Toxicological Effects of Plastic Composted Soil on Nitrifying Bacteria

The aim of this study was to evaluate the toxicological effects of plastic composted soil on some nitrifying bacteria which are Nitrosomonas sp. and Nitrobacter sp. Methodology: Five plastic composted soil samples were collected from different locations within the Edo State Waste Management site located at Iyowa in Benin City which were merged to form a composite sample. Nitrosomonas sp. and Nitrobacter sp. were isolated from the soil samples. Plastic composted soil concentrations were prepared for LC 50 and EC 50 determination. Nitrobacter and Nitrosomonas acute toxicity test was carried out. Initial nitrite concentrations were determined and plates of Winograsky agar were immediately inoculated by spread plate techniques. Nitrite accumulation and utilization were also determined and inoculation by spread plate method was carried out from the various plastic composted soil concentrations after 1 h, 2 h, 3 h and 4 h time Original Research Article intervals. Plates were incubated at room temperature (28+/-2C) for 24 h. The percentage inhibition of bacteria (Nitrosomonas sp. and Nitrobacter sp.) was determined using the probit regression analysis in Excel Microsoft.