Suburb Of Nanjing Research Articles

Pollution Characteristics and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Agricultural Soils of Different Land Use Types in Nanjing Suburbs

In order to clarify the pollution characteristics of PAHs in suburban agricultural soils, the content of 16 types of PAHs was measured in agricultural soils with different land use types (paddy fields, vegetable fields, and forest land) in the suburbs of Nanjing. The results showed that acenaphthene (Acy) was not detected in any soil samples. The concentration of 15 PAHs in agricultural soil in suburban Nanjing ranged from 24.49 to 925.54 μg·kg-1, with an average concentration of 259.88 μg·kg-1. In different land use types, the order of PAHs concentration in soil from high to low was:forest land>paddy fields>vegetable fields, and the high-ring PAHs content was dominant in general. The effects of different soil physicochemical properties on PAHs showed that there was a certain correlation between soil organic carbon (TOC) and clay (clay) content and PAHs, whereas pH and total nitrogen (TN) had no significant correlation with PAHs. The toxic equivalence method and CSI index method were used for ecological risk assessment, which showed that the ecological risk of PAHs in agricultural soils in suburban Nanjing was relatively small; however, the ecological risk of PAHs in forest land should be given some attention, and supervision should be strengthened. Health risk assessment using incremental lifetime cancer risk (ILCR) showed that the threat to the health of children was slightly greater than that of adults, and the CR of forest land was significantly higher than that of vegetable and paddy fields, though still within an acceptable range. Uncertain health assessments were performed in adults, showing that risk analyses of deterministic health risks underestimated the health risks of PAHs. The results of sensitivity analysis showed that the input parameter that had the greatest impact on the total variance of the total carcinogenic risk CR was the exposure frequency EF (50.7%), followed by the pollutant concentration CS (43.3%).

Development, characterization, and application of an improved online reactive oxygen species analyzer based on the Monitor for AeRosols and Gases in ambient Air (MARGA)

Abstract. Excessive reactive oxygen species (ROS) in the human body is an important factor leading to diseases. Therefore, research on the content of reactive oxygen species in atmospheric particles is necessary. In recent years, the online detection technology of ROS has been developed. However, there are few technical studies on online detection of ROS based on the dithiothreitol (DTT) method. Here, to modify the instrument, a DTT experimental module is added that is protected from light and filled with nitrogen at the end based on the Monitor for AeRosols and Gases in ambient Air (MARGA). The experimental study found that the detection limit of the modified instrument is 0.024 nmol min−1. The DTT consumption rate of blank sample (ultrapure water) is reduced by 44 %, which eliminates the influence of outside air and light in the experiment. And the accuracy of the online instrument is determined by comparing the online and offline levels of the samples, which yielded good consistency (slope 0.97, R2=0.95). It shows that the performance of the instrument is indeed optimized, the instrument is stable, and the characterization of ROS is accurate. The instrument not only realizes online detection conveniently and quickly, but also achieves the hour-by-hour detection of ROS based on the DTT method. Meanwhile, reactive oxygen and inorganic ions in atmospheric particles are quantified using the online technique in the northern suburbs of Nanjing. It is found that the content of ROS during the day is higher than that at night, especially after it rains; ROS peaks appear in the two time periods of 08:00–10:00 and 16:00–18:00 (China Standard Time, UTC+8:00; expressed here in local time – LT). In addition, examination of the online ROS, water-soluble ion (SO42-, NO3-, NH4+, Na+, Ca2+, K+), BC, and polluting gas (SO2, CO, O3, NO, NOx) measurements revealed that photo-oxidation and secondary formation processes could be important sources of aerosol ROS. This breakthrough enables the quantitative assessment of atmospheric particulate matter ROS at the diurnal scale, providing an effective tool to study sources and environmental impacts of ROS.

Exposure of preschool-aged children to highly-concerned bisphenol analogues in Nanjing, East China

Bisphenol analogues (BPs) have already attracted wide concern owing to the environmental and health risks they pose. The exposure pathways and health risk of preschool-aged children to BPs, however, are still poorly understood. In this study, we choose population survey with 184 preschool-age children from a suburb of Nanjing, eastern China, further reveal the internal and external exposures concentrations, distribution profiles, potential sources and eventually assess health risk of preschool-age children to eight kinds of BPs. The results verify that the 95th percentile (P95) concentrations of Ʃ8BPs ranged from 0.27 to 41.6 ng/mL, with a median concentration of 7.83 ng/mL in the urine samples. BPA, and BPF were the predominant BPs in urine, accounting for 67.3%, and 18.0% of Ʃ8BPs. The urine-based estimated daily intake (EDI) of Ʃ8BPs was 187 ng/kg body weight/day. Similarly, BPA, and BPF were the main BPs in the environmental exposure sources, accounting for 80.8%, and 11.7% of the total BPs. Moreover, the total external exposure dose of Ʃ8BPs via the environmental sources was 68.1 ng/kg body weight/day, including BPA (56 ng/kg body weight/day), BPF (7.68 ng/kg body weight/day) and BPB (2.62 ng/kg body weight/day). The oral intake of drinking water and food (vegetables and rice) was the main exposure pathways of BPs in preschool-age children. Furthermore, the hazard quotient (HQ) of BPs have been evaluated and the results show no occurrence of high risk. Additionally, the urine-based EDI was significantly higher than the total external exposure dose, suggesting the existence of other pathways of BP exposure to be further explored. To the best of our knowledge, this is the first study to conduct both an internal and external exposure assessment of BPs.

The interaction mechanism of rural housing land transition and rural development: A spatial governance perspective

AbstractAs a significant material carrier of rural production and life, rural housing land transition (RHLT) is an important field of rural spatial governance, and the transition process of its utilization is closely related to rural development. Applying the “matter‐ownership‐organization” perspective to the governance of rural space, this study constructs an analytic framework of the interaction between RHLT and rural development. Taking the case of Tangjiajia Village, a tourist village in the suburbs of Nanjing, this study analyzes empirically the interaction mechanism between RHLT and rural development. On the basis of the findings, the challenges of rural spatial governance of suburban tourism are discussed, and the process of multiple‐subject participation in rural spatial governance is clarified. This elucidation of the interaction mechanism between RHLT and rural development in the suburbs of big cities will provide a point of reference for rural development in underdeveloped areas.

Late Devonian–Early Carboniferous palynology of the CSDP-2 Borehole in the southern Yellow Sea, China

Late Devonian–Early Carboniferous spores recovered from the depths of 2140 m to 2031.3 m in the CSDP-2 Borehole in the southern Yellow Sea are systematically documented to characterize palynological associations for the stratigraphic correlation. The taxonomic study identifies 96 species belonging to 48 genera, including a re-examination of 33 previously described and indeterminate species. Three palynological associations are established for the Wutong Formation in the CSDP-2 Borehole. In ascending order, these are the late Famennian Aneurospora asthenolabrata–Geminospora lemurata (AL) Association from the proposed Guanshan Member, the latest Famennian Cymbosporites circinatus–Asperispora acuta (CA) Association from the lower part of the proposed Leigutai Member, and the Tournaisian Auroraspora macra–Lophozonotriletes involutus (MI) Association of the upper part of the latter member. The AL and CA associations are correlated with the palynological assemblages in the Guanshan Member, and those in the lower to middle parts of the Leigutai Member of the Wutong Formation that outcrops in the suburbs of Nanjing and southern Jiangsu. The MI Association is similar to those derived from the uppermost beds of the subsurface Wutong Formation and is dated as early Tournaisian.

On the topographic entity-oriented digital elevation model construction method for urban area land surface

Human activity transforms a land surface into a complex surface where artificial and natural landforms coexist and continuous and emergent landforms merge. In this background, the problems of conventional digital elevation models (DEMs), such as morphological distortion, complicated updates, and lack of information, are increasingly prominent. This study proposes a new idea of DEM construction based on the concept of geographic ontology. First, landforms with common features are abstracted into a certain type of topographic entity based on their morphologies and semantics. For each type of topographic entity, a DEM was constructed independently based on the available elevation information and other information about the semantics and spatial relationships. Second, individual DEMs were merged into a complete DEM following certain rules. A 1 km2 area located in the suburb of Nanjing, Jiangsu Province, China, was selected as the experimental area. The effectiveness of the model construction method proposed in this study was verified. The results show that the DEM constructed according to the idea of this study has a significantly better performance than the conventional DEMs. The constructed DEM in this study can well represent ground objects, such as slopes, farmland, and ditches. In particular, the constructed DEM ensures the morphological accuracy of the ground objects.

Evaluation of the CAM and PX Surface Layer Parameterization Schemes for Momentum and Sensible Heat Fluxes Using Observations

In this study, the performances of the Community Atmosphere Model (CAM) and Pleim–Xiu (PX) surface layer parameterization schemes are investigated by using field observations. The parameterization schemes are evaluated against continuous momentum and sensible heat flux observations measured at two flat and homogeneous grassland sites in the suburb of Nanjing, eastern China. The observations were conducted from 30 December 2014 to 18 April 2017 at Jiangxinzhou and from 9 February 2015 to 26 March 2018 at Jiangning. It is found that the momentum flux is overall in good agreement with the observation, and the sensible heat flux is overestimated. The parameterizations of the momentum and sensible heat fluxes well capture the diurnal and seasonal patterns seen in the observations at the two sites. At Jiangxinzhou, the PX parameterization underestimates the momentum flux throughout the day and the CAM parameterization slightly overestimates it around the noon, while they underestimate the momentum flux throughout the year. The two parameterizations overestimate the sensible heat flux in the daytime as well as over the entire year. At Jiangning, the two parameterizations overestimate the momentum flux throughout the day and the sensible heat flux in the daytime, and overestimate both of them over the entire year. The two parameterizations are not significantly different from each other in reproducing the turbulent fluxes at the same site, while they perform differently at the two sites in terms of statistics. In addition, the parameterized fluxes increase with increased roughness length.

Retrieving homogeneous liquid cloud microphysical properties using multiple-field-of-view lidar

Liquid water content (LWC) and cloud droplet effective size (CDES) are important factors affecting atmospheric radiative transfer, and measurement of these parameters in clouds is essential. For homogeneous liquid cloud (constant extinction coefficient) with a gamma size distribution of cloud droplets, we find that LWC and CDES can be retrieved from two parameters obtained from a multiple-field-of-view (MFOV) Lidar: the intercept of the range-corrected Lidar signal (IRCLS) and the slope of the range-corrected Lidar signal (SRCLS) at different sizes of FOV. Monte Carlo simulations reveal that IRCLS at different sizes of FOV varies with both extinction coefficient and CDES while SRCLS varies only with the extinction coefficient, which depends on both LWC and CDES. This means that, after extracting the extinction coefficient using SRCLS, we can easily obtain CDES from IRCLS, and LWC can then be determined using the extinction coefficient. An innovative MFOV Lidar system is constructed to measure the LWC and CDES. A series of experiments is conducted in the northern suburb of Nanjing, China, and the LWC and CDES of homogeneous liquid cloud are obtained. Comparisons among results from the MFOV Lidar, theoretical calculation, and the global precipitation measurement satellite verify our proposed method.

Regulations and patterns of soil moisture dynamics and their controlling factors in hilly regions of lower reaches of Yangtze River basin, China

Time-domain reflectometry was used to make continuous measurements of soil moisture to 18 sample points with depth of 2 m for 36 months in a typical artificial secondary oak forest located in a hilly area on Zijin Mountain in the suburbs of Nanjing, China. The data were then used to examine the patterns of soil moisture variations on temporal and spatial scales and predict the relationships between soil moisture and major factors of both meteorology and topography. Water in the topsoil was active, and the upper 30 cm of soil supplied about 43% of the water content variation during the whole year. This difference of water content changes among layers could be due to the distribution conditions of some soil physical properties. When initial soil moisture was in the range from 10% to 40%, the impact of a single storm event on soil moisture was extremely significant, especially on sunny slope. Both climate and slope condition were related to soil moisture change, and the impact of slope gradient on soil moisture was higher that on shady slope. Moreover, root uptake was another important path of soil water consumption.

Accelerated phosphorus accumulation and acidification of soils under plastic greenhouse condition in four representative organic vegetable cultivation sites

Organic vegetable cultivation under plastic greenhouse conditions is expanding rapidly in the suburb of big cities in China due to the increasing demand for organic, out-of-season green vegetables and the sustainable development of agriculture. Phosphorus (P) is not only an important plant nutrient, but also a major contaminant in the water environment. However, information on the accumulation and distribution of P in organic vegetable soils under plastic greenhouse conditions is limited, relative to the open cultivation systems. Therefore, twenty-six plastic greenhouse vegetable soils (PGVS) were selected randomly from four representative organic vegetable cultivation sites located in the suburb of Nanjing, China. For comparison, 15 open vegetable soils (OVS) near the PGVS with similar soil and cultivation practices were selected. Soil pH, organic matter (OM) and the various P accumulation characteristics were investigated. We found that soil pH in PGVS were significantly decreased by 0.57–1.17 unit with obvious signs of acidification, compared with that in OVS. Soil OM was different for different sampling locations, but in general it was higher in PGVS than OVS. Soil total P (TP), inorganic P (Pi) and Olsen-P of PGVS were higher than those in the OVS. Olsen-P of all soil samples were far above the recommended optimum value of 20mgkg−1 for field crops, and over 60% soil samples were considered excessive (>150mgkg−1) in the PGVS and OVS. There were significant correlations between total P, available P and soil pH in those vegetable soils. Al-P/Fe-P ratio was also significantly correlated with vegetable soil pH (YpH=7.44–1.32 XAl-P/Fe-P, r=− 0.705, p<0.01). Soil total Pi was negatively correlated with soil pH in vegetable soils (r=−0.328, p<0.05), but the interactive effect of soil various Pi and soil pH need to be further investigated through a series of controlled tests. Our results suggest that the rapid P accumulation and acidification make the current plastic greenhouse vegetable production in the study area unsustainable and better organic manure management practices need to be implemented to sustain crop yields while minimizing the impact of vegetable production on the environment.

Studies of a scanning light detection and ranging for three-dimensional detection of plume emission

Aerosol plays an important role in regularization of the earth’s energy balance. Compared with light detection and ranging (LIDAR) pointing vertically, scanning LIDAR is a useful tool for detection of the spatial and temporal distribution of aerosols. A scanning LIDAR is constructed in which a compact 532-nm laser is bound to the telescope. Under the command from the serial port, the LIDAR can observe in different scanning modes. We introduce the structure and key parameters of the scanning LIDAR, and then verify its measurement ability by comparison with the Rayleigh–Raman–Mie LIDAR. Observation of a plume emission from a chemical factory is conducted in the northern suburbs of Nanjing, China. In order to obtain the distribution of the plume emission, the slope method and Fernald method are combined to invert the extinction coefficient of the plume. Analysis of the data shows that the scanning LIDAR can be used to monitor the relative emission concentrations of pollutants and depict the process of the pollutants’ diffusion. The scanning LIDAR can also be used to measure the three-dimensional variation of the extinction coefficient by automatic volume scanning.

Phthalate esters contamination in soils and vegetables of plastic film greenhouses of suburb Nanjing, China and the potential human health risk

The contamination of phthalate esters (PAEs) has become a potential threat to the environment and human health because they could be easily released as plasticizers from the daily supply products, especially in polyethylene films. Concentration levels of total six PAEs, nominated as priority pollutants by the US Environmental Protection Agency (USEPA), were investigated in soils and vegetables from four greenhouse areas in suburbs of Nanjing, East China. Total PAEs concentration ranged from 930 ± 840 to 2,450 ± 710 μg kg(-1) (dry weight (DW)) in soil and from 790 ± 630 to 3,010 ± 2,130 μg kg(-1) in vegetables. Higher concentrations of PAEs were found in soils except in Suo Shi (SS) area and in vegetables, especially in potherb mustard and purple tsai-tai samples. Risk assessment mainly based on the exposures of soil ingestion and daily vegetable intake indicated that bis(2-ethylhexyl) phthalate (DEHP) in the samples from Gu Li (GL) and Hu Shu (HS) exhibited the highest hazard to children less than 6-year old. Therefore, the human health risk of the PAEs contamination in soils and vegetables should greatly be of a concern, especially for their environmental estrogen analog effects.

Source apportionment of VOCs in a suburb of Nanjing, China, in autumn and winter

Volatile organic compounds (VOCs) were measured in a suburb of Nanjing by on-line gas chromatography-flame ionization detector (GC-FID) instruments from September 2011 to January 2012. The measured VOC concentrations are dominated by alkanes (47 %), alkenes (25 %) and aromatics (20 %); in which alkenes attributed 57 % to the propylene-equivalent concentrations and 58 % to the ozone formation potential. The benzene to toluene (B/T) ratio was 1.60 ± 1.28, larger than 1, suggesting that the combustion sources might be significant at this site. Based on the measured VOC concentrations, a receptor model (PCA/APCS; principal component analysis/absolute principal component scores) coupled with the measured VOC source profiles was applied to identify the major VOC sources. Five surrogated VOC sources were identified: fossil-fuel/biomass/biofuel combustion accounted for 28 % of the total VOC concentrations, followed by the combination of solvent usage and industrial sources 1 (26 %), fuel evaporations (23 %), vehicular exhaust (18 %) and industrial sources 2 (5 %). Furthermore, the method was applied to analyze VOC sources in four quadrants (northeast, northwest, southeast and southwest) based on wind directions. Industrial sources were the most significant contributors (33 %) in the NE quadrant; VOCs in the NW quadrant were mainly contributed by the combination of fuel evaporation and fossil fuel/biomass/biofuel combustion (50 %). The most important source in the SE quadrant was the combination of solvent usage and industrial sources 1 (35 %), while 51 % of VOC concentrations were attributed to fossil fuel/biomass/biofuel combustion in the SW quadrant, indicating that the source contributions in various quadrants were quite different. This study may provide useful information for establishing effective air pollution control strategies in this region.

Size Distribution and Source Apportionment of Airborne Metallic Elements in Nanjing, China

In order to investigate the temporal and spatial variations and the size distribution of atmospheric particulate matter and associated airborne elements, atmospheric particulate matter (TSP, PM2.5 and size-segregated aerosol particles) were collected monthly for one year from the traditional central district and suburbs of Nanjing, China. Source identification of airborne elements in PM2.5 was carried out using multivariate statistical analysis. The annual mass concentrations ranged from 49.4 µg/m 3 to 391 µg/m 3 , with a mean of 135 µg/m 3 for TSP and from 20.4 µg/m 3 to 200 µg/m 3 with a mean of 80.5 µg/m 3 for PM2.5. The distribution of annual size-segregated aerosol particles showed a bimodal pattern of coarse and fine particle fractions. Spatial and seasonal variations of elemental composition in atmospheric particulates were observed. The major elements (A1, Ca, Fe, Mg, Na and Mn) were mainly distributed in coarse fractions, while toxic elements, such as As, Cd, Pb and Zn, were significantly enriched in the fine fractions. The enrichment factor indicated anthropogenic inputs of As, Cu, Ni, Pb and Zn in the TSP and PM2.5 examined in this work. Four potential sources for PM2.5 were identified by principal component analysis. The source contributions calculated using absolute principal component scores were 37.5% for the first component, 34.1% for the second, 9.0% for the third and 19.8% for the fourth. The Na/Cr/Cu component identified by principal component analysis was divided into Na/Cr and Cu groups using R-mode cluster analysis of PM2.5, and the Ti in the fourth component was assigned to Cluster 2, indicating a statistical difference in airborne metallic elements. The results of the investigation of element composition, size distribution, and source apportionment carried out in this work can help to better understand and manage the effects of these aerosols on health and air quality.

Chromatographic Fingerprint and the Simultaneous Determination of Five Bioactive Components of Geranium carolinianum L. Water Extract by High Performance Liquid Chromatography

A simple and sensitive HPLC method has been developed in combination with fingerprint analysis and simultaneous determination of five markers, namely gallic acid, corilagin, methyl brevifolincarboxylate, ellagic acid and rutin for evaluation and quality control of Geranium carolinianum L. water extract. Extraction methods were optimized by comparing the hydrolysis efficiency of geraniin, a major tannin of the herb, resulting in the method of extraction with water under reflux. Water extracts were analyzed by HPLC, with a mobile phase of 0.1% aqueous phosphoric acid (v/v) and acetonitrile in a gradient program within 65 min. Compounds were detected at 274 nm UV wavelength. For fingerprint analysis, 17 peaks were selected as the characteristic peaks to evaluate the similarities of different samples collected from the suburb of Nanjing. The correlation coefficients of similarity were greater than 0.993. In quantitative analysis, the five selected markers showed good regression (R > 0.9991) within test ranges, and the average recoveries were between 97.2–101.7% and their RSD values were less than 4.50%. The total contents of the five markers varied from 44.28 to 71.84 mg/g. The method can be very useful for further development of G. carolinianum L. extracts and preparations.

BIZARRE PERMIAN AMMONOID SUBFAMILY AULACOGASTRIOCERATINAE FROM SOUTHEAST CHINA

Since the 1960s, Chinese researchers have reported a series of bizarre paragastrioceratids associated with the endemic pseudohaloritids and/or kufengoceratins from the Permian Restricted-Sea area of Southeast China. They include Aulacogastrioceras Zhao and Zheng, 1977; “ Paragastrioceras ” carinatum Chao, 1965 (invalid name, = Chekiangoceras carinatum Ruzhencev, 1974, type species of the genus Chekiangoceras Ruzhencev, 1974); “ Paragastrioceras ” dongwuliense Zhao and Zheng, 1977; and Nodogastrioceras Ma and Li, 1998 (= Yongpingoceras Ma and Li, 1998; including “ Paragastrioceras ” dongwuliense ). All these taxa share the following characteristic features: 1) an eight-lobed paragastrioceratid suture; 2) a variably shaped, evolute conch, and prominent sculpture with transverse ribs, nodes, and coarse strigae in all ontogenetic stages, suggesting an affinity with the subfamily Paragastrioceratinae; 3) and, by contrast, a conspicuous ventral sinus formed by growth lines and constrictions, indicating a phylogenetic relationship to the subfamily Pseudogastrioceratinae. These endemic Chinese paragastriocertids constitute a separate subfamily, distinct from both Paragastrioceratinae and Pseudogastrioceratinae, for which the subfamily Aulacogastrioceratinae is herein proposed. The genus Nodogastrioceras was established by Ma and Li (1998) on the basis of specimens from the Hutang Formation of northeast Jiangxi. Actually, forms identical to the type species, N. discum Ma and Li, 1998, had been known since the 1950s from the Kufeng Formation in outcrops and quarries south of Longtan town, an eastern suburb of Nanjing, Jiangsu. However, most of these specimens are preserved as impressions that do not show sutures and ventral characteristics, and they were typically identified as “ Paragastrioceras ” by previous authors, based on conch shape and sculpture. The latter identification was problematic, however, because the fossil-bearing Kufeng Formation is no older than Middle Permian (Roadian), whereas true Paragastrioceras Tchernow, 1907 is restricted to the Lower Permian (Asselian through Kungurian). Chao (1965) had even considered …

Residual Levels and Bioaccumulation of Chlorinated Persistent Organic Pollutants (POPs) in Vegetables from Suburb of Nanjing, People’s Republic of China

Residual Levels and Bioaccumulation of Chlorinated Persistent Organic Pollutants (POPs) in Vegetables from Suburb of Nanjing, People’s Republic of China

Spectral Characteristics and Multi-Scale Structure of the Boundary-Layer Wind Field During Cold Front Passages Over East China

In this paper, data obtained from a 164 m and a195 m meteorological tower in the northern suburb ofNanjing have been used to estimate and analyzetime-space distributions for velocity spectra andscales of multi-scaling turbulence during thepassages of two cold fronts. Results show that anon-precipitating weak cold front and aprecipitating cold front were clearly revealed bytheir wind field structures. The frontal passageinfluenced all meteorological variables over aperiod of 18–24 hours for the former, and a longerperiod of 44–56 hours for the latter. During these periods there occurred gust surges and eddymotions of various meso- and micro-scales with periodsof 3–4 hours and 1–20 minutes respectively. In the inertialsubrange Kolmogorov's ‘-2/3’ power law for thevelocity spectrum is partly distorted and theturbulence in the atmospheric boundary layer is not isotropic.