Weeks Of Contamination Research Articles

Organic Manure Enhanced Phytoremediation of Crude Oil Contaminated Soils in The Niger Delta: The Potentials of Cowpea (Vigna Unguiculata)

In spite of frequent oil pollution, a cost effective, environmentally friendly and sustainable means of remediating polluted soils is yet to be discovered in the Niger Delta. This study, examined the effect of two rates of poultry manure (0 and 20 t/ha) remediating 0 and 5% oil in a 2x2x3 factorial, using cowpea (Vigna unguiculata) as possible phytoremediation plant. Two weeks after contamination, Total Petroleum Hydrocarbon (TPH) increased significantly (P<0.05) from 0.02 mgkg-1 to 125.1 mg/kg-1 and at eight weeks after remediation, TPH reduced from125.1 mgkg-1 to 91.86 mgkg-1 in the unamended contaminated soil and the poultry manure amended contaminated soil decreased significantly (P<0.05) to 73.08 mgkg-1. Soil pH increased significantly (P<0.05) from 5.34 to 5.80, two weeks after contamination and after eight-week of remediation, pH in the unamended contaminated soil increased to 5.85 and the amended contaminated soil increased to 5.97. Organic carbon increased significantly (P<0.05) from 1.15% to 2.32% after two weeks of contamination and eight weeks after remediation, increased to 2.45% in the unamended contaminated soil, and to 2.58% in the amended contaminated soil. Though oil contamination slowed germination, cowpea germination in the unamended contaminated soil recorded 60% while poultry manure amendment increased germination to only 66% indicating cowpea has phytoremediation qualities. However, poultry manure amendment increased cowpea germination energy. The study recorded no significant difference in cowpea germination percentage and growth parameters between the unamended contaminated soil and remediated oil contaminated soil indicating poultry manure application rate need to be increased.

Effect of mycorrhizal inoculation and organic fertiliser on bioremediation of spent engine oil contaminated soil

Abstract Hydrocarbon-related environmental pollution is a major environmental hazard due to its toxicity and widespread presence in the environment, resulting in stunted growth of soil microorganisms, plants, and animals. This study was therefore conducted to evaluate the effect of mycorrhizal inoculation and compost made from Cocoa Pod Husk (CPH) and cattle dung in the bioremediation of Spent Engine Oil (SEO)-contaminated soil. About 2.5 kg of sterilised soil was contaminated with SEO at different concentrations: 0, 100, and 150 mL / pot. Compost was then added after two weeks of contamination at the rate of 10 g / pot. Inoculation for treatments containing Glomus mossaea (consisting of 20 g of root soil-fungal mixture) was blended into the soil samples as well. It was a 2 × 2 × 3 factorial experiment that was laid out in a completely randomised design and replicated three times. The incubation was allowed to last for twelve (12) weeks before the termination of the experiment. Data were collected on the Total Petroleum Hydrocarbon (TPH), bacterial and fungal biomass of the SEO-contaminated soil. Results obtained indicate that combined application of mycorrhiza with 100 mL / pot SEO resulted in significantly (p < 0.05) lower residual TPH content (54.50% degradation) of the contaminated soil compared to the other treatment combinations whereas significantly higher residual TPH content (20.43% degradation) of the contaminated soil was obtained from the interaction between 150 mL / pot SEO and without mycorrhizal inoculation. Interaction between mycorrhiza and 10 g / pot compost had a significantly higher bacterial colony (6.58 CFU / g) compared to other treatment combinations. Mycorrhizal inoculation resulted in a significantly higher fungal colony (5.844 CFU / g) compared with non-mycorrhizal inoculation (3.222 CFU / g). Therefore, it can be concluded that mycorrhizal inoculation and compost were effective in the bioremediation of SEO-impacted soil.

Influence of daylight on potential biodegradation of diesel and crude oil in Antarctic seawater

The effects of daylight exposure on Antarctic coastal bacterial communities contaminated by diesel fuel and ‘Arabian light’ crude oil addition were studied in artificial mesocosms during the austral summers of 1991–1992, 1992–1993 and 1993–1994 in the Terre Adelie land area. In order to study the possible influence of photo-oxidation, two sets of experiments were conducted in covered and noncovered batches. Daily sampling allowed regular surveys of the changes of total bacterial abundance, mean cell volumes, saprophytic and hydrocarbon-utilizing bacterial communities. The results clearly revealed a significant response of the Antarctic bacterial community to crude oil addition. Two orders of magnitude increases were observed after contamination. Concomitant enrichments of saprophytic and hydrocarbon-utilizing bacteria occurred during these periods. Hydrocarbon-utilizing bacteria ranged from 0.001% of the total community before contamination to more than 80% after 2 weeks of contamination with crude oil. Chemical analysis of the residual hydrocarbon fraction after 5 weeks of contamination confirmed this potential biodegradation. Solar radiation had no measurable effect upon crude oil-contaminated seawater. In contrast, there was a clear toxic effect upon bacterial communities contaminated with diesel. Data suggest that the initial state of the bacterial communities can play a major role in the potential biodegradation. Some surface bacterial assemblages seem to demonstrate a better resistance to solar radiation than deeper ones.

Effectiveness of bioremediation for oil-polluted Antarctic seawater

The effectiveness of a specific fertiliser (INIPOL EAP 22) addition on bioremediation of oil-contaminated Antarctic coastal seawater was determined in the “Terre Adelie” area. Mesocosm studies were conducted to evaluate the effects of “Arabian light” crude oil contamination on coastal bacterioplanktonic communities. After oil addition, regular surveys of the bacterial changes of the oil-contaminated seawater were performed during 5-week periods during the austral summer of 1992/1993 and 1993/1994. All results (total, saprophytic and hydrocarbon-utilising bacterial abundance) clearly revealed a significant response of Antarctic bacterial communities to hydrocarbon contamination. A 1 order of magnitude increase of bacterial microflora occurred in seawater after crude oil contamination. A concomitant enrichment in oil-degrading bacteria was generally observed, from less than 0.001% of the community in uncontaminated samples to up to 50% after 3 weeks of contamination. Addition of fertiliser (INIPOL EAP 22) induced clear enhancement of both saprophytic and hydrocarbon-utilising microflora. Chemical analysis of the residual hydrocarbon fractions confirmed that fertiliser application increased the rate of oil biodegradation.

Development and survival of infective larvae of gastrointestinal nematodes of cattle on pasture in central Kenya.

On a series of pasture plots, 2 kg pats of bovine faeces containing known numbers of strongylid (Haemonchus, Cooperia, Oesophagostomum and Trichostrongylus) eggs were deposited at intervals of 4 weeks from July 1995 to June 1996. The plots were sampled every 2 weeks after contamination and infective larvae were identified and counted. Larvae of all the genera developed throughout the year, but the pats exposed during the rainy season yielded more abundant larvae on the herbage. Irrespective of the season of deposition of the pats, larvae were found in larger numbers from 2 to 6 weeks after deposition and generally declined to below detectable levels within 12 to 16 weeks of contamination. The comparatively short survival times noted in this experiment may present opportunities for manipulation of the population dynamics of the gastrointestinal nematodes in the tropical environment of Kenya.

Seasonal Variation of Bacteria in Sea Ice Contaminated by Diesel Fuel and Dispersed Crude Oil

The long-term effects of diesel fuel and ``Arabian light'' crude oil contamination on microbial communities was investigated in land-fast ice located in the Terre Adelie area (Antarctica). After oil addition, the changes in bacterial communities were studied in situ during a nine-month period in austral winter 1993. Weekly sampling in sea ice allowed a regular survey of total, saprophytic, and hydrocarbon utilizing bacteria. A clear seasonality was observed. In uncontaminated samples, maximal values of bacterial biomass occurred during ice formation and just before summer thaw. Minimal bacterial abundance (<105 cells ml−1) was observed during winter. All the results (bacterial abundance, colony-forming units, and most probable number counts of hydrocarbon-utilizing bacteria) clearly revealed a significant response of Antarctic bacterial communities to hydrocarbon contamination. Three orders of magnitude increases of bacterial counts occurred in sea ice after both diesel fuel and crude oil contamination. A concomitant enrichment in oil-degrading bacteria was generally observed from less than 0.001% of the community in uncontaminated samples to 10% after 30 weeks of contamination. Addition of fertilizer (Inipol EAP 22) enhanced both saprophytic and hydrocarbon-utilizing communities. The natural winter decline of saprophytic bacterial abundance was totally absent in sea ice treated with diesel fuel oil supplemented with Inipol.

Effect of dispersed oil on heterotrophic bacterial communities in cold marine waters

Mesocosm studies were conducted to evaluate the effect of dispersed oil on total and heterotrophic bacterial communities of under-ice seawater from the St. Lawrence Estuary. A regular survey of bacterial changes in the oil-contaminated seawater was performed during a two week period. The bacterial community structure was investigated by carrying out 27 morphological and biochemical tests on 168 isolated strains. The results show a detectable but transient response of the bacterial community to crude oil addition. While total bacterial counts were approximately constant during the experiment, dispersed oil induced an increase in heterotrophic bacterial microflora (from 10(4) to 10(5) bacteria ml(-1) after two weeks of contamination). The dispersed oil appeared to have an inhibitory effect on some components of the bacterial community. A decrease of most probable number values was observed just after addition of crude oil in the most polluted tanks and one day later in the less polluted tank. However, except for the most polluted tank, this adverse effect disappeared rapidly. While the dispersed oil induced a total disappearance of some components of the bacterial community in the most polluted tank, the structure of the bacterial community in the less polluted tank appeared relatively unchanged after 14 days of contamination.

Development and survival of infective larvae of Haemonchus contortus and Trichostrongylus colubriformis on pasture in a tropical environment

A trial to determine the seasonal pattern of egg hatching and larval survival on pasture was carried out in representative wet and dry zones of Fiji. Fourteen plots were established on parasite-free pasture at each of two sites. One plot at each site was contaminated every month with faeces from naturally infected goats containing a known proportion of Haemonchus contortus and Trichostrongylus colubriformis eggs. Pasture was sampled at regular intervals after contamination and infective larvae identified and counted. Larvae of both species developed throughout the year in the wet zone but development was more sporadic in the dry zone. Larval counts generally declined to below detectable levels within 9 weeks of contamination between September and March but longevity increased during the cooler weather from April to August. The comparatively short larval survival times noted in this experiment may present opportunities for manipulation of parasite population dynamics in the wet tropics.

Influence of 226 Ra on Bone Marrow Stem Cells in Mice: Effect of Radium Decorporation by a Long-Term Treatment with Na-Alginate on Stem-Cell Damage

Three-month-old male BALB/c mice were injected intraperitoneally with ${}^{226}{\rm RaCl}{}_{2}$ at dose levels of 4.5, 6.9, 9.0, and $13.5 \mu {\rm Ci} {}^{226}{\rm Ra}/{\rm kg}$ body wt. At the two highest doses, the number of multipotential bone marrow stem cells was severely depressed 8 weeks after the injection. By 30 weeks no depression was observed compared to controls. The number of peripheral red blood cells was never altered, while the number of white blood cells was slightly depressed after 8 weeks of contamination. Mice fed every other week with standard pellets and on alternate weeks with a diet containing 6% Na-alginate (first given 12 days after the injection of ${}^{226}{\rm RaCl}{}_{2}$ ) showed a significant reduction of stem-cell depression 8 and 12 weeks after contamination in three of the six treatment groups with manifest radiation effects on the stem cells.