BACKGROUND: Previously identified phenotypes of acute respiratory distress syndrome (ARDS) could not reveal the dynamic change of phenotypes over time. We aimed to identify novel clinical phenotypes in ARDS using trajectories of fluid balance, to test whether phenotypes respond differently to different treatment, and to develop a simplified model for phenotype identification. METHODS: FACTT (conservative vs liberal fluid management) trial was classified as a development cohort, joint latent class mixed models (JLCMMs) were employed to identify trajectories of fluid balance. Heterogeneity of treatment effect (HTE) for fluid management strategy across phenotypes was investigated. We also constructed a parsimonious probabilistic model using baseline data to predict the fluid trajectories in the development cohort. The trajectory groups and the probabilistic model were externally validated in EDEN (initial trophic vs full enteral feeding) trial. RESULTS: Using JLCMM, we identified two trajectory groups in the development cohort: Class 1 (n = 758, 76.4% of the cohort) had an early positive fluid balance, but achieved negative fluid balance rapidly, and Class 2 (n = 234, 24.6% of the cohort) was characterized by persistent positive fluid balance. Compared to Class 1 patients, patients in Class 2 had significantly higher 60-day mortality (53.5% vs. 17.8%, p < 0.001), and fewer ventilator-free days (0 vs. 20, p < 0.001). A significant HTE between phenotypes and fluid management strategies was observed in the FACTT. An 8-variables model was derived for phenotype assignment. CONCLUSIONS: We identified and validated two novel clinical trajectories for ARDS patients, with both prognostic and predictive enrichment. The trajectories of ARDS can be identified with simple classifier models.
Fluid Therapy , Phenotype , Respiratory Distress Syndrome , Water-Electrolyte Balance , Humans , Respiratory Distress Syndrome/therapy , Respiratory Distress Syndrome/physiopathology , Female , Male , Middle Aged , Fluid Therapy/methods , Water-Electrolyte Balance/physiology , Randomized Controlled Trials as Topic , Aged
Geochemical background and baseline values are important parameters for understanding the geochemical characteristics of soil elements, but the research degree of these two parameters is lacking in Hebei Province. Therefore, data from the multi-purpose regional geochemical survey and land quality geochemical assessment in Hebei Province from 2004 to 2018 were collected, covering approximately 71% of the land area of the whole province. Based on the data of surface soil and deep soil, scientific and robust methods including median value and median absolute deviation were used to calculate the geochemical background values, geochemical baseline values, as well as variation ranges of 54 indexes (Ag, Al2O3, As, Au, B, Ba, Be, Bi, Br, CaO, Cd, Ce, Cl, Co, Cr, Cu, F, Fe2O3, Ga, Ge, Hg, I, K2O, La, Li, MgO, Mn, Mo, N, Na2O, Nb, Ni, P, Pb, pH, Rb, S, Sb, Sc, Se, SiO2, Sn, Sr, Th, Ti, Tl, U, V, W, Y, Zn, Zr, total carbon (TC), and organic carbon (Corg)) in Hebei Province and 11 prefecture-level cities. The change rate in geochemical background for each index was also calculated. The results showed that the geochemical background and baseline values of most soil chemical elements in Hebei Province were lower than those nationwide, but the values of Ba, Br, Cl, MgO, Na2O, P, pH, S, Sr, and TC were higher, with CaO being the highest. Compared with those in north China, there was no significant difference in the geochemical background and baseline values for the 54 indexes, with the ratios of 0.83-1.17 and 0.79-1.19, respectively. Significant changes in the geochemical background for Corg, Hg, N, P, S, and Se were observed in Hebei Province, indicating that these indexes were greatly influenced by human factors. Preliminary analysis suggests that coal burning emissions and agricultural chemical use were two very important inducing factors.
Objective: To investigate the factors affecting the timing and prognosis of early tracheostomy in multiple rib fracture patients. Methods: A retrospective case-control study was used to analyze the clinical data of 222 patients with multiple rib fractures who underwent tracheotomy in the Affiliated Hospital of Yangzhou University from February 2015 to October 2021. According to the time from tracheal intubation to tracheostomy after admission, the patients were divided into two groups: the early tracheostomy group (within 7 days after tracheal intubation, ET) and late tracheostomy group (after the 7th day, LT). Propensity score matching (PSM) was used to eliminate the differences in baseline characteristics Logistic regression was used to predict the independent risk factors for early tracheostomy. Kaplan-Meier and Cox survival analyses were used to analyze the influencing factors of the 28-day survival. Results: According to the propensity score matching analysis, a total of 174 patients were finally included in the study. Among them, there were 87 patients in the ET group and 87 patients in the LT group. After propensity score matching, Number of total rib fractures (NTRF) (P < 0.001), Acute respiratory distress syndrome (ARDS) (P < 0.001) and Volume of pulmonary contusion(VPC) (P < 0.000) in the ET group were higher than those in the LT group. Univariate analysis showed that the patients who underwent ET had a higher survival rate than those who underwent LT (P = 0.021). Pearson's analysis showed that there was a significant correlation between NTRF and VPC (r = 0.369, P = 0.001). A receiver operating characteristic(ROC)curve analysis showed that the areas under the curves were 0.832 and 0.804. The best cutoff-value values of the VPC and NTRF were 23.9 and 8.5, respectively. The Cox survival analysis showed that the timing of tracheostomy (HR = 2.51 95% CI, 1.12-5.57, P = 0.004) and age (HR = 1.53 95% CI, 1.00-2.05, P = 0.042) of the patients had a significant impact on the 28-day survival of patients with multiple rib fractures. In addition, The Kaplan-Meier survival analysis showed that the 28-day survival of patients in the ET group was significantly better than that of the LT group, P = 0.01. Conclusions: NTRF, ADRS and VPC are independent risk factors for the timing and prognosis of early tracheotomy. A VPC ≥ 23.9% and/or an NTRF ≥ 8.5 could be used as predictors of ET in patients with multiple rib fractures. Predicting the timing of early tracheostomy also need prediction models in the future.
Investigating the pollution conditions of trace elements in the Poyang Lake basin, identifying the pollution sources, evaluating the ecological risks play an important part in formulating the effective strategies for protecting the basin ecosystem. To understand the concentration characteristics, pollution levels, and ecological risks of twelve trace elements (Cd, Hg, Pb, As, Cu, Zn, Cr, Ni, Mn, Sb, W, and Sn) in the floodplain sediments of the five main tributaries in Poyang Lake basin in the past twenty years, we used the enrichment factor (EF) and modified pollution index (MPI) to quantify the pollution levels of the trace elements, and analyzed and discussed the pollution sources in the areas with significant pollution level changes. The results indicated that the concentrations of cadmium, zinc, manganese, tungsten and lead in the floodplain sediments of the Poyang Lake basin during the past twenty years have increased by 134%, 26%, 41%, 25%, and 8%, respectively, and mercury, arsenic, chromium, nickel, antimony, and tin have decreased by 35%, 15%, 22%, 10%, 14%, and 13%, respectively, while copper has not changed significantly. The concentrations of cadmium in the Raohe River, Ganjiang River, and Xinjiang River basins have increased by 331%, 151%, and 107%, while mercury decreased in the Fuhe River, Ganjiang River, and Xiushui River basins by 87%, 41%, and 40%, respectively. The classification results based on the EF indicated that the changes in the pollution levels of trace elements in the Poyang Lake basin were characterized by the aggravation of cadmium pollution and the degradation of mercury pollution, the pollution level of cadmium in the Ganjiang River basin was upgraded to moderate and significant, the pollution level of cadmium in the Le'an River was upgraded to very high, and the pollution level of mercury in the Fuhe River basin was reduced to unpolluted or minimal. The MPI classification results established that the increase in the cadmium pollution had intensified the comprehensive pollution in the Poyang Lake basin, causing the proportion of severely and heavily polluted sites to be raised from 17% to 33%. The MRI classification results also demonstrated that the proportion of very high ecological risk sites have increased from 11% to 22%. The element with the highest MRI contribution rate changed from mercury to cadmium, which was caused by the reduction of the ecological risk level from very high to moderate. The results demonstrated that the significant pollution changes in the trace elements in the floodplain sediments of the Poyang Lake basin were primarily caused by human activities, such as mineral exploitation, smelting, and industrial and agricultural production. Our findings can provide scientific evidence for the prevention and control of river pollution and the optimal management of a watershed ecosystem.
To build a soil environmental quality monitoring network and collect the systematic soil geochemical data of heavy metals before and after the construction of Xiong'an New District(XND), long-term variations in soil heavy metal levels during the XND construction were monitored based on the land quality geochemical survey monitoring data and the geochemical distribution of heavy metals. Parameters such as sampling density, sampling quantity, and sampling period were estimated to construct the geochemical monitoring network, which provides a reference for the future long-term monitoring of soil heavy metal geochemistry in XND. The results indicate that variations in the amount of heavy metals As, Cd, Cu, Hg, and Pb are greater than 36%, while the nugget coefficients of Cd, Cu, and Pb are greater than 75% because of the superposition of manmade sources on the high natural background levels. At the 95% and 90% confidence levels, while the allowable error Δ of the sample mean value is 5%, 10%, and 15% and heavy metals as As, Cd, Cu, Hg,Ni, Pb and Zn is monitored in soil environmental quality monitoring network, the proper numbers in the study area are 1077, 270, 120 and 767, 192, 86, respectively. The minimum detectable change(MDC)of each heavy metal species is between 0.0025 and 2.54 mg ·kg-1. Soil heavy metal monitoring requires different revisit intervals under different annual change rates, but in the study area, revisit intervals of soil monitoring are approximately two years under the current conditions of constant annual change rates.
Mercury , Metals, Heavy , Soil Pollutants , China , Environmental Monitoring , Mercury/analysis , Metals, Heavy/analysis , Risk Assessment , Soil , Soil Pollutants/analysis
Heavy metals (HMs) are naturally occurring elements that have high natural background levels in the environment. Therefore, it is important to conduct ecological risk assessment and identify potential sources of HMs. In the past, studies were conducted at the regional scale. The accuracy of those studies could not meet the needs of spatial planning and natural resource management. Therefore, it is necessary to conduct ecological risk assessment at the township scale. In this study, 1092 soil samples (from 0-20 cm depth) were collected in the town of Reshui, an area with high background levels of soil HMs with the parent material of carbonatite, which is commonly found in Southwest China. The town of Reshui is a multi-ecological risk superimposed area where the ecological risk is high. In this study, concentrations of HMs (Cd, Cr, As, Hg, Pb, Cu, Zn, and Ni) in the topsoil were analyzed, and statistical analysis (SA), geographic information system (GIS) modeling, and positive matrix factorization (PMF) analysis were performed. The geoaccumulation index (Igeo) and potential ecological risk index (PERI) were applied for the ecological risk assessment and quantification of the sources of the soil HMs. The mean values of HM concentrations in the topsoil were 18.1, 1.18, 174.1, 202.2, 0.09, 71.1, 34.9, and 167.2 mg ·kg-1for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, respectively, which were considerably higher than the average background value (ABV) in soils in Yunnan Province except for As and Pb. The average concentrations of Cd, Cr, Cu, and Ni exceeded the screening values specified in the soil contamination risk in agricultural land (GB 15618-2018) by 5.82, 1.16, 4.04, and 1.02 times, respectively. The Igeo value shows that the major pollutant is Cu in the surface soil of the study area, followed by Cr, and Cd. Speciation analysis of HMs indicates that HMs (Cr, As, Pb, Cu, Zn, and Ni) mainly exist in the residual form, mostly from the geological background with low bioavailability. The potential effective components of Hg have higher levels, but the total amount of Hg and its pollution risk are lower. Cd has a high bioavailability ratio, is easy to enter the soil solution and be absorbed by crops, and is the HM with the highest pollution risk in the study area. The PERI shows that the proportions of low ecological risk, moderate risk, and high risk soil samples are 44.23%, 54.40%, and 1.37% of the total number of samples, respectively. Hg and Cd were the major sources of risk because of their high toxicity coefficient. The PMF analysis indicates that there are four major sources of HMs in the study area: human activity, natural sources, coal mining and traffic emissions, and agricultural sources with the risk contribution ratios of 9.29%, 53.67%, 11.23%, and 25.81%, respectively. The PMF analysis effectively quantified the ecological risk from these sources, providing a reference for further pollution control and prevention measures.
Metals, Heavy , Soil Pollutants , China , Cities , Environmental Monitoring , Humans , Metals, Heavy/analysis , Risk Assessment , Soil , Soil Pollutants/analysis
Urban soils are more easily subjected to modification, especially by contamination because of various human activities, and the environmental problems caused by urban soil pollution have become more prominent. To systematically investigate concentration characteristics, pollution levels, and exposure risks of 13 trace metals in urban soils of planning areas for 193 cities above the prefectural level, located in 31 provinces (autonomous regions and municipalities) of China, levels of pollution in urban soil were evaluated using the geoaccumulation index and integrated pollution index of trace metals, and health risks of residents exposed to urban soils were quantified using the health risk assessment method recommended by the US Environmental Protection Agency (USEPA). The results show that the median concentrations of As, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, Se, Tl, V, and Zn in topsoils of urban planning areas were 9.25, 2.14, 0.174, 12.4, 68.4, 28.2, 0.095, 27.7, 31.1, 0.29, 0.61, 82.7, and 82.2 mg·kg-1, respectively. Compared with the corresponding urban soil background values, the concentrations of Cd, Hg, and Se changed significantly. The geoaccumulation index (Igeo) values showed that Hg in urban soils of the planning area was the most severe pollutant, followed by Se and Cd, which caused pollution levels of uncontaminated to moderately contaminated levels, while other trace metals were uncontaminated. The Nemerow IPI (IPIN) revealed that the soils in 22 urban planning areas were heavily polluted and 16 urban planning areas were moderately polluted; in addition, the most polluted city in China was Zhuzhou in the Hunan province. The results of health risk assessment indicate that the soils in the five urban planning areas-Chenzhou City, Huangshi City, Zhuzhou City, Xiangtan City, and Longyan City-posed potential non-carcinogenic risks to children, and the major factor triggering risks was ingestion of Pb. To understand the soil pollution status and distribution of contaminated land parcel, it is suggested to carry out detailed investigation in cities with integrated moderate to heavy pollution to establish the list of contaminated land parcel and implement pollution control and restoration.
Herein, by using a structural design strategy of incorporating hetrometallic halide blocks, we prepared the first 3D bimetallic halide of [H2DABCO]2Cu6PbBr12 with new topological network based on two types of 6-connected nodes. Remarkably, this 3D framework displays highly efficient thermochromic luminescence from broadband yellow to green light emissions with remarkable stability.
In the past few decades, organic-inorganic hybrid metal halides acting as single-component white light emission diodes (LEDs) have attracted extensive attentions, but most of the studies concentrate on the low-dimensional lead perovskites. Here, by using the nontoxic silver as optically active metal center, a series of hybrid silver halides based on one-dimensional structures were constructed and realized broadband white light emission. Compounds [H2DABCO][Ag2X4(DABCO)] (X = Br (1), I (2)) feature one-dimensional [Ag2X4(DABCO)]2- structures charged balanced by [H2DABCO]2+ cations. Compound 1 exhibits an efficient broadband white-light emission with photoluminescence quantum efficiency (PLQE) of about 2.1% and excellent photochemical stability, while compound 2 gives a broadband yellow-white emission centered at 556 nm. [HDABCO]3Ag5Cl8 (3) gives a strong broadband yellow emission (585 nm) with high PLQE of 6.7%, which can be easily fabricated as a white light emitting device. Based on the temperature-dependent, particle-size-dependent, and time-resolved PL measurements as well as other detailed studies, the broadband white-light emissions are ascribed to the synergetic effects of the organic and inorganic components. Our work provides a unique structural assembly method to explore lead-free single-component white-light illuminants from molecular level.
Using Landsat 5/TM and Landsat 8/OLI images in 2000 and 2017, based on remote sensing ecological index (RSEI) model, combined with meteorological observation data and socio-economic data in Nanjing from 2000 to 2017, we analyzed and evaluated the ecological environment changes and the characteristic ecological areas in Nanjing. The results showed that the average RSEI of Nanjing decreased from 0.626 to 0.618 during 2000-2017. The RSEI values could be divided into five grades: bad, poor, fair, good and excellent. The proportion of area above good grade decreased from 61.0% to 57.1%, while that below poor grade increased slightly. Compared with 2000, the proportion of areas with improved ecological environment quality was 34.5%, 34.7% area had deteriorated, and 30.8% area remained unchanged in 2017. Among them, the ecological quality of main urban area had significantly improved, and the area with improved ecological quality exceeded that of deterioration. The ecological quality of new urban area and suburbs had deteriorated. The area with poor ecological environment exceeded the area of improvement. Among the three ecological protection areas, the ecological quality of Zijin Mountain was significantly better than that of Laoshan Mountain and Jiangxinzhou. The urbanization rate was negatively correlated with RSEI, with a correlation coefficient of -0.91. The urbanization process would have negative impacts on the ecological environment in general. However, strict protection and management measures could maintain the good ecological environment even improve it.
Ecosystem , Urbanization , China , Environmental Monitoring , Remote Sensing Technology
This study uses 68 sets of paddy soil and rice grain samples collected from an area of carbonate rocks in Guangxi Province, China, to explore the ecological risks of heavy metals (As, Cd, Cr, Cu, Hg, Pb, Ni, and Zn) in soils from a high background area. We analyzed the concentrations of these heavy metals in soil and grain samples, and their chemical speciation in soil, and use these data to assess the associated ecological risks by means of statistics, a geo-accumulation index, bioconcentration factors (BCF), and correlation analysis. The arithmetic mean values of heavy metals concentrations in soil samples from the study area were (75.8±50.1), (1.91±1.02), (467.0±253.1), (48.5±9.8), (0.21±0.08), (76.2±28.1), (84.2±25.0), and (258.0±122.6) mg·kg-1 for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, respectively, which were remarkably higher than of those from other regions within Guangxi Province and China. In comparison to China's soil environmental quality standard risk screening values (GB 15618-2018), the over-standard rates of Cd, As, and Cr were 95.6%, 86.8%, and 69.1%, respectively. In comparison to risk intervention values, the over-standard rates of Cd, As, and Cr were 27.9%, 17.6%, and 5.9%, respectively. Speciation analysis on heavy metals indicated that As, Cr, Cu, Ni, Pb, and Zn were mainly found in a residual form, and accounted for>80% of the total concentrations, and had a low bioavailability. The bioactive components (F1+F2+F3) of Cd accounted for 21%, and the bioactivity of Cd was higher than other elements. The potential bioavailable components (F4+F5+F6) of Hg accounted for 44%, with low total concentrations, which are understood to have little potential ecological harm for crops. However, the over-standard rates of Pb, Cd, and Cr in rice grains were only 23.5%, 8.8%, and 2.9%, respectively. Correlation analysis showed that there was no significant correlation between the concentrations of heavy metals in soils and the corresponding rice grains. The mean BCFs of each heavy metal were <0.1, and the BCFs of Hg, Pb, As, Cr, and Ni were <0.05. Overall, we found relatively high concentrations, low activity, and low ecological risks for heavy metals in the study area. For high geological background materials such as carbonate rocks, factors such as metal speciation, biological activity, and crop over-standard rates should be taken into account along with the traditional use of the total amount of heavy metals in a soil as the evaluation standard when formulating pollution control policies.
Carbonates , Environmental Monitoring , Metals, Heavy/analysis , Soil Pollutants/analysis , Biological Availability , China , Risk Assessment , Soil
Twenty-six polycyclic aromatic hydrocarbons (PAHs) and four synthetic musk compounds (SMCs) accumulated by Masson pine needles from different areas of Shanghai were investigated in the present study. Concentrations of Σ26PAHs (sum of 26 PAHs) ranged from 234â¯×â¯10-3 to 5370â¯×â¯10-3â¯mgâ¯kg-1. Levels of Σ26PAHs in different sampling areas followed the order: urban areas (Puxi and Pudong)â¯>â¯suburbsâ¯>â¯Chongming. Total concentrations of 16 USEPA priority PAHs ranged from 225â¯×â¯10-3 to 5180â¯×â¯10-3â¯mgâ¯kg-1, ranking at a relatively high level compared to other regions around the world. Factor analysis and multi-linear regression model has identified six sources of PAHs with relative contributions of 15.1% for F1 (vehicle emissions), 47.8% for F2 (natural gas and biomass combustion), 7.8% for F3 (oil), 10.6% for F4 (coal combustion), 15.7% for F5 ("anthracene" source) and 3.0% for F6 (coke tar). Total concentrations of 4 SMCs varied between 0.071â¯×â¯10-3 and 2.72â¯×â¯10-3â¯mgâ¯kg-1 in pine needles from Shanghai. SMCs with the highest detected frequency were Galaxolide and musk xylene, followed by musk ketone and Tonalide. The highest level of SMCs was found near industrial park and daily chemical plant. The results obtained from this study may have important reference value for local government in the control of atmospheric organic pollution.
Environmental Monitoring/methods , Environmental Pollution/analysis , Fatty Acids, Monounsaturated/analysis , Pinus/chemistry , Polycyclic Aromatic Hydrocarbons/analysis , Air Pollution/analysis , China , Coal/analysis , Coke/analysis , Traffic-Related Pollution/analysis , Vehicle Emissions/analysis
In this study, pine needles were used as biomonitors to investigate the levels, spatial distributions, and possible sources of polybrominated diphenyl ethers (PBDEs) and four emerging halogenated flame retardants (HFRs) in the atmosphere of Shanghai, China. The four emerging HFRs were hexabromocyclododecane (HBCD), decabromodiphenylethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), and dechlorane plus (DP), with the first 3 HFRs being non-polybrominated diphenyl ether brominated flame retardants (non-PBDE BFRs). The total concentrations ranged from 3.71 to 4020 ng g-1 dry weight (dw) for 52 PBDE congeners (Σ52BDEs), < MDL (method detection limit) to 15.2 ng g-1 dw for three non-PBDE BFRs (Σ3non-PBDE BFRs), and 0.815 to 1090 pg g-1 dw for two DP isomers (ΣDP), respectively. High levels of PBDEs, three non-PBDE BFRs, and DP were found in pine needles from suburbs and Pudong, which was a consequence of industrial activities. The fraction of anti-DP isomer (fanti) in pine needles ranged from 0.515 to 0.939 with a mean value of 0.721, and most of the fanti values were consistent with those of technical DP formulations. Principal component analysis-multiple linear regression (PCA-MLR) model identified four sources of PBDEs in pine needles with the quantified contributions: degradation of technical PBDE formulations (49.5%), technical deca-BDE (6.9%), technical penta-BDE (25.1%), and technical octa-BDE (18.5%). These findings are expected to help understand the pollution level, fate, and possible sources of HFRs in the atmosphere of Shanghai and provide a basis for air pollution control and management in Shanghai.
Air Pollutants/metabolism , Environmental Monitoring , Flame Retardants/metabolism , Halogenated Diphenyl Ethers/metabolism , Air Pollutants/analysis , Atmosphere/chemistry , China , Environmental Pollution , Flame Retardants/analysis , Halogenated Diphenyl Ethers/analysis , Halogenation , Hydrocarbons, Brominated , Hydrocarbons, Chlorinated , Pinus/chemistry , Plant Leaves/chemistry , Plant Leaves/metabolism , Polycyclic Compounds
The characteristics of regional environmental pollution of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) in river system from Shanghai were comprehensively investigated in this study for the first time. The total concentrations of SCCPs and MCCPs ranged from 15.0 to 1640â¯ngâ¯L-1 (median: 278â¯ngâ¯L-1) and 40.3 to 3870â¯ngâ¯L-1 (median: 939â¯ngâ¯L-1) in water, and from not detected (ND) to 2020â¯ngâ¯g-1 (median: 89.3â¯ngâ¯g-1) and 10.1 to 10,800â¯ngâ¯g-1 (median: 947â¯ngâ¯g-1) in sediments, respectively. The higher levels of SCCPs and MCCPs were found in water from Jinhui and Yexie rivers, and in sediments from Huangpu River, respectively. The concentrations of MCCPs were higher than those of SCCPs in both water and sediments, suggesting that the river system was mainly contaminated by MCCPs. Compared with other areas around the world, the concentrations of SCCPs and MCCPs were at medium to high levels in water and sediments. Factor analysis results revealed that SCCPs and MCCPs had different sources in both water and sediments. The log Koc values of CPs were significantly correlated with carbon chain lengths (pâ¯<â¯0.01), but not with chlorine number for both SCCPs and MCCPs (pâ¯>â¯0.05). A significant second-order polynomial relationship was observed between log Koc values and molecular weights of homologue groups of SCCPs (pâ¯<â¯0.001) and MCCPs (pâ¯<â¯0.01), respectively. SCCPs in water posed a low ecological risk at all sampling sites, and MCCPs in water posed a moderate ecological risk to aquatic life at nearly a fifth of sampling sites. SCCPs and MCCPs in sediments posed a low ecological risk to sediment dwelling organisms at most sampling sites.
The aims of this study were to investigate the levels, possible sources and potential ecological risks of 26 polycyclic aromatic hydrocarbons (PAHs) including highly carcinogenic dibenzopyrene (DBP) isomers and 4 synthetic musks (SMs) in river sediments from Shanghai. 74 sediment samples were collected from the Huangpu River and its main tributaries. The total concentrations ranged from 52.0 to 11400 ng g-1 for Σ26PAHs, 25.1-9910 ng g-1 for 16 USEPA priority PAHs (Σ16PAHs), 0.769-384 ng g-1 for Σ4DBPs, and 0.080-63.3 ng g-1 for Σ4SMs, respectively. Seven sources of PAHs in river sediments were identified by positive matrix factorization (PMF) model. Coal combustion, vehicle and creosote were the major emission sources for PAHs. SMs came mainly from domestic and industrial wastewaters. The toxic equivalent quantities of the benzo[a]pyrene (TEQBaP) ranged from 7.64 to 3920 ng g-1 for Σ24PAHs, 2.07-1150 ng g-1 for Σ16PAHs, and 5.53-3150 ng g-1 for Σ4DBPs. The TEQBaP of Σ4DBPs made up 73.9% of Σ24PAHs, which indicated that DBPs were the major carcinogenic contributors to total PAHs in sediments. According to sediment quality guidelines (SQGs) and mean PEL-Q values, the risks posed by PAHs in sediments were at medium level at most sampling sites, and SMs posed a low ecological risk to sediment-dwelling organisms in Shanghai.
Environmental Monitoring , Fatty Acids, Monounsaturated/analysis , Geologic Sediments/chemistry , Polycyclic Aromatic Hydrocarbons/analysis , Water Pollutants, Chemical/analysis , Benzo(a)pyrene , Carcinogens/analysis , China , Coal/analysis , Ecology , Risk Assessment , Rivers/chemistry
Monthly investigations of the phytoplankton community and the associated environmental drivers during the past eight years in the Shahe Reservoir, Jiangsu Province, China revealed the spatial and temporal variations of phytoplankton and the associated driving factors in the reservoir. The results show that the concentrations of total nitrogen (TN), total phosphorous (TP), turbidity (Turb), suspended solids (SS), and chlorophyll-a (CHL) were the highest in the upstream tributaries and the lowest in the downstream-linked reservoir. In contrast, the highest Secchi disk depth (SDD) was recorded in the Shahe Reservoir and that the lowest in the upstream tributaries. Significant differences in water quality indices were recorded among the upstream tributaries, the transition region, and the downstream-linked reservoir area (ANOVA, P<0.05). The biomass of phytoplankton was the highest in the upstream tributaries and the lowest in the reservoir. The highest biomass of phytoplankton was recorded in the summer and the lowest in the winter. Synedra, Cyclotella, Cryptomonas, and Achnanthes were the dominant genera in the spring; Synedra, Cryptomonas, Raphidiopsis, and Phormidium were dominant in the summer; Cryptomonas, Synedra, Raphidiopsis, and Aphanizomenon were dominant in the autumn; and Cryptomonas, Synedra, Achnanthes, and Cyclotella were dominant in the winter. Synedra and Cryptomonas were the dominant genera throughout the year. The correlation analysis shows that TP, water temperature, and SDD were the most important driving factors for the spatial and temporal variations of phytoplankton. Notable spatial differences were recorded for Cryptomonas, while minimal variations were recorded for the remaining species. A smaller number sampling sites and a higher sampling frequency are needed to characterize the phytoplankton community in the Shahe Reservoir.
Environmental Monitoring , Eutrophication , Fresh Water , Phytoplankton/growth & development , Biomass , China , Cyanobacteria , Nitrogen/analysis , Phosphorus/analysis , Seasons , Spatio-Temporal Analysis
The vertical distribution patterns, the source and correlation of heavy metals were characterized in the bulk soil and different soil aggregates of arable red soil profile (0-100 cm) in Hunan province. Their response to organic carbons in proflie was explored as well. Principal component analysis (PCA) suggested that elements could be divided into two principal components, the metals of the first group were Zn,Cu,Pb,As,Cd, and the second group metals were Cr, Ni. Priniciple component elements had similar sources. In 0-30 cm, The first group metals decreased with increasing depth, the second group metals increased with increasing depth. The concentrations of typical heavy metals were in the order of Zn >Cr >Cu >Pb >Ni >As >Cd. Cd in each soil layer was severely polluted, Zn was at level of light pollution, while other metals were at clean levels. In terms of different size of soil aggregate, it was found that colloids played an important role in facilitating transport of heavy metals, such as As, Cu, Zn, Cd, Cr, Ni. While Pb was still mainly enriched in clay component (<53 µm). Infrared spectrum analysis showed that the main functional groups of organic carbon were polysaccharide (22.07%-47.13%), aromatic (13.88%-34.37%) and alcohol (21.04%-59.49%). Correlation analysis showed that stable organic carbon such as polysaccharide and aromatic organic carbon could stablize the metals of first group in profiles, which would delay the migration of heavy metals to deeper soil. However, the active alcohol carbon would enhance the migration.
To investigate the polybrominated diphenyl ethers (PBDEs) pollution status, sediment samples were collected from major rivers in northeast China. Contents of 41 PBDEs congeners in sediments were measured using GC-NCI-MS. BDE209 was not detected, measured level of total PBDEs (excluding BDE209) ranged from 0.91 to 17.67 ng.g-1 dry weight, the highest concentrations of PBDEs were detected in the sediment samples from upstream and downstream of Jilin City in the Second Songhua River Basin, with 15.86 and 17.67 ng.g-1. BDE207 and BDE47 were the predominant PBDE congeners, with their concentrations accounting for 86. 5% and 76. 6% of the total PBDEs concentration measured in the samples. Each congener content difference was not obvious in other river sediments. PBDEs levels monitored in the present study were compared to those reported recently for districts located at home and abroad, and with ecological risk analysis. PBDEs content is at a low level in sediments of Northeast China River Basin and there is no ecological risk.
Environmental Monitoring , Geologic Sediments/chemistry , Halogenated Diphenyl Ethers/analysis , Rivers/chemistry , Water Pollutants, Chemical/analysis , China , Gas Chromatography-Mass Spectrometry , Risk Assessment
Three tropical forest soils were collected from Haikou, Qionghai and Tunchang in Hainan Island. Soil particle size fractionations were conducted using the standard dry-sieving procedure. Distribution of heavy metals in bulk samples and particle size fractions was determined by ICP-MS. The distribution characteristics and the response to organic carbon and iron were discussed. The results showed that the distribution of heavy metals was highly associated with the particle size fractions and variable patterns were found, which decreased with the increasing size. The accumulation of Cr, Ni, Cu, Zn, Cd and Cd was predominantly contributed by the particles finer than < 53 microm in diameter, whereas As mainly accumulated in particle size of 53-1 000 microm. Generally, the microaggregate (< 250 microm) contributed 14.38%-65.04% of heavy metals to the contents in bulk soil and the silt-clay aggregates (< 53 microm) contributed 2.61% -32.01%. The content of heavy metals except for As and Cd and Pb in Haikou soil in these different size fractions were controlled by the organic carbon and iron contents, which increased with the decreasing particle size.
Environmental Monitoring , Metals, Heavy/analysis , Soil Pollutants/analysis , Trees/growth & development , China , Particle Size , Soil/chemistry , Tropical Climate
For the valid use of urban land and the safety of public health, an extensive contamination survey of organochlorine pesticides from five soil cores was conducted in the highly urbanized areas of Beijing in China. For topsoils in five soil cores, level of ∑HCHs and ∑DDTs varied from 0.174 to 4,783 ng g(-1) and 0.62 to 57,849 ng g(-1), respectively. The profile in topsoil of cores displayed that levels of pollutants in four soil cores from the urban areas with dense population are higher than that from outskirts. The depth characteristics of pollutants indicated that the level of ∑HCHs and ∑DDTs in BY and WU was close to/below the background value of soil in China (50 ng g(-1)), but those in some soil samples from A, B and ZX core, especially A and B, was above the threshold value for the soil safety (1,000 ng g(-1)). In views of the usage history of the land and profiles of contaminants, the source in A and B probably came from the dumped waste chemical materials in the old chemical factories. The study of soil cores sampled revealed the existence of chemical "time bomb" in urban regions of Beijing. Also, the finding indicated the absolute necessity of assessing the soil quality with the unprecedented land use changes in the big city community.
Hydrocarbons, Chlorinated/analysis , Insecticides/analysis , Soil Pollutants/analysis , China , Cities , Environmental Monitoring , Soil/analysis
