Biodegradation of News Inks with Modified Sturm Test

For our previous studies using mixed cultures of soil microorganisms, the biodegradation of ink vehicles and formulated four colored inks was determined gravimetrically. Now, we report results from biodegradation of the four-colored news inks by using the Modified Sturm Test (Organization for Economic Cooperation and Development). In this method, test organisms are obtained from activated sludge, and the extent of degradation is determined by measuring carbon dioxide evolution. Biodegradation data for commercial news inks consisting of vehicles containing petroleum resins, and either soybean or mineral oil solvents, and USDA's vehicle containing 100% soy oil, are reported and discussed.