NOVELTY - A solid-chemical composition comprising one or more plant materials chosen from Leguminosae and Pheaeophyta, source of iron, being reducing agent, source of manganese (Mn), source of bacteria being a solid-media inoculum e.g., soil bacteria, metal-reducing bacteria, or legume-related bacteria, source of plant-fiber and organic-substrate degrading enzymes e.g., cellulases, amylases, or glucanases.    USE - (I) is useful for treating (M1) substance chosen from contaminated industrial solid or liquid waste, hazardous solid or liquid wastes, contaminated environmental soils, sediments, waters, aqueous sludges, and its mixtures, which involves adding (I) at a dosage of 0.15-1000 g per Kg of the substance (claimed). (I) is useful for promoting biodegradation of contaminants. (I) is useful for promoting anaerobic, biologically mediated degradation, transformation, and/or detoxification of contaminants present in solid and liquid waste, soils, sediments, and water bodies.    ADVANTAGE - (I) enhances the removal of broad range recalcitrant organic, inorganic contamination in the environment. (M1) is cost effective.    DETAILED DESCRIPTION - A solid-chemical composition (I) comprising:    (a) one or more plant materials chosen from plant families Leguminosae and Pheaeophyta, from 10-95%, weight percent, of the composition;    (b) a source of iron, being a reducing agent and a microbial electron acceptor for anaerobic respiration, chosen from metallic iron particles and steel particles and their combinations, from 1-70%, by weight percent of the composition;    (c) a source of manganese (Mn) (IV), being an oxidative catalyst and a microbial electron acceptor for anaerobic respiration, chosen from metallic manganese particles and particles of manganese (IV) minerals and their combinations, from 0.01-37.5%, by weight percent, of the composition;    (d) a source of bacteria being a solid-media inoculum for microorganisms, chosen from soil bacteria, metal-reducing bacteria, legume-related bacteria, plant-fiber and organic-substrate degrading bacteria, plant-fiber and organic-substrate degrading fungi, bacteria that produce enzymes for plant fiber and organic substrate degradation, and their combinations, from 0.0001-3%, by weight percent, of the composition;    (e) a source of plant-fiber and organic-substrate degrading enzymes chosen from cellulases, amylases, glucanases, hemi-cellulases, proteases, lipases, and its combinations, from 0.0001-3%, by weight percent, of the composition.    DESCRIPTION OF DRAWING(S) - The figure shows the effect of several chemical composition on toxaphene biodegradation rates.