Physicochemical Characterization and Heavy Metal Analysis of Effluents from the Tannerie Abidjanaise (Bonoua, Côte d’Ivoire)

The tanning industry, although essential for leather production, is one of the most polluting due to the significant discharge of effluents containing toxic chemicals. The objective of this study was to analyze physicochemical parameters and metals of composite samples from effluents of the Tannerie Abidjanaise (Côte d’Ivoire). All parameters of the effluents were measured using standardized methods. Hexavalent chromium (Cr (VI)) and other heavy metals (Copper, Iron, Manganese, Nickel, Plomb, Total chromium, Zinc) have been determined by means of an ion chromatograph and an Inductively Coupled Plasma Optical Emission Spectroscopy (ICP OES), respectively. Environmental Risk Assessment of Tannerie Abidjanaise were done with the heavy metal evaluation index (HEI). The Kruskal-Wallis test was made to bring out the relation between in value of all parameters of the different sampling. The mean concentration of temperature, pH, and SSM were 26.7, 7.04 and 414 mg/L, respectively. The average level of Total nitrogen, COD and BOD5 were 238 mg/L, 720 mg/L, and 249 mg/L, respectively. All of these parameters were higher than that of standard permissible limits. The BOD5 and COD ratio ranged from 0.3 to 0.4 indicated the low biodegradability of the effluents. The tannery effluents have TCr and Cr (VI) value with average concentrations of 122 mg/L and 49 mg/L, respectively. Like iron (average of 7.3 mg/L), TCr and Cr (VI) were higher than the standard permissible limits prescribed by National standards. Copper, lead, manganese, and zinc were determined at very low levels, while arsenic, cadmium, and nickel were below their detection limits. There is no significantly difference between the value of the different sampling for all parameters according to Kruskal-Wallis test. Tannerie Abidjanaise’s effluents present environmental risk to heavy metals provides according to HEI methodology.