Chemical valorization of cigarette butts into a nutrient bearing soil amendment via multi method elemental characterization and preliminary ecotoxicological assessment

Cigarette filters are one of the most common pollutants worldwide. Cellulose acetate filters degrade slowly and still contain some of the toxic compounds present in tobacco smoke. In this experiment an attempt was made to see whether filters could be repurposed as a nutrient-rich soil amendment that had a low level of the toxic elements. Methods included grinding the filters, water rinsing, oxidative degradation (H 2 O 2 ), water leaching, organic extraction (ethyl acetate), animal manure amendment, ICP-OES analysis after water leaching, HNO 3 digestion, and HF/HNO 3 digestion, and comparison with 13 elements in the INAA database, agreement within 2.1–3.2% and a Pearson coefficient of > 0.99. The final product was predicted to contain 2.83% P 2 O 5 , 3.23% K 2 O, 1.11% S, and 2.38% total N. Final material Cd, Pb, As, Ni, Cu, and Zn levels were all less than the maximum EU Fertilizer Directive levels. Final product metals levels were reduced 75–91% in leachate by the Toxicity Characteristic Leaching Procedure (TCLP). Results from germination tests on cress and lettuce showed > 93% germination rate and no avoidance or mortality of Eisenia fetida earthworms. This was a preliminary test with a single filter batch and brief laboratory tests on terrestrial species, and subsequent testing on complete soil systems will likely be necessary.