scholarly journals Occurrence, distribution and seasonal variation of organophosphate flame retardants and plasticizers in urban surface water in Beijing, China

2016 ◽  
Vol 209 ◽  
pp. 1-10 ◽  
Author(s):  
Yali Shi ◽  
Lihong Gao ◽  
Wenhui Li ◽  
Yuan Wang ◽  
Jiemin Liu ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Surface Water ◽  
Flame Retardants ◽  
Urban Surface ◽  
Beijing China

scholarly journals Occurrence, distribution and risks of antibiotics in urban surface water in Beijing, China

2015 ◽  
Vol 17 (9) ◽  
pp. 1611-1619 ◽  
Author(s):  
Wenhui Li ◽  
Lihong Gao ◽  
Yali Shi ◽  
Jiemin Liu ◽  
Yaqi Cai
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Urban Surface ◽  
Beijing China

The occurrence and distribution of 22 antibiotics, including eight fluoroquinolones, nine sulfonamides and five macrolides, were investigated in the urban surface waters in Beijing, China.

scholarly journals Hydrogeochemistry and surface water quality assessment of IB valley coalfield area, India

2021 ◽  
Vol 11 (9) ◽  
Author(s):  
Bishnu Prasad Sahoo ◽  
Himanshu Bhushan Sahu ◽  
Dhruti Sundar Pradhan
Keyword(s):  
Water Quality ◽  
Heavy Metal ◽  
Seasonal Variation ◽  
Surface Water ◽  
Water Samples ◽  
Nickel Aluminum ◽  
Acid Mine ◽  
Significant Seasonal Variation ◽  
Cadmium Selenium ◽  
High Degree

AbstractCoal mining and ancillary activities have the potential to cause water pollution characterized by acid mine drainage, acid mine leachates, extreme pH conditions and heavy metal contaminations. In the present work, 33 water samples in premonsoon and 34 water samples in monsoon were collected from the surface water bodies of Ib Valley coalfield, India for hydrogeochemical analysis. In premonsoon, pH, TSS, Turbidity, DO, BOD, COD, Magnesium, Cadmium, Selenium, Nickel, Aluminum and in monsoon, pH, TSS, Turbidity, DO, BOD, COD, Iron, Cadmium, Selenium, Nickel and Aluminum were nonconforming to the permissible limit set by the Bureau of Indian Standards, World Health Organisation and Ministry of Environment, Forest and Climate Change, Government of India. The average BOD/COD ratio of less than 0.6 in both seasons indicated Ib valley coalfield water was not fairly biodegradable. The analysis of variance (ANOVA) revealed that significant seasonal variation (p < 0.05) was observed in the hydro-chemical parameters viz. TSS, turbidity, redox potential, acidity, total hardness, bicarbonate alkalinity, chloride, sulfate, nitrate, sodium, calcium, magnesium, iron, cadmium, chromium and magnesium during the entire sampling period. Whereas, no significant seasonal variation (p > 0.05) was observed in pH, EC, TDS, DO, BOD, residual chlorine, COD, oil and grease, fluoride, potassium, zinc, copper, selenium, nickel, aluminum, boron, silica, temperature, salinity, cyanide and phenol. Water Quality Index revealed that 39.39% and 35.29% samples belong to poor water quality category in premonsoon and monsoon, respectively. As per Heavy Metal Pollution Index, Degree of Contamination (Cd) and Heavy metal evaluation index, medium degree of pollution were exhibited by 51.52%, 30.30% and 45.45% samples in premonsoon and 20.59%, 35.29% and 26.47% samples in monsoon. Whereas, 5.88%, 2.94% and 5.88% samples were having high degree of pollution in monsoon and 15.15% samples caused high degree of pollution with respect to Cd in premonsoon. However, EC, Na%, PI, SAR and RSC values suggested that the water can be used for irrigation. Water type of the region had been found to be Ca–Mg–Cl–SO4 by Piper diagram.

Diurnal and seasonal variation of the PM2.5 apparent particle density in Beijing, China

2015 ◽  
Vol 120 ◽  
pp. 328-338 ◽  
Author(s):  
Zirui Liu ◽  
Bo Hu ◽  
Dongsheng Ji ◽  
Yonghong Wang ◽  
Mingxing Wang ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Particle Density ◽  
Beijing China

scholarly journals Two-Step Urban Water Index (TSUWI): A New Technique for High-Resolution Mapping of Urban Surface Water

2018 ◽  
Vol 10 (11) ◽  
pp. 1704 ◽  
Author(s):  
Wei Wu ◽  
Qiangzi Li ◽  
Yuan Zhang ◽  
Xin Du ◽  
Hongyan Wang
Keyword(s):  
Surface Water ◽  
High Resolution ◽  
Urban Surface ◽  
Mapping Technique ◽  
Support Vector ◽  
Svm Classifier ◽  
P Value ◽  
Urban Water ◽  
Water Index ◽  
Water Mapping

Urban surface water mapping is essential for studying its role in urban ecosystems and local microclimates. However, fast and accurate extraction of urban water remains a great challenge due to the limitations of conventional water indexes and the presence of shadows. Therefore, we proposed a new urban water mapping technique named the Two-Step Urban Water Index (TSUWI), which combines an Urban Water Index (UWI) and an Urban Shadow Index (USI). These two subindexes were established based on spectral analysis and linear Support Vector Machine (SVM) training of pure pixels from eight training sites across China. The performance of the TSUWI was compared with that of the Normalized Difference Water Index (NDWI), High Resolution Water Index (HRWI) and SVM classifier at twelve test sites. The results showed that this method consistently achieved good performance with a mean Kappa Coefficient (KC) of 0.97 and a mean total error (TE) of 2.28%. Overall, classification accuracy of TSUWI was significantly higher than that of the NDWI, HRWI, and SVM (p-value < 0.01). At most test sites, TSUWI improved accuracy by decreasing the TEs by more than 45% compared to NDWI and HRWI, and by more than 15% compared to SVM. In addition, both UWI and USI were shown to have more stable optimal thresholds that are close to 0 and maintain better performance near their optimum thresholds. Therefore, TSUWI can be used as a simple yet robust method for urban water mapping with high accuracy.

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