Nitrogen Compounds In Groundwater Research Articles

Groundwater chemistry, pollution and health risk assessment for nitrogen compounds. A case study in a suburban region of Romania

As groundwater is used as a source of drinking water, monitoring its quality is essential due to possible adverse effects on human health. Nitrogen compounds (nitrates, nitrites, ammonia) within certain concentration limits are natural components of the nitrogen cycle. Due to anthropogenic activities, high concentrations of nitrogen compounds are released into groundwater. The aim of this study was to evaluate the chemistry of groundwater in a suburban area in northeastern Romania, the sources of pollution with nitrogen compounds (nitrates, nitrites, ammonium), and the non-carcinogenic risk to human health associated with consumption in different groups age (women, men, and children) in the investigated region. The results showed that the concentration of nitrogen compounds varies from 5.12 to 98.3 mg/L for nitrates, from 0.008 to 85.2 mg/L for ammonium, and from 0.001 to 1.12 mg/L for nitrites. The maximum admissible concentrations have been exceeding 25%, 40% and respectively 10% of the total analyzed samples Bivariate graphs and Principal Component Analysis (PCA) were used to identify potential sources of nitrate, nitrites, and ammonium pollution of groundwater in the study area. The non-carcinogenic risk assessment for water consumption showed a hazard index (HItotal) for nitrogen compounds in groundwater in the investigated region, which ranged from 0.037 to 2.856 for men, between 0.054 and 3.427 for women, respectively between 0.080 and 6.145, for children. Spatial distribution maps using the Inverse Distance Weighting technique presented the geographical areas with the probability of groundwater contamination with nitrate, nitrite, and ammonium and the areas that pose a risk to human health by consuming groundwater in the study area for the three groups: men, women and children.

Simultaneous electrocatalytic removal of inorganic nitrogen compounds in groundwater: Modeling and mechanistic studies

The use of biological and chemical methods for the simultaneous removal of inorganic nitrogen compounds containing nitrate, ammonia, and nitrite in groundwater typically cannot achieve synchronous oxidation and reduction in an undivided reactor. In the present study, with the strict regulation of the oxidation reaction in the anode zone and reduction reaction in the cathode zone, simultaneous removal of nitrate, ammonia, and nitrite was achieved in an undivided electrochemical system. Our results indicated that ammonia and nitrite had been completely removed, and the concentration of nitrate was reduced to 8.58 mg N/L with initial nitrate, ammonia, and nitrite concentrations of 50.00, 10.00 and 5.00 mg N/L, respectively. Cyclic voltammetry (CV) and potentiostatic electrolysis revealed that the electrode surface reaction process, that is, nitrate, ammonia, and nitrite in the system, could be converted into nitrogen via ClO− generated from Cl− produced from the electrochlorination process during multiple cycle attenuation. Moreover, both CV and Density functional theory (DFT) calculations revealed the inhibitory effect of coexisting ammonia and nitrite on the electrochemical reduction of nitrate on the Cu cathode. This strategy opens a paradigm for the simultaneous efficient electrocatalytic removal of nitrate, nitrite, and ammonia in an undivided single reactor.

A Comparison of Some Interpolation Techniques for Determining Spatial Distribution of Nitrogen Compounds in Groundwater

The aim of the study was to analyse spatial variability of selected parameters of subsurface waters in the area of approximately 10 ha, located in the valley of the Ciemięga River in the village of Snopków, near Lublin, Poland. For the purpose of this study, nine sections were delimited, each with four points of collecting groundwater. In the groundwater samples, there were measured {text{NH}}_{4}^{ + }, {text{NO}}_{3}^{-} , and {text{NO}}_{2}^{-}. Due to the small number of samples, the analysis was limited to deterministic interpolation methods. The following methods were compared using leave-one-out cross-validation procedure: triangulation, inverse distance weighting, radial base function, and modified Shepard’s method. The methods which proved to be optimal were used to create spatial variability maps of the analysed parameters. Spatial interpolation and visualization of the results were performed in Surfer ver.16, and other calculations were conducted using R software.

Evaluation of the sources of nitrogen compounds and their influence on the biological communities in the hyporheic zone of the Sagittario River, Italy: an isotopic and biological approac

In groundwater-dependent ecosystems (GDEs) a significant contribution of nitrogen contamination of the surface waters arises from groundwater input by shallow and deep flow systems. In general, nitrogen surface-groundwater exchanges and processes at the hyporheic scale are difficult to monitor. In order to have a better understanding about these interactions, it is proposed to use stable isotopes (15N-NO3-, 18O-NO3-, 15N-NH4+) as environmental tracers to identify the sources and fate of the nitrogen compounds in groundwater in the Sagittario River basin, central Italy. The detrimental effect of the groundwater ammonium on the meiofaunal organisms is also evaluated in the hyporheic zone, where N-NH4+ concentrations reach a maximum value of 0.6 mg L-1. The main source of the nitrogen contamination originates from agricultural and urban activities at the catchment scale. The nitrogen compounds reach the gaining stretches of the hyporheic zone along the streambed as nitrate associated to a shallow flow system and ammonium related to a deep flow system. δ15N data demonstrate that sewage and fertilizers including manure are the main sources of NO3- and NH4+, the latter being the major pollutant in the study area. δ18O-NO3- data are consistent with the nitrification of ammonium to nitrate, along with the contribution from inorganic fertilizers. Furthermore, δ15N-NO3- and δ18O-NO3- data reveal that denitrification does not play any role on nitrate attenuation in the shallow aquifer and near the discharge areas to the river. The meiofaunal communities, represented by the Crustacea Copepoda selected as the target group, were shown to be sensitive to the high concentration of ammonium found at several hyporheic sites. The statistical analyses indicated a significant reduction of species abundance in the sites polluted by N-NH4+ concentrations > 0.0653 mg L-1.

Observations on Groundwater Contamination with Nitrogen Compounds: A Case Study from Medias town, Sibiu County

Worldwide, the groundwater (water well and public spring) is used as drinking water source. The water quality is important due to the possible negative effects on the consumers’ health, especially for infants. Nitrogen compounds (NO2-, NO3-, NH4+) are present as natural components of the nitrogen cycle and their presence in the groundwater is ubiquitous. But, due to the anthropogenic activities high concentrations of nitrogen compounds are release into the groundwater, thereby the chemical compounds concentrations exceed the maximum allowable concentrations (MACs). The purpose of the present study was to assess the content of nitrogen compounds in groundwater, namely private water wells and public springs used as drinking water sources by the Medias town population. The study results show alarming NO2- and NO3- concentrations; the NO3- concentrations exceed 5 times the MAC and NO2- concentrations exceed3 times the MAC.

Pollution indicators in groundwater of two agricultural catchments in Lower Silesia (Poland)

Abstract The article discusses the content and source of mineral nitrogen compounds in groundwater, based on the data collected in two river catchments in two series (spring and autumn 2014). The study area comprises two catchments located in Lower Silesia, Poland - Cicha Woda and Sąsiecznica. Both catchments are characterised agricultural character of development. In the both researched areas, the points of State Environmental Monitoring (SEM) are located but only the Cicha Woda area is classified as nitrate vulnerable zone (NVZ). To analyse and compare the contamination of Quaternary and Neogene aquifers, the concentration of nitrates, nitrites, ammonium and potassium ions was measured primarily. Results showed the exceedance of nitrogen mineral forms of shallow groundwater Quaternary aquifer in both basins. The concentration of nitrates range from 0.08 to 142.12 mgNO3 −−/dm3 (Cicha Woda) and from 2.6 to 137.65 mg NO3 −−/dm3 (Sąsiecznica). The major source of pollution is probably the intensive agriculture activity. It causes a degradation of the shallow groundwater because of nitrate, nitrite, potassium, phosphates and ammonium contents. There was no observed contamination of anthropogenic origin in the deeper Neogene aquifer of Cicha Woda catchment.

Nitrogen compound pollution associated with the use of sewage sludge compost and limestone outcrop residue under saline irrigation

The use of composted sewage sludge and limestone outcrop residue in land rehabilitation, soil improvement, and technosol making can influence the mobility of nitrogen compounds in groundwater. This experiment analyzed this source of possible pollution under an experimental design based on the use of columns (0–30 cm) formed by both wastes and a heavy irrigation regime. Two waters of different quality (saline and non-saline) were used for irrigation. The presence of nitrate, nitrite, and ammonium in the leachates was checked. The environmental risk due to the presence of nitrogen species associated with the use of these materials was very low in general, although nitrate was the most important compound affected by the use of sewage sludge compost and saline water. The combination of saline water for irrigation with the compost has to be seriously considered as a source of pollution for surface and ground waters, and the use of both resources may be a key factor to be studied (low-quality water and sewage sludge compost).

A summary of the biogeochemistry of nitrogen compounds in ground water

The biogeochemistry of nitrogen compounds in ground waters is exceedingly complex. The exclusive chemical monitoring of nitrates in ground waters is overly simplistic and may lead to errors in data interpretation. Nitrogen compounds are biodegradable and an understanding of the physical, chemical, and biologic systems through which transient water is moving is important in analyzing chemical data. Ground water nitrate contamination is generally encountered in shallow aquifers which have direct or indirect hydraulic continuity with the ground surface. Surface sources of ground water nitrate contamination related to man's activities include domestic sewage, agricultural practices, and high-density animal confinement.