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Groundwater Waters
Ramón Llamas,Emilio Custodio
Revista CIDOB d'Afers Internacionals , 1999,
Abstract: The groundwaters released through springs constituted a basic element for the survival and progressive development of human beings. Man came to learn how to take better advantage of these waters by digging wells, irrigation channels, and galleries. Nevertheless, these activities do not require cooperation nor the collective agreement of relatively large groups of people, as in the case of creating the necessary structures to take advantage of the resources of surfacewaters. The construction and operation of these structures was a powerful factor in the birth of an urban or civil society – the designated water civilizations. The difference between people taking advantage of groundwater, quasi-individually, and those of surface water, where people work in a group, has continued to the present day. Whereas earlier, this difference did not bring about any special problems, the technological advances of this century, especially theturbine pump, have led to a spectacular increase in the use of roundwater. This advance has significantly contributed to reducing hunger in the world and has provided potable water in developing countries. However, the almost generalized lack of planning and control in the exploitation of these groundwaters reflects that they are little or badly understood by the managers of water policy in almost every country. As such, problems have occurred which have often become exaggerated, giving rise to water-myths. These problems, though, should be addressed if the aim is the sustainable usage of surface water as well as groundwater. To counter any misconceptions and to seek solutions to the problems, distinct plans of action can be highlighted: educating the public; fomenting a system of participative management and decisive support for the communities of users of subterranean waters; integrating a sufficient number of experts in hydrology in the various water management organizations;and assuring transparency of the data on water and its corresponding economic impact.
Journal of Applied Technology in Environmental Sanitation , 2012,
Abstract: This study assessed the nitrate contamination in groundwater sources in an agro-ecosystem situated in Laguna, Philippines. Grab water samples were obtained in groundwater sources situated in an agro-ecosystem in Laguna, Philippines, and analyzed for nitrate-nitrogen. Results of the study showed that the groundwater sources had a mean SEM nitrate-nitrogen concentrations for all sites of 5.83 3.76 ppm. No significant differences on the obtained nitrate-nitrogen on the waters from the well were observed (p > 0.05) except for the significant differences in the seasons, availability of septic tanks and the usage of the wells (p < 0.05). All the water resources tested for nitrate-nitrogen concentrations were below the standards. Continuous water monitoring of the groundwater resources is necessary to safeguard people’s well-being from the effects brought about by the utilization of contaminated water sources.
Identification of sources and infiltration regimes of nitrate in the semi-arid Kalahari: Regional differences and implications for groundwater management
S Stadler, AS Talma, G Tredoux, J Wrabel
Water SA , 2012,
Abstract: The Kalahari region of southern Africa offers much potential for nitrogen input into its groundwater. High nitrate concentrations in Kalahari groundwater are therefore quite common and are caused by both anthropogenic and natural sources. Forecasting groundwater nitrate concentrations remains challenging. Source identification of nitrate contamination in groundwater is an important first step for groundwater management and quality prediction, and is aided by isotope analysis of nitrate in the water. Comparative data from 3 groundwater study sites in the Kalahari of Botswana and Namibia with widely different characteristics are presented. Two of the sites (Ghanzi and Gobabis) have shallow water tables in fractured quartzite. These aquifers were affected by pollution from cattle wastes (manure) and septic tank outflows resulting in groundwater nitrate levels exceeding 1 000 mg NO3/. and in 15N values of between +7 and +20 AIR. Short-term increases of groundwater nitrate concentrations were triggered by exceptional rainfall events occurring every 10-20 years. At the third site (Serowe in Botswana) there is similar land use and land cover, yet the aquifers are deeper, groundwater dates to Late-Pleistocene age and borehole levels do not show a response to present-day high-rainfall episodes. Nitrate levels up to 219 mg/. are found, but lower 15N content ( 15N of +3 to +8 ) indicates a natural origin of the nitrate. In this area pollution nitrate is sufficiently delayed in the vadose zone, reaching the saturated zone much later. The data from all 3 sites suggest that nitrogen management options can only be evaluated once an understanding of sources, processes and flow patterns has been established.
Groundwater nitrate pollution in Souss-Massa basin (south-west Morocco)
T Tagma, Y Hsissou, L Bouchaou, L Bouragba, S Boutaleb
African Journal of Environmental Science and Technology , 2009,
Abstract: The objective of our study was to determine the current status of alluvial aquifer in the Souss-Massa basin, where the nitrate pollution of groundwater is being increasing along the last decades. A multiapproach methodology using hydrogeology, nitrate concentrations, irrigation type and oxygen-18 and deuterium data, was carried out to identify the sources of this pollution. According to the spatial distribution of nitrate contents, nitrate pollution occurs mainly in Chtouka-Massa plain. More than 36% of the sampled wells exceed the value of 50 mg/L as NO3 -. Groundwater in Souss plain is less polluted comparing it to Chtouka-Massa; only 7% of wells exceed the permitted level. Agricultural practices in the study sites are the main cause of serious nitrate pollution given the uperimposition of high nitrate concentrations with the distribution of irrigated perimeters. High nitrate levels are associated with high 18O values, clearly indicating that significant quantities of evaporated irrigation waters infiltrate along with fertilizer nitrate to groundwater system. Different 18O-NO3 - trends suggest isotopically distinct, non-point source origins which vary spatially and temporally, due to different degrees of evaporation/recharge and amounts of fertilizer applied.
Nitrate Concentration in Groundwater in Isfahan Province  [cached]
A. Jafari Malekabadi,M. Afyuni,S. F. Mousavi,A. Khosravi
Journal of Science and Technology of Agriculture and Natural Resources , 2004,
Abstract: In recent decades, the use of nitrogen fertilizers has increased irrespective of their effects on soil properties, agricultural products and, particularly, on environmental pollution. Nitrate easily leaches from soils into groundwater. The objective of this study was to determine temporal and spatial nitrate concentrations in groundwater in agricultural, industrial and urban regions in some parts of Isfahan Province. Water samples were collected monthly from 75 agricultural, industrial, and urban wells of Isfahan, Najaf-abad, Shahreza, Natanz and Kashan during January-May 2001. The results indicated that NO3-N concentrations in most of the regions studied were higher than the standard level (10 mg/l) and nitrate pollution must be reckoned among the most serious problems of sustainable agriculture and exploitation of groundwater resources. Average NO3-N concentration in different wells ranged from 1.03 to 50.78 mg/l (4.64 to 228.5 mg/l as nitrate). The average NO3-N concentration in groundwater of Najaf-abad, Shahreza, Isfahan and Natanz-Kashan was 17.56, 14.6, 16.04, and 8.24 mg/l and 95.5, 100, 84 and 33.3 % of total wells in these regions had nitrate concentrations above the standard level, respectively. Maximum NO3-N concentration was detected in the agricultural region south of Najaf-abad (64.6 mg/l). Nitrate pollution in most of the sampling areas was mainly linked to agricultural activities. The average NO3-N concentration in groundwater of all agricultural, industrial, and urban regions, except for urban regions of Natanz and Kashan, were above the standard level. Generally, nitrate concentration level in groundwater increased with time and was maximum in March and April.
Impact of Large Poultry Operations on Groundwater : Stable 15N Isotopes of Nitrate Assessment
William J. Showers,C.M. Williams,Gregory D. Jennings
International Journal of Poultry Science , 2006,
Abstract: The rapid growth of livestock and poultry operations over the past 25 years has led to concern regarding environmental impacts of land applied animal wastes in many parts of the world. This study investigated the impact of dense poultry populations on ground and surface water quality in central North Carolina using the stable 15N isotopes of nitrate. On a field scale, the 15N of groundwater nitrate was not related to the type of poultry waste applied to the fields, but was controlled by the types of soils found in the litter application fields. Hydric soils had enriched groundwater nitrate 15N compositions and reduced nitrate concentrations, most likely associated with denitrification. Partially hydric and non-hydric soils did not show elevated groundwater 15N nitrate compositions. The 15N composition of groundwater nitrate in litter application fields with non-hydric soils indicates that the source of groundwater nitrate is a combination of poultry litter and fertilizer. On a watershed scale, the 15N composition of surface water nitrate was not related to the distribution of poultry operations, but was related to the distribution of hydric soils within the basin. Nitrate concentrations in stream waters remained low through out the basin studied, and the 15N composition of stream nitrate decreased downstream suggesting minimal impact on surface water quality from the surrounding poultry operations. The practice of placing poultry houses on poor quality swampy land also places them in areas dominated by hydric soils. Denitrification proceeds quickly in areas with hydric soils, which minimizes offsite nitrate transport and mitigates surface water quality impacts. This data suggests that surface water quality impacts from animal agriculture can be predicted from the spatial analysis of hydric soils within a watershed.
Nitrate Leaching Losses from Miscanthus x giganteus Impact on Groundwater Quality  [PDF]
E.M. Curley,M.G. O`Flynn,K.P. McDonnell
Journal of Agronomy , 2009,
Abstract: The objective of this study was to determine whether there was an increase in nitrate concentrations in soil water samples as a result of fertilizer nitrogen (N), in the form of cattle slurry, being applied at various rates to an establishing crop of Miscanthus; this trial was conducted during 2008/09. The crop received either no fertilizer (0-unfertilized control) or an annual application of 60, 120 or 180 kg N ha-1. Soil water solution samples were collected fortnightly from porous ceramic cup samplers. Nitrate (NO3ˉ) levels in these soil water samples were determined and monitored. In 2008, the soil water nitrate concentrations were high on all treatments, 14, 16 and 20 mg l-1, respectively for 0, 60 and 120 kg N ha-1. However, there was no significant difference between treatments. Soil water nitrate concentrations were again high (12-21 mg l-1) in 2009, particularly at the 180 kg N ha-1 levels which showed significantly higher levels of nitrate leaching when compared to all other treatments. A high level of nitrate is seen as a threat to both public health and natural waters. Of these threats the latter is the more immediate, but the health issue has attracted more public concern, as the presence of nitrate in drinking water has been linked to a number of medical conditions such as blue baby syndrome (methaemoglobinaemia) in infants. The results indicate that leaching losses were closer to those recorded under arable land than extensively managed grassland; slurry application on an establishing Miscanthus crop does not appear to contribute adversely to levels of nitrate in groundwater when compared to other more extensive cropping systems.
Nitrate and dissolved nitrous oxide in groundwater within cropped fields and riparian buffers
D.-G. Kim,T. M. Isenhart,T. B. Parkin,R. C. Schultz
Biogeosciences Discussions , 2009,
Abstract: Transport and fate of dissolved nitrous oxide (N2O) in groundwater and its significance to nitrogen dynamics within agro-ecosystems are poorly known in spite of significant potential of N2O to global warming and ozone depletion. Increasing denitrification in riparian buffers may trade a reduction in nitrate (NO3 ) transport to surface waters for increased N2O emissions resulting from denitrification-produced N2O dissolved in groundwater being emitted into the air when groundwater flows into a stream or a river. This study quantifies the transport and fate of NO3 and dissolved N2O moving from crop fields through riparian buffers, assesses whether groundwater exported from crop fields and riparian buffers is a significant source of dissolved N2O emissions, and evaluates the Intergovernmental Panel on Climate Change (IPCC) methodology to estimate dissolved N2O emission. We measured concentrations of NO3 ; chloride (Cl ); pH; dissolved N2O, dissolved oxygen (DO), and organic carbon (DOC) in groundwater under a multi-species riparian buffer, a cool-season grass filter, and adjacent crop fields located in the Bear Creek watershed in central Iowa, USA. In both the multi-species riparian buffer and the cool-season grass filter, concentrations of dissolved N2O in the groundwater did not change as it passed through the sites, even when the concentrations of groundwater NO3 were decreased by 50% and 59%, respectively, over the same periods. The fraction of N lost to leaching and runoff (0.05) and the modified N2O emission factor, [ratio of dissolved N2O flux to N input (0.00002)] determined for the cropped fields indicate that the current IPCC methodology overestimates dissolved N2O flux in the sites. A low ratio between dissolved N2O flux and soil N2O emission (0.0003) was estimated in the cropped fields. These results suggest that the riparian buffers established adjacent to crop fields for water quality functions (enhanced denitrification) decreased NO3 and were not a source of dissolved N2O. Also, the flux of dissolved N2O from the cropped field was negligible in comparison to soil N2O emission in the crop fields.
The Source of Arsenic and Nitrate in Borrego Valley Groundwater Aquifer  [PDF]
Mohammad Hassan Rezaie-Boroon, Jessica Chaney, Bradley Bowers
Journal of Water Resource and Protection (JWARP) , 2014, DOI: 10.4236/jwarp.2014.617145
Abstract: Groundwater in California is very precious, yet what we can withdraw is often contaminated with natural and anthropogenic pollution sources. We have examined the Borrego Valley (BV) groundwater (N = 6 wells) in southern California to understand the source of arsenic and nitrate in some of its groundwater production wells. The results show that the arsenic values range from <2 ppb to 12.2 ppb and the nitrate values from <1 ppm to 10.2 ppm for different wells respectively. The results showed that the arsenic concentration increased 270% for the well # ID1-10 since 2004 and showed an increase of 63% since 2013 respectively. For other wells the results showed an increase of 147% and 72% since 2001. The nitrate concentration has jumped 42% in concentration since last year in one of the wells. The objective of this study is to understand the nature and source of arsenic and nitrate in BV groundwater aquifer as to how this change in arsenic and nitrate concentration occurs through the time. The arsenic retention in the sediments is highly variable and controlled by local processes as a result of natural weathering process of metamorphic bedrock. The second results from the development of strongly reducing conditions at near-neutral pH values, leading to the desorption of arsenic from mineral oxides and to the reductive dissolution of Fe and Mn oxides, also leading to arsenic release. The high arsenic concentrations in some groundwater wells in Borrego Valley CA require the need for reconnaissance surveys in mineralized areas of fractured crystalline basement. Net groundwater extraction values are based on an irrigation efficiency of 78 percent with 14 to 22 percent irrigation return. We believe that the return flow from irrigational activity could be one of the major sources of nitrate transferring the agricultural contaminants such as nitrate to Borrego Valley aquifer.
RVM based on PSO for Groundwater Level Forecasting  [cached]
Weiguo Zhao,Yanfeng Gao,Chunliu Li
Journal of Computers , 2012, DOI: 10.4304/jcp.7.5.1073-1079
Abstract: Relevance Vector Machine (RVM) is a novel kernel method based on Sparse Bayesian, which has many advantages such as its kernel functions without the restriction of Mercer’s conditions, the relevance vectors automatically determined. In this paper, a new RVM model optimized by Particle Swarm Optimization (PSO) is proposed, and it is applied to groundwater level forecasting. The simulation experiments demonstrate that the proposed method can reduce significantly both relative mean error and root mean squared error of predicted groundwater level. Moreover, the model achieved is much sparser than its counterpart, so the RVM based on PSO is applicable and performs well for groundwater data analysis.
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