2019 Vol. 38, No. 3
Endocrine disrupting chemicals (EDCs) are ubiquitous contaminants in surface water, and they may be accumulated by aquatic organisms, posing potential threats to ecosystem and human health. In this study, occurrence and bioaccumulation of five phenolic EDCs, including bisphenol A (BPA), 4-tert-octylphenol (4-t-OP), estrone (E1), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2), were investigated in the surface water and plasma of wild fish collected from the middle and lower reaches of the Yangtze River, China. And a fish plasma model for the estimation of BAF (Bioaccumulation factor) was selected to compare the predicted value with the measured plasma BAF. The results indicated that BPA, 4-t-OP and E1 were the frequently detected pollutants in the river, with the detection rates higher than 50% in both surface water and fish plasma, while E2 and EE2 were detected at relatively lower frequencies and levels. The detection rates and concentrations level for the five phenolic EDCs followed the order:BPA > 4-t-OP > E1 > E2 and EE2, with the maximum concentrations of 99.7, 22.3, 2.47 ng·L-1, ND (not detected) and ND in water, and 172, 91.5, 21.1, 5.34, 5.90 ng·mL-1 in fish plasma, respectively. The detected log BAF values for BPA, 4-t-OP and E1 were in the range of 2.29-4.20, 3.18-4.18 and 3.29-3.75, respectively, indicating strong bioaccumulation ability of these EDCs in fish plasma. Compared with the modeling results, the measured log BAF values were significantly higher than the predicted log BAF. This difference may be due to the factors such as hypothesis of the fish plasma model, water temperature, dissolved oxygen and so on. The results of this study contribute to better understanding of the bioaccumulation of the phenolic EDCs in fish from the middle and lower reaches of Yangtze River, which can support the risk assessment and management for these compounds.
Human production activities release excessive heavy metals and directly harm human health. At present, the researches on the heavy metal-induced central nervous system diseases has received increasing attention. Absorption through the gastrointestinal tract is one of the major pathways for the entry of heavy metals into the human body. The intestine is the largest micro-ecological system in the human body, which plays an important biological role in maintaining the normal functions of the nervous system. This study describes the sequencing method for characterizing the diversity of intestinal microbes, and summarizes the potential mechanisms of the microbe-gut-brain axis effects on the neurological diseases caused by the widespread presence of heavy metals, including manganese (Mn), lead (Pb), cadmium (Cd), and arsenic (As) in the environment. We will provide the prevention and treatment of heavy metals-induced neurological diseases based on intestinal microbes.
Contamination of pesticides in the environment has attracted public attention, especially with respect to food safety. As the world's largest producer and consumer of organophosphorus pesticides (OPPs), the occurrence of OPPs in China's environment is particularly emphasized. OPPs that remain in surface water, soil, and living organisms may enter the human body through mouth, skin contact, respiration, etc, and bring about health risks. It is important to understand the occurrence of OPPs in major rivers, lakes,soils, and organism in China and conduct risk assessment. This review summarized the occurrence, detection rate, and distribution characteristics of major OPPs in water bodies, soils, and organisms in the Chinese environment, and assessed health risks through US RBCA health risk assessment model and RQ quotient method for aquatic ecological risk assessment. The results showed that the five highest levels of OPPs were dichlorvos, dimethoate, parathion, malathion, and methyl parathion in Chinese surface waters, OPPs concentrations ranged from ND to 30180 ng·L-1. OPPs levels in northern China were higher than the south. OPPs risk assessment results showed that the non-carcinogenic risk value (HQ) of OPPs in surface water, soil, and vegetables were 7.25×10-5-6.93×10-1, 9.56×10-7-5.30×10-2, and 1.08×10-2-7.01×10-1. None of them yet exceeded the safety standards of 1 and would not have significant adverse effects on human health. The carcinogenic risk value (R) of dichlorvos in surface water ranged from 2.86×10-8 to 6.25×10-6, within the safety value range of 10-5 to 10-6. Comparing the HQ values of surface water, soil and vegetables, residual OPPs in vegetables had a greater exposure to human health than surface water and soil.OPPs in aquatic ecology are at high risk for Opossum Shrimp and Water Flea, value(RQ) >1.
A review is provided on a variety of approaches to soil remediation by advanced chemical oxidation technologies, which are wildly used in chlorhydrocarbon contaminated sites. These approaches include Fenton reaction, persulfate oxidation, permangant oxidation, ozone oxidation, physical chemical and biological remediation and so forth. The degradation mechanisms, types of degradable contaminants, oxidant applicability, and mulitiple scale pilot studies are also analyzed. Besides, research direction in future study are proposed after sorting out excellent work done in the past, which might provide some guidance for site remediation when encountering those contaminants in the future.
A device for the rapid extraction of organic contaminants solvent and target organic pollutants in aquatic sediments was designed and tested in this study. Taking 16 priority polycyclic aromatic hydrocarbon (PAHs) as the target analytes, a series of experiments, including method detection limits and laboratory method blanks of each target, laboratory fortified blank, recoveries of targets in fortified water and sediment samples and duplicate extraction in aquatic sediments, were conducted to verify the extraction efficiency of the 16 priority PAHs by the device. The results showed that the average recovery for 16 the priority PAHs was between 80% and 120%, and the relative standard deviation (RSD) was less than 20%, which meet the requirements of United States Environmental Protection Agency (US EPA). The RSD for 16 total priority PAHs (ΣPAHs) in lake sediments was found to be less than 10%, while that of the river sediments' was less than 20%. The device was characterized by efficiently extracting organic targets (80%-100% for low rings PAHs) in short time (only for 2 h) on a large scale. This device was superior to Soxhlet extraction in terms of extraction time and reagent consumption and also was superior to microwave assisted extraction (MAE) and supercritical fluid extraction (SFE) in terms of easy operation and low analysis cost. This device may also have the possibility of synchronously extracting different types of organic pollutants, which could provide a technical support for exploring the ecological effect of compound pollution in aquatic environment.
Tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD) are currently widely used brominated flame retardants. They have drawn great concern due to their potential harmful implications in human and wildlife. This article provides a comprehensive review of the available literature on TBBPA and HBCD analytical methods in biota matrix, including different sample preparation techniques as well as instrumental approaches. This review focuses on the most recent developments for pretreatment methods, including soxhlet extraction (SE), liquid-liquid extraction (LLE), soild phase extraction (SPE), and accelerated solvent extraction (ASE), and instrumental approaches, such as gas chromatography coupled to mass spectrometry (GC-MS) and high performance lipid chromatography coupled to mass spectrometry (LC-MS). The pros and cons of each method were compared. This review will provide accurate determination of TBBPA and HBCD in biota matrix, and scientific basis for the future research on bioavailabilty and health risk assessment of TBBPA and HBCD.
In order to study the rapid detection method of chloramphenicol (CAP) in water environment, single\walled carbon nanotubes (SWCNTs) -nano-copper (CuNPs) composites were used to modify glassy carbon electrodes (GCE) combined with molecular imprinting polymer (MIP) technology. Cyclic voltammetry (CV) was used to conduct electrode conductivity test. Linear scan voltammetry (LSV) was used to optimize the experimental conditions. Differential pulse voltammetry (DPV) was used to study the electrochemical behavior of CAP in aqueous solution. The results show that the CAP redox current signal of the modified electrode was significantly enhanced compared with the GCE electrode, which indicated that the modified electrode has strong selectivity to CAP and accelerated electron transport. At the same time, the experimental conditions were optimized, such as the eluent type, the pH value of the buffer solution, the scanning speed, the enrichment time and the loading of the modifier. Under the optimal conditions, it was found that the peak current of CAP reduction showed a good linear relationship with the concentration in the range of 5-500 nmol·L-1. The linear equation is I(μA)=0.9204C + 41.285 (R2=0.9984). The limit is 4.8 nmol·L-1 (S/N=3), and the modified electrode has the good reproducibility and stability. When the modified electrode was applied to the actual sample analysis, the spiked recovery rate of chloramphenicol eye drops was 95.1%-102.5%, and spike recovery of the actual surface water sample was 96.5%-102.1%.
New water-soluble nitrogen-doped carbon quantum dots (N-CQDs) were facilely synthesized by one-step hydrothermal method using hybrid carbon and nitrogen sources of phenol and ethylenediamine, and were applied to fluorescent detection of Azo dyes. The surface morphology, composition and fluorescence properties of the as-prepared N-CQDs were characterized, and the remarkable fluorescence quenching effects of tartrazine and ponceau 4R dyes on N-CQDs were investigated along with experimental condition optimization. Experimental results showed that the fluorescence efficiency of N-CQDs was effectively improved owing to the formation of large amount of strong electron-donating groups on the N-CQDs surface when the molar ratio of phenol-ethylenediamine approached 1:1. Other two main parameters were optimized as the reaction incubation time at 5 min and reaction medium in phosphate buffer (pH=7.5), and hence the highest quenching efficiency was obtained. The quenching mechamism for the two dyes belonged to static quenching. Under the optimum conditions, excellent linear relationship between the ratio of fluorescence intensities (lgF0/F) and the dye concentration was attained in the range of 0-80 nmol·L-1 for tartrazine (lg F0/F=0.0047[Q]-0.015, R2=0.994) and 0-40 nmol·L-1 for ponceau 4R (lg F0/F=0.0252[Q]-0.0052, R2=0.996). The detection limits were down to 8.20 nmol·L-1 and 1.54 nmol·L-1 for tartrazine and ponceau 4R, respectively. It was demonstrated that such N-CQDs system can provide an effective fluorescence sensing platform for the simple, fast and sensitive determination of azo dyes (such as tartrazine and ponceau 4R) in waste water samples.
Using on-line observational data from a local ambient air monitoring station in urban Changsha and non-methane hydrocarbons and aldehydes ketones species determined by GC/Dean-switch/FID/FID coupled with a three-stage preconcentration and adsorption tube sampling-high performance liquid chromatography respectively, we applied an observation-based model (OBM) to analyze the sensitivity of typical ozone formation to ozone precursors in May and September 2017. The results showed clear diurnal variation of ozone with typical unimodal distribution and high peak concentration around 15:00, and nocturnal titration effects of enhanced nitric oxide on ozone were obvious in this study. Concentrations of non-methane hydrocarbons, aldehydes and ketones were much higher in May than those in September. In both months the main components of non-methane hydrocarbon were alkanes, aromatics and biogenic volatile organic compounds, and formaldehyde, acetaldehyde and acetone were the most abundant compounds for aldehydes and ketones. As the photochemical processes developed in daytime, non-methane hydrocarbons were consumed gradually and subsequently lowered the activity concentrations. Model analysis found that nitrous oxides and biogenic volatile organic compounds contributed mainly to ozone formation in May, and ozone formation was more sensitive to alkenes and aromatics in September. We therefore propose that abatement of nitrous oxides in May and alkenes and aromatics from anthropogenic sources in September would be an effective way to control ozone in urban Changsha.
In this study, whole air samples were collected with stainless steel canister in Changsha. The mixing ratios of 59 ambient volatile organic compounds (VOCs) were analyzed by GC/Dean-switch/FID/FID coupled with a three-stage preconcentration, and concentrations of carbonyl were obtained using high-performance liquid chromatography as the 2,4-dinitrophenylhydrazine derivative. The composition and source of non-methane hydrocarbons and carbonyls were characterized and apportioned. The results showed that the total average mixing ratio of non-methane hydrocarbons was (43.31±33.86) ×10-9, and the total concentration of carbonyl was (9.17±3.16) μg·m-3. In order of abundance, acetone, formaldehyde and acetaldehyde were the top three species, which contributed more than 90% of the total concentration of carbonyl. Sources apportionment using principal component analysis showed that gasoline volatilization, vehicle emissions, and solvent use were the main sources of atmospheric non-methane hydrocarbons in this area, which contributed 16.65%, 16.61%, and 22.65% of the total concentration. In addition, the results from species ratio analysis show that vehicle emission was the main source of aromatic, and the carbonyl pollutants mainly came from urban emissions.
Composition analysis of water-soluble ions (WSIs) in fine particulate aerosol is of great significance for understanding the physical and chemical characteristics, sources and formation mechanism of PM2.5. In the present study, a total of eighty PM2.5 samples were collected in Guiyang urban area from September to November, 2017. Eight water-soluble ions were deterained to investigate the composition and sources of PM2.5 water-soluble ions during autumn in Guiyang. Results showed that the average concentration of inorganic ions was 15.99 μg·m-3, while the averaged mass concentrations of anions and cations were respectively 10.90 μg·m-3 and 5.09 μg·m-3. Among the interested ionic species, SO42- (8.53±4.63 μg·m-3) was the highest, followed by NH4+ (2.56±1.62 μg·m-3), NO3- (2.21±2.96 μg·m-3) and Ca2+ (1.98±0.88 μg·m-3), while other ions ranked as K+ (0.37±0.24 μg·m-3),Cl- (0.16±0.11 μg·m-3),Mg2+ (0.11±0.03 μg·m-3)、Na+ (0.07±0.06 μg·m-3). In general, NH4+, SO42- and NO3- were the main water-soluble ions, accounting for 83% of total inorganic ions. The ratio of NO3-/SO42- (0.21±0.12) was much lower than unit, indicating that Guiyang PM2.5 mainly suffered stationary source pollution during the sampling time. The correlation analysis showed that most of NH4+ existed in the form of (NH4) 2SO4, NH4HSO4 and NH4NO3 in PM2.5. Enrichment factor analysis relative to seawater and soil indicated that NO3-, SO42-, Ca2+, K+, and Mg2+ were basically derived from terrestrial sources, while SO42- and NO3- were from the anthropogenic source, Ca2+, K+, and Mg2+ mainly from crustal sources, a part of Mg2+ was from the sea source.
In order to study the characteristic of atmospheric fine particulate matter (PM2.5) and water-soluble ions in PM2.5 in Zhoushan, 168 PM2.5 samples were collected at three state monitoring stations in Apr.2016, Jul.2016, Oct.2016 and Jan.2017. Concentrations of 9 water-soluble ions (Cl-, NO3-, SO42-, NH4+, K+, F-, Na+, Mg2+ and Ca2+) in the samples were measured by ion chromatography. Combined with meteorological data in the area and numerical analysis, PM2.5 and water-soluble mass concentration characteristics, particle acidity as well as secondary ion influencing factors (meteorological parameters, precursors) were studied. The results show that, during the sampling period, the concentration of PM2.5 varied with time, decreasing in the order of spring, winter, summer, and autumn, but has a uniform spatial distribution in Zhoushan. The secondary ions were the main water-soluble composition in PM2.5, and had consistent seasonal variation characteristics. The analysis based on charge balance demonstrated that the aerosol in Zhoushan was overall acidic, with the lowest acidity in summer and the highest acidity in autumn. Temperature was the main meteorological factor that affects secondary ion concentration in Zhoushan. Coal-firing was the main source of water-soluble pollutants in Zhoushan. The SO42- and NO3- at Tanfeng and Lincheng sampling sites were seriously affected by the emissions from power plants and coal-fired boilers. Putuo District, which is featured with a large volume of passenger and cargo transportation, was the major source of pollution for the secondary ion precursors in Putuo sampling site.
To investigate chemical characteristics and source profiles of different size aerosol particles, eight-size particulate matter (PM) were collected in Baoji urban and suburban areas by Anderson atmospheric particle sampler and their water-soluble inorganic ions were analyzed using Ion chromatography. Additionally, the influence of air regional transport on atmospheric particulate matter in Baoji was analyzed by combining the wind direction and the air mass back trajectory method. The concentrations of daily PM were higher in the urban area than those in the suburbs and vice versa during haze periods. The pollution of fine particle matter (PM2.1) was serious in urban and suburban areas in Baoji, with the higher concentrations in the urban area. Higher fraction of total water-soluble inorganic ions was observed in haze PM than that in non-haze PM. The concentrations of secondary ions (SNA) in haze days in both urban and suburban areas were higher than those in non-haze days. During haze days, the concentration of SNA, especially NO3-, were the highest at night than those in daytime. The concentrations of Ca2+ in haze days were lower than those in non-haze days. The SNA displayed a bimodal distribution and showed typical peaks in the droplet modes (0.43-1.1 μm). The peaks of K+ concentration both occurred at smaller size distribution (0.65-1.1 μm) and larger size distribution (2.1-10.0 μm), respectively, illustrating that K+ in coarse and fine particles may have a certain correlation with the conversion between day and night in urban and suburban areas. In contrast, the particle size distribution of Ca2+ exhibited a unimodal distribution with a high peak at the size of 4.7-5.8 μm. The transport of air pollutants from eastern to western part was an important reason for heavy pollution in Baoji.
A wet air oxidation (WAO) device was used to regenerate the flack activated carbon (AC) saturated by m-cresol. The regeneration efficiency of saturated AC was measured by adsorption method, and the optimum reaction time and temperature of WAO process were determined through this method. The changes of total organic carbon(TOC) and m-cresol concentration in the regeneration process were measured by total organic carbon tester and high performance liquid chromatography(HPLC),m-cresol concentration was influenced by the desorption and degradation process. The degradation products of m-cresol were determined by HPLC and gas chromatography-mass spectrometry(GC-MS),which include acetic acid,acrylic acid and some stable macromolecule. The concentration of acetic acid is the main factor that caused the change of TOC. During the regeneration process,the surface of AC was partially collapsed,which was determined by the nitrogen adsorption and desorption tests. The number of surface function groups of AC especially the carboxylic acid anhydride and lactone increased significantly after regeneration process,which was measured by the temperature programmed desorption-mass spectrometry techniques,indicating that part of the AC surface was oxidized in the regeneration process. Combining the analysis of solution with characterization results, a possible mechanism of regeneration process was proposed.
A gold nanoparticle-aluminum oxide (AuNPs-Al2O3) adsorbent was prepared by simple adsorption of AuNPs on the surface of the activated Al2O3, and was applied in the enrichment of the dissolved total mercury in the environmental water samples. The prepared adsorbent could adsorb both inorganic and organic mercury, and organic mercury could be transformed into element mercury under the catalytic effect of AuNPs. In our experiment, the factors influencing the enrichment and determination of total mercury were investigated, such as pH of the samples, the type and volume of the eluent, the time of the enrichment, and the effect of coexisting ions. Under the optimized condition, the limit of detection (LOD) of total mercury was 0.3 ng·L-1 based on 400 mL samples, with a linear range of 1.0-40 ng·L-1 and correlation coefficient of 0.998. The results showed that the method proposed in this work could be applied in the enrichment and determination of the dissolved total mercury in the natural water such as surface water and seawater for routine use.
In order to improve the denitrification efficiency, it is important to develop new materials which can adsorb nitrate and release the carbon source slowly. Modified canna leaves (MCL), modified rice straw (MRS), and modified peanut shells (MPS) were prepared by chemical method as nitrate adsorbents. Physicochemical characteristics of those materials were analyzed by SEM, FTIR, and elementary analyzer. The performance of nitrate removal and carbon release of materials was investigated. The results showed that the removal rate of nitrate was respectively 56.5%, 65.85% and 65.72% by adding 1g·L-1 MCL, MRS and MPS (initial concentration 25 mg·L-1; pH 6.72; temperature 20℃). The adsorption processes could be described by pseudo-second-order kinetic equation better. Isothermal adsorption processes of nitrate by MCL, MRS and MPS followed the Langmuir isotherm (R2 > 0.99). Adsorption capacity of nitrate by MCL, MRS and MPS dropped with the increase of temperature. The maximum adsorption capacity of MCL, MRS and MPS was 27.17, 29.85 and 29.59 mg·g-1 at 25℃, respectively. Thermodynamic parameters calculation showed that adsorption of nitrate by MCL, MRS and MPS was all exothermic and spontaneous process. In addition, the carbon release rate reached 50, 60, and 88 mg·(g·L·d) -1 by MCL, MRS and MPS respectively after 5 days of experiment. Thus it can be seen that MCL, MRS and MPS could be used as solid carbon sources for intensifying heterotrophic denitrification.(Cao Xin, Awet Arefe).
In order to solve the problems of granular drinking water treatment residuals (WTR) in wastewater treatment application, globular WTR-sodium alginate (WTR-SA) beads were prepared using the sodium alginate embedding method, and the adsorption characteristics of phosphorus on WTR-SA beads was examined in this study. Results showed that the kinetics of phosphorus adsorption on WTR-SA beads followed pseudo-second-order kinetic model. (R2=0.9957), and its adsorption isotherm was well described by Freundlich equation (R2=0.9907).The maximum adsorption amount of phosphorus simulated by the Langmuir equation was 1.88 mg·g-1. With the increase of solution pH from 3 to 11, the amount of phosphorus adsorption in WTR-SA beads showed a trend of increasing first and then decreasing. The optimal initial pH value for phosphate adsorption was 5. The desorption rate of phosphorus was only 0.72% under the condition of near saturation adsorption. Phosphorus fractionation results showed that phosphorus existed mainly in Al-bound, Fe-bound and Ca-bound forms, accounting for 43.2%, 22.7%, and 21.3%, respectively.
The microbial flocculants have the advantage of green production and low toxicity, so they can be safely used in water treatment and sewage wastewater treatment. In this paper, MBF-NⅢ2 was cationized and compounded with inorganic flocculants to enhance their flocculation ability for sewage and waste. By using CHTAC as cationic etherifying agent, the novel cationic microbial klebsiella flocculant CMBF-NⅢ2 is synthesized from MBF-NⅢ2. We want to figure out the law of the CMBF-NⅢ2 flocculation capacity from changing the dosing quantity, pH value, precipitation time and temperature. By orthogonal experiment, get the optimized optimum conditions. In the laboratory, the modified before of MBF-NⅢ2 and the modified after of CMBF-NⅢ2 are used for wastewater treatment in campus, by contrast, found that the CMBF-NⅢ2 flocculation better than the original MBF-NⅢ2. Flocculation rate of CMBF-NⅢ2 is 91.5% and COD removal rate was 87.8%, while MBF-NⅢ2 is only 47.61% on flocculation rate. It is also found that MBF-NⅢ2 compounded with ferric chloride not only has a good flocculation rate on treatment of domestic sewage, but also reduces the dosage of flocculant.
A potted inoculation experiment was used to study the cumulative effects of 10 nutrient elements in rhizosphere soil and medicinal herbs treated with different AM fungi,such as N、P、K、Mg、Na、Ca,etc. The results showed that inoculation with different AM fungi increased the contents of Mg、Na、Zn、Ni and decrease the contents of heavy metal ion Cu at the Paris at the fruit maturing stage, but there was no significant difference at the senescence stage. It also influenced the concentrations of nutrient elements in the rhizosphere soil,such as N、P、K、Mn、Ni, and enhance the enrichment ability to Mg、Zn、Ni.There was a correlation between the contents of nutrient elements in rhizosphere soil and medicinal materials during the growth process of Paris polyphylla var.yunnanensis, and there was a positive correlation between the content of Na in rhizosphere soil and the content of N in Paris polyphylla var.yunnanensis at the maturity. The contents of P in rhizosphere soil was negatively correlated with the contents of N、Mg in Pairs during senescence stage.The content of nutrient elements in soil directly affects the content of nutrient elements in medicinal materials, and had a great effect on the yield and quality of medicinal materials. Therefore, in actual production, AM fungi inoculation can increase the content of related nutrient elements in the rhizosphere soil and medicinal herbs, so as to play a role in improving the quality of Paris polyphylla var.yunnanensis.
The biosorption of Cr(Ⅲ) from aqueous solutions by Lactobacillus brevis was studied. The effects of initial pH, contact time, initial Cr(Ⅲ) concentration, bacterial concentration and temperature of biosorption of Cr(Ⅲ) from aqueous solutions were investigated. The results indicate that the adsorption of Cr(Ⅲ) ions was low under low pH, temperature and initial Cr(Ⅲ) ion concentration conditions. Under the experimental conditions, as the initial solution pH, temperature, initial Cr(Ⅲ) ions concentration increased, Cr(Ⅲ) ion adsorption capacity of strains increased. At the temperature of 40℃, pH of 6, initial Cr(Ⅲ) ion concentration of 200 mg·L-1, strain had the maximum adsorption amount. With the increase of bacterial concentration, Cr(Ⅲ) ion adsorption capacity decreased by unit bacterial concentration but the total adsorption capacity increased, with the maximum reached at the concentration of 6 g·L-1. The adsorption of Cr(Ⅲ) ions was very fast and the equilibrium reached at the contact time of 1h. As showed by correlation regression coefficients, that the model with the biosorption process fitted with Langmuir isotherm was better than the one fitted with Freundlich、Redlich-Peterson and Temkin. Fitted with Elovich, pseudo-first-order and pseudo-second-order kinetic, Lagergren pseudo-second order equation gave the best fitting degree to the data of kinetics experiment.
In order to understand the concentrations and correlations of mercury(Hg) and arsenic(As) in the Potamogeton crispus(P. crispus) -overlying water-sediment system of Dongping Lake, P. crispus, overlying water and surface sediment samples were collected in 33 sampling sites during the vigorous growing period of P. crispus in May, 2015. The total concentrations of Hg and As in the samples were analyzed, and the bioconcentration factors(BCFs) were calculated to assess the enrichment of Hg and As in overlying water and surface sediments by P. crispus. The results showed that the average concentrations of Hg and As were 0.769 and 7.86 μg·L-1 in the overlying water, respectively. The As concentrations in the overlying water samples were all lower than the class Ⅲ standard value of National Environmental Quality for Surface Water(GB 3838-2002), while the mercury concentrations in 73.3% samples exceeded the standard value and the average concentration of Hg was about 7.7 times of the standard value. The average concentrations of Hg and As in the surface sediments were 0.072 and 17.09 mg·kg-1 respectively, which were about 3.6 and 1.8 times of the soil background values of Shandong Province. The average concentrations of Hg and As in P. crispus were 0.169 mg·kg-1 and 2.11 mg·kg-1 based on the dry weight. The BCFs of P. crispus for Hg and As in the overlying water and surface sediments showed great spatial difference, and the BCFs (16.2-2581.9) of P. crispus for Hg and As in the overlying water were far higher than those (0.07-26.2) in the surface sediments, indicating that P. crispus had higher enrichment capacities for Hg and As in the overlying water than in the surface sediments. The concentrations of mercury, arsenic and organic matter in the surface sediments were significantly positively correlated with each other, neither of Hg and As had significant correlations within the P. crispus-overlying water-sediment system, which indicated the complexity of the transportation of Hg and As in the system.
In the sewage irrigated area of Xiaoqing River, 31 surface soil samples were collected to determine the total concentrations of heavy metals (Cd, Cr, Cu, Zn, Ni, As, Pb). A modified BCR sequential extraction procedure was used to identify the fraction distribution of heavy metals in the soil. The average concentrations of Cd, Cr, Cu, Zn, Ni, As, Pb in the soil were 0.37, 51.61, 32.62, 68.49, 34.12, 40.77, 32.26 mg·kg-1 in this area. The ecological risk of heavy metals was assessed by using two methods including potential ecological risk index and risk assessment code (RAC). The results showed that Cr, Zn, Ni and As were dominated by the residual fractions, Cu was mainly composed of the residual and oxidizable fractions, and mass fractions of Pb existed mainly in the reducible fractions, while Cd was controlled by various fractions. The bioavailability of heavy metals was in the descending order of Cd > Pb > Cu > Zn > As > Ni > Cr. Based on the calculation of the potential ecological risk index, it was found that Cd was at the level of medium to high risk, As was at the level of low to medium risk, and other metals were of low risk to the environment. The integrate potential ecological risk index (RI) of the heavy metals was in the range of 51.23-199.33, which was at low to medium potential risk level. Particularly, it was found that both Cd and As were the major risk resources to the environment, since the contribution rates of Cd and As were 57% and 31%, respectively. Finally, the results of the RAC showed that Cd was at a moderate to high risk level, Zn was at a low to medium ecological risk level, and other metals presented low level of risk to the environment.
Phosphorus is one of key factors leading eutrophication of fresh water bodies. In this study, the chemical continuous extraction procedure was used to analyze the content and distribution of total phosphorus (TP) and different forms of phosphorus in sediments of Caohai, a karst wetland in Guizhou Province. It was trying to reveal the impact of water level uplift on the risk of phosphorus release from the sediments of Caohai wetland. The results showed that the content of TP in sediments of Caohai wetland ranged from 206.30 to 577.30 mg·kg-1, with an average value of 378.60 mg·kg-1. Under the water level gradient, the distribution of TP concentration is in the shape of "U" with high concetrations at both ends and low concentrations in middle. The composition of phosphorus forms is dominated by organic phosphorus (Or-p), followed by autogenous calcium phosphate (ACa-p), detrital calcium phosphate (De-p) and closed storage phosphorus (Oc-p), and the least part is exchangeable phosphorus (Ex-p), aluminum-bound phosphorus (Al-p) and iron-bound phosphorus (Fe-p). Therefore, phosphorus in the sediments of Caohai wetland mainly existed as potential release and inactivity forms, while the active part presented little effect to the cover water. The gradient distribution of Act-p was relatively uniform, and the Or-p increased gradually along with the variation of water depth. The Ina-p content was stable and had no significant correlation with water level.Therefore, there would be no significant increase in the direct release risk of phosphorus with the water level uplift. However, there might be an accumulation of potential release risk.
Four synthetic musks(galaxolide,tonalide,musk xylene and musk ketone) in 23 surface sediments of Beidai River wetland were determined by Soxhlet extraction coupled with gas chromatography-mass spectrometry(GC-MS) analysis.Distribution and environmental risk assessment were conducted as well.The concentration of synthetic musks were in the range of 19.50-34.93 ng·g-1 for galaxolide(average content:28.46 ng·g-1,dw) and 16.37-29.29 ng·g-1 for tonalide(average content:23.30 ng·g-1,dw).Musk ketone was detected only in 5 samples,with a concentration rang from below the detection limit(LOD) to 37.89 ng·g-1.Musk xylene was not detected in all samples(MX).The results showed that galaxolide and tonalide were the main musk contaminants in sediment,which accounted for 50.65%-100.00% of synthetic musk.Kolmogorov-Smirnov(K-S) inspection of 3 synthetic musks from 23 sediment samples were analyzed.It was found that the concentrations of HHCB and AHTN were statistically significant(<0.01),which indicated there were similar sources and fate between HHCB and AHTN.The estimation of AHTN and HHCB accumulations in the sediments of Beidaihe wetland were 510.270 g and 623.274 g,respectively.The environmental risk assessment showed that the actual detection concentration was lower than the predicted ineffective concentration of HHCB and AHTN in sediments,and there was no acute risk in theory.
Concentrations of organochlorine pesticides (OCPs) in surface water and sediment samples from 40 sampling sites in Chaohu Lake and its inflow rivers were determined by GC-MS. The results show that the total concentrations of OCPs (∑OCPs) in surface water from Chaohu lake and its inflow rivers were rather low throughout the year, and they ranged 6.09-11.53 ng·L-1 for the spring, 6.32-11.10 ng·L-1 for the summer, 6.76-16.23 ng·L-1 for the autumn, and 5.97-16.29 ng·L-1 for the winter. The mean values for the four seasons were 8.33±1.19 ng·L-1, 8.43±1.21 ng·L-1, 9.25±1.96 ng·L-1 and 8.33±2.14 ng·L-1, respectively. The detected OCPs in surface water mainly originated from industrial hexachloro-cyclohexane soprocide (HCHs) and lindane. However, the concentrations of ∑OCPs in surface sediments (ng·g-1 levels), which ranged 2.55-19.03 ng·g-1 with a mean value of 5.80±4.07 ng·g-1, were far higher than those in the surface waters (ng·L-1 levels). The pollution levels in the western lake were higher than those in the eastern lake. The high concentrations of dieldrin and endosulfan suggested that Chaohu Lake suffered from these two pollutants. The results also showed that pesticides spraying, surface runoff and terrestrial input from industrial HCHs and lindane were the other primary sources of OCPs. Based on the composition characteristics of dichloro-diphenyl-trichloroethane (DDTs), the detected DDTs in surface sediments from most sampling sites mainly originated from historical usage. The ecological risk assessment demonstrated that the OCPs in the surface water induced negligible effect on Chaohu Lake and its inflow rivers, and the OCPs in the surface sediments might put fairly low ecological risks to the Chaohu Lake ecosystem.
Concentrations and distribution characteristics of seven typical organophosphates esters (OPEs) in soils and crops from the urban/suburban areas of Chengdu were quantitatively analyzed by GC-MS. The concentrations of Σ7OPEs in the urban/suburban areas in Chengdu ranged from 91.24 to 544.97 ng·g-1, and the pollution level of OPEs in the suburban area was more serious than in the urban area. Tri-n-butyl phosphate (TnBP), tributoxyethyl phosphate (TBEP) and tris(2-ethylhexyl) phosphate (TEHP) were detected with higher concentrations in any samples, while tridichloropropyl phosphate(TDCPP) and triphenyl Phosphate(TPhP) were not detected in all samples. The longitudinal migration profile of OPEs in the soil was observed, which showed significant migration difference. Trichloropropyl phosphate(TCPP) was accumulated more by broad bean, while celery accumulated more TBEP and TEHP, chard easily accumulated TEHP.
To explore the sources and transport characteristics of nitrogen in the main inflow rivers of Dianchi Lake, the concentration of nutritious nitrogen contained in the surface runoff was systematically monitored within the Baoxiang River watershed during the rainy season. The environmental processes, such as nitrogen concentration, occurrence characteristics and associated varying pattern during the runoff flow process were explored. In addition, the nitrogen sources in different reaches were traced as well. The results showed:The total nitrogen (TN) concentration in the main stream of Baoxiang River increased from upstream to downstream. Nitrate nitrogen (NO3--N) dominates as the primary occurrence form of nitrogen from the source of river to the middle reaches, while ammonia nitrogen (NH4+-N) is the main form of occurrence from lower reaches to the estuary. TN concentrations from the main nitrogen sources in the basin can be ranked from high to low as:rainwater, rural sewage outlets, farmland ditch runoff, urban sewage outlets, among which, NO3--N is the main form of nitrogen in farmland ditch runoff, while the remaining three are dominated by NH4+-N. In the rainy season, the import from the main nitrogen sources within the basin is the leading factor to the variance of nitrogen concentration and its occurrence forms, the forms of nitrogen from different nitrogen sources determines the nitrogen forms within runoff in the receiving areas to a certain extent. In main stream, δ15N-NO3--N content ranges through 6.576‰ to 9.708‰, and it shows a decreasing trend after an increase at first from upstream to downstream. The δ15N-NO3--N concentrations of nitrogen sources, i.e., rainwater, rural sewage outlets, farmland ditch runoff, urban sewage outlets, are 3.389‰-5.619‰, 6.681‰-19.623‰, 5.031‰-9.278‰ and 5.497‰-7.02‰, respectively. Rainfall and soil runoff are the main contributors of nitrogen to the area of the river source, and agricultural sources and village sources are the main contributors of nitrogen in the up and middle reaches. In addition on the sources of agriculture and village, urban source is the main contributor of the downstream as well. In conclusion, the results can be a basis for precise control and regulation of non-point nitrogen source pollution in the Dianchi River Basin.
This application use canister for sampling, combine with Agilent 7890B GC-5977B MS system for the analysis of 13 aldehyde and ketone volatile organic compounds in ambient air. In combination with Deans Switch technology, this method also enables one run for analysis of all the 117 volatile organic compounds in air, which improved efficiency and meet the requirement of "2018 Environmental Air Volatile Organic Compound Monitoring Program in Key Areas".
A simultaneous multi-class analysis method for new adrenaline drugs and its metabolites (3,4-dihydroxymandelic acid and vanillylmandelic acid), and promethazine based on the mechanism of "epinephrine reversal" in pork by high performance liquid chromatography-tandem mass spectrometry was established.In the corresponding concentration range, 4 targets had good linear relationships with correlation coefficients more than 0.999. The limits of quantification (LOQs) were 25,100, 5, 0.1 μg·kg-1 in pork, respectively. The average recoveries were 78.3%-92.5% and relative standard deviations were below 10%.
A method for simultaneous determination of five water-soluble ions (F-,Cl-,NO3-,SO42-,NH4+) in airborne submicrometer particles was established. And the method was used to analyze the contents of the water-soluble ions in airborne submicrometer particles collected in east urban Beijing during 2017-2018 heating season. The airborne submicrometer particle samples in residential areas in the east of urban Beijing were collected using quartz fiber filter membrane. After ultrasonic extraction with ultra-pure water, the contents of F-,Cl-,NO3-,SO42- and NH4+ were determined simultaneously by ion chromatography. Shimazin IC-SA2 column was chosen for separation of F-,Cl-,NO3-,SO42- with sodium carbonate/sodium bicarbonate solution as leaching solutions, and Shimazin IC-C4 column was for NH4+ separation with oxalic acid solution as leaching solution. The conductivity detector was used. The linear correlation coefficients of F-,Cl-,NO3-,SO42- and NH4+ were not less than 0.9990 within the linear range of 0.078-25 μg·mL-1, and the RSD was in the range of 0.016%-0.76%.
In this study, eight nitrosamines in water were determined by liquid chromatograpHy-tandem mass spectrometry. The effect of the pH, storage time and ion source selection on the assay was discussed. The samples can be determined by solid pHase extraction or direct injection, and quantified by internal standard method. Using liquid chromatograpHy tandem mass spectrometry, the response of each component was good, and the linear equation correlation coefficient was greater than 0.995. Liquid chromatograpHy tandem mass spectrometry has high sensitivity, good selectivity, fast and accurate. When the injection volume is 10 μL, the detection limit of solid pHase extraction is 5.47-8.24 ng·L-1, and the detection limit of direct injection is 1.01-1.12 μg·L-1.