Lesson plan
Lead cycle
cycle. All values indicated are fluxes with unit of Mg/yr; the values have been obtained from Cullen and McAlister (2017). The size of the arrows are approximately proportional to their flux. The major reservoir for lead is the crust and mantle with a concentration of 11–14.8 ppm. The natural sources (green arrows) of lead in the atmosphere are volcanic eruptions, plant exudates, forest fires, extraterrestrial particles, radioactive decay, and physical and chemical weathering of rocks. The major anthropogenic sources (red arrows) are mining and smelting of ores, non-ferrous metal production, stationary fossil fuel combustion platforms, and mobile fossil fuel combustion platforms. The sinks (blue arrows) of lead are wet deposition of aerosols on to the ocean water surface and the subsequent burial in deep sediments. Since lead is toxic to life, there are no predominant metabolic pathways. The lead cycle is the biogeochemical cycle of lead through the atmosphere, lithosphere, biosphere, and hydrosphere, which has been influenced by anthropogenic activities.
Article summary
cycle. All values indicated are fluxes with unit of Mg/yr; the values have been obtained from Cullen and McAlister (2017). The size of the arrows are approximately proportional to their flux. The major reservoir for lead is the crust and mantle with a concentration of 11–14.8 ppm. The natural sources (green arrows) of lead in the atmosphere are volcanic eruptions, plant exudates, forest fires, extraterrestrial particles, radioactive decay, and physical and chemical weathering of rocks. The major anthropogenic sources (red arrows) are mining and smelting of ores, non-ferrous metal production, stationary fossil fuel combustion platforms, and mobile fossil fuel combustion platforms. The sinks (blue arrows) of lead are wet deposition of aerosols on to the ocean water surface and the subsequent burial in deep sediments. Since lead is toxic to life, there are no predominant metabolic pathways. The lead cycle is the biogeochemical cycle of lead through the atmosphere, lithosphere, biosphere, and hydrosphere, which has been influenced by anthropogenic activities.
Key claims
No claims recorded.
Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
No sources recorded.
Key claims and bibliography are generated from the same tracked claims and sources as the article page.