Occurrence, Distribution, and Risk Assessment of Antibiotics in the Aquatic Environment of the Karst Plateau Wetland of Yangtze River Basin, Southwestern China.

In this study, the occurrence, distribution, and ecological risk of 40 commonly used antibiotics, including 15 sulfonamides (SAs), 9 fluoroquinolones (FQs), 7 macrolides (MCs), 3 tetracyclines (TCs), 2 chloramphenicols (CAPs), and 4 other categories, in the aquatic environment of the karst plateau wetland Caohai of the Yangtze River basin in southwestern China are reported. In total, 27 antibiotics were detected, with the detection rate ranging from 5% to 100%. The total concentration at each site ranged from 21.8 ng/L to 954 ng/L, with the average concentration being 189 ng/L. FQs and MCs were the most predominant categories, contributing 29.3% and 25.0% of the total antibiotic burden. The five most commonly detected antibiotics were ciprofloxacin (CIP), oxytetracycline (OTC), acetyl sulfamethoxazole (ASMZ), norfloxacin (NOR), and florfenicol (FF). The spatial distribution of the total concentration at each site demonstrated a decreasing trend from the southeastern area upstream adjoining the main counties to the northwestern area downstream, indicating that human activities have a great impact. Meanwhile, the natural attenuation rates of different types of antibiotics in the direction of flow ranged from 17.6% to 100%, which implied the natural purification potential of the wetland for antibiotics. The cluster analysis results indicated that domestic sewage and wastewater from agriculture and animal husbandry were the main sources of contamination in the surrounding wetland. Risk quotients (RQs) assessment showed that most of the individuals were at low to medium risk and that the adverse risks posed by mixtures of antibiotics were higher than those posed by the individual antibiotics.

Characterization and risk assessment of polycyclic aromatic hydrocarbon emissions by coal fire in northern China.

Coal spontaneous combustion is known to emit a variety of organic carcinogenic pollutants, polycyclic aromatic hydrocarbons (PAHs) are the most prominent. The Wuda coalfield is a coal fire-prone region in northern China. Coal fire sponges (CFS), a sponge-like contaminated soil protrusion, occur widely in the Suhaitu mining area. PAHs concentrations in CFS were measured via GC × GC-TOFMS. The average total PAHs concentration in the central annulus (A) was 17,416 µg kg-1 and ranged from 292 to 218,251 µg kg-1. Moreover, the study exhibited a heavily contaminated level (1000 µg kg-1). Low molecular weight PAHs were dominant, accounting for more than 50% of the total PAHs. Among them, naphthalene (Nap) and phenanthrene (Phe) were the most prominent, and the correlation between Phe and Nap + Phe was highly significant (R2 > 0.9). Our findings indicated that Nap and Phe contents may constitute a novel indicator to identify coal fire emission sources. Cancer risk calculations indicated that all annulus is already at a potential risk stage (10-6-10-4) for child or adults. CFS is not only a coal fire-associated PAH sink but also an atmospheric PAH emission source and, therefore, warrants the attention of local authorities.

[Occurrence Characteristics and Health Risk Assessment of Endocrine Disrupting Chemicals in Groundwater in Wuxi-Changzhou].

The concentrations of 22 endocrine disrupting chemicals, including 4 categories of sex hormones, progesterones, glucocorticoids, and phenolic hormones, in groundwater of Wuxi-Changzhou were analyzed using solid-phase extraction and ultra-performance liquid chromatography tandem mass spectrometry. The results indicated that 20 EDCs were detected, among which bisphenol A (BPA), estrone (E1), estradiol (E2), and 17α-ethinyl estradiol (EE2) were the main components with detection ratios greater than 90%, followed by estriol (E3) and methyl-prednisolonel (Meprednl), which had detection rates 67.7% and 48.4%, respectively. The average concentration of BPA was the highest (4.95 ng·L-1), followed by that of Meprednl, E2, prednisolone (Prednl), testosterone propionate (TES-pro), and megestrol-acetate (MA; 2.84, 0.71, 0.64, 0.58, and 0.53 ng·L-1, respectively). The total concentration in each site ranged from 0.38 to 147.35 ng·L-1. The sites with higher concentration were mainly distributed in the Xinbei District, Liyang City, and the Zhonglou District of Changzhou City. The potential sources were analyzed by a principal component analysis (PCA) combining the point sources near sample sites. The results showed that domestic sewage, aquaculture, and industrial wastewater were the main sources, following by medical wastewater. A non-carcinogenic risk assessment showed a low risk of EDCs in the groundwater of the study area, and the risk of drinking water was greater than that of skin exposure. EE2 had the highest non-carcinogenic risk and is suggested to be monitored in priority.

Fully automated identification and quantification of five polar pesticides in groundwater by isotope dilution-online solid phase extraction coupled with high-performance liquid chromatography-quadrupole Orbitrap high-resolution mass spectrometry.

A fully automated method for identification and quantification of five polar pesticides in groundwater by isotope dilution-online solid-phase extraction (SPE) coupled with high-performance liquid chromatography-quadrupole Orbitrap high-resolution mass spectrometry was developed. After one step of filtration, an aliquot of a 7.5-ml water sample was automatedly preconcentrated and purified on a turbulent Cyclone SPE column. The analytes were eluted in backflush mode, then separated on an analytical column and acquired by full MS/dd-MS2 scan in negative and positive ions mode. The major parameters for sample loading, cleanup, and elution were optimized in detail. Preconcentration and ionization efficiency were highly improved by using 0.1% acid solution in the mobile phase. The method provided good linearity of calibration coefficients (R2 > 0.995), sensitive method limits of detection (0.5-10.0 ng/L), accurate mass spectra (within 5 ppm error), satisfactory matrix spiking recoveries (98.4% to 109%), and high precision (intraday/interday relative standard deviations 1.57-8.90%). The method was successfully applied to analyze large batch groundwater of National Groundwater Monitoring Project and suspect screening of potential pesticides in groundwater. The study provided a practical alternative for a simple, robust, sensitive, and accurate identification and qualification of five polar pesticides in groundwater.

[Characterization of Microplastic Pollution of Sediments from Urban Lakes].

In recent years, microplastics (MPs) in the environment has become a topic of increasing concern. In this study, typical urban lakes, such as Yushan Lake and Nanhu Lake in Maanshan City, were selected to study the physical morphology and spatial distribution characteristics of MPs in sediments in spring and summer and to explore the sources of MPs in the lakes. On average, MPs in sediments occurred with a content of (0.0284±0.0597) g·kg-1 and abundance of (278.9±529.1) n·kg-1 in spring, and (0.0317±0.0778) g·kg-1 and (277.1±395.6) n·kg-1 in summer, respectively. Using a paired sample T-test, it was found that there was no significant correlation difference between the content (N=22, t=-0.269, P=0.791) and the abundance (N=22, t=0.035, P=0.973) of MPs in the spring and summer sediments. Regarding shape, the MPs in the sediments in the study area were divided into three types:fiber, film, and particle, accounting for 52.9%, 28.9%, and 18.2%, respectively. Size-fraction analysis indicated MPs<1 mm made up the majority, accounting for 83.9% of the total number. It was found that the MPs were mainly polyethylene (PE) and polypropylene (PP) polymers with seriously weathered surfaces. The sediments, which were adjacent either to land with a large stream of people and vehicles or to areas with frequent watersports, had notably high abundance of MPs, revealing the close correlation between the spatial distribution of MPs in lake sediments and human activities. It is thought that atmospheric precipitation (fiber), stormwater, washing of clothes (fiber), degradation of large plastics in the lake, and fishing activities (fishing nets, foam) are the main sources of MPs in lake sediments.

Source Tracking and Risk Assessment of Pharmaceutical and Personal Care Products in Surface Waters of Qingdao, China, with Emphasis on Influence of Animal Farming in Rural Areas.

The occurrence and potential sources of pharmaceuticals and personal care products (PPCPs) in surface waters from a large coastal city Qingdao, North China, were investigated. Forty-five compounds were analyzed by high-performance liquid chromatography-tandem mass spectrometry. The results showed that 28 compounds of PPCPs were detected. The most frequently detected compounds were atrazine, clarithromycin, nonylphenol, and bisphenol A with the detection rates > 90%. Paracetamol showed the highest concentration up to 4400 ng/L (mean 152.5 ng/L), followed by ampicillin (max. 2980 ng/L) with the highest mean concentration (229.3 ng/L), iopromide (max. 1744 ng/L, mean 74.5 ng/L), atrazine (max. 1612 ng/L, mean 96.1 ng/L), and bisphenol A (max. 1384 ng/L, mean 78.3 ng/L). The contamination levels and composition profiles of PPCPs along the rivers flowing through rural and urban areas and in seawater showed large spatial variability. Typical source markers and principle component analysis were used to track and differentiate the potential PPCP sources. The emphases of the study were the influence of animal farming in rural areas on PPCP composition profiles and the ecological risk. The results indicated that PPCPs in Qingdao surface water mainly came from three potential sources, i.e., treated wastewater (effluents from WWTPs), untreated wastewater, and nonpoint sources in agricultural areas.

A study on the mechanism of oxidized quinoline removal from acid solutions based on persulfate-iron systems.

Quinoline (Qu) and its derivatives have been widely regarded as hazardous pollutants in the world because of their acute toxicity to humans and animals, and potential carcinogenic risks. In this study, a novel sulfate radical system co-activated by ferrous and ZVI was developed to remove Qu from acidic solutions. The optimal ratio of ferrous and ZVI in the system and the mechanism of Qu removal from acidic solutions are also explored. The ZVI can initiate activation using hydrogen ions, which are released from the reaction of Fe2+, organics and PS in acidic solutions. This may dramatically improve the overall removal efficiency of Qu. The results indicated that the initial removal rate of Qu increases from 85.8% to 92.9%. The cleavage pathway of Qu is speculated by Frontier molecular orbital (FMO) theory and verified by GC/MS analysis.

Microplastics in Sediments of River Yongfeng from Maanshan City, Anhui Province, China.

This study was performed to evaluate the microplastics (MPs) pollution of sediments from River Yongfeng. It was observed that the MPs in sediments were present with contents of 0.5-16.75 mg/kg and abundances of 5-72 items/kg, coupled by variation coefficients of 109% and 91%, respectively, indicating that the distribution of MPs had high spatial variation. The land-based source of business zone is thought to be the significant contributor to accumulation of MPs in those sites with high quantity of MPs. Film was the predominant shape of MPs in river sediments followed by the line and fragment ones. Meanwhile, the MPs detected were mainly composed by four types including Polypropylene (24%), Polyethylene (61%), Polyethylene Terephthalate (8%) and Polystyrene (7%) based on number fraction, respectively, which indicates that Polypropylene and Polyethylene were the major types of MPs in the sediments. Size fraction performance suggests that those MPs < 1000 µm were of ubiquitous presence. The weathering of fringes was universally observed regardless of varying surface among MPs. Despite digestion with oxidative acid solution and subsequent washing by distilled water unexpected elements can still be detected, which should be considered as determining the materials associated.

[Distribution of 16 Polycyclic Aromatic Hydrocarbons in Dianchi Lake Surface Sediments After the Integrated Water Environment Control Project].

The external pollution of Dianchi Lake has been effectively controlled with the implementation of the integrated water environment control project. However, further attention should be paid to endogenous pollutants, such as surface sediments. To investigate the distribution of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Dianchi Lake, PAH concentrations in 19 surface sediment samples (collected in December 2016) were quantitatively measured by gas chromatography-mass spectrometry (GC-MS). The spatial and temporal distribution, sources, and ecological risks were also analyzed. The concentration of total PAHs (TPAHs) in the Dianchi Lake surface sediments varied in the range of 92.31-1546.78 ng·g-1 with an average of 496.30 ng·g-1. The average concentration of TPAHs in the surface sediments from Caohai (932.37 ng·g-1) was much greater than that from Waihai (380.02 ng·g-1). With the implement of the integrated water environment control project, the concentration of TPAHs in the surface sediments from Dianchi Lake was significantly lower than those detected in 2012, and was already relatively low level among other key waterbodies in China. The PAH with the highest concentration was fluoranthene (80.65 ng·g-1) and the substance with the highest toxic equivalent quantity (TEQ) was dibenz[a, h] anthracene (42.97 ng·g-1). The PAHs were mainly composed of 4 ring and 5-6 ring compounds (with the concentration ratio of 40.38% and 40.22%, respectively), which indicated that the proportions of middle-ring and high-ring compounds were generally consistent. The results of the molecular diagnostic ratio analysis showed that the primary source of PAHs in Dianchi Lake surface sediments are biomass and coal combustion. Based on the potential ecological risk marker comparison method, the entire lake was classified as having a low ecological risk, while the ecological risk of Caohai was relatively higher, which should be concerned further. The results provide initial data and act as an important reference for the conservation and improvement of water quality in Dianchi Lake.

Characteristics and Health Risk Assessment of Semi-Volatile Organic Contaminants in Rural Pond Water of Hebei Province.

Pond water as surface water has certain environmental impacts on environmental media such as groundwater, lakes, atmosphere, and soil. Organic pollutants present in pond water may pose health risks to humans, but research on organic pollutants in pond water is rare. Here, taking pond water collected in rural areas of Hebei province as the sample, we analyzed and evaluated four categories of semi-volatile organic compounds (SVOCs), including 11 phenolic compounds, 7 aniline compounds, 16 parent polycyclic aromatic hydrocarbons (PAHs), 14 PAH derivatives, and 16 phthalate esters (PAEs). The results show that the 10 water samples contained 26.2-17034 ng/L of Σ phenols, 33.7-2612 ng/L of Σ anilines, 33.9-1651 ng/L of Σ PAHs, and 59.0-2800 ng/L of Σ PAEs. Furthermore, non-carcinogenic risk and carcinogenic risk caused by SVOCs through direct ingestion and dermal exposure were also assessed. The current levels of non-carcinogenic risks and carcinogenic risks through these two means of exposure are within acceptable limits, except for the site 1 and site 5 in Hebei province where a total cancer risk exceeds 10-6. It can be concluded that the pond water studied had a low risk of carcinogenicity to the human.

Characterization of polycyclic aromatic hydrocarbons in urban-rural integration area soil, North China: Spatial distribution, sources and potential human health risk assessment.

The promotion of urbanization has accelerated the development of small manufacturing workshops and brought serious environmental problems. In this study, spatial distribution, sources and potential health risk for polycyclic aromatic hydrocarbons (PAHs) in urban-rural integration area soil in North China (800 km2) were discussed. The average total concentration of 16 PAHs was 225 µg kg-1, and range from 25 to 15155 µg kg-1 (n = 250). According to the European soil quality standards, more than 70% of the samples don't reach the pollution level, while around the small workshop concentration area and non-ferrous metal smelter were more contaminated than other area. The spatial distribution of soil PAHs concentration shows that low molecular weight, medium molecular weight and high molecular weight is very similar to the distribution of total PAHs, indicating that is likely to be caused by point source pollution. The sources of PAHs were identified by positive matrix factorization. The main six sources in the region are coal and biomass combustion, creosote, coke tar, vehicle and oil, which is consistent with the local energy consumption structure. Finally, a deterministic assessment of the cancer risk showed that the range for children was 5.94 × 10-8 to 2.53 × 10-5, and adults it ranged from 2.11 × 10-8 to 9.01 × 10-6. There is not a carcinogenic risk value greater than 10-4 in the entire region, but potential carcinogenic risks persisted in some areas. We conclude that PAHs pollution of soil in the area is an issue that deserves urgent attention for the relevant departments.

Characteristics of particle size distribution and related contaminants of highway-deposited sediment, Maanshan City, China.

Road-deposited sediment (RDS) has been identified as both the source and sink of various pollutants. In this study, the highway-deposited sediment (HDS) in Spring, Summer, Autumn and Winter was characterized. On average, the mass proportions of particles with the size of 830-4750 µm, 500-830 µm, 250-500 µm, 150-250 µm, 63-150 µm and < 63 µm were 23.6 ± 8.6%, 16.9 ± 3.4%, 28.4 ± 3.5%, 10.0 ± 4.3%, 15.7 ± 5.8% and 5.3 ± 2.0%, respectively, wherein the HDS of 63-830 µm accounted for 71% of the total mass load. It was observed that the particle size distribution of HDS could be described using the gamma distribution function based on gravimetric and cumulative basis (R2 (determination coefficient) = 0.9960-0.9995). The bulk pollutant contents of HDS showed seasonal variation with the mean of COD (chemical oxygen demand), nitrogen, phosphorus, Zn (zinc), Pb (lead) and Cd (cadmium) as 57 g/kg, 839 mg/kg, 97 mg/kg, 627 mg/kg, 110 mg/kg and 1.00 mg/kg and the highest COD of 83 g/kg in Autumn, nitrogen 1164 mg/kg Autumn, phosphorus 133 mg/kg Winter, Zn 801 mg/kg Summer, Pb 133 mg/kg Spring and the highest Cd of 1.36 mg/kg in Summer, respectively. The contents of Zn, Pb and Cd in HDS were significantly above their local soil background values. Moreover, the size fractional pollutant contents overall increased as particles' size increased. Averagely, 40-52% pollutant loads were associated with the particles < 250 µm, which can be moved easily by runoff. This study suggests that the behaviors of HDS different from city RDS should be considered as nonpoint source pollution control is performed.

Pharmaceutical and Personal Care Products in Surface Waters from the Inner City of Beijing, China: Influence of Hospitals and Reclaimed Water Irrigation.

Surface waters from five districts in the inner city of Beijing were collected for analysis of 43 target compounds of pharmaceuticals and personal care products (PPCPs) to understand the spatial distribution patterns of different groups of PPCPs in the central urban area of a metropolitan city characterized by many hospitals and public parks. The total concentrations of PPCPs showed large spatial variability, ranging from 71.1 to 2400 ng/L. The x-ray contrast medium iopromide was the compound with the highest concentrations. Pharmaceuticals showed similar spatial distributional patterns with large hospitals. Positive correlations between iopromide and pharmaceuticals were observed. In contrast, in general there is no correlation between iopromide and personal care products. The concentrations of PPCPs in the landscape waters were not high but were characterized by high proportions of acidic, nonsteroidal anti-inflammatory drugs with low or even negative removal efficiencies in the WWTP in Beijing, suggesting that the reclaimed water irrigation can be another source of PPCPs in surface waters in the inner city of Beijing.

Simultaneous Determination of 32 Polycyclic Aromatic Hydrocarbon Derivatives and Parent PAHs Using Gas Chromatography-Mass Spectrometry: Application in Groundwater Screening.

A simple, practical and precise method for the simultaneous analysis of 32 different polycyclic aromatic hydrocarbon (PAHs) including 16 parent PAHs, 8 oxygenated-PAHs (oxy-PAHs), 4 chloro-PAHs, and 4 nitrogen-containing heterocyclic PACs (N-PACs), in groundwater was established via gas chromatography-mass spectrometry (GC-MS) combined with liquid-liquid extraction (LLE). The obtained detection method possesses instrument detection limits (at a signal to noise of 3:1) in the range of 0.05-10 ng/mL and method detection limits in the range of 1.7-13.2 ng/L. The average recoveries of the 32 analytes were in the range of 54.3%-127.0% with relative standard deviations (RSDs) < 20%, and the recoveries of 16 PAH derivatives ranged from 54.3 to 115.1% with RSDs < 17.9%. The method has been successfully applied to the screening of 64 groundwater samples from eastern China. The results revealed that 30 types of targets including 16 PAHs and 14 PAH derivatives were detected and that the groundwater in most areas is slightly polluted, while the pollution of Jiangsu Province and Shandong Province was more serious.

Headspace Solid-Phase Microextraction Coupled to Comprehensive Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry for the Determination of Short-Chain Chlorinated Paraffins in Water Samples.

Short-chain chlorinated paraffins (SCCPs) are a new type of persistent organic pollutants. In this work, a simple and effective method involving headspace solid-phase microextraction (HS-SPME) and comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOF-MS) was developed and optimized for the determination of trace SCCPs in water samples. The key parameters related to extraction and separation efficiency were systematically optimized. The SCCP congener groups were best resolved using an Rxi-5Sil MS (30 m × 0.25 mm × 0.25 µm) column followed by an Rxi-17Sil MS (1.0 m × 0.15 mm × 0.15 µm) column; the optimum extraction conditions were achieved with a 100 µm polydimethylsiloxane SPME fiber, when a 10 mL water sample added with 3.6 g sodium chloride was incubated for 15 min at 90°C and then extracted during 60 min at 90°C and desorption at 260°C for 2 min. The proposed method showed good linearity in the concentration range of 0.2-20.0 µg/L with the determination coefficient greater than 0.995. The detection and quantification limits ranged from 0.06 to 0.13 µg/L and 0.18 to 0.40 µg/L, respectively, which are sufficient to meet the regulatory detection limits as set by most environmental regulations. The accuracy and precision of the method was also good, where the recoveries ranged from 82.5 to 95.4%, and intra- and interday precision was within 7.2% and 14.5%, respectively. The optimized method has been applied to the determination of SCCPs in ten freshwater samples of three different types.

Polycyclic aromatic hydrocarbons in soil of the backfilled region in the Wuda coal fire area, Inner Mongolia, China.

The Wuda coal fire area in Inner Mongolia, China, has existed for 50 years and been controlled by digging and backfilling for many years. However, few studies have focused on its impact on the local environmental and ecological systems due to emission of organic contaminants from the backfilled region. In the study, topsoil samples were collected at a 0-5 cm depth from the backfilled region of the Wuda coal fire area, which has existed for five years. The samples were analyzed for 16 priority control contaminants, namely polycyclic aromatic hydrocarbons (PAHs), with a standard operation procedure and high-performance liquid chromatograph (HPLC). The results showed that the total mass contentration of 16 PAHs (∑16PAHs) ranged from 279 to 8258 µg kg-1, with an average value of 2853 ±â€¯2948 µg kg-1, which exceeded the stipulated limit for heavily contaminated soil (1000 µg kg-1). Among the 16 PAHs, 2- and 3-ring compounds accounted for more than half of ∑16PAHs. Furthermore, the results show that the main contaminants were the naphthalene (Nap), phenanthrene (Phe), pyrene (Pyr), chrysene (Chr), and benzo[b]fluoranthene (BbF) in this area (24.8%, 51.1%, 3.9%, 4.5%, and 5.7% of ∑16PAHs, respectively). The diagnostic ratio of FLA/(FLA + PYR) exceeded 0.4 and IcdP/(IcdP + BghiP) was less than 0.5, indicating gentle smoldering or spontaneous combustion of coal fire, which differs from traditional coal burning. The environmental health risk or specifically the cancer risk (CR), calculated using the surface soil of the backfilled region, was 2.84 × 10-6 for adults and 1.01 × 10-6 for children, thus indicating potential cancer risks. Therefore, PAHs pollution in the surface soil of the backfilled region in the studied coal fire area is an issue that deserves urgent attention.

Occurrence and incidence of 18 per- and polyfluoroalkyl compounds in edible oils commonly consumed in Guiyang, China.

A systematic examination was conducted for the first time of a wide carbon-chain range of per- and polyfluoroalkyl compounds (PFASs) in 83 samples of edible vegetable and animal oils from Guiyang, China. The occurrence and levels of 18 PFASs in seven types of edible oil were analysed. Analytes were determined based on a simplified, sensitive and reliable solvent extraction and liquid chromatography-tandem mass spectrometry method. Ten target PFASs were found and the most frequently detected compounds with maximum concentration were PFOS (88%, 1.93 ng g-1), PFNA (55.4%; 6.76 ng g-1), PFHxS (39.8%; 0.36 ng g-1), and PFOA (16.9%; 0.15 ng g-1), respectively. The total PFASs concentrations ranged from 0.02 to 6.76 ng g-1, with a mean of 0.94 ng g-1. Significant differences of occurrence between vegetable oils and animal oils were demonstrated based on comparative analysis of the existing data. The investigation results showed that the effect of production reductions of PFOS and PFOA by regulatory was also reflected in edible oils. The dietary intakes of PFOS and PFOA for adults were estimated, which were lower than the available tolerable daily intake (TDI). Because of the global lack of food regulatory thresholds for most per- or polyfluoroalkyl compounds, it was difficult to draw any conclusion at this stage as to how human health is affected through exposure to these compounds. The baseline information of this study will assist in guiding the direction for future investigations and monitoring studies on occurrence, fate and human health-effect research of PFASs.

Perfluorinated compounds in soil, surface water, and groundwater from rural areas in eastern China.

Little research on perfluorinated compounds (PFCs) has been conducted in rural areas, although rural PFC sources are less complicated than in urban and industrial areas. To determine the levels and geographical distribution of 17 PFC compounds, samples of soil, surface water, and groundwater were collected from eight rural areas in eastern China. The total PFC concentrations (∑PFCs) in soils ranged from 0.34 to 65.8 ng/g ∑PFCs in surface waters ranged from 7.0 to 489 ng/L and ∑PFCs in groundwater ranged from 5.3 to 615 ng/L. Ratios of perfluorononanoic acid/perfluorooctanoic acid (PFNA/PFOA), perfluoro-n-butyric acid/perfluorooctanoic acid (PFBA/PFOA), and perfluoroheptanoic acid/perfluorooctanoic acid (PFHpA/PFOA) in rainwater increased due to the fluorine chemical plants in the surrounding rural and urban areas, suggesting that atmospheric precipitation may carry PFCs and their precursors from the fluorochemical industrial area to the adjacent rural areas.

A Survey of 42 Semi-Volatile Organic Contaminants in Groundwater along the Grand Canal from Hangzhou to Beijing, East China.

The status of organic pollution in groundwater in eastern China along the Grand Canal from Hangzhou to Beijing was evaluated. Forty-two semi-volatile organic contaminants were analyzed, including 16 polycyclic aromatic hydrocarbons (PAHs), seven polychlorinated biphenyls (PCBs), 12 organochlorine pesticides (OCPs) and seven organophosphorus pesticides (OPPs). Among the detected contaminants, PAHs were the most widespread compounds. One PCB and six OCPs were detected in the groundwater samples, but none of the target OPPs was detected. The total concentration of the 16 PAHs ranged from 0.21 to 1006 ng/L, among which phenanthrene (271 ng/L) and fluoranthene (233 ng/L) were present at very high concentrations and naphthalene (32 positive detections in 50 samples) and fluorene (28 detections in 50 samples) were the most frequently detected. Benzo[a]pyrene equivalents indicated a high environmental risk related to PAHs in a few groundwater samples. To identify the possible sources of PAHs, three concentration ratios, low molecular weight PAHs/high molecular weight PAHs, anthracene/(anthracene + phenanthrene) and fluoranthene/(fluoranthene + pyrene), were determined, that indicated that the PAHs mainly originated from mixed sources: pyrolytic and petrogenic sources with different ratios at different sites.

New modeling method and mechanism analyses for active control of interior noise in an irregular enclosure using piezoelectric actuators.

A new modeling method is developed in this paper for the active minimization of noise within a three-dimensional irregular enclosure using distributed lead zirconate titanate piezoelectric (PZT) actuators, and the control mechanisms for irregular enclosure are analyzed. The irregular enclosure is modeled with four rigid walls and two simply supported flexible panels, and PZT actuators are bound to one of the flexible panels. The process of the new modeling method is as follows. First, the modal coupling method is used to establish the motion equations, which contain important coefficients such as modal masses and modal coupling coefficients, etc., of acoustic-structural-piezoelectric coupling system. Then, the acoustic modes and the modal masses of irregular enclosure are calculated by numerical methods. Last, the modal coupling coefficients in motion equations are calculated according to the numerical results of the acoustic modes of irregular enclosure and the modes of two panels. The validity of this modeling method is verified by a regular hexahedron enclosure. Two cost functions are applied to this model. With the two cost functions, good results are obtained in minimizing the sound-pressure level (SPL) within irregular enclosure according to numerical investigations. By comparing the results obtained under controlled and uncontrolled states, the control mechanisms of the system are discussed. It is found that the control mechanisms vary with disturbance frequencies. At most disturbance frequencies, the SPL within enclosure is reduced by restructuring the modes of two panels simultaneously. When the disturbance frequency comes close to one of the natural frequencies of panel a, the dominant mode of panel a is suppressed, while the modes of panel b are reconstructed. While the disturbance frequency is near one of the natural frequencies of panel b, the modes of two panels are restructured at the same time.