In recent years,herbicide sulfometuron-methyl(SM)has been used to kill the invasive plant Spartina alterniflora in some coastal areas of China,which may lead to the toxic effects on non-target marine organisms.The 96-...In recent years,herbicide sulfometuron-methyl(SM)has been used to kill the invasive plant Spartina alterniflora in some coastal areas of China,which may lead to the toxic effects on non-target marine organisms.The 96-h median effective concentrations(96-h EC50)of SM on six species of marine microalgae were measured in growth inhibition tests,and were then compared with other published toxicity data,based on which a method of species sensitivity distribution(SSD)was built to estimate the hazardous concentration of SM for 5%of species(HC5)and potentially affected fraction(PAF)for a certain concentration.Results indicate that SM exhibited a high toxicity to two species of green algae(Chlorella pacifica and Dunaliella salina)with a 96-h EC50 of 0.11 and 0.13 mg/L respectively,had a medium toxicity to two species of golden algae(Diacronema viridis and Isochrysis galbana)with a 96-h EC50 of 14.24 and 21.48 mg/L respectively,and showed a low toxicity to two species of diatoms(Skeletonema costatum and Phaeodactylum tricornutum)with a 96-h EC50 of 148.99 and>100 mg/L,respectively.The estimated values of HC5 and the predicted no-effect concentrations(PNEC)for SM were 0.077 and 0.015 mg/L,respectively.According to the current dosage for killing S.alterniflora in tidal flats in Fujian Province,China,SM entering the sea by spraying might cause the acute injury or death of 14%of marine species.This hazard could last for about a month for those sensitive species.Therefore,on the premise of inhibiting the growth of this invasive plant,the dosage of SM should be reduced as much as possible to avoid severe damage to the marine ecosystem.The results provide a valuable information for marine ecological risk assessment on SM and for marine environmental management.展开更多
Modeling Light propagation within human head to deduce spatial sensitivity distribution(SSD)is important for Near-infrared spectroscopy(NIRS)/imaging(NIRI)and diffuse correlation tomography.Lots of head models have be...Modeling Light propagation within human head to deduce spatial sensitivity distribution(SSD)is important for Near-infrared spectroscopy(NIRS)/imaging(NIRI)and diffuse correlation tomography.Lots of head models have been used on this issue,including layered head model,artificial simplified head model,MRI slices described head model,and visible human head model.Hereinto,visible Chinese human(VCH)head model is considered to be a most faithful presentation of anatomical structure,and has been highlighted to be employed in modeling light propagation.However,it is not practical for all researchers to use VCH head models and actually increasing number of people are using magnet resonance imaging(MRI)head models.Here,all the above head models were simulated and compared,and we focused on the effect of using di®erent head models on predictions of SSD.Our results were in line with the previous reports on the effect of cerebral cortex folding geometry.Moreover,the in fluence on SSD increases with thefidelity of head models.And surprisingly,the SSD percentages in scalp and gray matter(region of interest)in MRI head model were found to be 80%and 125%higher than in VCH head model.MRI head models induced nonignorable discrepancy in SSD estimation when compared with VCH head model.This study,as we believe,is the first to focus on comparison among full serials of head model on estimating SSD,and provided quantitative evidence for MRI head model users to calibrate their SSD estimation.展开更多
This study systematically assessed microplastics(MPs)pollution status and ecological risk in Yazhou Bay,South China Sea.The results revealed that the abundance of MPs in the surface water of Yazhou Bay was 3436.67...This study systematically assessed microplastics(MPs)pollution status and ecological risk in Yazhou Bay,South China Sea.The results revealed that the abundance of MPs in the surface water of Yazhou Bay was 3436.67±1581.37 n/m^(3),while the abundance estimated based on a power-law distribution reached as high as 2.41×10^(5)n/m^(3).Within biota,the abundance of MPs ranged from 0 to 0.40±0.52 n/Ind,predominantly consisting of transparent polyester fibers(12 mm),indicating a relatively low contamination level.Characterization of MPs showed significant differences in particle size,color,and type between those in water and biota,reflecting selectivity in biological ingestion.To evaluate the ecological risk of MPs,species sensitivity distribution(SsD)was constructed using antioxidant enzyme activities as toxicity endpoints,combined with risk quotient(RQ)and joint probability curve(JPC)methods.The results indicated that although RQ values exceeded 1 at some sampling sites,suggesting potential threats,the JPC analysis revealed that the overall ecological risk in Yazhou Bay waters was low,with insignificant oxidative stress impacts on local biota.The innovation of this study lies in being the first to construct an SSD model using a single oxidative stress indicator,integrating literature data with laboratory results.This approach provides more precise toxicity data for MPs ecological risk assessment and explores the potential application of key biomarkers in risk evaluation.This methodology offers a new perspective and reference for future research.Future studies should investigate the sources of fiber pollution,while policymakers could prioritize reducing polyesters in wastewater treatment to mitigate MPs pollution.展开更多
Species sensitivity analysis is one of the major techniques applied to derive water quality criteria. Presently, the toxicity data used for development of water quality criteria are mainly in the biological individual...Species sensitivity analysis is one of the major techniques applied to derive water quality criteria. Presently, the toxicity data used for development of water quality criteria are mainly in the biological individual level. With the increase of ecotoxicogenomics toxicity data, it is worth studying whether the gene expression effect data can be used to derive water quality criteria. Taking cadmium, copper and zinc as examples, we analyzed the toxic effects of the three heavy metals by constructing the species sensitivity distribution curves on the basis of extensive toxicity data. The results showed that the rank of species sensitivity for the acute, chronic and gene expression effect toxicity data of cadmium is "chronic>gene>acute". Although the gene expression effect data of copper and zinc are insufficient, the trend of data sensitivity of zinc is similar to cadmium. However, the trend of species sensitivity of copper is different from that of cadmium and zinc with higher sensitivity of gene expression data. It suggested that though the existing data of gene expression effects are not sufficient enough, they have the potential to be used in the development of chronic water quality criteria. For application in the derivation of water quality criteria, illogical test concentration design and insufficient target genes are two main weaknesses in the study of gene expression effects.展开更多
AIM:To construct Hsp90 antisense RNA eukaryotic expression vector, transfect it into SGC7901 and SGC7901/VCR of MDR-type human gastric cancer cell lines, HCC7402 of human hepatic cancer and Ec109 of human esophageal c...AIM:To construct Hsp90 antisense RNA eukaryotic expression vector, transfect it into SGC7901 and SGC7901/VCR of MDR-type human gastric cancer cell lines, HCC7402 of human hepatic cancer and Ec109 of human esophageal cancer cell lines, and to study the cell cycle distribution of the gene transected cells and their response to chemotherapeutic drugs.METHODS:A 1.03kb cDNA sequence of Hsp90beta was obtained from the primary plasmid phHSP90 by EcoR I and BamH I nuclease digestion and was cloned to the EcoR I and BamH I site of the pcDNA by T4DNA ligase and an antisense orientation of Hsp90beta expression vector was constructed. The constructs were transfected with lipofectamine and positive clones were selected with G418. The expression of RNA was determined with dot blotting and RNase protection assay, and the expression of Hsp90 protein determined with western blot. Cell cycle distribution of the transfectants was analyzed with flow cytometry, and the drug sensitivity of the transfectants to Adriamycin (ADR), vincrinstine (VCR), mitomycin (MMC) and cyclophosphamide (CTX) with MTT and intracellular drug concentration of the transfectants was determined with flow cytometry.RESULTS:In EcoR I and BamH I restriction analysis, the size and the direction of the cloned sequence of Hsp90beta remained what had been designed and the gene constructs were named pcDNA-Hsp90.AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones all expressed Hsp90 anti-sense RNA. The expression of Hsp90 was down-regulated in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones. Cell cycle distribution was changed differently. In AH-SGC7901/VCR and AH-Ec109 cells, G(1) phase cells were increased; S phase and G(2) phase cells were decreased as compared with their parental cell lines. In AH-SGC7901 cell, G(1)phase cells were decreased, G(2) phase cells increased and S phase cells were not changed, and in AH-HCC7402 cells G(1), S and G(2) phase cells remained unchanged as compared with their parental cell lines. The sensitivity of AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 to chemotherapeutic drugs, the sensitivity of AH-SGC7901/VCR to ADR, VCR, MMC and CTX the sensitivity of AH-HCC7402 to ADR and VCR, and the sensitivity of Ec109 to ADR, VCR and CTX all increased as compared with their parental cell lines. The mean fluorescence intensity of ADR in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 was also significantly elevated (P 【 0.05).CONCLUSION: Down-regulation of Hsp90 could change cell cycle distribution and increase the drug sensitivity of tumor cells.展开更多
Traditional Global Sensitivity Analysis（GSA） focuses on ranking inputs according to their contributions to the output uncertainty.However,information about how the specific regions inside an input affect the output ...Traditional Global Sensitivity Analysis（GSA） focuses on ranking inputs according to their contributions to the output uncertainty.However,information about how the specific regions inside an input affect the output is beyond the traditional GSA techniques.To fully address this issue,in this work,two regional moment-independent importance measures,Regional Importance Measure based on Probability Density Function（RIMPDF） and Regional Importance Measure based on Cumulative Distribution Function（RIMCDF）,are introduced to find out the contributions of specific regions of an input to the whole output distribution.The two regional importance measures prove to be reasonable supplements of the traditional GSA techniques.The ideas of RIMPDF and RIMCDF are applied in two engineering examples to demonstrate that the regional moment-independent importance analysis can add more information concerning the contributions of model inputs.展开更多
After large fresh food chain stores have opened online channels,distribution costs are a key factor affecting consumers'online buying behavior,which affects dual-channel pricing.This paper studies the dual-channel...After large fresh food chain stores have opened online channels,distribution costs are a key factor affecting consumers'online buying behavior,which affects dual-channel pricing.This paper studies the dual-channel pricing strategy of large fresh food chain stores on the premise of dividing the quotation,considering the consumer's acceptance of online channels and the sensitivity to distribution costs.The research found that the optimal pricing of online channels is lower than that of retail channels.The optimal pricing of online channels is positively correlated with the acceptance of online channels,and negatively correlated with the sensitivity of consumer distribution costs.Moreover,after retailers have opened online channels,the market scale has expanded compared with traditional retail channels.Finally,numerical experiments are used to analyze the influence of various influencing factors on retailers'decision-making.展开更多
Lakes are critical sinks for terrigenous microplastics(MPs),yet understanding their ecological risks remains hindered by data uncertainties and the absence of local background values.In this study,an enhanced pollutio...Lakes are critical sinks for terrigenous microplastics(MPs),yet understanding their ecological risks remains hindered by data uncertainties and the absence of local background values.In this study,an enhanced pollution load index(PLI)model integrating stochastic mathematical methods and species sensitivity distributions(SSD)was developed.The model was applied to assess and predict the ecological risk posed by MPs in the surface water and sediments of Dongting Lake,the second-largest freshwater lake in China.Results revealed average MP abundances of 4889(range:1667-9667)items/m^(3)in surface water and 7058(range:3935-10,736)items/kg in sediments within the Dongting Lake District.Small microplastics accounted for 90%of total MP particles,predominantly as polyethylene fragments.SSD-derived predicted no-effect concentrations values were determined as 8620 items/m^(3)for water and 7022 items/kg for sediments.While surface water exhibited low MP pollution risk and sediments were classified as unpolluted,both compartments showed signs of potential pollution escalation,suggesting non-negligible ecological risks.Through conditional fragmentation modeling,primary MP sources were identified as Yangtze River upstream inputs,atmospheric deposition,and soil erosion.In conclusion,the enhanced PLI model demonstrates effective ecological risk assessment and forecasting capabilities across environmental media,providing strategic insights for lake MP pollution mitigation.展开更多
Acetochlor is a widely used herbicide in agricultural production. Studies have shown that acetochlor has obvious environmental hormone effects, and long-term exposure may pose a threat to human health. To quantify the...Acetochlor is a widely used herbicide in agricultural production. Studies have shown that acetochlor has obvious environmental hormone effects, and long-term exposure may pose a threat to human health. To quantify the hazards of acetochlor in drinking water, a health risk assessment of acetochlor was conducted in major cities of China based on the data of acetochlor residue concentrations in drinking water. The approach of the Species Sensitivity Distributions(SSD) method is used to extrapolate from animal testing data to reflect worst case human toxicity. Results show that hazard quotients related to acetochlor residues in drinking water for different age groups range from 1.94 × 10-4 to 6.13 × 10-4, so, there are no indication of human risk. Compared to the total estimated hazard quotient from oral intake of acetochlor, the chronic exposure imputed to acetochlor residues in drinking water in China accounts for 0.4%. This paper recommends 0.02 mg/L to be the maximum acetochlor residue concentration level in drinking water and source water criteria.展开更多
With the rapid development of industrialization and urbanization of coastal regions,eutrophication and metal pollution have caused serious environmental problems in China.To better understand the potential environment...With the rapid development of industrialization and urbanization of coastal regions,eutrophication and metal pollution have caused serious environmental problems in China.To better understand the potential environmental risks associated with nutrients and heavy metals,the surface water was comprehensively investigated in the coastal Bohai Sea.A total of 150 sites were sampled from seven coastal regions,and the concentrations of nutrients(DIN and DIP)and metals(Cd,Pb,Zn,Cu,Cr,As and Hg)in the surface seawater were measured.The results showed that the DIN concentration of about 50%sites exceeded the Grade-I of Seawater Quality Standard of China.Due to high concentrations of DIN,the status of eutrophication was serious in the Bohai Bay and Shuangtaizi Estuary.According to Seawater Quality Standard of China,Pb,Zn,Hg and Cu were the main metal pollutants in the coastal Bohai Sea.There was generally low ecological risk caused by heavy metals,but certain hotspots existed near Shuangtaizi Estuary and Changxingdao Island.展开更多
Determining the appropriate soil cadmium(Cd)criteria for vegetable production is important for ensuring that the Cd concentrations of the vegetables meet food safety standards.The soil extractable Cd criteria for vege...Determining the appropriate soil cadmium(Cd)criteria for vegetable production is important for ensuring that the Cd concentrations of the vegetables meet food safety standards.The soil extractable Cd criteria for vegetable production are also essential for both food safety and environmental management,especially in areas with a high natural background level.In the present study,soil total and extractable Cd criteria were derived using the approach of species sensitivity distribution integrated with soil aging and bioavailability as affected by soil properties.A dataset of 90 vegetable species planted in different soils was compiled by screening the published in literature in five bibliographic databases using designated search strings.The empirical soil-plant transfer model was applied to normalize the bioaccumulation data.After normalization,the intra-species variability was reduced by 18.3 to 84.4%.The soil Cd concentration that would protect 95%(HC_(5))of the species was estimated by species sensitivity distribution curves that were fitted by the Burr III function.The soil Cd criteria derived from the added approach for risk assessment were proposed as continuous criteria based on a combination of organic carbon and pH in the soil.Criteria for total Cd and EDTA-extractable Cd in the soil ranged from 0.23 to 0.61 mg kg^(-1)and from 0.09 to 0.25 mg kg^(-1),respectively.Field experimental data were used to validate the applicability and validity of these criteria.Most of the predicted HC5 values in the field experimental sites were below the 1:1 line.These results provide a scientific basis for soil Cd criteria for vegetable production that will ensure food safety.展开更多
We describe a new two phase flow electrical capacitance tomography algorithm of image reconstruction which is based on 12 electrode capacitance transducers. According to the result of computer simulation, this algor...We describe a new two phase flow electrical capacitance tomography algorithm of image reconstruction which is based on 12 electrode capacitance transducers. According to the result of computer simulation, this algorithm is able to greatly increase the imaging fidelity without decreasing the imaging velocity.展开更多
The thermal behavior,non-isothermal thermal decomposition reaction kinetics and specific heat capacity of hexanitro-hexaazaisowurtzitane(HNIW)were studied by differential scanning calorimeter(DSC)and Micro-DSCIapparat...The thermal behavior,non-isothermal thermal decomposition reaction kinetics and specific heat capacity of hexanitro-hexaazaisowurtzitane(HNIW)were studied by differential scanning calorimeter(DSC)and Micro-DSCIapparatus,The kinetic parameters of the thermal decomposition reaction(the apparent activation energy(E,)and pre-exponential factor(A))were calcu-lated by non-isothermal DSC curves.The results show that the differential mlechanism function and values of E,and A of the ther-mal decomposition reaction of HNIW are 3(1-a)[-ln(1-a)]"·,155.04 kJ·mol^(-1)and 10""s^(-1),respectively.The critical tem-perature of thermal explosion of the title compound is 226.60℃.The entropy of activation(AS·),enthalpy of activation(AH·)and free energy of activation(AG·)of this reaction are 11.60J·mol·K^(-1),152.04 kJ·mol^(-1)and 146.29 kJ·mol^(-1),respec-tively.The equation of specific heat capacity of HNIW with temperature is C,=0.2472+0.002705992Tin the temperature range of 283 K to 343K.The values of self-accelerating decomposition temperature,adiabatic time-to-maximum decomposition rate and adiabatic time-to-explosion are 486.5K,54.81s and 54.31s,respectively.Thermal sensitivity probability density distribution curve of HNIW is constructed.展开更多
An inversion of bidirectional reflection distribution fiJnedon (BRDF) wastested using NK Model and NOAA AVHRR datu. The test involVed sensitiveanalysis, optimum inversion selecting, ground simulated expenment, calibra...An inversion of bidirectional reflection distribution fiJnedon (BRDF) wastested using NK Model and NOAA AVHRR datu. The test involVed sensitiveanalysis, optimum inversion selecting, ground simulated expenment, calibrahngmeasuremed with satellite and computer image processmg. Results of comparisonwith NDVI indicatal that inversion of BRDF will have brigh developing prospect inthe next decade.展开更多
In this work we consider a general notion of distributional sensitivity,which measures the variation in solutions of a given physical/mathematical system with respect to the variation of probability distribution of th...In this work we consider a general notion of distributional sensitivity,which measures the variation in solutions of a given physical/mathematical system with respect to the variation of probability distribution of the inputs.This is distinctively different from the classical sensitivity analysis,which studies the changes of solutions with respect to the values of the inputs.The general idea is measurement of sensitivity of outputs with respect to probability distributions,which is a well-studied concept in related disciplines.We adapt these ideas to present a quantitative framework in the context of uncertainty quantification for measuring such a kind of sensitivity and a set of efficient algorithms to approximate the distributional sensitivity numerically.A remarkable feature of the algorithms is that they do not incur additional computational effort in addition to a one-time stochastic solver.Therefore,an accurate stochastic computation with respect to a prior input distribution is needed only once,and the ensuing distributional sensitivity computation for different input distributions is a post-processing step.We prove that an accurate numerical model leads to accurate calculations of this sensitivity,which applies not just to slowly-converging Monte-Carlo estimates,but also to exponentially convergent spectral approximations.We provide computational examples to demonstrate the ease of applicability and verify the convergence claims.展开更多
In this study, toxicological data for zinc （Zn）, cadmium （Cd）, hexavalent chromium （Cr （VI））, benzene, and nitrobenzene were collected from various databases and publications, screened and then constructed int...In this study, toxicological data for zinc （Zn）, cadmium （Cd）, hexavalent chromium （Cr （VI））, benzene, and nitrobenzene were collected from various databases and publications, screened and then constructed into species sensitivity distribution （SSD） curves. Then water quality criteria （WQC） were derived for protection of the freshwater aquatic life in China against five representative pollutants. The values derived in this study were compared with those issued by the US Environmental Protection Agency and the Chinese national environmental standard for surface water to identify factors underlying the differences. The results showed that the SSD curves for the five pollutants differed significantly, with the examined aquatic species being gen- erally more sensitive to Zn, Cd, and Cr （VI） than benzene and nitrobenzene. The acute WQC were： 48.43 μg L-1 for Zn, 0.4218 μg L-1 for Cd, 45.79μg L-1 for Cr （VI）, 2651 μg L-1 for benzene, and 1426 μg L-1 for nitrobenzene. The chronic WQC were： 20.01μg L-1 for Zn, 0.2428 μg L-j for Cd, 14.22 μg L-1 for Cr （VI）, 530.2 μg L J for benzene, and 286.2 μg L-1 for nitroben- zene. The results of this comparative study of representative pollutants may offer guideline values for future WQC studies for China.展开更多
Neonicotinoid insecticides(NNIs)have been intensively used and exploited,resulting in their presence and accumulation in multiple environmental media.We herein investigated the current levels of eight major NNIs in th...Neonicotinoid insecticides(NNIs)have been intensively used and exploited,resulting in their presence and accumulation in multiple environmental media.We herein investigated the current levels of eight major NNIs in the Harbin section of the Songhua River in northeast China,providing the first systematic report on NNIs in this region.At least four NNIs in water and three in sediment were detected,with total concentrations ranging from 30.8 to 135 ng L^(-1) and from 0.61 to 14.7 ng g^(-1) dw,respectively.Larger spatial variations in surface water NNIs concentrations were observed in tributary than mainstream(p<0.05)due to the intensive human activities(e.g.,horticulture,urban landscaping,and household pet flea control)and the discharge of wastewater from many treatment plants.There was a significant positive correlation(p<0.05)between the concentrations of residual imidacloprid(IMI),clothianidin(CLO),and S4NNIs in the sediment and total organic carbon(TOC).Due to its high solubility and low octanol-water partition coefficient(Kow),the sediment-water exchange behavior shows that NNIs in sediments can re-enter into the water body.Human exposure risk was assessed using the relative potency factor(RPF),which showed that infants have the highest exposure risk(estimated daily intake(SIMIeq EDI):31.9 ng kg^(-1) bw$d^(-1)).The concentration thresholds of NNIs for aquatic organisms in the Harbin section of the Songhua River were determined using the species sensitivity distribution(SSD)approach,resulting in a value of 355 ng L^(-1) for acute hazardous concentration for 5%of species(HC5)and 165 ng L^(-1) for chronic HC5.Aquatic organisms at low trophic levels were more vulnerable to potential harm from NNIs.展开更多
We collated and synthesized previous studies that reported the impacts of microplastics on soil parameters.The data were classified and integrated to screen for the proportion of significant effects,then we suggest se...We collated and synthesized previous studies that reported the impacts of microplastics on soil parameters.The data were classified and integrated to screen for the proportion of significant effects,then we suggest several directions to alleviate the current data limitation in future experiments.We compiled 106 datasets capturing significant effects,which were analyzed in detail.We found that polyethylene and pellets(or powders)were the most frequently used microplastic composition and shape for soil experiments.The significant effects mainly occurred in broad size ranges(0.1–1 mm)at test concentrations of 0.1%–10%based on soil dry weight.Polyvinyl chloride and film induced significant effects at lower concentrations compared to other compositions and shapes,respectively.We adopted a species sensitivity distribution(SSD)and soil property effect distribution(SPED)method using available data from soil biota,and for soil properties and enzymes deemed relevant for microplastic management.The predicted-no-effect-concentration(PNEC)-like values needed to protect 95%of soil biota and soil properties was estimated to be between 520 and 655 mg kg^(-1).This study was the first to screen microplastic levels with a view toward protecting the soil system.Our results should be regularly updated(e.g.,quarterly)with additional data as they become available.展开更多
The establishment of ecological risk thresholds for arsenic(As)plays a pivotal role in developing soil conservation strategies.However,despite many studies regarding the toxicological profile of As,such thresholds var...The establishment of ecological risk thresholds for arsenic(As)plays a pivotal role in developing soil conservation strategies.However,despite many studies regarding the toxicological profile of As,such thresholds varying by diverse soil properties have rarely been established.This study aims to address this gap by compiling and critically examining an extensive dataset of As toxicity data sourced from existing literature.Furthermore,to augment the existing information,experimental studies on As toxicity focusing on barley-root elongation were carried out across various soil types.The As concentrations varied from 12.01 to 437.25 mg/kg for the effective concentrations that inhibited 10%of barley-root growth(EC10).The present study applied a machine-learning approach to investigate the complex associations between the toxicity thresholds of As and diverse soil properties.The results revealed that Mn-/Fe-ox and clay content emerged as the most influential factors in predicting the EC10 contribution.Additionally,by using a species sensitivity distribution model and toxicity data from 21 different species,the hazardous concentration for x%of species(HCx)was calculated for four representative soil scenarios.The HC5 values for acidic,neutral,alkaline,and alkaline calcareous soils were 80,47,40,and 28 mg/kg,respectively.This study establishes an evidence-based methodology for deriving soil-specific guidance concerning As toxicity thresholds.展开更多
A study was conducted on the effect of atmospheric parameters, including temperature, wind speed, and relative humidity, on fine particulate mass concentrations measured in Jiading District of Shanghai, China, during ...A study was conducted on the effect of atmospheric parameters, including temperature, wind speed, and relative humidity, on fine particulate mass concentrations measured in Jiading District of Shanghai, China, during the period from January 2009 to January 2010. A sensitivity analysis was applied to investigate the interaction between atmospheric parameters and particulate mass concentration. The experiment revealed that the concentration of particulates increased with particle size from 0.1 to 1.0 μm, and decreased with the increase of particle size from 1.0 to 2.5 μm. The effects of atmospheric parameters on fine mass concentrations were significantly particle size-dependent. The PM1.0-2.5 may come from the size increase of smaller particulates after moisture absorption, And the variation of concentrations of PM0.1-l.0 was mainly attributed to the accumulation of PM0.1. The ventilation index and dilution index were calcu- lated on the basis of data collected in December 2009. A correlation analysis indicated that there was a significant relation between these two indexes and the particulate concentration by examining the three particle size ranges, 0.0-0.1, 0.1-1.0, and 1,0-2.5 μm. The Spearman correlation coefficients that related the ventilation index to the concentration for the three particle size ranges were -0.45, -0.56 and -0.47, respectively, while the coefficients that related the dilution index to the concentration were -0.36, -0.42 and -0.45, respectively.展开更多
基金Supported by the National Natural Science Foundation of China(No.42077335)。
文摘In recent years,herbicide sulfometuron-methyl(SM)has been used to kill the invasive plant Spartina alterniflora in some coastal areas of China,which may lead to the toxic effects on non-target marine organisms.The 96-h median effective concentrations(96-h EC50)of SM on six species of marine microalgae were measured in growth inhibition tests,and were then compared with other published toxicity data,based on which a method of species sensitivity distribution(SSD)was built to estimate the hazardous concentration of SM for 5%of species(HC5)and potentially affected fraction(PAF)for a certain concentration.Results indicate that SM exhibited a high toxicity to two species of green algae(Chlorella pacifica and Dunaliella salina)with a 96-h EC50 of 0.11 and 0.13 mg/L respectively,had a medium toxicity to two species of golden algae(Diacronema viridis and Isochrysis galbana)with a 96-h EC50 of 14.24 and 21.48 mg/L respectively,and showed a low toxicity to two species of diatoms(Skeletonema costatum and Phaeodactylum tricornutum)with a 96-h EC50 of 148.99 and>100 mg/L,respectively.The estimated values of HC5 and the predicted no-effect concentrations(PNEC)for SM were 0.077 and 0.015 mg/L,respectively.According to the current dosage for killing S.alterniflora in tidal flats in Fujian Province,China,SM entering the sea by spraying might cause the acute injury or death of 14%of marine species.This hazard could last for about a month for those sensitive species.Therefore,on the premise of inhibiting the growth of this invasive plant,the dosage of SM should be reduced as much as possible to avoid severe damage to the marine ecosystem.The results provide a valuable information for marine ecological risk assessment on SM and for marine environmental management.
基金The authors thank Qingming Luo's group for providing VCH dataset.This research was supported by the Fundamental Research Funds for the Central Universities (grant No.ZYGX2012J114)the National Natural Science Foundation of China (grant No.61308114)the Specialized Research Fund for the Doctoral Program of Higher Education (grant No.20130185120024).
文摘Modeling Light propagation within human head to deduce spatial sensitivity distribution(SSD)is important for Near-infrared spectroscopy(NIRS)/imaging(NIRI)and diffuse correlation tomography.Lots of head models have been used on this issue,including layered head model,artificial simplified head model,MRI slices described head model,and visible human head model.Hereinto,visible Chinese human(VCH)head model is considered to be a most faithful presentation of anatomical structure,and has been highlighted to be employed in modeling light propagation.However,it is not practical for all researchers to use VCH head models and actually increasing number of people are using magnet resonance imaging(MRI)head models.Here,all the above head models were simulated and compared,and we focused on the effect of using di®erent head models on predictions of SSD.Our results were in line with the previous reports on the effect of cerebral cortex folding geometry.Moreover,the in fluence on SSD increases with thefidelity of head models.And surprisingly,the SSD percentages in scalp and gray matter(region of interest)in MRI head model were found to be 80%and 125%higher than in VCH head model.MRI head models induced nonignorable discrepancy in SSD estimation when compared with VCH head model.This study,as we believe,is the first to focus on comparison among full serials of head model on estimating SSD,and provided quantitative evidence for MRI head model users to calibrate their SSD estimation.
基金supported by the Natural Science Foundation of Hainan Province(No.422QN443)the National Natural Science Foundation of China(No.42206149)the Basic and Applied Basic Research Project of Guangzhou Municipal Science and Technology Bureau(No.2023A04J0194).
文摘This study systematically assessed microplastics(MPs)pollution status and ecological risk in Yazhou Bay,South China Sea.The results revealed that the abundance of MPs in the surface water of Yazhou Bay was 3436.67±1581.37 n/m^(3),while the abundance estimated based on a power-law distribution reached as high as 2.41×10^(5)n/m^(3).Within biota,the abundance of MPs ranged from 0 to 0.40±0.52 n/Ind,predominantly consisting of transparent polyester fibers(12 mm),indicating a relatively low contamination level.Characterization of MPs showed significant differences in particle size,color,and type between those in water and biota,reflecting selectivity in biological ingestion.To evaluate the ecological risk of MPs,species sensitivity distribution(SsD)was constructed using antioxidant enzyme activities as toxicity endpoints,combined with risk quotient(RQ)and joint probability curve(JPC)methods.The results indicated that although RQ values exceeded 1 at some sampling sites,suggesting potential threats,the JPC analysis revealed that the overall ecological risk in Yazhou Bay waters was low,with insignificant oxidative stress impacts on local biota.The innovation of this study lies in being the first to construct an SSD model using a single oxidative stress indicator,integrating literature data with laboratory results.This approach provides more precise toxicity data for MPs ecological risk assessment and explores the potential application of key biomarkers in risk evaluation.This methodology offers a new perspective and reference for future research.Future studies should investigate the sources of fiber pollution,while policymakers could prioritize reducing polyesters in wastewater treatment to mitigate MPs pollution.
基金supported by the Great Program of National Water Body Pollution Control and Treatment (Grant No. 2012ZX07501-003-006)Special Project of Revolution Startup of CRAES (Grant No. 2011GQ-02)
文摘Species sensitivity analysis is one of the major techniques applied to derive water quality criteria. Presently, the toxicity data used for development of water quality criteria are mainly in the biological individual level. With the increase of ecotoxicogenomics toxicity data, it is worth studying whether the gene expression effect data can be used to derive water quality criteria. Taking cadmium, copper and zinc as examples, we analyzed the toxic effects of the three heavy metals by constructing the species sensitivity distribution curves on the basis of extensive toxicity data. The results showed that the rank of species sensitivity for the acute, chronic and gene expression effect toxicity data of cadmium is "chronic>gene>acute". Although the gene expression effect data of copper and zinc are insufficient, the trend of data sensitivity of zinc is similar to cadmium. However, the trend of species sensitivity of copper is different from that of cadmium and zinc with higher sensitivity of gene expression data. It suggested that though the existing data of gene expression effects are not sufficient enough, they have the potential to be used in the development of chronic water quality criteria. For application in the derivation of water quality criteria, illogical test concentration design and insufficient target genes are two main weaknesses in the study of gene expression effects.
基金Project supported by the National Natural Science Foundation of China,No.39570806National Excel1ent Youth Scientific Foundation,No.3952020.
文摘AIM:To construct Hsp90 antisense RNA eukaryotic expression vector, transfect it into SGC7901 and SGC7901/VCR of MDR-type human gastric cancer cell lines, HCC7402 of human hepatic cancer and Ec109 of human esophageal cancer cell lines, and to study the cell cycle distribution of the gene transected cells and their response to chemotherapeutic drugs.METHODS:A 1.03kb cDNA sequence of Hsp90beta was obtained from the primary plasmid phHSP90 by EcoR I and BamH I nuclease digestion and was cloned to the EcoR I and BamH I site of the pcDNA by T4DNA ligase and an antisense orientation of Hsp90beta expression vector was constructed. The constructs were transfected with lipofectamine and positive clones were selected with G418. The expression of RNA was determined with dot blotting and RNase protection assay, and the expression of Hsp90 protein determined with western blot. Cell cycle distribution of the transfectants was analyzed with flow cytometry, and the drug sensitivity of the transfectants to Adriamycin (ADR), vincrinstine (VCR), mitomycin (MMC) and cyclophosphamide (CTX) with MTT and intracellular drug concentration of the transfectants was determined with flow cytometry.RESULTS:In EcoR I and BamH I restriction analysis, the size and the direction of the cloned sequence of Hsp90beta remained what had been designed and the gene constructs were named pcDNA-Hsp90.AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones all expressed Hsp90 anti-sense RNA. The expression of Hsp90 was down-regulated in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones. Cell cycle distribution was changed differently. In AH-SGC7901/VCR and AH-Ec109 cells, G(1) phase cells were increased; S phase and G(2) phase cells were decreased as compared with their parental cell lines. In AH-SGC7901 cell, G(1)phase cells were decreased, G(2) phase cells increased and S phase cells were not changed, and in AH-HCC7402 cells G(1), S and G(2) phase cells remained unchanged as compared with their parental cell lines. The sensitivity of AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 to chemotherapeutic drugs, the sensitivity of AH-SGC7901/VCR to ADR, VCR, MMC and CTX the sensitivity of AH-HCC7402 to ADR and VCR, and the sensitivity of Ec109 to ADR, VCR and CTX all increased as compared with their parental cell lines. The mean fluorescence intensity of ADR in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 was also significantly elevated (P 【 0.05).CONCLUSION: Down-regulation of Hsp90 could change cell cycle distribution and increase the drug sensitivity of tumor cells.
基金supported by the National Natural Science Foundation of China(No.NSFC51608446)the Fundamental Research Fund for Central Universities of China(No.3102016ZY015)
文摘Traditional Global Sensitivity Analysis（GSA） focuses on ranking inputs according to their contributions to the output uncertainty.However,information about how the specific regions inside an input affect the output is beyond the traditional GSA techniques.To fully address this issue,in this work,two regional moment-independent importance measures,Regional Importance Measure based on Probability Density Function（RIMPDF） and Regional Importance Measure based on Cumulative Distribution Function（RIMCDF）,are introduced to find out the contributions of specific regions of an input to the whole output distribution.The two regional importance measures prove to be reasonable supplements of the traditional GSA techniques.The ideas of RIMPDF and RIMCDF are applied in two engineering examples to demonstrate that the regional moment-independent importance analysis can add more information concerning the contributions of model inputs.
文摘After large fresh food chain stores have opened online channels,distribution costs are a key factor affecting consumers'online buying behavior,which affects dual-channel pricing.This paper studies the dual-channel pricing strategy of large fresh food chain stores on the premise of dividing the quotation,considering the consumer's acceptance of online channels and the sensitivity to distribution costs.The research found that the optimal pricing of online channels is lower than that of retail channels.The optimal pricing of online channels is positively correlated with the acceptance of online channels,and negatively correlated with the sensitivity of consumer distribution costs.Moreover,after retailers have opened online channels,the market scale has expanded compared with traditional retail channels.Finally,numerical experiments are used to analyze the influence of various influencing factors on retailers'decision-making.
基金National Natural Science Foundation of China,Grant/Award Number:42277262China Institute of Water Resources and Hydropower Research,Grant/Award Number:WE0199A042021。
文摘Lakes are critical sinks for terrigenous microplastics(MPs),yet understanding their ecological risks remains hindered by data uncertainties and the absence of local background values.In this study,an enhanced pollution load index(PLI)model integrating stochastic mathematical methods and species sensitivity distributions(SSD)was developed.The model was applied to assess and predict the ecological risk posed by MPs in the surface water and sediments of Dongting Lake,the second-largest freshwater lake in China.Results revealed average MP abundances of 4889(range:1667-9667)items/m^(3)in surface water and 7058(range:3935-10,736)items/kg in sediments within the Dongting Lake District.Small microplastics accounted for 90%of total MP particles,predominantly as polyethylene fragments.SSD-derived predicted no-effect concentrations values were determined as 8620 items/m^(3)for water and 7022 items/kg for sediments.While surface water exhibited low MP pollution risk and sediments were classified as unpolluted,both compartments showed signs of potential pollution escalation,suggesting non-negligible ecological risks.Through conditional fragmentation modeling,primary MP sources were identified as Yangtze River upstream inputs,atmospheric deposition,and soil erosion.In conclusion,the enhanced PLI model demonstrates effective ecological risk assessment and forecasting capabilities across environmental media,providing strategic insights for lake MP pollution mitigation.
基金supported by the Foundation of Major Science and Technology Program for Water Pollution Control and Treatment (No. 2018ZX07502001)the National Natural Science Foundation of China (Nos. 21976205, 21477158 and 11771241)。
文摘Acetochlor is a widely used herbicide in agricultural production. Studies have shown that acetochlor has obvious environmental hormone effects, and long-term exposure may pose a threat to human health. To quantify the hazards of acetochlor in drinking water, a health risk assessment of acetochlor was conducted in major cities of China based on the data of acetochlor residue concentrations in drinking water. The approach of the Species Sensitivity Distributions(SSD) method is used to extrapolate from animal testing data to reflect worst case human toxicity. Results show that hazard quotients related to acetochlor residues in drinking water for different age groups range from 1.94 × 10-4 to 6.13 × 10-4, so, there are no indication of human risk. Compared to the total estimated hazard quotient from oral intake of acetochlor, the chronic exposure imputed to acetochlor residues in drinking water in China accounts for 0.4%. This paper recommends 0.02 mg/L to be the maximum acetochlor residue concentration level in drinking water and source water criteria.
基金grant from the National Natural Science Foundation of China(No.31572595).
文摘With the rapid development of industrialization and urbanization of coastal regions,eutrophication and metal pollution have caused serious environmental problems in China.To better understand the potential environmental risks associated with nutrients and heavy metals,the surface water was comprehensively investigated in the coastal Bohai Sea.A total of 150 sites were sampled from seven coastal regions,and the concentrations of nutrients(DIN and DIP)and metals(Cd,Pb,Zn,Cu,Cr,As and Hg)in the surface seawater were measured.The results showed that the DIN concentration of about 50%sites exceeded the Grade-I of Seawater Quality Standard of China.Due to high concentrations of DIN,the status of eutrophication was serious in the Bohai Bay and Shuangtaizi Estuary.According to Seawater Quality Standard of China,Pb,Zn,Hg and Cu were the main metal pollutants in the coastal Bohai Sea.There was generally low ecological risk caused by heavy metals,but certain hotspots existed near Shuangtaizi Estuary and Changxingdao Island.
基金This study was funded by the Science and Technology Development Fund,Macao SAR,China(File 0159/2019/A3)the National Key Research and Development Program of China(2016YFD0800406).
文摘Determining the appropriate soil cadmium(Cd)criteria for vegetable production is important for ensuring that the Cd concentrations of the vegetables meet food safety standards.The soil extractable Cd criteria for vegetable production are also essential for both food safety and environmental management,especially in areas with a high natural background level.In the present study,soil total and extractable Cd criteria were derived using the approach of species sensitivity distribution integrated with soil aging and bioavailability as affected by soil properties.A dataset of 90 vegetable species planted in different soils was compiled by screening the published in literature in five bibliographic databases using designated search strings.The empirical soil-plant transfer model was applied to normalize the bioaccumulation data.After normalization,the intra-species variability was reduced by 18.3 to 84.4%.The soil Cd concentration that would protect 95%(HC_(5))of the species was estimated by species sensitivity distribution curves that were fitted by the Burr III function.The soil Cd criteria derived from the added approach for risk assessment were proposed as continuous criteria based on a combination of organic carbon and pH in the soil.Criteria for total Cd and EDTA-extractable Cd in the soil ranged from 0.23 to 0.61 mg kg^(-1)and from 0.09 to 0.25 mg kg^(-1),respectively.Field experimental data were used to validate the applicability and validity of these criteria.Most of the predicted HC5 values in the field experimental sites were below the 1:1 line.These results provide a scientific basis for soil Cd criteria for vegetable production that will ensure food safety.
文摘We describe a new two phase flow electrical capacitance tomography algorithm of image reconstruction which is based on 12 electrode capacitance transducers. According to the result of computer simulation, this algorithm is able to greatly increase the imaging fidelity without decreasing the imaging velocity.
基金The National Nature Science Foundation of China(21173163)
文摘The thermal behavior,non-isothermal thermal decomposition reaction kinetics and specific heat capacity of hexanitro-hexaazaisowurtzitane(HNIW)were studied by differential scanning calorimeter(DSC)and Micro-DSCIapparatus,The kinetic parameters of the thermal decomposition reaction(the apparent activation energy(E,)and pre-exponential factor(A))were calcu-lated by non-isothermal DSC curves.The results show that the differential mlechanism function and values of E,and A of the ther-mal decomposition reaction of HNIW are 3(1-a)[-ln(1-a)]"·,155.04 kJ·mol^(-1)and 10""s^(-1),respectively.The critical tem-perature of thermal explosion of the title compound is 226.60℃.The entropy of activation(AS·),enthalpy of activation(AH·)and free energy of activation(AG·)of this reaction are 11.60J·mol·K^(-1),152.04 kJ·mol^(-1)and 146.29 kJ·mol^(-1),respec-tively.The equation of specific heat capacity of HNIW with temperature is C,=0.2472+0.002705992Tin the temperature range of 283 K to 343K.The values of self-accelerating decomposition temperature,adiabatic time-to-maximum decomposition rate and adiabatic time-to-explosion are 486.5K,54.81s and 54.31s,respectively.Thermal sensitivity probability density distribution curve of HNIW is constructed.
文摘An inversion of bidirectional reflection distribution fiJnedon (BRDF) wastested using NK Model and NOAA AVHRR datu. The test involVed sensitiveanalysis, optimum inversion selecting, ground simulated expenment, calibrahngmeasuremed with satellite and computer image processmg. Results of comparisonwith NDVI indicatal that inversion of BRDF will have brigh developing prospect inthe next decade.
基金supported by NSF awards DMS-0645035 and IIS-0914447AFOSR award FA9550-08-1-0353DOE award DE-FC52-08NA28617.
文摘In this work we consider a general notion of distributional sensitivity,which measures the variation in solutions of a given physical/mathematical system with respect to the variation of probability distribution of the inputs.This is distinctively different from the classical sensitivity analysis,which studies the changes of solutions with respect to the values of the inputs.The general idea is measurement of sensitivity of outputs with respect to probability distributions,which is a well-studied concept in related disciplines.We adapt these ideas to present a quantitative framework in the context of uncertainty quantification for measuring such a kind of sensitivity and a set of efficient algorithms to approximate the distributional sensitivity numerically.A remarkable feature of the algorithms is that they do not incur additional computational effort in addition to a one-time stochastic solver.Therefore,an accurate stochastic computation with respect to a prior input distribution is needed only once,and the ensuing distributional sensitivity computation for different input distributions is a post-processing step.We prove that an accurate numerical model leads to accurate calculations of this sensitivity,which applies not just to slowly-converging Monte-Carlo estimates,but also to exponentially convergent spectral approximations.We provide computational examples to demonstrate the ease of applicability and verify the convergence claims.
基金supported by National Basic Research Program of China(Grant No. 2008CB418200)Environmental Public Welfare Program(Grant No. 2010009032)National Natural Science Foundation of China (Grant Nos. U0833603, 40973090)
文摘In this study, toxicological data for zinc （Zn）, cadmium （Cd）, hexavalent chromium （Cr （VI））, benzene, and nitrobenzene were collected from various databases and publications, screened and then constructed into species sensitivity distribution （SSD） curves. Then water quality criteria （WQC） were derived for protection of the freshwater aquatic life in China against five representative pollutants. The values derived in this study were compared with those issued by the US Environmental Protection Agency and the Chinese national environmental standard for surface water to identify factors underlying the differences. The results showed that the SSD curves for the five pollutants differed significantly, with the examined aquatic species being gen- erally more sensitive to Zn, Cd, and Cr （VI） than benzene and nitrobenzene. The acute WQC were： 48.43 μg L-1 for Zn, 0.4218 μg L-1 for Cd, 45.79μg L-1 for Cr （VI）, 2651 μg L-1 for benzene, and 1426 μg L-1 for nitrobenzene. The chronic WQC were： 20.01μg L-1 for Zn, 0.2428 μg L-j for Cd, 14.22 μg L-1 for Cr （VI）, 530.2 μg L J for benzene, and 286.2 μg L-1 for nitroben- zene. The results of this comparative study of representative pollutants may offer guideline values for future WQC studies for China.
基金This work was supported by the National Natural Science Foundation of China(No.51779047)the Excellent Youth Science Foundation of Heilongjiang Province(YQ2019E001).
文摘Neonicotinoid insecticides(NNIs)have been intensively used and exploited,resulting in their presence and accumulation in multiple environmental media.We herein investigated the current levels of eight major NNIs in the Harbin section of the Songhua River in northeast China,providing the first systematic report on NNIs in this region.At least four NNIs in water and three in sediment were detected,with total concentrations ranging from 30.8 to 135 ng L^(-1) and from 0.61 to 14.7 ng g^(-1) dw,respectively.Larger spatial variations in surface water NNIs concentrations were observed in tributary than mainstream(p<0.05)due to the intensive human activities(e.g.,horticulture,urban landscaping,and household pet flea control)and the discharge of wastewater from many treatment plants.There was a significant positive correlation(p<0.05)between the concentrations of residual imidacloprid(IMI),clothianidin(CLO),and S4NNIs in the sediment and total organic carbon(TOC).Due to its high solubility and low octanol-water partition coefficient(Kow),the sediment-water exchange behavior shows that NNIs in sediments can re-enter into the water body.Human exposure risk was assessed using the relative potency factor(RPF),which showed that infants have the highest exposure risk(estimated daily intake(SIMIeq EDI):31.9 ng kg^(-1) bw$d^(-1)).The concentration thresholds of NNIs for aquatic organisms in the Harbin section of the Songhua River were determined using the species sensitivity distribution(SSD)approach,resulting in a value of 355 ng L^(-1) for acute hazardous concentration for 5%of species(HC5)and 165 ng L^(-1) for chronic HC5.Aquatic organisms at low trophic levels were more vulnerable to potential harm from NNIs.
文摘We collated and synthesized previous studies that reported the impacts of microplastics on soil parameters.The data were classified and integrated to screen for the proportion of significant effects,then we suggest several directions to alleviate the current data limitation in future experiments.We compiled 106 datasets capturing significant effects,which were analyzed in detail.We found that polyethylene and pellets(or powders)were the most frequently used microplastic composition and shape for soil experiments.The significant effects mainly occurred in broad size ranges(0.1–1 mm)at test concentrations of 0.1%–10%based on soil dry weight.Polyvinyl chloride and film induced significant effects at lower concentrations compared to other compositions and shapes,respectively.We adopted a species sensitivity distribution(SSD)and soil property effect distribution(SPED)method using available data from soil biota,and for soil properties and enzymes deemed relevant for microplastic management.The predicted-no-effect-concentration(PNEC)-like values needed to protect 95%of soil biota and soil properties was estimated to be between 520 and 655 mg kg^(-1).This study was the first to screen microplastic levels with a view toward protecting the soil system.Our results should be regularly updated(e.g.,quarterly)with additional data as they become available.
基金supported by the National Key R&D Programof China(2021YFC1809102)the National Natural Science Foundation of China(42225701,42107041,41977027)the Natural Science Foundation of Jiangsu Province,China(BK20210997).
文摘The establishment of ecological risk thresholds for arsenic(As)plays a pivotal role in developing soil conservation strategies.However,despite many studies regarding the toxicological profile of As,such thresholds varying by diverse soil properties have rarely been established.This study aims to address this gap by compiling and critically examining an extensive dataset of As toxicity data sourced from existing literature.Furthermore,to augment the existing information,experimental studies on As toxicity focusing on barley-root elongation were carried out across various soil types.The As concentrations varied from 12.01 to 437.25 mg/kg for the effective concentrations that inhibited 10%of barley-root growth(EC10).The present study applied a machine-learning approach to investigate the complex associations between the toxicity thresholds of As and diverse soil properties.The results revealed that Mn-/Fe-ox and clay content emerged as the most influential factors in predicting the EC10 contribution.Additionally,by using a species sensitivity distribution model and toxicity data from 21 different species,the hazardous concentration for x%of species(HCx)was calculated for four representative soil scenarios.The HC5 values for acidic,neutral,alkaline,and alkaline calcareous soils were 80,47,40,and 28 mg/kg,respectively.This study establishes an evidence-based methodology for deriving soil-specific guidance concerning As toxicity thresholds.
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences(KJCX-3SYW-N3)the National Natural Science Foundation of China(10775174)+2 种基金the National Natural Science Foundation of China(11005144)Basic Research Key Project of Shanghai Committee of Science and Technology (10JC1417200)the Shanghai Natural Science Foundation (3109ZR1438200)
文摘A study was conducted on the effect of atmospheric parameters, including temperature, wind speed, and relative humidity, on fine particulate mass concentrations measured in Jiading District of Shanghai, China, during the period from January 2009 to January 2010. A sensitivity analysis was applied to investigate the interaction between atmospheric parameters and particulate mass concentration. The experiment revealed that the concentration of particulates increased with particle size from 0.1 to 1.0 μm, and decreased with the increase of particle size from 1.0 to 2.5 μm. The effects of atmospheric parameters on fine mass concentrations were significantly particle size-dependent. The PM1.0-2.5 may come from the size increase of smaller particulates after moisture absorption, And the variation of concentrations of PM0.1-l.0 was mainly attributed to the accumulation of PM0.1. The ventilation index and dilution index were calcu- lated on the basis of data collected in December 2009. A correlation analysis indicated that there was a significant relation between these two indexes and the particulate concentration by examining the three particle size ranges, 0.0-0.1, 0.1-1.0, and 1,0-2.5 μm. The Spearman correlation coefficients that related the ventilation index to the concentration for the three particle size ranges were -0.45, -0.56 and -0.47, respectively, while the coefficients that related the dilution index to the concentration were -0.36, -0.42 and -0.45, respectively.
