The occurrence of organochlorine pesticides (OCPs) in riverine sediments of hilly region of southern China: Implications for sources and transport processes

2020 ◽  
Vol 216 ◽  
pp. 106580
Author(s):  
Xionghu Gong ◽  
Qianyu Li ◽  
Lu Zhang ◽  
Zhonghua Zhao ◽  
Bin Xue ◽  
...  
Keyword(s):  
Organochlorine Pesticides ◽  
Southern China ◽  
Transport Processes ◽  
Hilly Region ◽  
Riverine Sediments

scholarly journals Mineral leaching chemicals transport with runoff and sediment from severely eroded rare earth tailings in southern China

2017 ◽  
Author(s):  
Huizhong Lu ◽  
Longxi Cao ◽  
Yin Liang ◽  
Jiuqin Yuan ◽  
Yayun Zhu ◽  
...  
Keyword(s):  
Rare Earth ◽  
Southern China ◽  
Transport Processes ◽  
Clear Trend ◽  
Rainfall Events ◽  
Transport Distance ◽  
Sediment Deposits ◽  
Rare Earth Tailings ◽  
Positive Correlations ◽  
Mineral Leaching

Abstract. Rare earth mining has led to severe soil erosion in southern China. Furthermore, the presence of the mineral leaching chemical ammonium sulfate in runoff and sediment poses a serious environmental threat to downstream water bodies. To study the transport characteristics of mineral leaching chemicals, soil on rare earth tailings was sampled in different positions, and runoff and sediment samples were collected along flow routes during three typical rainfall events. The results demonstrated that the NH4+ contents in the surface sediment deposits increased from the top of the heap (6.56 mg/kg) to the gully (8.23 mg/kg) and outside the tailing heap (13.03 mg/kg). The contents of SO42− in the different locations of the tailing heaps ranged from 27.71 to 40.33 mg/kg. During typical rainfall events, the absorbed NH4+ concentrations (2.05, 1.26 mg/L) in runoff were higher than the dissolved concentrations (0.93, 1.04 mg/L), while the absorbed SO42− concentrations (2.87, 1.92 mg/L) were lower than the dissolved concentrations (6.55, 7.51 mg/L). The dissolved NH4+ and SO42− concentrations in runoff displayed an exponentially decreasing tendency with increasing transport distance (Y=1.02*exp(-0.00312X), Y=3.34*exp(-0.0185X)). No clear trend with increasing distance was observed for the absorbed NH4+ and SO42− contents in transported sediment. The NH4+ and SO42− contents had positive correlations with the silt and clay ratio in transported sediment but negative correlations with the sand ratio. These results provide a better understanding of the transport processes and can be used to develop equations to predict the transport of mineral leaching chemicals in rare earth tailings.

Runoff processes and lateral transport of soil total carbon induced by water erosion in the hilly region of southern China under rainstorm conditions

Geomorphology ◽  
2019 ◽  
Vol 340 ◽  
pp. 143-152 ◽  
Author(s):  
Kai Fei ◽  
Longzhou Deng ◽  
Tianyu Sun ◽  
Liping Zhang ◽  
Yanhong Wu ◽  
...  
Keyword(s):  
Southern China ◽  
Water Erosion ◽  
Total Carbon ◽  
Lateral Transport ◽  
Hilly Region

scholarly journals Mineral-leaching chemical transport with runoff and sediment from severely eroded rare-earth tailings in southern China

Solid Earth ◽  
2017 ◽  
Vol 8 (4) ◽  
pp. 845-855 ◽  
Author(s):  
Huizhong Lu ◽  
Longxi Cao ◽  
Yin Liang ◽  
Jiuqin Yuan ◽  
Yayun Zhu ◽  
...  
Keyword(s):  
Rare Earth ◽  
Soil Erosion ◽  
Southern China ◽  
Transport Processes ◽  
Clear Trend ◽  
Natural Rainfall ◽  
Transport Distance ◽  
Sediment Deposits ◽  
Rare Earth Tailings ◽  
Mineral Leaching

Abstract. Rare-earth mining has led to severe soil erosion in southern China. Furthermore, the presence of the mineral-leaching chemical ammonium sulfate in runoff and sediment poses a serious environmental threat to downstream water bodies. In this paper, the characteristics of mineral-leaching chemicals in surface soil samples collected in the field were studied. In addition, NH4+ and SO42− transport via soil erosion was monitored using runoff and sediment samples collected during natural rainfall processes. The results demonstrated that the NH4+ contents in the surface sediment deposits increased from the top of the heap (6.56 mg kg−1) to the gully (8.23 mg kg−1) and outside the tailing heap (13.03 mg kg−1). The contents of SO42− in the different locations of the tailing heaps ranged from 27.71 to 40.33 mg kg−1. During typical rainfall events, the absorbed NH4+ concentrations (2.05, 1.26 mg L−1) in runoff were significantly higher than the dissolved concentrations (0.93, 1.04 mg L−1), while the absorbed SO42− concentrations (2.87, 1.92 mg L−1) were significantly lower than the dissolved concentrations (6.55, 7.51 mg L−1). The dissolved NH4+ and SO42− concentrations in runoff displayed an exponentially decreasing tendency with increasing transport distance (Y = 1. 02 ⋅ exp( − 0. 00312X); Y = 3. 34 ⋅ exp( − 0. 0185X)). No clear trend with increasing distance was observed for the absorbed NH4+ and SO42− contents in transported sediment. The NH4+ and SO42− contents had positive correlations with the silt and clay ratio in transported sediment but negative correlations with the sand ratio. These results provide a better understanding of the transport processes and can be used to develop equations to predict the transport of mineral-leaching chemicals in rare-earth tailings, which can provide a scientific foundation for erosion control and soil management in rare-earth tailing regions in southern China.

Impacts of forest types on soil C, N and DOC loss in runoff in the laterite hilly region of southern China

2015 ◽  
Vol 74 (2) ◽  
pp. 1391-1402 ◽  
Author(s):  
Sun Liying ◽  
Yang Fengting ◽  
Wang Jingyuan ◽  
Fang Haiyan ◽  
Qi Junyu
Keyword(s):  
Southern China ◽  
Forest Types ◽  
Soil C ◽  
Hilly Region

ORGANOCHLORINE PESTICIDES IN SEAFOOD PRODUCTS FROM SOUTHERN CHINA AND HEALTH RISK ASSESSMENT

2007 ◽  
Vol 26 (6) ◽  
pp. 1109 ◽  
Author(s):  
Jian-Yang Guo ◽  
Eddy Y. Zeng ◽  
Feng-Chang Wu ◽  
Xiang-Zhou Meng ◽  
Bi-Xian Mai ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Health Risk ◽  
Organochlorine Pesticides ◽  
Health Risk Assessment ◽  
Southern China ◽  
Seafood Products

scholarly journals Comprehensive selection of the wood properties of Paulownia clones grown in the hilly region of southern China

BioResources ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 1098-1111
Author(s):  
Yanzhi Feng ◽  
Lingjun Cui ◽  
Yang Zhao ◽  
Jie Qiao ◽  
Baoping Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Genetic Parameters ◽  
Southern China ◽  
Selection Index ◽  
Genetic Correlations ◽  
Wood Properties ◽  
Color Difference ◽  
Hilly Region ◽  
Cleavage Strength ◽  
Selection Of

The wood properties of Paulownia clones determine their ultimate price and uses. This study selected superior clones with good color and mechanical properties using selection indexes. Variation in 23 5-year-old Paulownia clones was analyzed using genetic parameters, correlation analysis, and a comprehensive assessment of two color characteristics [color difference (ΔE) and whiteness (WH)] and six mechanical properties [density (ρ), hardness of the tangential, radial, and end surfaces (Ht, Hr, and He), and cleavage strength of the tangential and radial surfaces (qt, qr)]. There were significant differences (p < 0.01) in each of the eight traits among the 23 clones. There were significant negative phenotypic and genetic correlations between ΔE and WH. The six mechanical properties were significantly positively correlated genetically, showing significant positive phenotypic correlations with each other, except for ρ, Ht, and qt. With a selection rate of 8.70%, clones MB04 and L01 were selected as superior using the comprehensive selection index. Compared with the control (9501), the genetic gains of clones MB04 and L01 in ΔE, WH, ρ, qr, qt, He, Hr, and Ht were 0.40, 0.21, 10.32, 12.57, 14.81, 26.05, 28.04, and 6.84%, respectively, and the actual gains were 0.59, 0.31, 17.21, 28.45, 28.09, 34.90, 40.08, and 11.12%.

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