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Both oil spill and microplastics (MPs) are major issues in marine environments. After a spill, the oil film may disperse into the water column as droplets under the function of sea waves. The oil dispersion may be affected due to the attachment of oil to MPs. In this paper, the impacts of salinity and temperature on the dispersion of spilled oil in the presence of MPs were individually studied by batch conical flask oscillation experiments. The results indicated that the rise in salinity or temperature displayed a more significant effect on promoting, rather than inhibiting, oil dispersion with MPs. When the salinity rose from 15% to 35%, the oil dispersion efficiency (ODE) with the 13 μm polyethylene (PE) and polystyrene (PS) MPs was increased by 10.4% and 12.9%, respectively; when the temperature rose from 10 °C to 25 °C, the corresponding ODE was increased by 15.6% and 12.7%, respectively. In addition, the volumetric mean diameter (VMD) of the dispersed oil droplets decreased with an increase in salinity or temperature. Furthermore, the 13 μm MPs showed a higher impact on the oil dispersion than 106 μm of MPs, and the ODE with PE MPs was greater than that with PS MPs. The findings of this study expanded the understanding of the migration of spilled oil in seawater in the presence of MPs and may further improve the capability of predicting the impact of oil spills by marine environment managers.

Heavy fuel oil (HFO) spills pose serious threat to coastlines and sensitive resources. Stranded HFO that occurs along the coastline could cause long-term and massive damage to the marine environment and indirectly affect the survival of parental marine invertebrates. However, our understanding of the complex associations within invertebrates is primarily limited, particularly in terms of the toxicity effects on the offspring when parents are exposed to stranded HFO. Here, we investigated the persistent effects on the early development stage of the offspring following stranded HFO exposure on the sea urchin Strongylocentrotus intermedius. After 21 d exposure, sea urchins exhibited a significant decrease in the reproductive capacity; while the reactive oxygen species level, 3-nitrotyrosine protein level, protein carbonyl level, and heat shock proteins 70 expression in the gonadal tissues and gametes significantly increased as compared to the controls, indicating that HFO exposure could cause development toxicity on offspring in most traits of larval size. These results suggested that the stranded HFO exposure could increase oxidative stress of gonadal tissues, impair reproductive functions in parental sea urchins, and subsequently impact on development of their offspring. This study provides valuable information regarding the persistent toxicity effects on the offspring following stranded HFO exposure on sea urchins.

Currently, oil spill pollution is one of the major environmental concerns for sea cucumber (Apostichopus japonicus) aquaculture. During oil spills, spraying chemical dispersants is generally considered an efficient oil spill response. However, the impact of chemical dispersant deployment during oil spills on sea cucumbers is still less known. In this study, we treated sea cucumbers with physically and chemically (by GM-2 chemical dispersant) dispersed Oman crude oil for 24 h. For antioxidant defense capacities, our results showed that physically dispersed crude oil caused a significant elevation on superoxide dismutase (SOD) and catalase (CAT) activities, and glutathione (GSH) content, while chemically dispersed crude oil caused a significant decrease in SOD activity and GSH content with no apparent change in CAT activity. As for non-specific immune responses, our results indicated that physically dispersed crude oil up-regulated acid phosphatase (ACP) and lysozyme (LZM) activities but had no obvious impact on alkaline phosphatase (ALP) activity. Differently, chemically dispersed crude oil down-regulated ACP and LZM activities while up-regulating ALP activity. Based on the integrated biomarker response analysis, the overall impact of chemically dispersed crude oil on antioxidant defense capacities and non-specific immune responses of sea cucumbers was more severe than physically dispersed crude oil.

Objective:To investigate the effects of iridoid-rich fraction from Valeriana jatamansi Jones on oxidative stress in rats with spinal cord injury(SCI)from the histological and molecular biological levels.Methods:A total of sixty male Sprague-Dawley rats weighing(250±30)g were randomly divided into three groups(20 rats per group):the sham-operated group, the model group, and the treatment group with 10 mg/kg iridoid-rich fraction from Valeriana jatamansi Jones. The model of SCI was established by a medical aneurysm clip, the sham-operated group was only performed by laminectomy without injuring the spinal cord. Two hours after model establishment successfully, the treatment group was given iridoid-rich fraction from Valeriana jatamansi Jones by intragastrical administration with 10 mg/kg, and the sham-operated group and the model group were given an equal volume of sodium carboxymethylcellulose(CMC-Na)solution with the same way. And each of groups was given intragastrical administration once a day. The rats were sacrificed on third days after administration, and the contents of oxidative stress indexes superoxide dismutase(SOD)and malondialdehyde(MDA)in serum were detected by enzyme linked immunosorbent assay(ELISA); the related biochemical kit was used to test glutathione peroxidase(GSH-PX)and catalase(CAT)viability of the spinal cord tissue; the expression levels of apoptosis-related proteins of Caspase-3, B cell lymphoma(Bcl-2)associated X protein(Bax), and Bcl-2 were detected by Western blot; and the Hematoxylin/eosin(HE)staining was used to observe the pathological changes of the spinal cord tissue at the perilesional area; and Terminal-deoxynucleoitidyl transferase mediated nick end labeling(TUNEL)was used to observe the apoptosis of nerve cells of the spinal cord tissue at the perilesional area.Results:The results of ELISA showed that compared with the sham-operated group, the SOD content in the serum of the model group decreased, and the MDA content increased; compared with the model group, the SOD content in the serum of the treatment group with iridoid-rich fraction from Valeriana jatamansi Jones increased significantly(P< 0.05), and the MDA content decreased significantly(P< 0.01). The results of the biochemical kit tests showed that the activity of GSH-PX and CAT antioxidant enzymes in the spinal cord of the model group was lower than that in the sham-operated group; compared with the model group, in the treatment group with iridoid-rich fraction from Valeriana jatamansi Jones the activity of the antioxidant enzymes of GSH-PX(P< 0.05)and CAT(P< 0.01)of the spinal cord tissue increased significantly. The Western blot results showed that compared with the sham-operated group, the expression of pro-apoptosis protein increased and the anti-apoptotic protein decreased in the model group; compared with the model group, the expression of pro-apoptotic protein(Caspase-3 and Bax)decreased significantly(P< 0.05), and the expression of anti-apoptotic protein(Bcl-2)increased significantly(P< 0.05), and simultaneously, the proportion of Bax/Bcl-2 decreased significantly(P< 0.01)in the treatment group. The results of the HE staining showed that the structure of gray matter and white matter of the spinal cord tissue in the sham-operated group were normal at the perilesional area, the structure of the neurons was also clear, and no significant spinal cord injured was found; compared with the sham-operated group, the spinal cord structure was severely damaged in the model group: the gray matter of the central part of the spinal cord and the white matter of the surrounding part of the spinal cord turned into blur because of injury and a large number of neurons degenerated, a number of nerve cells even appeared necrosis, and the cell structure was seriously destroyed at the same time, and in addition, the nuclear turned into shrinkage or dissolution and passed away, accompanying with varying degrees of neutrophil infiltration and a large number of microglia proliferation; compared with the model group, the spinal cord structure of the treatment group with iridoid-rich fraction from Valeriana jatamansi Jones significantly improved, and there were only small areas presenting a neuronal necrosis, a small amount of eosinophils increasing and a small number of eosinophils microglia infiltration in the spinal cord tissue at the perilesional area, and at the same time, the histopathological scores in tissue sections were lower(P< 0.05). The results of the TUNEL method showed that there were not obvious brown-yellow nerve apoptotic cells in the spinal cord tissue of the sham-operated group, and, however, there were obvious brown-yellow apoptotic nerve cells in the spinal cord tissue at the perilesional area of the model group; compared with the model group, the number of brown-yellow apoptotic nerve cells in the treatment group with iridoid-rich fraction from Valeriana jatamansi Jones attenuated apparently(P< 0.05).Conclusion:The iridoid-rich fraction from Valeriana jatamansi Jones has neuroprotective effects on rats with spinal cord injury, and its mechanism may be related to the reduction of oxidative stress after SCI.

Objectives Spinal cord injury (SCI) is a disabling central nervous system disorder. This study aimed to explore the effects of repetitive trans-spinal magnetic stimulation (rTSMS) of different spinal cord segments on movement function and growth-associated protein-43 (GAP43) and 5-hydroxytryptamine (5-HT) expression in rats after acute SCI and to preliminarily discuss the optimal rTSMS treatment site to provide a theoretical foundation and experimental evidence for clinical application of rTSMS in SCI. Methods A rat T10 laminectomy SCI model produced by transient application of an aneurysm clip was used in the study. The rats were divided into group A (sham surgery), group B (acute SCI without stimulation), group C (T6 segment stimulation), group D (T10 segment stimulation), and group E (L2 segment stimulation). Results In vivo magnetic stimulation protected motor function, alleviated myelin sheath damage, decreased NgR and Nogo-A expression levels, increased GAP43 and 5-HT expression levels, and inhibited terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells and apoptosis-related protein expression in rats at 8 weeks after the surgery. Conclusions This study suggests that rTSMS can promote GAP43 and 5-HT expression and axonal regeneration in the spinal cord, which is beneficial to motor function recovery after acute SCI.

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 2.0–2.5 kg COD/(m3·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.

Sea cucumber (Apostichopus japonicus) is mainly cultured in the coastal zone, where it is easily threatened by accidental oil spills. Chemical dispersant is one of the efficient oil spill responses for mitigating the overall environmental damage of oil spills. However, the impact of crude oil and chemical dispersants on sea cucumber is less well known. Hence, the present study focused on exploring the antioxidant response and oxidative stress in the respiratory tree of sea cucumber following exposure to GM-2 chemical dispersant (DISP), water-accommodated fractions (WAF), and chemically enhanced WAF (CEWAF) of Oman crude oil for 24 h. Results manifested that WAF exposure caused a significant increase in the reactive oxygen species (ROS) level (5.29 ± 0.30 AU·mgprot−1), and the effect was much more obvious in CEWAF treatment (5.73 ± 0.16 AU·mgprot−1). Total antioxidant capacity (T-AOC), as an important biomarker of the antioxidant defense capacity, showed an increasing trend following WAF exposure (0.95 ± 0.12 U·mgprot−1) while a significant reduction in T-AOC was observed following CEWAF exposure (0.23 ± 0.13 U·mgprot−1). Moreover, we also evaluated the oxidative damage of the macromolecules (DNA, protein, and lipid), and our results revealed that the presence of chemical dispersant enhanced oxidative damage caused by crude oil to sea cucumber.

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.

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 4−6 rings tended to partition to sediment compared with low molecular weight (LMW) PAHs with 2−3 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.

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.

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−) during steadily operational period. Gas chromatography–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 1.5–2.0 kg COD/(m3·d).

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.