An innovative classification system for ranking the biological effects of marine aromatic hydrocarbons based on fish embryotoxicity

Petroleum hydrocarbon pollution is a global concern,particularly in coastal environments.Polycyclic aromatic hydrocarbons(PAHs) are regarded as the most toxic components of petroleum hydrocarbons.In this study,the biomonitoring and ranking effects of petroleum hydrocarbons and PAHs on the marine fish model Oryzias melastigma embryos were determined in the Jiulong River Estuary(JRE) and its adjacent waters in China.The results showed that the levels of petroleum hydrocarbons from almost all sites met the primary standard for marine seawater quality,and the concentrations of the 16 priority PAHs in the surface seawater were lower compared with those in other coastal areas worldwide.A new fish expert system based on the embryotoxicity of O.melastigma(OME-FES) was developed and applied in the field to evaluate the biological effects of petroleum hydrocarbons and PAHs.The selected physiological index and molecular indicators in OME-FES were appropriate biomarkers for indicating the harmful effects of petroleum hydrocarbons and PAHs.The outcome of OME-FES revealed that the biological effect levels of the sampling sites ranged from level Ⅰ(no stress) to level Ⅲ(medium stress),which is further corroborated by the findings of nested analysis of variance(ANOVA) models.Our results suggest that the OME-FES is an effective tool for evaluating and ranking the biological effects of marine petroleum hydrocarbons and PAHs.This method may also be applied to evaluate other marine pollutants based on its framework.

Geochemical identification of a source rock affected by migrated hydrocarbons and its geological significance:Fengcheng Formation,southern Mahu Sag,Junggar Basin,NW China

The Fengcheng Formation is a crucial source rock and the primary reservoir for oil accumulation in the Mahu Sag.Crude oils are distributed throughout the Fengcheng Formation,ranging from the edge to the interior of the sag in the southern Mahu Sag.These crude oils originate from in-situ source rocks in shallowly buried areas and the inner deep sag.During migration,the crude oil from the inner deep sag affects the source rocks close to carrier beds,leading to changes in the organic geochemical characteristics of the source rocks.These changes might alter source rock evaluations and oil-source correlation.Based on data such as total organic carbon(TOC),Rock-Eval pyrolysis of source rocks,and gas chromatography-mass spectrometry(GC-MS)of the saturated fraction,and considering the geological characteristics of the study area,we define the identification characteristics of source rock affected by migrated hydrocarbons and establish the various patterns of influence that migrated hydrocarbons have on the source rock of the Fengcheng Formation in the southern Mahu Sag.The source rocks of the Fengcheng Formation are mostly fair to good,containing mainly Type II organic matter and being thermally mature enough to generate oil.Source rocks affected by migrated hydrocarbons exhibit relatively high hydrocarbon contents(S1/TOC>110 mg HC/g TOC,Extract/TOC>30%,HC:hydrocarbon),relatively low Rock-Eval Tmax values,and relatively high tricyclic terpane contents with a descending and mountain-shaped distribution.Furthermore,biomarker composition parameters indicate a higher thermal maturity than in-situ source rocks.Through a comparison of the extract biomarker fingerprints of adjacent reservoirs and mudstones in different boreholes,three types of influence patterns of migrated hydrocarbons are identified:the edge-influence of thin sandstone-thick mudstone,the mixed-influence of sandstone-mudstone interbedded,and the full-influence of thick sandstone-thin mudstone.This finding reminds us that the influence of migrated hydrocarbons must be considered when evaluating source rocks and conducting oil-source correlation.

Single-atom catalysts for the electrochemical reduction of carbon dioxide into hydrocarbons and oxygenates

The electrochemical reduction of carbon dioxide offers a sound and economically viable technology for the electrification and decarbonization of the chemical and fuel industries.In this technology,an electrocatalytic material and renewable energy-generated electricity drive the conversion of carbon dioxide into high-value chemicals and carbon-neutral fuels.Over the past few years,single-atom catalysts have been intensively studied as they could provide near-unity atom utilization and unique catalytic performance.Single-atom catalysts have become one of the state-of-the-art catalyst materials for the electrochemical reduction of carbon dioxide into carbon monoxide.However,it remains a challenge for single-atom catalysts to facilitate the efficient conversion of carbon dioxide into products beyond carbon monoxide.In this review,we summarize and present important findings and critical insights from studies on the electrochemical carbon dioxide reduction reaction into hydrocarbons and oxygenates using single-atom catalysts.It is hoped that this review gives a thorough recapitulation and analysis of the science behind the catalysis of carbon dioxide into more reduced products through singleatom catalysts so that it can be a guide for future research and development on catalysts with industry-ready performance for the electrochemical reduction of carbon dioxide into high-value chemicals and carbon-neutral fuels.

Efficient adsorption separation of methane from C_(2)-C_(3) hydrocarbons in a Co(Ⅱ)-nodes metal-organic framework

Methane(CH_(4))as a substitute for other mineral fuels plays a crucial role in reducing energy consumption and preventing environmental pollution.The present study employs a solvothermal method to fabricate a porous framework Co-metal-organic framework(Co-MOF)containing two distinct secondary building units(SBUs):an anionic[Co_(2)(μ_(2)-OH)(COO)_(4)(H_(2)O)]and a neutral[CoN_(2)(COO)_(2)].Notably,within the anionic SBUs,the coordinated water molecules induce the generation of divergent unsaturated Co(Ⅱ)centers in the unidirectional porous channels,thereby creating open metal sites.The adsorption performance of Co-MOF towards pure component gases was systematically investigated.The results demonstrated that Co-MOF exhibits superior adsorption capacity for C_(2)-C_(3) hydrocarbons compared to CH_(4),which offers the potential for efficient adsorption and separation of CH_(4) from C_(2)-C_(3) hydrocarbons.The gas selectivity separation ratios of Co-MOF for C_(2)H_(6)/CH_(4) and C_(3)H_8/CH_(4) were calculated using the ideal adsorbed solution theory method at 273/298 K and 0.1 MPa.The results revealed that Co-MOF achieved remarkable equilibrium separation selectivity for CH_(4) and C_(2)-C_(3) hydrocarbon gases among non-modified MOFs,signifying the potential of the synthesized Co-MOF for efficient recovery and purification of CH_(4) from C_(2)-C_(3) hydrocarbons.Breakthrough experiments further demonstrate the ability of Co-MOF to purify methane from C_(2)-C_(3) hydrocarbons in practical gas separation scenarios.Additionally,molecular simulation calculations further substantiate the propensity of anionic SBUs to interact with C_(2)-C_(3) hydrocarbon compounds.This study provides a novel paradigm for the development of porous MOF materials in the application of gas mixture separation.

Changes in the Non-targeted Metabolomic Profile of Three-year-old Toddlers with Elevated Exposure to Polycyclic Aromatic Hydrocarbons

Objective To investigate changes in the urinary metabolite profiles of children exposed to polycyclic aromatic hydrocarbons(PAHs)during critical brain development and explore their potential link with the intestinal microbiota.Methods Liquid chromatography-tandem mass spectrometry was used to determine ten hydroxyl metabolites of PAHs(OH-PAHs)in 36-month-old children.Subsequently,37 children were categorized into low-and high-exposure groups based on the sum of the ten OH-PAHs.Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used to identify non-targeted metabolites in the urine samples.Furthermore,fecal flora abundance was assessed by 16S rRNA gene sequencing using Illumina MiSeq.Results The concentrations of 21 metabolites were significantly higher in the high exposure group than in the low exposure group(variable importance for projection>1,P<0.05).Most of these metabolites were positively correlated with the hydroxyl metabolites of naphthalene,fluorine,and phenanthrene(r=0.336–0.531).The identified differential metabolites primarily belonged to pathways associated with inflammation or proinflammatory states,including amino acid,lipid,and nucleotide metabolism.Additionally,these distinct metabolites were significantly associated with specific intestinal flora abundances(r=0.34–0.55),which were mainly involved in neurodevelopment.Conclusion Higher PAH exposure in young children affected metabolic homeostasis,particularly that of certain gut microbiota-derived metabolites.Further investigation is needed to explore the potential influence of PAHs on the gut microbiota and their possible association with neurodevelopmental outcomes.

Eco-toxicity and health risk assessment of polycyclic aromatic hydrocarbons in surface sediments of Burullus Lake in Egypt

Polycyclic aromatic hydrocarbons(PAHs)are ubiquitous environmental contaminants of growing concern due to their potential ecological and human health risks.This study presents a comprehensive assessment of PAHs contamination in the surface sediments of Burullus Lake,a vital and second largest delta lake in Egypt.The aim was to evaluate the eco-toxicity and potential health risks associated with the presence of these compounds.Surface seven sediment samples were collected from various drains in the southern part of Burullus Lake.Soxhlet extraction method was employed to extract PAHs(16PAHs)from the sediment sample.Analytically,target compounds were located using HPLC.The results showed that samples contained PAHs levels ranging from 0.038×10^(-6)to 0.459×10^(-6),which is considered heavily polluted by the European standard for PAHs pollution.Additionally,there was no apparent source of PAHs in the ElKhashah drain or the Brinbal Canal,as HPLC found none of the compounds.The most prevalent compound in sediment samples along the study area was fluoranthene.The diagnostic indices in the present study indicated that the hydrocarbons in the region originated from pyrolytic and man-made sources along the drains of Burullus Lake.The principal component analysis(PCA)and diagnostic ratios revealed that coal combustion and pyrolytic sources were responsible for the PAHs contamination in the surface sediments.The non-carcinogenic risk(HI),which is the product of the HQs for the adult and child populations,respectively,was calculated.HI values under 1,therefore,demonstrated that they had no carcinogenic effects on human health.TEQs and MEQs in the sediments of Burullus Lake do not have a cancer-causing impact on people.For the safety of nearby wildlife,aquatic life,and people,all activities that raise petroleum hydrocarbon levels in Burullus Lake must be adequately regulated and controlled.According to the ecological risk assessment,there is little chance that PAHs will be found in the sediments of Burullus Lake.This study underscores the urgent need for effective pollution control measures and regular monitoring of PAHs levels in Burullus Lake sediments to protect the aquatic ecosystem and public health.It also highlights the importance of considering eco-toxicity and human health risks in integrated risk assessments of PAHs-contaminated environments.

Mitigation of polycyclic aromatic hydrocarbons(PAHs)in roasted beef patties by cold plasma treatment and products quality evaluation

The cold plasma(CP)technique was applied to alleviate the contamination of polycyclic aromatic hydrocarbon(PAH)in this investigation.Two different CP treatments methods were implemented in the production of beef patties,to investigate their inhibition and degradation capacity on PAHs.With 5 different cooking oils and fats addition,the inhibition mechanism of in-package cold plasma(ICP)pretreatment was explored from the aspect of raw patties fatty acids composition variation.The results of principal component analysis showed that the first two principal components accounted for more than 80%of the total variation in the original data,indicating that the content of saturated fatty acids was significantly positively correlated with the formation of PAHs.ICP pretreatment inhibited the formation of PAHs by changing the composition of fatty acids,which showed that the total amount of polyunsaturated fatty acids decreased and the total amount of monounsaturated fatty acids increased.Sensory discrimination tests demonstrated there were discernable differences between 2 CP treated samples and the controls,utilization of the ICP pretreatment in meat products processing was expected to achieve satisfying eating quality.In conclusion,CP treatment degraded PAHs through stepwise ring-opening oxidation in 2 reported pathways,the toxicity of PAHs contaminated products was alleviated after CP treatment.

Investigation of the effect of hydrocarbons and monoesters in the gelators’composition on the properties of edible oleogel

Natural wax gelators have different compositions of compounds(hydrocarbons,wax esters,free fatty alcohols,and free fatty acids),which results in oleogels with varying properties.To maintain a consistent composition,the individual components can be added to the original wax gelator.The content of hydrocarbons and wax esters greatly affects the structuring process of liquid edible oils with waxes.The aim of this study was to evaluate the possibility of modifying the properties of beeswax as a gelling agent by adding hydrocarbons or monoesters to obtain oleogels with specific properties.Various tests were conducted to assess the changes in the oleogel properties,such as color,microstructure,oil-binding capacity,thermal and textural properties.The research results have shown that the addition of the studied fractions has led to a significant change in all properties of oleogels.The initial size of oleogel crystals(7.29±1.80μm)changed after adding fractions,varying from 5.28μm to 12.58μm with hydrocarbons and from 9.95μm to 30.41μm with wax esters.The addition of 30%–50% hydrocarbons decreased the ability of the oleogels to bind oil and made them less firm compared to samples with 10%-20% hydrocarbons.Adding 10%-20% monoesters increased the firmness of the oleogels,but this indicator decreased when their content was increased to 50%.The obtained data indicate that hydrocarbons and wax esters can be used for targeted correction of the gelling properties of beeswax.

Study on Adsorption Removal of Polycyclic Aromatic Hydrocarbons by Modified Mussel Shells

Polycyclic aromatic hydrocarbons(PAHs)are typical persistent organic pollutants(POPs)that are commonly found in the environment.They are carcinogenic,teratogenic,mutagenic and biodegradable obviously.In this paper,the modified mussel shells were used to adsorb and remove anthracene.The results show that the adsorption removal rate of the mussel shells was higher after calcination at 600℃.5%H_(3)PO_(4) solution was more suitable for shell treatment than 3 mol/L ZnCl_(2) solution.As the dosage of the modified shells was 0.5 g/L,the adsorption reached a stable state,and the removal rate of PAHs was about 69.44%;the adsorption efficiency rose with the increase of time.It can be seen that as a new and cheap biological adsorbent,the modified shells can be used to remove PAHs from wastewater.

Tracing of natural gas migration by light hydrocarbons:A case study of the Dongsheng gas field in the Ordos Basin,NW China

Based on the analysis of light hydrocarbon compositions of natural gas and regional comparison in combination with the chemical components and carbon isotopic compositions of methane,the indication of geochemical characteristics of light hydrocarbons on the migration features,dissolution and escape of natural gas from the Dongsheng gas field in the Ordos Basin is revealed,and the effect of migration on specific light hydrocarbon indexes is further discussed.The study indicates that,natural gas from the Lower Shihezi Formation(Pix)in the Dongsheng gas field displays higher iso-C5-7contents than n-C5-7contents,and the C6-7light hydrocarbons are composed of paraffins with extremely low aromatic contents(<0.4%),whereas the C7light hydrocarbons are dominated by methylcyclohexane,suggesting the characteristics of coal-derived gas with the influence by secondary alterations such as dissolution.The natural gas from the Dongsheng gas field has experienced free-phase migration from south to north and different degrees of dissolution after charging,and the gas in the Shiguhao area to the north of the Borjianghaizi fault has experienced apparent diffusion loss after accumulation.Long-distance migration in free phase results in the decrease of the relative contents of the methylcyclohexane in C7 light hydrocarbons and the toluene/n-heptane ratio,as well as the increase of the n-heptane/methylcyclohexane ratio and heptane values.The dissolution causes the increase of isoheptane values of the light hydrocarbons,whereas the diffusion loss of natural gas in the Shiguhao area results in the increase of n-C5-7contents compared to the iso-C5-7contents.

Gas source of the Middle Jurassic Shaximiao Formation in the Zhongjiang large gas field of Western Sichuan Depression:Constraints from geochemical characteristics of light hydrocarbons

The Zhongjiang gas field is a typical large gas field in terrigenous strata of the Western Sichuan Depression.It remains debatable which member of the Upper Triassic Xujiahe Formation served as the source rocks and how significant the member contributed to the gas accumulations in the Zhongjiang gas field.In this study,we analyzed the essential characteristics of the Lower Jurassic source rocks and the geochemical features of light hydrocarbons in natural gas from the 2nd(T_(3)χ^(2))and 4th members(T_(3)χ^(4))of the Upper Triassic Xujiahe Formation(T_(3)χ),as well as the Middle Jurassic Shaximiao(J_(2)s)and Qianfoya(J_(2)q)formations.Based on this,we explored the sources of the natural gas in the Zhongjiang gas field and determined the natural gas migration patterns and their effects on the properties of light hydrocarbons in the natural gas.The results indicate that the Lower Jurassic lacustrine source rocks of the Zhongjiang gas field contain humic organic matter,with vitrinite reflectance(R_(0))values ranging from 0.86%to 0.98%.Samples meeting the criterion for effective source rocks[total organic carbon(TOC)content≥0.75%]exhibited an average TOC content of merely 1.02%,suggesting significantly lower hydrocarbon generation potential than source rocks in the underlying T3x,which show higher thermal maturity and TOC contents.For natural gas samples from T_(3)χ^(2),T_(3)χ^(4),J_(2)s,and J_(2)q reservoirs,their C_(5-7)iso-alkane content was significantly higher than their n-alkane content,and their methylcyclohexane(MCH)index ranged from 59.0%to 77.3%,indicating the predominance of methylcyclohexane in C_(7)light hydrocarbons.As indicated by the origin identification and gas-source correlation based on the geochemical features of light hydrocarbons,the natural gas in the Zhongjiang gas field is typical coal-derived gas.The gas from the primary pay zone of the Shaximiao Formation,with significantly high K_(1),(P_(2)+N_(2))/C_(7),and P_(3)/C_(7)values,predominantly originated from the 5th member of the T3x and migrated in the free phase,with a small amount possibly sourced from the Lower Jurassic source rocks.The dissolution and adsorption during gas migration led to a decrease in the aromatic content in C_(6-7)light hydrocarbons and an increase in the isoheptane values.Therefore,their effects must be considered when determining the gas origin and thermal maturity based on the aromatic content in C_(6-7) light hydrocarbons and iso-heptane values.

Extraction of the Residual Polycyclic Aromatic Hydrocarbons in the Long-term Contaminated Soil in the Field

[Objective] The aim of this study was to find a better method to exactly quantify the residual polycyclic aromatic hydrocarbons（PAHs）in the long-term contaminated soil in the field so as to provide basis for the remediation for PAHs contaminated soil.[Method]The comparisons of soxhlet extraction,ultrasonic extraction and shaking extraction were studied in the agricultural soil irrigated with oil sewage over a long period of time.[Result]The total PAHs extracted by soxhlet extraction were the highest（6 873.7 μg/kg）,followed by shaking extraction（6 698.8 μg/kg）and ultrasonic extraction（5 737.6 μg/kg）.Among these methods,the highest extracted 4 and 6 rings PAHs were in the soxhlet extraction,the highest extracted 2 and 5 rings PAHs were in the shaking extraction,and the highest extracted 3 rings PAHs were in the ultrasonic extraction.[Conclusion]This study had provided basis for the selection of the assessment method of residual PAHs in the field soil.

Distribution and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Mussels from the Middle and Lower Main Stream of Huaihe River

[ Object] The aim was to discuss the pollution status of polycyclic aromatic hydrocarbons （PAHs） in mussels from the middle and lower main stream of Huaihe River, which will provide a scientific basis for dietary safety of mussels. [ Method] Suspended matter, sediment, and mussel samples were collected from Wuxiaojie and Fushanji in middle and lower reaches of Huaihe River. All samples were extracted with Soxhlet, separated through Silica GeI-Al2O3 column, and determined by GC-MS, and then 16 typical PAHs contents in the prior table listed by American EPA were obtained. [ Result] The results indicated that total PAHs concentrations in suspended matters and sediments of Wuxiaojie were significantly higher than those in Fushanji respectively. However, PAHs concentrations in mussels of the two samplings showed little difference; as for single PAH component, low-ring PAHs were more advantaged in suspended matters of two sampling sites, while high-ring PAHs were more advantaged in mussels. PAHs in sediments of Wuxiaojie assumed low-ring aspect, though PAHs in sediments of Fushanji assumed high-ring aspect. [ Conclusion] In spite of that sediments and mussels were not yet contaminated according to the ecological risk assessment of PAHs, its potential hazards couldn＇t be ignored any more.

Geochemical Characterizations of Source and Depositional Environment of Hydrocarbons in the Lake Albert Rift Basin

Despite the upsurge in hydrocarbon exploration in the Lake Albert Rift Basin(LARB)over the past three decades,systematic characterization of hydrocarbon compositions remains lacking,leading to uncertainties in source rock and oil generation determination.We characterized crude oil compositions and oil sand samples in the northern and southern subbasins of LARB.The relative abundance of normal and branched linear alkanes,hopanes,steranes,and aromatic hydrocarbon suggest that northern and southern hydrocarbons were deposited in anoxic to suboxic lacustrine environments and share similar biological source compositions(i.e.,a mixture of plants and aquatic algae and bacteria).Relative to southern samples,northern samples show more negative δ^(13)C values for oils,saturates and aromatics,indicating longer migration paths,and exhibit higher MPI-1,DNR-1 and 4-/1-MDBT ratios,indicating higher maturity.Between the two possible sets of source rocks(upper Miocene and Jurassic strata),the positive δ^(13)C values of saturated hydrocarbons(average=-20.5‰)suggest that the upper Miocene lacustrine shale is the most likely candidate.Oleanane index(<5% in our samples)does not exclude either source rock possibility,and C_(28)/C_(29) regular sterane(average=0.63)may be biased by high terrestrial inputs in a lacustrine setting.Together,our data show that northern and southern oils originate from the same source rocks but different oil kitchens.Given the similar geochemical characteristics of southern and northern oils,previous exploration successes in the northern subbasin likely suggest similar potential in the southern sector,while other elements influencing exploration success must be also evaluated.

Polycyclic aromatic hydrocarbons in soils of Beijing and Tianjin region: Vertical distribution, correlation with TOC and transport mechanism

The contents and distribution of 20 polycyclic aromatic hydrocarbons （PAHs） and heterocyclic aromatic hydrocarbons （HAHs） were investigated in 16 soil profiles of Beijing and Tianjin region. Transport of high molecular weight PAHs （HMWPAHs） and the correlation between total organic carbon （TOC） and their concentrations were also discussed. The results indicated that highly contaminated sites were located at urban or wastewater irrigation areas and pollutants mainly accumulated in topsoil （〈 40 cm）, with a sharp content decrease at the vertical boundary of 30-40 cm. Total PAHs/HAHs concentrations in soils from Tianjin were markedly greater than those from Beijing. Even the contents at bottoms of soil profiles in Tianjin were higher than those in topsoils of Beijing soil profile. HMWPAHs dominated the PAH profiles, exhibiting a uniform distribution of pyrogenic origin between topsoils and deep layers. Furthermore, the percentages of HMWPAHs remained relative constant with the depth of soil profiles, which were consistent with the distribution of particulate matter-associated PAHs in the local atmospheric environments. Therefore, HMWPAHs transport with particulates might be the predominant source found in soil profiles.

Geochemical characterization of aromatic hydrocarbons in crude oils from the Tarim,Qaidam and Turpan Basins,NW China

Based on the systematic study of aromatic hydrocarbons in over 100 crude oil samples collected from the Tabei and Tazhong uplifts in the Tarim Basin,the western depression area in the Qaidam Basin and the Tabei depression in the Turpan Basin,the geochemical characteristics of the marine（Tarim Basin）,saline lacustrine（Qaidam Basin）,and swamp（Turpan Basin） oils were investigated.The marine oils from the Tarim basin are characterized by relatively low abundance of diaromatic hydrocarbons such as biphenyl and naphthalene,and relatively high abundance of triaromatic hydrocarbons including phenanthrene,dibenzothiophene and fluorene.In contrast,the swamp oils from the Turpan Basin are dominated by the highest relative abundance of diaromatic hydrocarbons and the lowest relative abundance of triaromatic hydrocarbons in all the oil samples in this study.The relative abundance of diaromatic and triaromatic hydrocarbons in the saline lacustrine oils from Qaidam Basin is between that in Tarim oils and Turpan oils.Aromatic parameters based on the isomer distributions of dimethylnaphthalenes（DMN）,trimethylnaphthalenes（TMN）,tetramethylnaphthalenes（TeMN） and methylphenanthrenes（MP）,i.e.,1,2,5-trimethylnaphthalene（TMN）/1,3,6-TMN ratio,1,2,7-TMN/1,3,7TMN ratio,（2,6-＋2,7-）-dimethylnaphthalenes（DMN）/1,6-DMN ratio,1,3,7-TMN/（1,2,5-＋1,3,7-）TMN,1,3,6,7-TeMN/（1,3,6,7-＋1,2,5,6-＋1,2,3,5-）-TeMN ratio and MP index,may reflect the diversity of organic source input,thermal maturity and depositional environments.In addition,the dibenzothiophenes（DBTs）/fluorenes（Fs） and dibenzofurans（DBFs）/Fs ratios were found to the very useful and effective in determining genetic types of crude oils for the marine,saline lacustrine,and swamp depositional environments,and for oil-oil correlations.

Emission characteristics of dioxins,furans and polycyclic aromatic hydrocarbons during fluidized-bed combustion of sewage sludge

Pre-dried sewage sludge with high sulfur content was combusted in an electrically heated lab-scale fluidized-bed incinerator. The emission characteristics of polychlorinated dibenzo-p-dioxins （PCDDs）, polychlorinated dibenzofurans （PCDFs） and polycyclic aromatic hydrocarbons （PAHs） were studied. Coal and calcium oxide （CaO） were added during the sewage sludge combustion tests to optimize combustion conditions and control SO2 emission. The results indicated that the flue gases emitted during mono-combustion of sewage sludge were characterized by relatively high concentrations of SO2, NOx and organic pollutants, due to the high sulfur, nitrogen, and volatile matter content of sewage sludge. The total 16 USEPA priority PAHs and 2,3,7,8-substituted PCDD/Fs produced from sewage sludge combustion were found to be 106.14 μg/m^3 and 8955.93 pg/m^3 in the flue gas, respectively. In the case of cocombustion with coal （msludge/mcoal =1：1）, the 16 PAHs and 2,3,7,8-substituted PCDD/Fs concentrations were markedly lower than those found during mono-combustion of sewage sludge. During co-combustion, a suppressant effect of CaO on PCDD/Fs formation was observed.

Influences of Cu or Cd on the neurotoxicity induced by petroleum hydrocarbons in ragworm Perinereis aibuhitensis

The ecotoxicological effects of heavy metals and petroleum hydrocarbons （PHCs） on ragworms are still vague. The relationships between toxicological indices （mortality and acetylcholinesterase （ACHE） activity） and concentrations of toxicants （Cu, Cd, and PHCs） were examined in the estuary keystone species Perinereis aibuhitensis in laboratory conditions. The results of single toxicant indicated that three toxicants had potentially physiological toxicity to P. aibuhitensis. The estimated 4-d and 10-d LC50 for Cu, Cd, and PHCs was derived from the relationships between mortality and toxicants concentrations. Notable changes in the morphological signs and symptoms of P. aibuhitensis exposed to PHCs were observed. The ACHE activity of P. aibuhitensis was more sensitive to the toxicity of PHCs than the others. The results of combined toxicants implied that the combined toxicity of Cu or Cd and PHCs to P. aibuhitensis was related to the concentration combination of toxicants. Compared to single PHCs treatment, the addition of Cu or Cd significantly mitigated the neurotoxicity of PHCs to ACHE activity in P. aibuhitensis, which showed an antagonistic effect.

Separation of light hydrocarbons with ionic liquids: A review

Light hydrocarbons(C1–C4) are fundamental raw materials in the petroleum and chemical industry. Separation and purification of structurally similar paraffin/olefin/alkyne mixtures are important for the production of highpurity or even polymer-grade light hydrocarbons. However, traditional methods such as cryogenic distillation and solvent absorption are energy-intensive and environmentally unfriendly processes. Ionic liquids(ILs) as a new alternative to organic solvents have been proposed as promising green media for light hydrocarbon separation due to their unique tunable structures and physicochemical properties resulting from the variations of the cations and anions such as low volatility, high thermal stability, large liquidus range, good miscibility with light hydrocarbons, excellent molecular recognition ability and adjustable hydrophylicity/hydrophobicity. In this review, the recent progresses on the light hydrocarbon separation using ILs are summarized, and some parameters of ILs that influence the separation performance are discussed.

Distribution and deposition of polycyclic aromatic hydrocarbons in precipitation in Guangzhou, South China

Polycyclic aromatic hydrocarbons （PAHs） were measured in precipitation from March to August 2005 in Guangzhou, South China. Fourteen PAHs were studied, and their total concentrations varied from 616.6 to 3486.7 ng/L in dissolved phase and from 403.8 to 3125.5 ng/L in particulate phase. The estimated deposition loading of PAHs was 3568 ug/m^2 during the monitoring period. The deposition of PAHs was a potential source for Pearl River comparing with the contents of surface water. In addition, the high concentration in precipitation here implied that PAHs pollution was a potential environmental problem in Guangzhou. Most precipitation concentrations of PAHs in March （the last month in winter in Guangzhou） were higher than in the other months （in rainy season）. PAHs inclined to be adsorbed to particulate phase with the increase of molecular weight in rainwater. Combustion of fossil fuel and biomass might be the major source of PAHs, while the direct leakage or volatilization from petroleum products might be insignificant.