Evaluation of the physio-chemical properties and microbial load of the soil polluted with coffee processing wastes

Abstract

Aim: The study was designed to evaluate the physio-chemical properties and microbial load of the soil polluted with coffee processing wastes such as coffee husk and coffee pulp. Methodology and results: A total of ten soil samples were taken from three taluks of Coorg district of Karnataka, India. Out of which five soil samples were taken from places where the coffee processing wastes were dumped as landfills. The other five soil samples were taken from places free from coffee processing wastes which represent the control soil samples. The physical and chemical properties of the soil were measured using standard protocols. The highlight of the study was quantification of chemicals of ecotoxicological concern such as caffeine, polyphenols and tannin in soil samples. The identification and enumeration of soil bacteria, fungi, actinomycetes, yeast and plant growth promoting microorganisms were also done. The pollution with the coffee processing wastes make the soil acidic. The concentration of chemicals of ecotoxicological concern such as caffeine, polyphenols and tannins were significantly high in polluted soil. The colony forming units of plant growth promoting microorganism were declined significantly in the polluted soil. Instead of all these detrimental factors, the organic carbon, nitrogen, potassium, phosphorus and micronutrient content of the polluted soil was significantly high. Conclusion, significance and impact of study: This study revealed the fact that the unscientific disposal of coffee processing wastes as landfill make the soil less fertile, damage the normal microbial diversity of the soil and would cause severe pollution problems.