Effects of Pharmaceutical Effluents on Soil Microbiome and Physicochemical Parameters

Abstract

Soil contamination from pharmaceuticals is an evolving issue, consequently measurable data on their microbial effects are deficient. Thus, this study investigated the effects of pharmaceutical effluents on soil microbiome and the physicochemical parameters of soil samples obtained from Ugbowo, Benin City, Nigeria using standard procedures. The experiment which lasted for four weeks consists of four treatments of soil samples with pharmaceutical effluents of different percentages and one soil sample without pharmaceutical effluents (control). These include: soil treated with 250 ml of pharmaceutical effluents (25%); soil treated with 500 ml of pharmaceutical effluents (50%); soil treated with 750 ml of pharmaceutical effluents (75%), soil treated with 1000 ml of pharmaceutical effluents (100%) and soil treated without pharmaceutical effluents (0%). There was significant increase in the soil microbial counts in all effluent treatments compared to the control soil. A total of 16 isolates were identified. Ten were isolates belonging to the genera Bacillus, Arthrobacter, Proteus, Pseudomonas, Staphylococcus, Escherichia, Klebsiella, Enterobacter, Streptococcus, and Chromobacterium, while Fusarium sp., Mucor sp., Saccharomyces sp., Aspergillus niger, Rhizopus sp. and Penicillium sp. were the observed fungal isolates. The mean values of the soil physicochemical properties were all significantly higher in the treated groups compared to the control. This study revealed that pharmaceutical effluents altered the soil microbiological and physicochemical properties. The possibility of these alterations was due to the high nutrient content of the effluent which enriched the soil with additional nutrients needed for microbial growth.