Heavy oils and petroleum coke raising vanadium emissions
| Date: Dec 19, 2017 |
| “Human emissions of vanadium to the atmosphere now exceed those from all natural sources combined—by a factor of 1.7,” said William H. Schlesinger, James B. Duke Professor Emeritus of Biogeochemistry at Duke’s Nicholas School of the Environment, who led the study.
“Less than two decades ago, the ratio of human to natural emissions was 0.59 to 1, or less than half the current level,” Schlesinger said. “Our analysis suggests that much of this rapid rise can be traced to the increased use of unconventional heavy-petroleum fuels.” Vanadium is a trace metal found in many earth materials, including petroleum and coal. It is emitted as particulate matter when these materials are burned, and can also be released as accidental, or “fugitive,” emissions during mining, extraction and processing. Natural sources of vanadium emissions include volcanic eruptions and the weathering of rocks. The health risks of exposure to airborne vanadium particles are not as well documented as those for other metallic airborne contaminants such as mercury or lead, but growing evidence suggests breathing vanadium-rich aerosols can impair respiratory functions and exacerbate conditions such as asthma and chronic obstructive pulmonary disease (COPD). Oil and coke refineries are generally built in areas where residents don’t have the political or economic clout to fight back, Schlesinger noted. For instance, one of North America’s largest coke refineries is on the southeast side of Chicago. “We’re still in the early phase of understanding the risks people living in these areas face,’ he said, “but I suspect we’ll see a growing focus on the issue as the use of heavy oils and petroleum coke continues to rise in coming years.” |
