Bioacumulación y toxicidad subaguda mecánica y químicamente dispersas de aceite combustible pesado de erizo de mar (Glyptocidaris crenulari)

Oil spills have a disastrous ecological impact on ecosystems but few data are available for the effects of dispersed oil on benthic marine organisms. In order to provide information for assessment, we analysed the hydrocarbon compositions of the mechanically dispersed water accommodated fraction (MDWAF) and the chemically dispersed water accommodated fraction (CDWAF) of No. 120 fuel oil, their bioaccumulation, and DNA damage related to oil exposure, using the sea urchin as a sentinel organism. The results show that the concentration of polycyclic aromatic hydrocarbon in the tissues of sea urchin exposed to the CDWAF is higher than that of those exposed to the MDWAF. The single cell gel electrophoresis assay results also indicated higher DNA damage from exposure to the CDWAF of oil. Thus, dispersants should be applied with caution in oil spill accidents.El derrame de petróleo tiene un desastroso impacto ecológico en los ecosistemas. Sin embargo, hay una falta de datos de los efectos de aceite disperso sobre los organismos marinos bentónicos. Con el fin de proporcionar información de evaluación de su efecto, hemos analizado la composición de hidrocarburos de fracción disuelta mecánicamente en el agua (MDWAF) y la fracción disuelta químicamente en el agua (CDWAF) No. 120 de aceite combustible, su bioacumulación y daños en el ADN relacionados con la exposición al petróleo, utilizando el erizo de mar como organismo centinela. Los resultados muestran que la concentración de hidrocarburos aromáticos policíclicos (PAH) en los tejidos de erizo de mar expuesta en CDWAF es mayor que en MDWAF. También que la concentración de hidrocarburos aromaticos policiclicos (HAP) en los tejidos de erizo de mar expuestos en CDWAF es mayor que en MDWAF. El resultado del ensayo de la célula individual por electroforesis en gel (SCGE) también indica el mayor daño en el ADN en CDWAF de aceite. Por lo tanto, la aplicación de dispersantes en accidentes de derrames de crudo ha de hacerse bajo control

Bioaccumulation and subacute toxicity of mechanically and chemically dispersed heavy fuel oil in sea urchin (<em>Glyptocidaris crenulari</em>)

Oil spills have a disastrous ecological impact on ecosystems but few data are available for the effects of dispersed oil on benthic marine organisms. In order to provide information for assessment, we analysed the hydrocarbon compositions of the mechanically dispersed water accommodated fraction (MDWAF) and the chemically dispersed water accommodated fraction (CDWAF) of No. 120 fuel oil, their bioaccumulation, and DNA damage related to oil exposure, using the sea urchin as a sentinel organism. The results show that the concentration of polycyclic aromatic hydrocarbon in the tissues of sea urchin exposed to the CDWAF is higher than that of those exposed to the MDWAF. The single cell gel electrophoresis assay results also indicated higher DNA damage from exposure to the CDWAF of oil. Thus, dispersants should be applied with caution in oil spill accidents

A Semianalytical Model Using MODIS Data to Estimate Cell Density of Red Tide Algae (Aureococcus anophagefferens)

A multiband and a single-band semianalytical model were developed to predict algae cell density distribution. The models were based on cell density (N) dependent parameterizations of the spectral backscattering coefficients, b ( ), obtained from in situ measurements. There was a strong relationship between b ( ) and N, with a minimum regression coefficient of 0.97 at 488 nm and a maximum value of 0.98 at other bands. The cell density calculated by the multiband inversion model was similar to the field measurements of the coastal waters (the average relative error was only 8.9%), but it could not accurately discern the red tide from mixed pixels, and this led to overestimation of the area affected by the red tide. While the single-band inversion model is less precise than the former model in the high chlorophyll water, it could eliminate the impact of the suspended sediments and make more accurate estimates of the red tide area. We concluded that the two models both have advantages and disadvantages; these methods lay the foundation for developing a remote sensing forecasting system for red tides

A Semianalytical Model Using MODIS Data to Estimate Cell Density of Red Tide Algae ( Aureococcus anophagefferens

A multiband and a single-band semianalytical model were developed to predict algae cell density distribution. The models were based on cell density (N) dependent parameterizations of the spectral backscattering coefficients, bb(λ), obtained from in situ measurements. There was a strong relationship between bb(λ) and N, with a minimum regression coefficient of 0.97 at 488 nm and a maximum value of 0.98 at other bands. The cell density calculated by the multiband inversion model was similar to the field measurements of the coastal waters (the average relative error was only 8.9%), but it could not accurately discern the red tide from mixed pixels, and this led to overestimation of the area affected by the red tide. While the single-band inversion model is less precise than the former model in the high chlorophyll water, it could eliminate the impact of the suspended sediments and make more accurate estimates of the red tide area. We concluded that the two models both have advantages and disadvantages; these methods lay the foundation for developing a remote sensing forecasting system for red tides

Oil Spill Response Information System and Contingency Planning for Guinean Waters

AbstractOver the years there has been many well documented cases of major oil pollution from leaked offshore oil rigs, ships in distress and from coastal oil facilities. In response to concerns about the possibility of a major oil spillage occurring along the coast of Guinea, the Guinean government drew up a plan and organisation. The purpose of this research was to develop Guinean Marine Oil Spill Response Information System. To do this, we simulated an oil spill concentration transport. The results show that the numerical model in oil spill accident simulation is important in allowing setting up of possible response and contingency planning. From the results we conclude that, the search strategies for futures responses and contingency planning to possible oil spill case in Guinean coasts has been clarified. Implications of research findings allow international community to consider reasonable estimation of spilled oil trajectory with limited environmental input data

Performance Evaluation of Pilot-scale Hybrid Anaerobic Baffled Reactor (HABR) to Process Dyeing Wastewater Based on Grey Relational Analysis

A pilot-scale six-compartment hybrid anaerobic baffled reactor (HABR) with effective volume of 18 m3 was used to treat dyeing wastewater. The HABR system was able to treat the wastewater efficiently after FeSO4 pretreatment, as indicated by removal efficiencies of 33.7% for chemical oxygen demand (COD), 39.9% for suspended solid (SS), and 22.5% for sulfate (SO42&#8722;) during steadily operational period. Gas chromatography&#8211;mass spectrometry (GC-MS) showed that the concentrations of alkanes, amides, organic acids, ketones, phenols, and esters were much lower in the effluent than those in the influent; many high-molecular-weight compounds such as cyclanes, quinolines, and phenols were successfully transformed to low-molecular-weight ones. As illustrated from the results of generalized grey relational analysis (GGRA), COD removal efficiency was more closely associated with flow rate, organic loading rate (OLR), water temperature, and influent SS among the whole selected possible factors. Based on the overall treating effectiveness and the GGRA study, the optimized operation strategy of the dyeing wastewater treatment by HABR was obtained as the hydraulic retention time (HRT) of 12 h for steady-state operation with an up-flow velocity of 1.7 m/h as well as OLR of 1.5&#8211;2.0 kg COD/(m3&#183;d)

Pilot-Scale Anaerobic Treatment of Printing and Dyeing Wastewater and Performance Prediction Based on Support Vector Regression

Printing and dyeing wastewater is characterized with complex water quality and poor biodegradability. In this study, a pilot-scale anaerobic baffled reactor (ABR) with packing was verified to effectively degrade the complex organic pollutants in the wastewater through the hydrolysis and acidification of anaerobic microorganisms. At a hydraulic retention time (HRT) of 12 h and an organic loading rate (OLR) of 2.0&ndash;2.5 kg COD/(m3&middot;d), the ABR stabilized the fluctuation range of pH and achieved an average colority removal rate of 10.5%, which provided favorable conditions for subsequent aerobic treatment. During the early operation period, the reactor increased the alkalinity of the wastewater; after 97 days of operation, the volatile fatty acid (VFA) content in the wastewater decreased. To demonstrate the suitability of the support vector regression (SVR) technology in predicting the performance of the reactor, two SVR algorithms with three kernel functions were employed to relate the chemical oxygen demand (COD) removal rate to its influencing factors, and the predictions of both the training and validation groups agreed with the measurements. The results obtained from this study can contribute to the design and optimal operation of the anaerobic treatment project of the industrial wastewater treatment plant

Design and Experimental Investigation of a Piezoelectric Rotation Energy Harvester Using Bistable and Frequency Up-Conversion Mechanisms

Harvesting energy from rotational motion for powering low-power electrical devices is attracting increasing research interest in recent years. In this paper, a magnetic-coupled buckled beam piezoelectric rotation energy harvester (MBBP-REH) with bistable and frequency up-conversion is presented to harvest low speed rotational energy with a broadband. A buckled beam attached with piezoelectric patches under dynamical axial load enables the harvester to achieve high output power under small excitation force. The electromechanical coupling dynamical model is developed to characterize the MBBP-REH. Both the simulations and experiments are carried out to evaluate the performance of the harvesters in various conditions under different excitations. The experimental results indicate that the proposed harvester is applicable for low speed rotation and can generate stable output power under wideband rotating excitation. For the harvester with two magnets that produce attractive forces with the center magnet of the buckled beam, the average power is 682.7 &mu;W and the maximum instantaneous power is 1450 &mu;W at 360 r/min

Distribution of Polycyclic Aromatic Hydrocarbons in Sunken Oils in the Presence of Chemical Dispersant and Sediment

The formation of sunken oils is mainly dominated by the interaction between spilled oils and sediments. Due to their patchiness and invisibility, cleaning operations become difficult. As a result, sunken oils may cause long-term and significant damage to marine benthonic organisms. In the present study, a bench experiment was designed and conducted to investigate the quantitative distribution of polycyclic aromatic hydrocarbons (PAHs) in sunken oils in the presence of chemical dispersant and sediment. The oil sinking efficiency (OSE) of 16 priority total PAHs in the sediment phase was analyzed with different dosages of dispersant. The results showed that the synergistic effect of chemical dispersant and sediment promoted the formation of sunken oils, and the content of PAHs partitioned in the sunken oils increased with the increase of dispersant-to-oil ratios (DORs). Furthermore, with the addition of chemical dispersant, due to the solubility and hydrophobicity of individual PAHs, the high molecular weight (HMW) PAHs with 4&ndash;6 rings tended to partition to sediment compared with low molecular weight (LMW) PAHs with 2&ndash;3 rings. The synergistic effect of chemical dispersant and sediment could enhance the OSE of HMW PAHs in sunken oils, which might subsequently cause certain risks for marine benthonic organisms

Effects of Wave Conditions and Particle Size on the Release of Oil from Oil-Contaminated Sediments in a Wave Tank

The floating oil can drift to the coastal areas and interact with the shoreline substrates after oil spill accidents. This process is demonstrated to be the cause of the formation of oil-contaminated sediments, which has attracted much attention. However, no systematic study has concerned the desorption process of oil from oil-contaminated sediments when the coastal hydrodynamic conditions change. This work determines the effects of wave conditions and particle size on the release of oil from artificially prepared sediments in a wave tank. Nonlinear fitting results show that the oil release kinetic curves can be correctly estimated with the Lagrangian first-order (LFO) first-order equation. Under different test conditions. The oil concentration in the water increases rapidly within 6 h. However, the oil desorption is inhibited thereafter and the process of sorption occurs dominantly. Under higher wave energy, the process of desorption is significantly enhanced and more large oil droplets release from sediments. Under the same wave condition, small oil droplets firstly release from the sediments. Besides, more oil especially with a larger size can release from larger sediment while oil releases more quickly from smaller sediment