Hydrogeochemical processes and vulnerability of a typical karst underground river system, southwest China

2015 ◽  
Vol 49 (3) ◽  
pp. 259-269 ◽  
Author(s):  
Xuchun Ye ◽  
Pingheng Yang ◽  
Qi Zhang
Keyword(s):  
Southwest China ◽  
River System ◽  
Hydrogeochemical Processes ◽  
Underground River

scholarly journals Anthropogenic Disturbances and Precipitation Affect Karst Sediment Discharge in the Nandong Underground River System in Yunnan, Southwest China

2020 ◽  
Vol 12 (7) ◽  
pp. 3006 ◽  
Author(s):  
Yanqing Li ◽  
Zhongcheng Jiang ◽  
Zhihua Chen ◽  
Yang Yu ◽  
Funing Lan ◽  
...  
Keyword(s):  
Southwest China ◽  
Driving Forces ◽  
Erosion Control ◽  
River System ◽  
Control Measures ◽  
Anthropogenic Factors ◽  
Sediment Discharge ◽  
Forest Protection ◽  
Conservation Projects ◽  
Underground River

In fragile karst environments that have seen past and current human exploitation of agricultural and forest resources, the quantification of underground riverine sediment has been widely used to evaluate subterranean stream basin erosion. These measures are highly influenced by both precipitation and anthropogenic factors; therefore, soil erosion control measures must be urgently designed and applied. In this study, 17 years of sediment discharge across the Nandong underground river system in southwest China was monitored. To achieve this goal, the Mann–Kendal mutation test and proxy indicators were used to estimate the general influence of human activities and precipitation on sediment discharge. The results showed that: (1) Both anthropologic disturbance and rainfall have impacted the sediment discharge, although the influence of the anthropologic factor on sediment discharge was greater (61.53%), and (2) rainfall showed a hysteresis effect on sediment discharge. We obtained three different stages based on the mutation points and variation characteristics of the studied sediment discharge resulting from different driving forces, from 1998 to 2014. Prior to 2004, in the whole basin, the decrease of sediment yield was the result of the Natural Forest Protection Project. During the period from 2004 to 2008, due to continuous droughts, flood disasters, and intensive cultivation practices on the steeper hillslopes, the total sediment discharge of the whole basin increased. After 2009, the sediment discharge decreased due to the development of soil conservation projects and mushrooming reservoirs. These findings are expected to provide insights into watershed management and ecological restoration in fragile karst ecosystems, specifically, in southwestern Chinese river systems. More research must be conducted to monitor, with in situ measurements and observations, possible extreme events that can determine the exact erosion control measures that need to be designed and applied.

scholarly journals The occurrence and distribution of antibiotics in the Karst river system in Kaiyang, Southwest China

2018 ◽  
Vol 18 (6) ◽  
pp. 2044-2052 ◽  
Author(s):  
Shengzhang Zou ◽  
Fuyang Huang ◽  
Liang Chen ◽  
Fei Liu
Keyword(s):  
Southwest China ◽  
River Flow ◽  
Wastewater Treatment Plants ◽  
River System ◽  
Contamination Source ◽  
Antibiotic Concentration ◽  
Detection Frequency ◽  
Karst River ◽  
Flow Quantity ◽  
Total Concentrations

Abstract To our knowledge, this was the first study to investigate the occurrence and distribution of antibiotics in the Karst river system in Kaiyang, Southwest China. Ten water samples were collected from the Karst river in Kaiyang, Southwest China. Thirty-five antibiotics, including nine sulfonamides, four tetracyclines, five macrolides, sixteen quinolones and chloramphenicol, were analyzed. The results suggest that antibiotics are widely prevalent in the Karst river, with macrolides and quinolones being the most dominant and occupying 47% and 43% of total antibiotic concentration, respectively. The maximum total concentrations of sulfonamides, tetracyclines, macrolides, and quinolones were 30.4, 421, 884, and 1,807 ng/L, respectively. Lincomycin, roxithromycin, nalidixic acid, ofloxacin, and norfloxacin were detected in all samples with a detection frequency of 100%. The main sources of antibiotics were wastewater treatment plants (WWTPs) and rural dumps that did not contain sanitary treatment, which accounted for 33% and 40% of the total antibiotics present in the Karst river. Due to an increase in river flow quantity, the presence of WWTPs and rural dumps did not affect the concentration and distribution of antibiotics in the Karst river; however, the mass flux of antibiotics were significantly affected by the contamination source and the poor natural attenuation.

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