Evaluating Ecotoxicity of Leather by Luminescent Bacteria

Leather industry plays an important role in our national economy, whereas both leather shavings and discarded leather products may pose potential environmental risks. This paper studied the species sensitivity of hexavalent chromium, formaldehyde, pentachlorophenol, tetrachlorophenol, o-phenylphenol, and nonylphenol which are hazardous substances concerned by global leather industry. The comparative analysis showed that luminescent bacteria had high sensitivity to these six substances. Then four types of dyed crust leather were collected from different factories and extracted with deionized water at a solid/liquid ratio of 1∶20 g/mL, 100 rpm, and 25 ℃ for 8 h. The ecotoxicity of the leachates was tested with Photobacterium phosphoreum, and the EC₅₀ values of the crust leather tanned by chrome, organics, vegetable tannin, and zirconium-aluminum were 21.46%, 26.76%, 49.50%, and 88.56%, respectively, indicating the ecotoxicity of crust leathers followed the sequence based on tanning agent: chrome > organics > vegetable tannin > zirconium-aluminum, chrome tanned crust leather showed a large negative ecological effect. This study showed that luminescent bacteria can distinguish the ecotoxicity of different leathers, which provides a convenient and feasible method for comprehensive ecological evaluation of leather.