scholarly journals Impact of Sediment-Spiked Fludioxonil On Benthic Macroinvertebrates And Zooplankton From The Yangtze River Delta, China

2021 ◽  
Author(s):  
Jian Sun ◽  
Pengfei Xiao ◽  
Xiaohui Yin ◽  
Kun Zhang ◽  
Guonian Zhu ◽  
...  
Keyword(s):  
Benthic Macroinvertebrates ◽  
Benthic Invertebrates ◽  
Yangtze River ◽  
Single Species ◽  
Yangtze River Delta ◽  
The Yangtze River ◽  
Microcosm Experiment ◽  
The Yangtze River Delta ◽  
Assessment Factor

Abstract In China, the fungicide fludioxonil, that accumulates and persists in sediments, has a widespread agricultural use to control various fungal diseases. Its residues may cause toxic effects to benthic and pelagic aquatic fauna, thereby impacting ecosystem service functions of aquatic ecosystems.To assess the environmental risks of fludioxonil, sediment-spiked single-species toxicity tests with benthic macroinvertebrates as well as a sediment-spiked indoor freshwater microcosm experiment were performed. The microcosm test systems were populated with benthic invertebrates also used in the single-species tests. In all experiments artificial sediment was used. The single-species tests were conducted with 8 benthic macroinvertebrates covering different taxonomic groups typical for the Yangtze River Delta, China. The 28d-EC10 values thus obtained were used to construct species sensitivity distributions (SSDs) and the hazardous concentration to 5% of the species tested (HC5) was used to derive a provisional long-term Tier-2 regulatory acceptable concentration (RAC) for benthic invertebrates by applying an assessment factor of 3.The microcosm experiment was conducted to study treatment-related responses of benthic macroinvertebrates and pelagic zooplankton. The lowest No Observed Effect Concentrations (NOECs) of benthic invertebrate and of pelagic zooplankton populations were used to derive provisional long-term Tier-3 RACs for, respectively, benthic and pelagic invertebrates by applying an assessment factor of 2. The RACs thus obtained were compared with Predicted Environmental Concentrations (PECs) of fludioxonil in overlying water and the sediment compartment of edge-of-field ponds after application of this fungicide in rice, grape, wheat, maize and tomato crops. Overall, the risks of long-term exposure of fludioxonil to benthic invertebrates and pelagic zooplankton species in these Chinese edge-of-field ponds appear to be relatively small, but some risks cannot be excluded for ponds adjacent to rice.

Long-term trend of haze pollution and impact of particulate matter in the Yangtze River Delta, China

2013 ◽  
Vol 182 ◽  
pp. 101-110 ◽  
Author(s):  
Zhen Cheng ◽  
Shuxiao Wang ◽  
Jingkun Jiang ◽  
Qingyan Fu ◽  
Changhong Chen ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
The Yangtze River ◽  
Term Trend ◽  
Haze Pollution ◽  
Long Term Trend ◽  
The Yangtze River Delta

scholarly journals Separating emission and meteorological contributions to long-term PM<sub>2.5</sub> trends over eastern China during 2000–2018

2021 ◽  
Vol 21 (12) ◽  
pp. 9475-9496
Author(s):  
Qingyang Xiao ◽  
Yixuan Zheng ◽  
Guannan Geng ◽  
Cuihong Chen ◽  
Xiaomeng Huang ◽  
...  
Keyword(s):  
Machine Learning ◽  
Yangtze River ◽  
Eastern China ◽  
Yangtze River Delta ◽  
Meteorological Conditions ◽  
River Delta ◽  
The Yangtze River ◽  
The Yangtze River Delta ◽  
Meteorological Effects

Abstract. The contribution of meteorology and emissions to long-term PM2.5 trends is critical for air quality management but has not yet been fully analyzed. Here, we used the combination of a machine learning model, statistical method, and chemical transport model to quantify the meteorological impacts on PM2.5 pollution during 2000–2018. Specifically, we first developed a two-stage machine learning PM2.5 prediction model with a synthetic minority oversampling technique to improve the satellite-based PM2.5 estimates over highly polluted days, thus allowing us to better characterize the meteorological effects on haze events. Then we used two methods to examine the meteorological contribution to PM2.5: a generalized additive model (GAM) driven by the satellite-based full-coverage daily PM2.5 retrievals and the Weather Research and Forecasting/Community Multiscale Air Quality (WRF/CMAQ) modeling system. We found good agreements between GAM estimations and the CMAQ model estimations of the meteorological contribution to PM2.5 on a monthly scale (correlation coefficient between 0.53–0.72). Both methods revealed the dominant role of emission changes in the long-term trend of PM2.5 concentration in China during 2000–2018, with notable influence from the meteorological condition. The interannual variabilities in meteorology-associated PM2.5 were dominated by the fall and winter meteorological conditions, when regional stagnant and stable conditions were more likely to happen and when haze events frequently occurred. From 2000 to 2018, the meteorological contribution became more unfavorable to PM2.5 pollution across the North China Plain and central China but were more beneficial to pollution control across the southern part, e.g., the Yangtze River Delta. The meteorology-adjusted PM2.5 over eastern China (denoted East China in figures) peaked in 2006 and 2011, mainly driven by the emission peaks in primary PM2.5 and gas precursors in these years. Although emissions dominated the long-term PM2.5 trends, the meteorology-driven anomalies also contributed −3.9 % to 2.8 % of the annual mean PM2.5 concentrations in eastern China estimated from the GAM. The meteorological contributions were even higher regionally, e.g., −6.3 % to 4.9 % of the annual mean PM2.5 concentrations in the Beijing-Tianjin-Hebei region, −5.1 % to 4.3 % in the Fenwei Plain, −4.8 % to 4.3 % in the Yangtze River Delta, and −25.6 % to 12.3 % in the Pearl River Delta. Considering the remarkable meteorological effects on PM2.5 and the possible worsening trend of meteorological conditions in the northern part of China where air pollution is severe and population is clustered, stricter clean air actions are needed to avoid haze events in the future.

Observed long-term differential settlement of metro structures built on soft deposits in the Yangtze River Delta region of China

2020 ◽  
Vol 57 (6) ◽  
pp. 840-850
Author(s):  
Honggui Di ◽  
Shunhua Zhou ◽  
Peijun Guo ◽  
Chao He ◽  
Xiaohui Zhang ◽  
...  
Keyword(s):  
Yangtze River ◽  
Yangtze River Delta ◽  
Differential Settlement ◽  
Bridge Piers ◽  
The Yangtze River ◽  
Yangtze River Delta Region ◽  
Adjacent Structures ◽  
Elevated Structure ◽  
The Yangtze River Delta

In this study, the measured differential settlements of five metro lines built on soft deposits were analyzed. The different structural combinations at various characteristic locations in the metro lines were examined, including at 67 joints of stations and tunnels, 55 connecting passage locations, 4 wind well locations, and at 3 joints of U-shaped grooves and adjacent structures. Moreover, the differential settlement between the track slabs and the bridge piers of a 16.57 km long elevated structure was analyzed. The results showed that the settlements of ∼85% of the stations were less than those of adjacent shield tunnels, and the settlements at the connecting passages of ∼73% of the tunnels were greater than those on either sides of the tunnel. The wind well exhibited lower settlement than its adjacent tunnels. The settlement of the U-shaped groove was greater than that of its adjacent elevated structure, but was less than those of the cut-and-cover and shield tunnels. Approximately 86% of the track slabs exhibited arch deformation, and the settlements of the bridge piers were greater than those of the track slabs. The stiffness transition between the different structures should be considered in the design of metro structures on soft deposits.

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