Vegetable composting: is it safe to compost the ink on paper coming from computer printers?
Pigments combine with a “vehicle” and a “binder” to create specific inks for various printing projects. The pigment and the vehicle are the bad boys. Paper composting and mulching is haunted by the specter of the heavy metals used as pigment in commercial inks in the past. For years, the vehicle was petroleum-based, but the industry is slowly switching over to soy- or vegetable-based inks. However, inks labeled “soy-based” are still permitted (and likely) to contain some amount of petroleum. Pigments themselves still contain heavy metals such as zinc and copper, although overall amounts of heavy metals have been reduced. Although toxins are present in quite small amounts, all the sources I consulted agreed that contemporary printed newsprint, including colored newsprint, and cardboard boxes are safe for garden use. Glossy inserts, shiny ink of any sort, magazines, and colored paper do not make appropriate compost or mulch materials, due to a higher prevalence of toxics within the paper
