Characteristics of and human influences on nitrogen contamination in Yellow River system, China
| Autor: | Jingsheng Chen, Shubin Cui, Na Zhang, Dawei He |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
China
Nitrogen Drainage basin Management Monitoring Policy and Law Disasters chemistry.chemical_compound Animal science Nutrient Nitrate Rivers Tributary Water Movements Humans Water pollution General Environmental Science Hydrology geography geography.geographical_feature_category Agriculture General Medicine Contamination Pollution chemistry Environmental science Water quality Seasons Surface water Environmental Monitoring |
| Zdroj: | Environmental monitoring and assessment. 93(1-3) |
| ISSN: | 0167-6369 |
| Popis: | Nitrogen (N) contamination in the Yellow River mainstream and its tributaries was studied using data from 1960 to 2000 from 312 monitoring sites in the Yellow River system. Data showed that N concentrations in the Yellow River have increased since 1960, especially after 1990. N concentrations in the Yellow River mainstream increased from the upper reaches (less than 1.0 mg L(-1) for TN and less than 0.10 mg L(-1) for NH4(+)-N) to lower reaches (higher than 4-5 mg L(-1) for TN and higher than 1.0 mg L(-1) for NH4(+)-N). However, the highest N contaminations (50-250 mg L(-1) for TN and 10-20 mg L(-1) for NH4(+)-N) was found in some tributaries, which was attributed as an effect of industrial wastewater and municipal sewage. Nitrogen concentrations from several monitoring sites were positively correlated with several regional socio-economic indices, such as population density, fertilization rates, livestock, industrial input and GDP. Depending on location, seasonal N concentrations contrasted among watersheds. Monitoring stations located in rural and agricultural areas showed higher N concentrations during the flood season while those located in areas with urban and industrial centers showed higher N concentration during the dry season. Mainstream flow and N concentrations showed a strong inverse relationship; with higher N concentrations as the river flow declined. Intensive water extraction for agricultural irrigation and increasing N input to the river from fertilized agricultural fields could explain the increasing N concentrations during extensive droughts. |
| Databáze: | OpenAIRE |
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