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Characterizing the antibiotic resistance genes in a river catchment： Influence of anthropogenic activities

Journal of Environmental Sciences 2018年第7期30卷 125-132页

作者： Haoyu Jiang Renjun Zhou Ying Yang Baowei Chen Zhineng Cheng Mengdi Zhang Jun Li Gan Zhang Shichun Zou School of Marine Sciences Sun Yat-Sen University Guangzhou 510006 China State Key Laboratory of Organic Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China Graduate University of the Chinese Academy of Sciences Beijing 100039 China

Previous studies on environmental antibiotics resistance genes（ARGs） have focused on the pollution sources such as wastewater treatment plants, aquaculture and livestock farms,etc. Few of them had addressed this issue in a regional scale such as river catchment. Hence,the occurrence and abundances of 23 ARGs were investigated in surface water samples collected from 38 sites which located from the river source to estuary of the Beijiang *** them, 11 ARGs were frequently detected in this region and 5 ARGs（sul Ⅰ, sul Ⅱ, tet B,tet C, and tet W） were selected for their distribution pattern analysis. The abundances of the selected ARGs were higher in the upstream（8.70 × 10^6 copies/ng DNA） and downstream areas（3.17 × 10^6 copies/ng DNA） than those in the midstream areas（1.23 × 10^6 copies/ng DNA）, which was positively correlated to the population density and number of pollution sources. Pollution sources of ARGs along the Beijiang river not only had a great impact on the abundances and diversity, but also on the distribution of specific ARGs in the water samples. Both sul Ⅰ and sul Ⅱ were likely originated from aquaculture farms and animal farms,tet W gene was possibly associated with the mining/metal melting industry and the electric waste disposal and tet C gene was commonly found in the area with multiple pollution ***, the abundance of tet B was not particularly related to anthropogenic impacts. These findings highlight the influence of pollution sources and density of population on the distribution and dissemination of ARGs at a regional scale.

关键词： Antibiotic resistance genes Anthropogenic activities Pollution sources river catchment

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Surface Water Quality Response to Land Use Land Cover Change in an Urbanizing catchment: A Case of Upper Chongwe river catchment, Zambia

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Journal of Geographic Information System 2021年第5期13卷 578-602页

作者： Alick Nguvulu Agabu Shane Claude S. Mwale Tewodros M. Tena Phenny Mwaanga John Siame Brian Chirambo Musango Lungu Frank Mudenda Dickson Mwelwa Sydney Chinyanta Jackson Kawala Victor Mwango Bowa Levi S. Mutambo Nicholas Okello Charles Musonda Department of Geomatics Engineering Copperbelt University Kitwe Zambia Department of Mining Engineering Copperbelt University Kitwe Zambia Department of Environmental Engineering Copperbelt University Kitwe Zambia Department of Chemical Engineering Copperbelt University Kitwe Zambia Department of Civil Engineering University of Pretoria Pretoria South Africa Department of Civil and Environmental Engineering University of Zambia Lusaka Zambia Business and Information Technology Department Cavendish University Lusaka Zambia

The Upper Chongwe river catchment has recently been overexploited for water resources with increased complaints by various water users about the deteriorating quality of surface water within the sub-catchment. This study was motivated by the need to investigate and understand the response of surface water quality to land use land cover (LULC) change due to urbanization. Water samples, collected at 9 sampling sites from 2006 to 2017, were analyzed for water quality using the weighted arithmetic water quality index and trend using the Mann-Kendall statistics. LULC change is detected and analyzed in ERDAS Imagine 2014 and ArcGIS 10.4 using 2006 Landsat 5 TM and 2017 Landsat 8 OLI imageries. The relationship between LULC change and water quality was performed with multiple regression analysis and Pearson correlation. The results reveal that Built-up area, Grassland and surface water increased by 5.48%, 13.34% and 0.03% respectively while Agricultural land and Forest Land decreased by −13.41% and −5.42% respectively. The water quality index ranged from 43.04 to 110.40 in 2006 and from 170 to 430 in 2017 indicating a deterioration in the quality of surface water from good to unsuitable for drinking at all the sampled sites. Built-up/bare lands exhibited a significant positive correlation with EC (R2 = 0.61, p ≤ 0.05), turbidity (R2 = 0.69, p ≤ 0.05), TDS (R2 = 0.61, p ≤ 0.05), Cl (R2 = 0.62, p ≤ 0.05) and a significant negative correlation with NH4 (R2 = −0.729, p ≤ 0.05). Agriculture exhibited a significant positive correlation with turbidity (R2 = 0.71, p ≤ 0.01) and Fe (R2 = 0.75, p ≤ 0.01. Forest cover correlated negatively with most of the water quality parameters apart

关键词： Water Quality LULC Change Water Quality Index river catchment Watershed

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Modelling Land Use/Land Cover Change of river Rwizi catchment, South-Western Uganda Using GIS and Markov Chain Model

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Journal of Water Resource and Protection 2024年第2期16卷 181-206页

作者： Lauben Muhangane Morgan Andama Faculty of Agriculture Uganda Martyrs University Nkozi Uganda Faculty of Science Muni University Arua Uganda

Analysis of catchment Land use/Land cover (LULC) change is a vital tool in ensuring sustainable catchment management. The study analyzed land use/land cover changes in the Rwizi catchment, south western Uganda from 1989-2019 and projected the trend by 2040. Landsat images, field observations, key informant interviews and focus group discussions were used to collect data. Changes in cropland, forestland, built up area, grazing land, wetland and open water bodies were analyzed in ArcGIS version 10.2.2 and ERDAS IMAGINE 14 software and a Markov chain model. All the LULC classes increased in area except grazing land. Forest land and builtup area between 2009-2019 increased by 370.03% and 229.53% respectively. Projections revealed an increase in forest land and builtup area by 2030 and only built up area by 2040. LULCC in the catchment results from population pressure, reduced soil fertility and high value of agricultural products.

关键词： Land Cover river catchment Geographic Information System Markov Model Sustainable Land Management

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STATISTICAL RELATIONS BETWEEN GEOMORPHIC PARAMETERS——A CASE STUDY OF THE YUNNAN REACH OF THE LANCANGJIANG river IN SOUTHWESTERN CHINA

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International Journal of Sediment Research 2007年第2期22卷 131-141页

作者： Suiji WANG1, Shaohong WU2 and Erfu DAI31,3 Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China, 2 Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China, Chinese Acad Sci Inst Geog Sci & Nat Resources Res Key Lab Water Cycle & Related Land Surface Proc Beijing 100101 Peoples R China

The properties of rivers and their catchments can be expressed by statistical relationships between geomorphic parameters. These statistical relationships may reveal some inherent differences in geomorphic evolution for different reaches or different order tributaries of a river basin. A case study was undertaken of the Yunnan reach of the Langcangjiang river. The catchment area, channel length and gradient of the first-, second- and third-order tributaries all with catchment areas larger than 100 km2 in the Yunnan reach were the main geomorphic parameters evaluated. The correlation between catchment area and channel length as well as between catchment area and channel gradient with respect to the total tributaries, different reach tributaries, and different order tributaries were revealed using statistical methods. In general, the channel length as a function of catchment area, was best expressed by a quadratic function where channel length increases with increasing catchment area (half parabola), while the channel gradient as a function of catchment area is best expressed by an exponential decay function. Comparison of the best-fit formulas revealed the following phenomena: the lower Yunnan reach tributaries and the first-order tributaries have a dominant effect on geomorphic parameters of the total tributaries. In addition, the statistical relationships indicate that the river geomorphic system in the upper and lower Yunnan reaches evolved differently. This study method used to differentiate river characteristics by determining statistical relationships between geomorphic parameters may be extended to other rivers and their catchments.

关键词： river catchment Geomorphic parameter Correlation river characteristics

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Assessing Water Availability and Unmet Water Demand Using the WEAP Model in the Semi-Arid Bweengwa, Kasaka and Magoye Sub-catchments of Southern Zambia

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Journal of Environmental Protection 2021年第4期12卷 280-295页

作者： Tewodros M. Tena Alick Nguvulu Dickson Mwelwa Phenny Mwaanga Department of Environmental Engineering Copperbelt University Kitwe Zambia Department of Geomatics Engineering Copperbelt University Kitwe Zambia Business and Information Technology Department Cavendish University Lusaka Zambia

Located in the semi-arid zone of Zambia, the Mutama-Bweengwa, Kasaka and Magoye sub-catchments have witnessed a high demand for water due to increase in population and socio-economic activities putting more pressure on water resources. This study assesses the hydrological components and ascertains the available water resources and unmet demand in the sub-catchments using the Water Evaluation And Planning (WEAP) Model and hydrometeorological data collected between 1951 and 2018. The model was calibrated and validated on 1971-1981 and 2008-2018 data respectively. The results reveal that the sub-catchments have transitioned from positive to negative water balance with -164.295 Mm3/year for Mutama-Bweengwa, -19.021 Mm3/year for Kasaka and -86.368 Mm3/year for Magoye. Evaporation was 1815.259 Mm3/year for Mutama-Bweengwa, 1162.655 Mm3/year for Kasaka and 1505.664 Mm3/year for Magoye. The demand for water has been increasing over time for various purposes such as irrigation, domestic, urban/rural water supply and livestock. The overall water storage in the sub-catchments showed a negative water balance for the year 2018. The observed and simulated peak streamflow were 8.16 m3/s and 7.7 m3/s occurring during the month of January and February respectively. The WEAP model performance achieved R2 of 0.98 during calibration and 0.95 for validation, and an NSE of 0.83 for calibration and 0.85 during validation. The values of objective functions show that the hydrology of the Mutama-Bweengwa, Kasaka and Magoye sub-catchments as predicted by the WEAP model provides satisfactory confidence for prediction of future streamflow and hence projection based on future scenarios.

关键词： Water Availability Water Use WEAP Model river catchment Streamflow Semi-Arid catchment Hydrology

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