Bacteriological Analysis of Top Soil from an Electronic Waste Dumpsite in Port Harcourt Metropolis

Abstract

Aim: To determine the bacterial and physicochemical analysis of topsoil from an electronic waste (e-waste) dumpsite within Port Harcourt metropolis using standard procedures.
 Place and Duration of Study: The study area was Kaduna street, beside Fruit and Vegetable Garden Market, Mile l which is located in Port Harcourt, Rivers State, Nigeria. The coordinates are 4o47’57.5” N 7o00’02.7” E. The duration of study was between March and September, 2019.
 Methodology: The waste disposed were mainly television sets, computer monitors, radio sets, stoves, laptops and central processing units. Soil samples were cleared off top debris, collected within 5cm of the top soil from four (4) different points of the dumpsite and a control was collected from area devoid of waste disposal, 20m away from the dumpsite. The five samples were kept in clean sterile polythene bags. Contamination observed from soil samples was attributed to the waste disposal. The total heterotrophic bacterial count was performed using l gram of soil from e-waste dumpsite in a 9-fold serial dilution using a spread plate method, in duplicates on dried nutrient agar plates and incubated at 30°C for 24hours. Centrimide agar plates were used to obtain Pseudomonas isolates and incubated at 37°C for 24 hours while MacConkey agar plates were used to isolate coliform bacteria, incubated at 0c for 48 hours. The physicochemical parameters were determined using standard methods.
 Results: Seven (7) bacterial genera were isolated from the topsoil of the e-waste dumpsite and they were Staphylococcus, Pseudomonas, Kluyvera, Bacillus, Micrococcus, Chromobacterium and Pectobacteria species. Staphylococcus spp. had the highest percentage composition of 42.3% and Kluyvera spp, the lowest percentage composition of l.9% of bacterial isolates found in the topsoil of the electronic waste dumpsite. The total heterotrophic bacterial count ranged from l.30 x l06 to l.97 x l06 cfu/g, total coliform count was 3.05 x l03 to 7.98 x l03 cfu/g and total Pseudomonas count ranged from l.00 x l02 to 2.88 x l03 cfu/g with a significant difference at .05 probability level to the control samples. The temperature ranged from 27.67±0.580C to 28.00±l.000C with a control of 29.00±l.000C, pH value ranged from 6.33±0.58 with a control of 7.00±0.00. The pH values were lower than the control indicating that the soil was slightly acidic to neutral. Moisture content had 4% with a control of 2.7%, an organic matter of l7.33±0.58 with a control of 4.47±0.58.
 Conclusion: The presence of the isolated organisms could cause public health risk or environmental hazard. Proper education and legislations on handling of e-waste in the society should be intensified to forestall waste related problems along the food chain.