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Ding J.,Beijing Normal University | Xi B.,Chinese Research Academy of Environmental Sciences | Gao R.,Chinese Research Academy of Environmental Sciences | He L.,Chinese Research Academy of Environmental Sciences | And 3 more authors.
Science of the Total Environment | Year: 2014

Nitrate (NO3 -) pollution is a severe problem in aquatic systems in Taihu Lake Basin in China. A dual isotope approach (δ15NNO3 - and δ18ONO3 -) was applied to identify diffused NO3 - inputs in a stream in an agricultural field at the basin in 2013. The site-specific isotopic characteristics of five NO3 - sources (atmospheric deposition, AD; NO3 - derived from soil organic matter nitrification, NS; NO3 - derived from chemical fertilizer nitrification, NF; groundwater, GW; and manure and sewage, M&S) were identified. NO3 - concentrations in the stream during the rainy season [mean±standard deviation (SD)=2.5±0.4mg/L] were lower than those during the dry season (mean±SD=4.0±0.5mg/L), whereas the δ18ONO3 - values during the rainy season (mean±SD=+12.3±3.6‰) were higher than those during the dry season (mean±SD=+0.9±1.9‰). Both chemical and isotopic characteristics indicated that mixing with atmospheric NO3 - resulted in the high δ18O values during the rainy season, whereas NS and M&S were the dominant NO3 - sources during the dry season. A Bayesian model was used to determine the contribution of each NO3 - source to total stream NO3 -. Results showed that reduced N nitrification in soil zones (including soil organic matter and fertilizer) was the main NO3 - source throughout the year. M&S contributed more NO3 - during the dry season (22.4%) than during the rainy season (17.8%). AD generated substantial amounts of NO3 - in May (18.4%), June (29.8%), and July (24.5%). With the assessment of temporal variation of diffused NO3 - sources in agricultural field, improved agricultural management practices can be implemented to protect the water resource and avoid further water quality deterioration in Taihu Lake Basin. © 2014.

Li C.,Nanjing Forestry University | Chao W.,Changzhou Environmental Monitoring Center | Dai X.,Changzhou Environmental Monitoring Center
Chinese Journal of Environmental Engineering | Year: 2015

Indirect air-acetylene flame atomic absorption spectrometry is the widely used detection method and can be easily popularized for determination of aluminum in China. The interference of Mg2+, Ca2+, Zn2+, Ni2+ to the measurement of Al3+ (0.40 mg/L) were studied separately. The results showed that:(1) no-interference concertration limitation of Mg2+, Ca2+, Zn2+and Ni2+ for the determination of the solution Al3+ (0.40 mg/L) were 15.10 mg/L, 105.00 mg/L, 0.23 mg/L and 0.88 mg/L, respectively within the scope of ±5% error. (2) Despite of its complex operation, this method has been characterized by lower cost, higher sensitivity, wider detecting concentration and better stability. Considering the recovery rate (96%~99%), detection limitation (0.04 mg/L) and measurement range (0.05~100 mg/L), this method is suitable for determining of Al3+ in the drinking water, river water and underground water. ©, 2015, Science Press. All right reserved.

PubMed | Beijing Normal University, Chinese Research Academy of Environmental Sciences and Changzhou Environmental Monitoring Center
Type: | Journal: Journal of environmental sciences (China) | Year: 2015

The great spatial and temporal variability in hydrological conditions and nitrogen (N) processing introduces large uncertainties to the identification of N sources and quantifying N cycles in plain river network regions. By combining isotopic data with chemical and hydrologic measurements, we determined the relative importance of N sources and biogeochemical N processes in the Taige River in the East Plain Region of China. The river was polluted more seriously by anthropogenic inputs in winter than in summer. Manure and urban sewage effluent were the main nitrate (NO3-) sources, with the nitrification of N-containing organic materials serving as another important source of NO3-. In the downstream, with minor variations in hydrological conditions, nitrification played a more important role than assimilation for the decreasing ammonium (NH4+-N) concentrations. The N isotopic enrichment factors () during NH4+ utilization ranged from -13.88 in March to -29.00 in July. The ratio of the increase in 18O and 15N of river NO3- in the downstream was 1.04 in January and 0.92 in March. This ratio indicated that NO3- assimilation by phytoplankton was responsible for the increasing 15N and 18O values of NO3- in winter. The relationships between 15N of particulate organic nitrogen and isotopic compositions of dissolved inorganic nitrogen indicated that the phytoplankton in the Taige River probably utilized NH4+ preferentially and mainly in summer, while in winter, NO3- assimilation by phytoplankton was dominant.

Xiang C.,Hohai University | Liu X.,Hohai University | Jiang A.,Hohai University | Yan B.,Shandong University of Science and Technology | Xia J.,Changzhou Environmental Monitoring Center
MobiSys 2016 Companion - Companion Publication of the 14th Annual International Conference on Mobile Systems, Applications, and Services | Year: 2016

Urban air quality in China has been a social concern because of the impact on public health. However, traditional equipments at fixed location only report a global index of the whole city, rather than an index of local area in a city. We present a mobile sensing system using a public bicycle system for monitoring urban air quality, which has a low cost and high spatial resolution. An approach was proposed to calibrate the bicycle- borne sensor. The test indicates that the calibrated data from our sensors approximate to the governmental measurements, and it is feasible to create high-resolution air pollution maps using our mobile sensing system based on the shared bicycle network. © 2016 Copyright held by the owner/author(s).

Ma Z.,Nanjing University | Ma Z.,Emory University | Hu X.,Emory University | Sayer A.M.,Universities Space Research Association | And 8 more authors.
Environmental Health Perspectives | Year: 2016

Background: Three decades of rapid economic development is causing severe and widespread PM2.5 (particulate matter ≤ 2.5 μm) pollution in China. However, research on the health impacts of PM2.5 exposure has been hindered by limited historical PM2.5 concentration data. Objectives: We estimated ambient PM2.5 concentrations from 2004 to 2013 in China at 0.1° resolution using the most recent satellite data and evaluated model performance with available ground observations. Methods: We developed a two-stage spatial statistical model using the Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6 aerosol optical depth (AOD) and assimilated meteorology, land use data, and PM2.5 concentrations from China’s recently established ground monitoring network. An inverse variance weighting (IVW) approach was developed to combine MODIS Dark Target and Deep Blue AOD to optimize data coverage. We evaluated modelpredicted PM2.5 concentrations from 2004 to early 2014 using ground observations. Results: The overall model cross-validation R2 and relative prediction error were 0.79 and 35.6%, respectively. Validation beyond the model year (2013) indicated that it accurately predicted PM2.5 concentrations with little bias at the monthly (R2 = 0.73, regression slope = 0.91) and seasonal (R2 = 0.79, regression slope = 0.92) levels. Seasonal variations revealed that winter was the most polluted season and that summer was the cleanest season. Analysis of predicted PM2.5 levels showed a mean annual increase of 1.97 μg/m3 between 2004 and 2007 and a decrease of 0.46 μg/m3 between 2008 and 2013. Conclusions: Our satellite-driven model can provide reliable historical PM2.5 estimates in China at a resolution comparable to those used in epidemiologic studies on the health effects of long-term PM2.5 exposure in North America. This data source can potentially advance research on PM2.5 health effects in China. © 2016, Public Health Services, US Dept of Health and Human Services. All rights reserved.

Su G.,Nanjing University | Saunders D.,University of Saskatchewan | Yu Y.,Nanjing University | Yu Y.,Changzhou Environmental Monitoring Center | And 6 more authors.
Chemosphere | Year: 2014

Since the phase-out of PBDEs, reports regarding occurrences of these compounds in the environment have become less frequent. To characterize potential influences of the phase-out of PBDEs' on concentrations in the environment, trends in concentrations as a function of time were investigated for two additive brominated flame retardants, PBDEs and HBCDs. Three aquatic species, including shrimp, common carp, and yellow catfish, were collected from Meiliang Bay of Tai Lake, 2009-2012. The analysis of PBDEs in three aquatic organisms has shown a downward-trend in the first three years but a significant upward-trend in the final year. Concentrations of HBCDs have not shown temporal increases in the investigated environments. Concentrations of both PBDEs and HBCDs in the three studied organisms increased as a function of trophic level, which suggested that these additive flame retardants can be biomagnified through the food web of Tai Lake. In accordance with previous publications, PBDE-47 contributed the greatest proportion of ∑PBDEs and had a detection frequency of 100% α-HBCD was the predominate isomer that contributed to ∑HBCDs. Both β-HBCD and γ-HBCD were likely detected at lesser concentrations than the α-isomer due to differences in bioavailability. Concentrations of ∑PBDEs in the three aquatic organisms from Tai Lake ranged from 1.13 to 97.59ngg-1 lipid. These concentrations were generally less than those in biota from other countries, but equal to those found at other locations in China. Specimens from the Yangtze River had greater concentrations of ∑HBCDs (169.6-316.5ngg-1 lipid) than those collected at Tai Lake, which were comparatively greater than many reported concentrations in freshwater organisms from other countries. © 2014 Elsevier Ltd.

Shi H.,East China Normal University | Sun Z.,East China Normal University | Liu Z.,Shanghai Ocean University | Xue Y.,Changzhou Environmental Monitoring Center
Toxicological and Environmental Chemistry | Year: 2012

Pharmaceuticals have been recognized as a continuing threat to environmental stability. Few experimental data are available for the effects of clotrimazole and amiodarone on the ecological environment. An acute test with embryos and a chronic test with larvae of amphibian (Xenopus tropicalis) were thus conducted to determine the influence of clotrimazole or amiodarone on early amphibian development. In acute test, % survival and the body length were numerically decreased by both pharmaceuticals treatments compared to control. In chronic test, the cumulative mortality was 22.2% with 0.1 μg L -1 clotrimazole treatment and 21.7% with 1 μg L -1 amiodarone. The whole body length and the biomass were significantly decreased and developmental stages significantly delayed by both pharmaceuticals. The results of our study suggest that clotrimazole exerted adverse effects on larvae of X. tropicalis at environmentally relevant concentrations. © 2011 Taylor and Francis Group, LLC.

PubMed | East China Normal University and Changzhou Environmental Monitoring Center
Type: Journal Article | Journal: Journal of applied toxicology : JAT | Year: 2016

The frog embryo teratogenesis assay-Xenopus (FETAX) is an established method to evaluate the developmental toxicity of chemicals. In FETAX, a 48h continuous exposure is usually conducted when the X. tropicalis embryo is used as the test model. In the present study, we exposed X. tropicalis embryos to nine known teratogens for four separate 12-h periods. The embryos showed great variations in response to nine tested compounds during different exposure periods. Based on the value of the score of malformations, the most sensitive 12h exposure periods of embryos were significantly distinguished for all the compounds with the exception of NiCl2 . The embryos were the most sensitive to retinols (e.g. all-trans-retinoic acid and 9-cis-retinoic acid) during 0-12h and to metal compounds (e.g. triphenlytin and CdCl2) during a 24 to 36h exposure period. In the further 3h exposure experiment, the most sensitive period could only be determined for one of three tested compounds. Based on the present results, we proposed an assay to determine a 12h sensitive window of embryos to chemical exposure using Xenopus tropicalis.

PubMed | Changzhou Environmental Monitoring Center, CAS Wuhan Institute of Hydrobiology and CAS Chongqing Institute of Green and Intelligent Technology
Type: Journal Article | Journal: Toxins | Year: 2016

Lake Taihu is the third-largest freshwater lake in China and has been suffering from cyanobacterial blooms for over two decades. The northern part of the lake, Meiliang Bay, is known to be at high risk of dense and sustained Microcystis blooms and toxins. This study aimed to investigate and record the annual and seasonal dynamics of toxic genotype, Microcystis morphospecies succession and microcystin variation. It also aimed to find out the underlying driving factors influencing the dynamic changes. Microcystin (MC) and the Microcystis genotype were quantified using HPLC and quantitative real-time PCR, respectively. Our study, over three consecutive years, showed that the pattern of morphospecies succession was seasonally distinct and annually consistent. During the same period in 2012, 2013 and 2014, the average MC were, on dry weight basis, 733 gg(-1), 844 gg(-1), 870 gg(-1), respectively. The proportion of toxic Microcystis accounted for 41%, 44% and 52%, respectively. Cell bound microcystin was found to correlate with the percentage of toxic Microcystis. Based on historical and current data, we conclude that annual bloom toxicity was relatively stable or possibly increased over the last decade.

PubMed | East China Normal University, National Marine Environmental Monitoring Center and Changzhou Environmental Monitoring Center
Type: | Journal: Chemosphere | Year: 2016

Microplastic is an emerging contaminant affecting freshwater and marine ecosystem across the globe. In the present study, the filter feeding tadpoles of Xenopus tropicalis were exposed to polystyrene microspheres (1 and 10m) for 48h. Microspheres were observed in gills and digestive tract of tadpoles within 1h after exposure as well as in feces 6h after exposure. The accumulation of microspheres in the tadpoles were concentration dependent (Univariate ANOVA, p<0.001), but no time dependent accumulation of microspheres was observed in tadpoles 48h after exposure (Univariate ANOVA, p>0.05). After the exposed tadpoles were transferred to clean water, the number of microspheres in the tadpoles decreased dramatically after 1d and continued to decrease gradually afterwards. The absorbed polystyrene particles in unfed tadpoles was significantly higher than those in the fed tadpoles at 12 and 24h after exposure. After transfer to clean water, the fed tadpoles showed a significant decrease in the amount of absorbed polystyrene particles, while the unfed tadpoles showed no significant change in the amount of absorbed polystyrene particles. Our results suggested that microspheres were likely to be ingested and egested relatively fast by tadpoles. Our results indicated that aquatic vertebrate organisms might ingest more microplastics if the abundance of microplastics continues to increase while the available food becomes less.

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