Pencil sharpener of 6 cuts and takes practice to master without breaking the lead. Specialized sharpeners are available that operate on non-standard sizes of pencil, such as crayons used in primary schools. Sharpeners that have two openings, one for normal pencils and one for larger crayons, are fairly common. An artist's or draftsman's pencil sharpener leaves the graphite untouched and sharpens only the wood (some models can switch from standard to wood-only by an adjustment). The graphite lead is then honed to a sharp point with a lead pointer, which sharpens only the lead without wood. Lead pointers are also used with
Lead conducted on how to remove lead from biosystems by biological means: Fish bones are being researched for their ability to bioremediate lead in contaminated soil. The fungus "Aspergillus versicolor" is effective at removing lead ions. Several bacteria have been researched for their ability to remove lead from the environment, including the sulfate-reducing bacteria "Desulfovibrio" and "Desulfotomaculum", both of which are highly effective in aqueous solutions. Lead Lead is a chemical element with symbol Pb (from the Latin "plumbum") and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and