mining, oil drilling, and the best practices for exploiting unconventional fossil fuels.…”

“…These piles were stored outdoors in a densely populated community of color that has experienced a long history of environmental racism, including an ongoing concern with heavy metal contamination from steel mills (Hawthorne, 2018). Unconventional fossil fuels, like petcoke, are substantial contributors to heavy metal contamination (Schlesinger, Klein, & Vengosh, 2017). In the clarification statement of HS-ESS3-2, and in the "nature of science" appendix, the NGSS argue that "Science knowledge indicates what can happen in natural systems-not what should happen."…”