PHYTOREMEDIATION OF CRUDE OIL-CONTAMINATED SOIL IN EKPAN, DELTA STATE, NIGERIA

Wed, 01 Apr 2015 00:00:00 GMT

Title: PHYTOREMEDIATION OF CRUDE OIL-CONTAMINATED SOIL IN EKPAN, DELTA STATE, NIGERIA Authors: ETAGHENE, J. O. Abstract: Crude oil spillage poses a threat to public health in the Niger Delta as a result of gross pollution of the environment. Physical and chemical remediation methods are expensive for addressing the situation. Several plants have been used in previous studies for phytoremediation of crude oil-contaminated soils. This study was therefore designed to identify native plants with phytoremediation potential for the degradation of Total Petroleum Hydrocarbon (TPH) in crude oil-contaminated soils in Ekpan, Delta State. Composite soil samples collected from an uncontaminated area were deliberately contaminated with Bonny light crude oil to a level of 5 g/kg (w/w) resulting in 8.510.0±50.5 mg TPH/kg soil. Four native plants (Brachiaria ruziziensis, Cyperus esculentus, Kyllinga bulbosa and Telfairia occidentalis) were purposively affected and screened for their tolerance to crude oil-contamination for three weeks. Three of the selected plants (excluding B. ruziziensis) which showed tolerance to crude oil were grown for eight weeks on the contaminated soil amended with six levels (0, 1.5, 2.5, 5.0, 10.10 and 20.0 tons/hectare) of organic manure (OM), which was added to improve soil fertility under greenhouse conditions (temperature 26.7±1.2⁰ humidity, 74.1±2.3%). Plant height (cm) was monitored weekly using a metre rule. Plant weight (g) was determined monthly using a mettler balance. Soil samples collected monthly from the pots were analysed for TPH using gas chromatography (Varian 3400). Field experiment was done in a randomised block design with for treatment groups: (A) contaminated soil amended with 10 tons/ha OM; (B) contaminated soil without OM; (C) uncontaminated soil without OM (control) and (D) an unplanted contaminated soil without OM (control). Kyllinga bulbosa, the plant with the best phytommediation potential in the greenhouse experiment was grown on a plot contaminated with 0.8 liter Bonny light crude oil/m² (8,546.0±20.0 mg TPH/kg soil). All experiments were conducted in triplicates and randomised with controls. Total heterotrophic soil bacteria were counted at eight weeks using standard bacteriological methods. Data were analysed using descriptive statistics and ANOVA at 0.05 level of significance. The three crude oil tolerant plants used in the greenhouse experimenti at eight weeks and at 10 tons/ha reduced TPH in the contaminated soil: Kyllinga 97.0%; Cyperus 92.8% and Telfaira 91.0%. Plant dry weight progessively increased (Kyllinga: 2.4±0.1 to 7.9±1.3g: Cyperus 2.1±0.1 to 7.4 ±1.6g: Telfairia 20.2±0.5 to 48.1±2.3 g) with increasing rates of OM application. In the field experiment, after eight weeks, significant reductions in soil TPH were recorded in two treatment groups: A (93.6%) and B (88.8%) compared with the controls, C (0.0%) and D (35.8%). The composition of the composite soil showed 84.3±0.6% and 9.3±0.3% Clay and 6.4±0.2% Silt. Total heterotrophic bacterial counts (cfu/g) were significantly higher in the planted OM amended soil (1.92±4.25x10¹¹) compared to the unplanted OM untreated soil (1.70 ±0.01 x 10⁵). The highest concentration of total petroleum hydrocarbon (97%) removal from the contaminated soil was obtained with Kyllinga bulbosa plants. This result was enhanced by the application of organic manure and the presence of soil bacteria. Kyllinga is therefore recommended for phytoremediation of crude oil-contaminated soils. Description: A Thesis in the Department of Environmental Health Sciences, submitted to the Faculty of Public Health, College of Medicine in partial fulfillment of the requirements for the Degree of Doctor of Philosophy of Public Health (Environmental Health) of the University of Ibadan, Nigeria

HAZARD ANALYSIS CRITICAL CONTROL POINTS WITH GENDER COHORT IN CASSAVA PROCESSING FACTORY IN IBADAN, NIGERIA

Tue, 01 Jan 2008 00:00:00 GMT

Title: HAZARD ANALYSIS CRITICAL CONTROL POINTS WITH GENDER COHORT IN CASSAVA PROCESSING FACTORY IN IBADAN, NIGERIA Authors: EKOP, M. O. Abstract: Surveillance and reporting of food-borne disease outbreaks are scanty in developing countries. There is no data on the magnitude of contribution of cassava food products to food-borne hazards. Therefore, the objectives of the study was to conduct Hazard Analysis Critical Control Points (HACCP) in cassava processing chains of "foofoo", "lafun" and "gari", the staple food in Southern Nigeria. The study was conducted in Onipepeye, Oremeji Agugu cassava processing factory in lbadan, Nigeria. A multi-stage sampling technique was used to select one processor per cassava food out of the 60 processors screened. Thus three processors were selected and studied for possible Critical Control Points (CCPs) for cyanide and significant pathogens. Forty samples from the processing steps of raw and fermented cassava were analyzed for cyanide toxicity while 152 samples from the cassava processing chain of raw and fermented cassava, environment, equipment and swabs from processors were assessed for biological contaminants. Analysis of Variance (ANOVA) and T-Test were used to determine significant differences in cassava processing steps and stages for cyanide-level changes and microbial hazards associated with cassava processing. Related gender data were obtained through direct observation and interviews. Changes in cyanide-levels and microbial hazards associated with cassava processing steps and stages were computed at 5% confidence level. Gender as production/risk factor for CCPs and nature of other risk factors were also examined. The mean cyanide level (mg HCN eq Average/100g) foofoo was 5.06 at this point for unpeeled cassava, peeled cassava 5.45-CCP, peeled and washed cassava 9.05-CCP, final foofoo paste 0.69, with no significant difference in these changes (P>0.05). In Lafun unpeeled cassava 8.12-CCP, sun-dried fermented Lafun 0.09-CCP, peeled and washed cassava 8.12-CCP, sun-dried fermented Lafun 0.09-ccp with significant changes in cyanide level (p<0.0001). Gari, unpeeled cassava 3.62-CCP, peeled cassava 9.35-CCP, peeled and washed cassava 10.16-CCP, pressed mash 7.48-CCP, hold and sell 2.09-CCP, showed significant changes in cyanide level (p<0.0001). Predominant bacteria and their maximum mean counts found in foofoo, lafun, gari processiing chains were: Bacillus spp-1.5x10⁶ found in sieved fermented cassava mash processed by female adult. The major sources of contamination are gender, equipment and environment. Klebsiella-1.4x10⁶ in unpeeled cassava in Lafun was introduced by handling and manufacturing practices: Klebsiella 1.4 x 10⁷ and Esheichia coll 1.2 x 10⁶ were found from the swabs of hands and nose of the foofoo cook respectively. Hazardous levels of Escherchia spp counts in foofoo and gari, Escherichia coll counts in lafun were higher than accepted limits, with standard deviation at 7105.0, 7505.5 and 8485.2 respectively. There was no significant difference between microbial loads in raw and fermented stages of Foofoo (p>0.05) and Gari (p>0.05). However, significant differences were observed between microbial load in raw and fermented stages in lafun (p<0.04). Environment, equipment and processors were the major sources of contamination of cassava foods. Gender, handling and manufacturing practices are major risk factors. Therefore, cassava-processing system should be put on HACCP and CCPs safeguarded, Educating cassava processors on basic food safety principles using the HACCP system must take into consideration gender differences in food handling and manufacturing practices to enhance quality and safety. Description: A Thesis submitted to the Department of Epidemiology, Medical Statistics and Environmental Health, Faculty of Public Health, College of Medicine, In partial fulfillment of the requirements for the Degree of Doctor of Philosophy (Environmental Health) of the University of Ibadan.

DSpace Collection: Theses in Environmental Health Sciences

PHYTOREMEDIATION OF CRUDE OIL-CONTAMINATED SOIL IN EKPAN, DELTA STATE, NIGERIA

HAZARD ANALYSIS CRITICAL CONTROL POINTS WITH GENDER COHORT IN CASSAVA PROCESSING FACTORY IN IBADAN, NIGERIA