Contamination of Soil and Groundwater by Petroleum Products at the Mombasa Joint Terminal Changamwe, Mombasa County, Kenya
Loading...
Date
2022
Authors
Silas, Sanga Kiprono
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Globally, soil and groundwater contamination with petroleum products is becoming an environmental concern especially during storage, transportation and handling of petroleum products. The overall research objective of the study was to establish the levels of BTEX, TPH and PAH at MJT Changamwe on soil and groundwater pollution. Soil sampling was done at the Petroleum Terminal where ten (10) sampling points near the tank farm were purposively selected and samples obtained and transported to the laboratory. Water samples were extracted from the three (3) existing groundwater monitoring wells in the depot and were transferred in capped bottles to the laboratory. In the laboratory, the analytes were extracted following EPA Method 3510. For the soil sample, separation of volatile compounds from the soils was achieved through vortexing the soils with 10 g of anhydrous Sodium Sulphate. Prior to analysis, filtration, desiccation and concentration of the samples was done. For the groundwater samples, upon addition of 10 ml diethyl ether and swirling, the samples separated into layers. The solvent layer was extracted, filtered, desiccant dried and concentrated. The soil and groundwater analytes were then analysed using Gas Chromatography-Mass Spectrometry (GC/MS). Data analysis was conducted using SPSS Version 21 and laboratory analysis done using standard laboratory procedures. A non-parametric Wilcoxon Signed Rank test was used to test whether there are significant differences between the detected concentrations and the Dutch Intervention Values (DIV). The detected concentrations of BTEX, TPH and PAH revealed varied levels of these petroleum products in soil and groundwater. The detected mean from the sampling points for Benzene (<0.01 mg/kg), Ethylbenzene (37.588 mg/kg), Xylene (4.964 mg/kg) and TPH (702.047 mg/kg) the levels were below the recommended soil DIV levels of 1 mg/kg, 110.0 mg/kg, 17.0 mg/kg and 5,000 mg/kg respectively. However, the detected mean for Toluene (883.799 mg/kg) exceeded the Toluene DIV of 130 mg/kg. The Wilcoxon Signed Rank test results showed a statistically significant difference between Toluene (T = 1, Z = -2.701, P < .05.), Ethylbenzene (T = 53, Z = -2.606, P < .05) Xylene (T = 53, Z = -2.660, P < .05), TPH (T = 55, Z = -2.803, P < .05) and respective DIV levels for the soil samples. In groundwater samples, the detected mean from the Monitoring Wells for Benzene (45143 μg/l), Toluene (2553.33 μg/l), Ethylbenzene (290 μg/l), Xylene (113.33 μg/l) were above the recommended DIV levels for groundwater of 30 μg/l, 1000 μg/l, 150 μg/l, and 70 μg/l respectively. The levels of detected TPH in groundwater were {(C5_C12, 1,937 μg/l; C12_C28, 32, 660 μg/l and C28_C44, 11,453 μg/l)} which were all above the DIV of 600 μg/l. The Wilcoxon Signed Rank test results showed non-statistically significant difference between Benzene (T = 0, Z = -1.604, P > .05), Toluene (T = 0, Z = -1.604, P > .05) Ethylbenzene (T = 0, Z = -1.342, P > .05), Xylene (T = 3, Z = 0.00, P > .05), TPH (T = 0, Z = -1.604, P > .05) and respective DIV levels for the groundwater samples. Results indicate that the flow rate of the groundwater was 0.125 m/s flowing in the North West to south east direction showing groundwater sources in the South East direction of terminal will have more contaminants. In conclusion, the study was able to identify that there were significant levels of petroleum products contamination in soil and groundwater. It is therefore recommended that standards, guidelines and best practices should be developed to prevent soil and water contamination by petroleum products. Additionally, monitoring and evaluation should be undertaken in all petroleum facilities to ensure compliance with local, regional and international standards and best practice
Description
A Research Thesis Submitted in Partial Fulfillment of The Requirements for the Degree of Master of Environmental Science (Env. Sci) in the School of Agriculture and Environmental Sciences of Kenyatta University, September 2022
Keywords
Soil and Groundwater, Petroleum Products, Mombasa Joint Terminal Changamwe, Mombasa County, Kenya