A comparative study on the effect of dispersed and undispersed Kuwait crude oil on egg hatching and larval survival of Epinephelus coioides

Aim: The objective of the present study was to investigate the effects of dispersed and undispersed Kuwait crude oil on egg hatching and larval survival of Epinephelus coioides. Methodology: In the present study, the toxic effects of crude and dispersed oil using three formulations of oil dispersants against multiple life stages of Epinephelus coioides was assessed. The lethal concentration was calculated by ToxCal® software developed by Tidepool Scientific, LLC. Results: Specifically, the following life stages were investigated: embryonated eggs (EE), larvae hatched during exposure (LHE) and hatched larvae (HL). Chemical analysis showed that Total Petroleum Hydrocarbon (TPH) concentrations were higher in dispersed than undispersed oil solutions, indicating accommodation of more petroleum hydrocarbons in the aqueous phase. Acute static toxicity tests produced variable LC50 values for all chemical preparations and all fish life stages. Crude oil dispersed with both Corexit® EC 9500A and Corexit® EC 9527A separately was more toxic to both EE and LHE stages than undispersed oil, but crude oil dispersed with Slickgone® NS resulted in lower toxicity. Furthermore, all three types of dispersed oil exerted higher toxicity than undispersed oil at HL stage. Interpretation: A life stage dependent effect demonstrated variation in the toxicity of both dispersed and undispersed crude oil to fish. Few life stages were more sensitive than others to either dispersed or undispersed crude oil toxicity. While dispersion of an oil slick with oil dispersant has proved to be an effective tool in the oil response strategy, the fate of dispersed oil can exert lethal effects on embryo-larval stages of marine fish present near the spill.

In situ biosurfactant production and hydrocarbon removal by Pseudomonas putida CB-100 in bioaugmented and biostimulated oil-contaminated soil

In situ biosurfactant (rhamnolipid) production by Pseudomonas putida CB-100 was achieved during a bioaugmented and biostimulated treatment to remove hydrocarbons from aged contaminated soil from oil well drilling operations. Rhamnolipid production and contaminant removal were determined for several treatments of irradiated and non-irradiated soils: nutrient addition (nitrogen and phosphorus), P. putida addition, and addition of both (P. putida and nutrients). The results were compared against a control treatment that consisted of adding only sterilized water to the soils. In treatment with native microorganisms (non-irradiated soils) supplemented with P. putida, the removal of total petroleum hydrocarbons (TPH) was 40.6%, the rhamnolipid production was 1.54 mg/kg, and a surface tension of 64 mN/m was observed as well as a negative correlation (R = -0.54; p < 0.019) between TPH concentration (mg/kg) and surface tension (mN/m), When both bacteria and nutrients were involved, TPH levels were lowered to 33.7%, and biosurfactant production and surface tension were 2.03 mg/kg and 67.3 mN/m, respectively. In irradiated soil treated with P. putida, TPH removal was 24.5% with rhamnolipid generation of 1.79 mg/kg and 65.6 mN/m of surface tension, and a correlation between bacterial growth and biosurfactant production (R = -0.64; p < 0.009) was observed. When the nutrients and P. putida were added, TPH removal was 61.1%, 1.85 mg/kg of biosurfactants were produced, and the surface tension was 55.6 mN/m. In summary, in irradiated and non-irradiated soils, in situ rhamnolipid production by P. putida enhanced TPH decontamination of the soil.

Biorremediación de lodos contaminados con aceites lubricantes usados / Bioremediation of sludge contaminated with used lubricants

Los lodos contaminados con residuos de aceites lubricantes usados generan gran impacto ambiental negativo al no ser manejados adecuadamente. Se propuso la biorremediación para disminuir la concentración de dichos contaminantes. Los ensayos fueron realizados en las instalaciones de la planta de tratamiento de aguas residuales (PTAR) de Río Frío (Girón, Santander, Colombia), donde se evaluaron consorcios microbianos nativos, que posteriormente se adicionaron a las biopilas conformadas por lodos deshidratados provenientes del tratamiento primario de aguas residuales domésticas (usados como fuente de materia orgánica), lodos provenientes de lavaderos de carros y lodos de alcantarillado de la zona industrial de la ciudad de Bucaramanga (Colombia). Se aislaron, identificaron y conservaron cepas microbianas con capacidad degradadora de hidrocarburos totales de petróleo (TPH) como Pseudomonas spp., Acinetobacter spp, Enterobacter cloacae, Citrobacter spp., Bacillus brevis, Micrococcus spp y Nocardia spp. Se hizo una serie de pruebas piloto donde se inoculó cada montaje con un consorcio bacteriano a una concentración de 3x108 UFC/ml de bacterias y microorganismos fúngicos como Aspergillus spp., Fusarium spp., Trichoderma spp., a una concentración de 1x106 esporas/ml; se monitorearon parámetros de temperatura, pH, humedad y oxigenación. Se realizaron dos ensayos para verificar el comportamiento de dichos tratamientos; se analizó la variable continua TPH en ppm mediante el método de modelos mixtos lineares en bloques aleatorios completos, que revelaron diferencias significativas entre la biopila control y las biopilas bajo prueba; se obtuvieron porcentajes de remoción hasta de 94% de TPH en 120 días y 84% en 40 días, lo que reflejó un efecto positivo en la utilización de los consorcios de microorganismos bajo prueba en la descontaminación de lodos de alcantarillado industrial y lodos de lavaderos de carros.

The sludge contaminated with residues of used lubricating oils produce large negative environmental impact by not being handled properly. We proposed Biorremediation to decreasethe concentration of these polltants. The trials were conducted on the waste water treatment plant (WWTP) Río Frío (Girón, Santander, Colombia) ,we evaluate native microbial associations, and subsequently they were added to biopiles, made up of dried sludge the waste water treatment (source of organic mater) sludge from washing cars and sewage sludge from the industrial area of the city Bucaramanga (Colombia). Several pilot test were completed and we isolated, identified and retained microbial atrains with ability to degrading total petroleum hydrocarbons (TPH) such as Pseudomonas spp., Escherichia coli, Citrobacter spp., Bacillus brevis, Micrococcus spp., among others. We inoculated each pilot assembly with a bacterial concentration of 3x108 UFC/ml and fungal microorganisms like Aspergillus spp., Fusarium spp., Trichoderma spp. in a concentration of 1x106 Spores/ml. Parameters such as temperature, pH, humidity, oxygenation were monitoring frequently. Two trials were completed to verify the behabior and results of treatment, we analized continuously the concentration of TPH using linear mixed models approach in a randomized complete blocks, which revealed significant differences between control biopile (without microorganism consortia) and biopiles under test, obtaining removal percentages to 94% of TPH in 120 days, and 84% in 40 days, reflecting a positive effect on the use of consortia of microorganisms under test in the decontamination of domestic sewage sludge and industrial sludge and sludge the car wash.

Determination of Total Petroleum Hydrocarbons Content in Soil by Ultrasonic-Soxhlet Extraction-Gravimetric Analysis / 分析化学

The influencing factors of ultrasonic extraction(UE) and ultrasonic-soxhlet extraction(USE) were analyzed based on orthogonal experimental design. The optimum analytical conditions of two methods were determined. The three different methods: UE, USE and traditional soxhlet extraction(SE) were compared by simultaneous analysis with three different soil samples: fresh contaminated soil, soil after microbial remediation and soil after phytoremediation. The optimum condition of the UE was extracting 4 times with chloroform, 15 mL extractant every time. The optimum condition of the USE method was ultrasonic for 10 min at 60 W, followed by soxhlet extraction with 125 mL extractant for 6 h. Compared the three different methods, USE method showed the best result with the highest average extraction rate of 102.98%, the UE method with average extraction rate of 99.69%, and the SE method with low average extraction rate of 97.31%. The research indicates that USE method is effective in determining soil total petroleum hydrocarbons(TPH) within shorter time and higher efficiency and can be used as a method for determining TPH content in different soils.