Toxicity of an Organophosphate Pesticide (chloropyrifos) on a common Niger Delta Wetland Fish - Tilapia guineensis (Blecker 1862)

The acute and sublethal toxicity of an organophosphate pesticide (Chloropyrifos) on the juvenile of Tilapia guineensis was evaluated to determine its effect on the survival, body functions and heamatological values. The fish was exposed to varying levels of the toxicant (0.0125mg/l; 0.025mg/l; 0.05mg/l and 0.1mg/l) using 96hrs static bioassay to determine the median lethal concentration and median lethal time for the different concentrations. The mortality was found to increase with exposure and increase in concentration. The 96hrs median lethal concentration was 0.002mg/l while the 96hr median lethal time of 56.2hrs; 42.7hrs; 31.1 hrs and 18.2hrs were recorded for 0.0125mg/l; 0..025mg/l, 0.05mg/l and 0.1mg/l respectively. The operculum beat frequency (F = Cal 6.89 > P = 3.49)0.05 and Tail beat frequency (F = Cal 4.46 > P (3.49)0.05 were significantly affected by the exposure. A sublethal exposure to various concentrations (0.0006mg/l; 0.00125mg/l, 0.0025mg\\l, 0.005mg/l) were observed to cause a progressive reduction in the number of leucocyte (F - Cal 15.4 > P (3.01)0.05 and erythrocyte (F- Cal 14.39 > P(3.01)0.05 of the fish.The reduction in leucocye and erythrocyte number was significant indicating that the fish became anaemic.These conditions were more severe in the higher concentrations of the pesticide. Journal of Applied Sciences and Environmental Management Vol. 8(2) 2004: 11-1

Biostimulation of Petroleum-Contaminated Soil Using Organic and Inorganic Amendments

The most common approaches for the in-situ bioremediation of contaminated sites worldwide are bioaugmentation and biostimulation. Biostimulation has often proved more effective for chronically contaminated sites. This study examined the effectiveness of optimized water hyacinth compost in comparison with other organic and inorganic amendments for the remediation of crude oil-polluted soils. Water hyacinth was found to be rich in nutrients necessary to stimulate microbial growth and activity. An organic geochemical analysis revealed that all amendments in this study increased total petroleum hydrocarbon (TPH) biodegradation by ≥75% within 56 days, with the greatest biodegradation (93%) occurring in sterilized soil inoculated with optimized water hyacinth compost. This was followed by polluted soil amended with a combination of spent mushroom and water hyacinth composts (SMC + WH), which recorded a TPH biodegradation of 89%. Soil amendment using the inorganic fertilizer NPK (20:10:10) resulted in 86% TPH biodegradation. On the other hand, control samples (natural attenuation) recorded only 4% degradation. A molecular analysis of residual polycyclic aromatic hydrocarbons (PAHs) showed that the 16 PAHs designated by the US EPA as priority pollutants were either completely or highly degraded in the combined treatment (SMC + WH), indicating the potential of this amendment for the environmental remediation of soils contaminated with recalcitrant organic pollutants

Biostimulation of Petroleum-Contaminated Soil Using Organic and Inorganic Amendments

The most common approaches for the in-situ bioremediation of contaminated sites worldwide are bioaugmentation and biostimulation. Biostimulation has often proved more effective for chronically contaminated sites. This study examined the effectiveness of optimized water hyacinth compost in comparison with other organic and inorganic amendments for the remediation of crude oil-polluted soils. Water hyacinth was found to be rich in nutrients necessary to stimulate microbial growth and activity. An organic geochemical analysis revealed that all amendments in this study increased total petroleum hydrocarbon (TPH) biodegradation by ≥75% within 56 days, with the greatest biodegradation (93%) occurring in sterilized soil inoculated with optimized water hyacinth compost. This was followed by polluted soil amended with a combination of spent mushroom and water hyacinth composts (SMC + WH), which recorded a TPH biodegradation of 89%. Soil amendment using the inorganic fertilizer NPK (20:10:10) resulted in 86% TPH biodegradation. On the other hand, control samples (natural attenuation) recorded only 4% degradation. A molecular analysis of residual polycyclic aromatic hydrocarbons (PAHs) showed that the 16 PAHs designated by the US EPA as priority pollutants were either completely or highly degraded in the combined treatment (SMC + WH), indicating the potential of this amendment for the environmental remediation of soils contaminated with recalcitrant organic pollutants