Combining natural background levels (NBLs) assessment with indicator kriging analysis to improve groundwater quality data interpretation and management

2016 ◽  
Vol 569-570 ◽  
pp. 569-584 ◽  
Author(s):  
Daniela Ducci ◽  
M. Teresa Condesso de Melo ◽  
Elisabetta Preziosi ◽  
Mariangela Sellerino ◽  
Daniele Parrone ◽  
...  
Keyword(s):  
Groundwater Quality ◽  
Data Interpretation ◽  
Indicator Kriging ◽  
Quality Data ◽  
Natural Background ◽  
Background Levels ◽  
Kriging Analysis

scholarly journals Spatio-Temporal Analysis of Natural and Anthropogenic Arsenic Sources in Groundwater Flow Systems

2018 ◽  
Vol 15 (11) ◽  
pp. 2374 ◽  
Author(s):  
Claudia Avila-Sandoval ◽  
Hugo Júnez-Ferreira ◽  
Julián González-Trinidad ◽  
Carlos Bautista-Capetillo ◽  
Anuard Pacheco-Guerrero ◽  
...  
Keyword(s):  
Temporal Analysis ◽  
Indicator Kriging ◽  
World Health ◽  
Human Consumption ◽  
Natural Background ◽  
Background Levels ◽  
Arsenic In Groundwater ◽  
Flow Systems ◽  
Spatio Temporal

The presence of arsenic in groundwater constitutes a hazard for the environment and human health, and the determination of its source has become a global challenge, which can be approached by defining the natural background levels (NBL) in conjunction with the indicator kriging method, with the aim of delineating anthropogenically contaminated areas. However, having a unique value of NBL for large areas can generate interpretation errors. This research integrates the determination of the flow systems present in the Calera Aquifer, and the definition of the natural background levels in each flow system by making estimation maps in ArcGIS using two databases, 10 years apart, to evaluate the spatio-temporal variation of arsenic in groundwater. The results indicate a notable increase in the probability of exceeding the arsenic NBL, mainly in the intermediate flow, which may be due to movement resulting from mining activities as well as a mixture of regional and intermediate flows caused by the extraction of water for agriculture and drinking water supplies. The presented values exceed the maximum limits allowed for human consumption, as stated by the World Health Organization.

scholarly journals Assessing Natural Background Levels in the Groundwater Bodies of the Apulia Region (Southern Italy)

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 958
Author(s):  
Rita Masciale ◽  
Stefano Amalfitano ◽  
Eleonora Frollini ◽  
Stefano Ghergo ◽  
Marco Melita ◽  
...  
Keyword(s):  
Inorganic Compounds ◽  
Monitoring Network ◽  
Software Tool ◽  
National Standards ◽  
Quality Data ◽  
Natural Background ◽  
Apulia Region ◽  
Background Levels ◽  
Geochemical Parameters ◽  
Iron Manganese

Defining natural background levels (NBL) of geochemical parameters in groundwater is a key element for establishing threshold values and assessing the environmental state of groundwater bodies (GWBs). In the Apulia region (Italy), carbonate sequences and clastic sediments host the 29 regional GWBs. In this study, we applied the Italian guidelines for the assessment of the NBLs, implementing the EU Water Framework Directive, in a south-European region characterized by the typical Mediterranean climatic and hydrologic features. Inorganic compounds were analyzed at GWB scale using groundwater quality data measured half-yearly from 1995 to 2018 in the regional groundwater monitoring network (341 wells and 20 springs). Nitrates, chloride, sulfate, boron, iron, manganese and sporadically fluorides, boron, selenium, arsenic, exceed the national standards, likely due to salt contamination along the coast, agricultural practices or natural reasons. Monitoring sites impacted by evident anthropic activities were excluded from the dataset prior to NBL calculation using a web-based software tool implemented to automate the procedure. The NBLs resulted larger than the law limits for iron, manganese, chlorides, and sulfates. This methodology is suitable to be applied in Mediterranean coastal areas with high anthropic impact and overexploitation of groundwater for agricultural needs. The NBL definition can be considered one of the pillars for sustainable and long-term groundwater management by tracing a clear boundary between natural and anthropic impacts.

scholarly journals Investigating Groundwater Condition and Seawater Intrusion Status in Coastal Aquifer Systems of Eastern India

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1952
Author(s):  
Subrata Halder ◽  
Lingaraj Dhal ◽  
Madan K. Jha
Keyword(s):  
Groundwater Quality ◽  
Seawater Intrusion ◽  
Groundwater Level ◽  
Coastal Aquifer ◽  
Quality Data ◽  
Confined Aquifer ◽  
Groundwater Levels ◽  
Post Monsoon ◽  
Aquifer Systems ◽  
Sustainable Water Supply

Providing sustainable water supply for domestic needs and irrigated agriculture is one of the most significant challenges for the current century. This challenge is more daunting in coastal regions. Groundwater plays a pivotal role in addressing this challenge and hence, it is under growing stress in several parts of the world. To address this challenge, a proper understanding of groundwater characteristics in an area is essential. In this study, spatio-temporal analyses of pre-monsoon and post-monsoon groundwater-levels of two coastal aquifer systems (upper leaky confined and underlying confined) were carried out in Purba Medinipur District, West Bengal, India. Trend analysis of seasonal groundwater-levels of the two aquifers systems was also performed using Mann-Kendall test, Linear Regression test, and Innovative Trend test. Finally, the status of seawater intrusion in the two aquifers was evaluated using available groundwater-quality data of Chloride (Cl−) and Total Dissolve Solids (TDS). Considerable spatial and temporal variability was found in the seasonal groundwater-levels of the two aquifers. Further, decreasing trends were spotted in the pre-monsoon and post-monsoon groundwater-level time series of the leaky confined and confined aquifers, except pre-monsoon groundwater-levels in Contai-I and Deshpran blocks, and the post-monsoon groundwater-level in Ramnagar-I block for the leaky confined aquifer. The leaky confined aquifer in Contai-I, Contai-III, and Deshpran blocks and the confined aquifer in Nandigram-I and Nandigram-II blocks are vulnerable to seawater intrusion. There is an urgent need for the real-time monitoring of groundwater-levels and groundwater quality in both the aquifer systems, which can ensure efficient management of coastal groundwater reserves.

scholarly journals Measurement of the 36Cl deposition flux in central Japan: natural background levels and seasonal variability

2012 ◽  
Vol 106 ◽  
pp. 73-80 ◽  
Author(s):  
Yuki Tosaki ◽  
Norio Tase ◽  
Kimikazu Sasa ◽  
Tsutomu Takahashi ◽  
Yasuo Nagashima
Keyword(s):  
Seasonal Variability ◽  
Deposition Flux ◽  
Natural Background ◽  
Central Japan ◽  
Background Levels

scholarly journals Interpolation of groundwater quality parameters with some values below the detection limit

2011 ◽  
Vol 15 (9) ◽  
pp. 2763-2775 ◽  
Author(s):  
A. Bárdossy
Keyword(s):  
Detection Limit ◽  
Maximum Likelihood ◽  
Groundwater Quality ◽  
Likelihood Estimation ◽  
Quality Parameters ◽  
Indicator Kriging ◽  
West Germany ◽  
Marginal Distributions ◽  
Copula Models ◽  
Measuring Device

Abstract. For many environmental variables, measurements cannot deliver exact observation values as their concentration is below the sensitivity of the measuring device (detection limit). These observations provide useful information but cannot be treated in the same manner as the other measurements. In this paper a methodology for the spatial interpolation of these values is described. The method is based on spatial copulas. Here two copula models – the Gaussian and a non-Gaussian v-copula are used. First a mixed maximum likelihood approach is used to estimate the marginal distributions of the parameters. After removal of the marginal distributions the next step is the maximum likelihood estimation of the parameters of the spatial dependence including taking those values below the detection limit into account. Interpolation using copulas yields full conditional distributions for the unobserved sites and can be used to estimate confidence intervals, and provides a good basis for spatial simulation. The methodology is demonstrated on three different groundwater quality parameters, i.e. arsenic, chloride and deethylatrazin, measured at more than 2000 locations in South-West Germany. The chloride values are artificially censored at different levels in order to evaluate the procedures on a complete dataset by progressive decimation. Interpolation results are evaluated using a cross validation approach. The method is compared with ordinary kriging and indicator kriging. The uncertainty measures of the different approaches are also compared.

Natural background levels and threshold values for groundwater in fluvial Pleistocene and Tertiary marine aquifers in Flanders, Belgium

2008 ◽  
Vol 57 (5) ◽  
pp. 1155-1168 ◽  
Author(s):  
Marleen Coetsiers ◽  
Petra Blaser ◽  
Kristine Martens ◽  
Kristine Walraevens
Keyword(s):  
Threshold Values ◽  
Natural Background ◽  
Background Levels
Sign in / Sign up

Export Citation Format

Share Document