Nitrate in groundwater of China: Sources and driving forces
01 Oct 2013-Global Environmental Change-human and Policy Dimensions (Pergamon)-Vol. 23, Iss: 5, pp 1112-1121
TL;DR: In this article, the authors assessed groundwater nitrate contamination in China using literature analysis and N balance calculation in coupled human and natural systems, and found that reactive N leakage mainly occurred in relatively developed agricultural or urbanized regions with a large population.
Abstract: Identifying the sources of reactive nitrogen (N) and quantifying their contributions to groundwater nitrate concentrations are critical to understanding the dynamics of groundwater nitrate contamination. Here we assessed groundwater nitrate contamination in China using literature analysis and N balance calculation in coupled human and natural systems. The source appointment via N balance was well validated by field data via literature analysis. Nitrate was detected in 96% of groundwater samples based on a common detection threshold of 0.2 mg N L−1, and 28% of groundwater samples exceeded WHO's maximum contaminant level (10 mg N L−1). Groundwater nitrate concentrations were the highest beneath industrial land (median: 34.6 mg N L−1), followed by urban land (10.2 mg N L−1), cropland (4.8 mg N L−1), and rural human settlement (4.0 mg N L−1), with the lowest found beneath natural land (0.8 mg N L−1). During the period 1980–2008, total reactive N leakage to groundwater increased about 1.5 times, from 2.0 to 5.0 Tg N year−1, in China. Despite that the contribution of cropland to the total amount of reactive N leakage to groundwater was reduced from 50 to 40% during the past three decades, cropland still was the single largest source, while the contribution from landfill rapidly increased from 10 to 34%. High reactive N leakage mainly occurred in relatively developed agricultural or urbanized regions with a large population. The amount of reactive N leakage to groundwater was mainly driven by anthropogenic factors (population, gross domestic product, urbanization rate and land use type). We constructed a high resolution map of reactive N source appointment and this could be the basis for future modeling of groundwater nitrate dynamics and for policy development on mitigation of groundwater contamination.
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TL;DR: A substantially complete and coherent Nr budget for China and for 14 subsystems within China from 1980 to 2010 is presented, human health/longevity and environmental consequences of excess Nr are evaluated, and several scenarios for Nr in China in 2050 are explored.
Abstract: Reactive nitrogen (Nr) plays a central role in food production, and at the same time it can be an important pollutant with substantial effects on air and water quality, biological diversity, and human health. China now creates far more Nr than any other country. We developed a budget for Nr in China in 1980 and 2010, in which we evaluated the natural and anthropogenic creation of Nr, losses of Nr, and transfers among 14 subsystems within China. Our analyses demonstrated that a tripling of anthropogenic Nr creation was associated with an even more rapid increase in Nr fluxes to the atmosphere and hydrosphere, contributing to intense and increasing threats to human health, the sustainability of croplands, and the environment of China and its environs. Under a business as usual scenario, anthropogenic Nr creation in 2050 would more than double compared with 2010 levels, whereas a scenario that combined reasonable changes in diet, N use efficiency, and N recycling could reduce N losses and anthropogenic Nr creation in 2050 to 52% and 64% of 2010 levels, respectively. Achieving reductions in Nr creation (while simultaneously increasing food production and offsetting imports of animal feed) will require much more in addition to good science, but it is useful to know that there are pathways by which both food security and health/environmental protection could be enhanced simultaneously.
402 citations
Cites background from "Nitrate in groundwater of China: So..."
...Surface water eutrophication and nitrate accumulation in shallow groundwater threaten the safety of drinking water (7, 8)....
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...7 Tg·yr) increase in Nr stored within China, most of it in overfertilized cropland, where both organic N and nitrate accumulation have been observed (24, 25); in forests, which retain much of the Nr they receive from atmospheric deposition (26); in groundwater, through leaching from soil N accumulation and landfills [and consistent with observed shallow groundwater pollution (8)]; and in human systems, which accumulate abundant N-containing industrial materials....
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TL;DR: Risk levels for different crowds in the study area varied obviously, generally in the order of infants> children> adult females> adult males, and the potential health risks of residents, especially minors and rural residents, should cause enough attention both from the society and the academic community.
194 citations
TL;DR: Over-use of N fertilizer (and/or manure) and a declining groundwater table are the major causes for this huge nitrate reservoir in the vadose-zone of semi-humid croplands, where the nitrate cannot be denitrified due to the presence of oxygen and lack of carbon sources.
Abstract: Soil nitrate is important for crop growth, but it can also leach to groundwater causing nitrate contamination, a threat to human health. Here, we report a significant accumulation of soil nitrate in Chinese semi-humid croplands based upon more than 7000 samples from 141 sites collected from 1994 to 2015. In the 0–4 meters depth of soil, total nitrate accumulation reaches 453 ± 39, 749 ± 75, 1191 ± 89, 1269 ± 114, 2155 ± 330 kg N ha−1 on average in wheat, maize, open-field vegetables (OFV), solar plastic-roofed greenhouse vegetables (GHV) and orchard fields, respectively. Surprisingly, there is also a comparable amount of nitrate accumulated in the vadose-zone deeper than 4 meters. Over-use of N fertilizer (and/or manure) and a declining groundwater table are the major causes for this huge nitrate reservoir in the vadose-zone of semi-humid croplands, where the nitrate cannot be denitrified due to the presence of oxygen and lack of carbon sources. Future climatic change with more extreme rainfall events would increase the risk of accumulated nitrate moving downwards and threatening groundwater nitrate contamination.
192 citations
TL;DR: In this paper, a review on the use of different nanomaterials especially nanoparticles, nanotubes, nanofibers, nanoshells, nanoclusters, and nanocomposites for removal of nitrate from an aqueous system is presented.
Abstract: Nitrate is a water pollutant whose removal from water is necessary to lessen pollution and prevent damage to life. Several conventional techniques such as adsorption, ion exchange process, reverse osmosis, electrochemical, chemical, and biological methods have been developed for removal of nitrate, however they have several limitations such as requirement of post-treatment, less efficiency, and high installation costs. The field of Nanotechnology has observed tremendous growth in the past and has many environmental applications such as the use of nanomaterials for soil and water remediation, filtration of pollutants, water purification, biosensors, and in desalination. Recently, Nanotechnology has emerged as an excellent alternative for nitrate removal over conventional techniques. Nanomaterials due to their small size have large surface area and thus have high reactivity which, enables them to be used as reducing agents and adsorbents. This review focuses on the use of different nanomaterials especially nanoparticles, nanotubes, nanofibers, nanoshells, nanoclusters, and nanocomposites for removal of nitrate from an aqueous system. The limitations of using such nanomaterials for removal of nitrate and possible techniques to overcome these limitations have been discussed as well.
170 citations
TL;DR: In this paper, a seven-year field experiment was conducted to evaluate the effects of the rate of N application on crop yield, NUE, nitrate residue (NR), and nitrate leaching in an intensive wheat/maize rotation system on the Loess Plateau of China.
153 citations
References
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TL;DR: In this paper, the authors present a cross section of steel industry statistics and highlight the co operation of members and non members in supplying the information included in this publication, further details of the statistical sources used are given in the annex p 119.
Abstract: e china iworldsteel org worldsteel org preface this yearbook presents a cross section of steel industry statistics the co operation of members and non members in supplying the information included in this publication is gratefully acknowledged further details of the statistical sources used are given in the annex p 119, i china statistical yearbook 2018 is an annual statistical publication which reflects comprehensively the economic and social development of china it covers data for 2017 and key statistical data in recent years and some historically important years at the national level and the local levels of province autonomous region and municipality directly under the central government ii, the content of the statistical yearbook is oriented to serve a general readership the yearbook endeavours to provide information for various bodies of the united nations system as well as for other international organizations governments and non governmental organizations national statistical economic and social policy bodies scientific and educational institutions libraries and the public, summary china statistical yearbook 2011 is an annual statistical publication which covers data of 2010 and key statistical data in the most recent thirty years and some historically important years at the national level and the local levels of province autonomous region and municipality directly under the central government, in terms of demography education and health asean statistics also demonstrate the interconnectedness of the region in trade foreign direct investment and tourism among others every year the asean statistical yearbook asyb provides the regions latest statistical information on these social and economic indicators containing, china statistics amp facts the peoples republic of china prc is located in east asia governed by the communist party in the capital of beijing it has jurisdiction over 22 provinces five, 12 summary of key statistics category general survey region hong kong collected time 1
8,588 citations
TL;DR: Optimizing the need for a key human resource while minimizing its negative consequences requires an integrated interdisciplinary approach and the development of strategies to decrease nitrogen-containing waste.
Abstract: Humans continue to transform the global nitrogen cycle at a record pace, reflecting an increased combustion of fossil fuels, growing demand for nitrogen in agriculture and industry, and pervasive inefficiencies in its use. Much anthropogenic nitrogen is lost to air, water, and land to cause a cascade of environmental and human health problems. Simultaneously, food production in some parts of the world is nitrogen-deficient, highlighting inequities in the distribution of nitrogen-containing fertilizers. Optimizing the need for a key human resource while minimizing its negative consequences requires an integrated interdisciplinary approach and the development of strategies to decrease nitrogen-containing waste.
5,249 citations
"Nitrate in groundwater of China: So..." refers background in this paper
...However, considerable uncertainty remains in our knowledge of the magnitude and spatiotemporal changes of groundwater nitrate concentrations owing to the many sources involved (Galloway et al., 2008; Burow et al., 2010)....
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...There is almost no need for anthropogenic Nr input to soybean cultivation owing to its symbiotic N fixation (Galloway et al., 2008), which largely lower the per area Nr leakage to groundwater....
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TL;DR: Urban ecology integrates natural and social sciences to study these radically altered local environments and their regional and global effects of an increasingly urbanized world.
Abstract: Urban areas are hot spots that drive environmental change at multiple scales. Material demands of production and human consumption alter land use and cover, biodiversity, and hydrosystems locally to regionally, and urban waste discharge affects local to global biogeochemical cycles and climate. For urbanites, however, global environmental changes are swamped by dramatic changes in the local environment. Urban ecology integrates natural and social sciences to study these radically altered local environments and their regional and global effects. Cities themselves present both the problems and solutions to sustainability challenges of an increasingly urbanized world.
5,096 citations
TL;DR: Examination of grain yields and N loss pathways in 2 of the most intensive double-cropping systems in China found that current agricultural N practices with 550–600 kg of N per hectare fertilizer annually do not significantly increase crop yields but do lead to about 2 times larger N losses to the environment.
Abstract: Excessive N fertilization in intensive agricultural areas of China has resulted in serious environmental problems because of atmospheric, soil, and water enrichment with reactive N of agricultural origin. This study examines grain yields and N loss pathways using a synthetic approach in 2 of the most intensive double-cropping systems in China: waterlogged rice/upland wheat in the Taihu region of east China versus irrigated wheat/rainfed maize on the North China Plain. When compared with knowledge-based optimum N fertilization with 30– 60% N savings, we found that current agricultural N practices with 550–600 kg of N per hectare fertilizer annually do not significantly increase crop yields but do lead to about 2 times larger N losses to the environment. The higher N loss rates and lower N retention rates indicate little utilization of residual N by the succeeding crop in rice/wheat systems in comparison with wheat/maize systems. Periodic waterlogging of upland systems caused large N losses by denitrification in the Taihu region. Calcareous soils and concentrated summer rainfall resulted in ammonia volatilization (19% for wheat and 24% for maize) and nitrate leaching being the main N loss pathways in wheat/maize systems. More than 2-fold increases in atmospheric deposition and irrigation water N reflect heavy air and water pollution and these have become important N sources to agricultural ecosystems. A better N balance can be achieved without sacrificing crop yields but significantly reducing environmental risk by adopting optimum N fertilization techniques, controlling the primary N loss pathways, and improving the performance of the agricultural Extension Service. intensive agriculture synthetic N fertilizer denitrification nitrate leaching N deposition
2,085 citations
TL;DR: An examination ofMSW generation and composition in China is presented, providing an overview of the current state of MSW management, an analysis of existing problems in MSW collection, separation, recycling and disposal, and some suggestions for improving MSW systems in the future.
719 citations
"Nitrate in groundwater of China: So..." refers background in this paper
...was one of the most important sources in these developed provinces or cities, consistent with the plight of being ‘‘junk besieged’’ metropolitans in China (Zhang et al., 2010)....
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...Food waste in rural area generally is used for raising livestock in China; on the contrary, it is sent to landfill in the urban area (Zhang et al., 2010)....
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...components of landfill (Zhang et al., 2010; Gu et al., 2012c), accounting for over 93% of total Nr going to landfills in China....
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