Major Groundwater Quality Research Articles

A study on groundwater quality and its characteristics in Tuticorin coastal region using geo-statistical approaches, Tamil Nadu, India

The aim of the present research is to identify the factors and processes to manage groundwater susceptibility using geostatistical techniques. Shortage of freshwater and drinking water are the major problems in the southeast coast of Tuticorin district, Tamil Nadu, India. Due to the different landscape and geological frame work across the coastal area, ever increasing population and manmade activities there is a necessity to check the groundwater quality in drinking and domestic water supply. Geostatistical analysis has been carried out through the field samples (24 nos) which were analyzed and visually interpreted in a graphical representation. The quality characteristics of the samples analysed using multivariate statistical analysis in the study area have been identified to be abnormal (EC, TDS, Cl and Na). The values are approximately 3 times exceeding the WHO standard for the villages of Sahupuram, Kayalpattinam, Arumuganeri, Vaalasamuthram and Arasadi spread over 300 km2. Principle Component Analysis (PCA) indicates that the field of groundwater quality is predominantly associated with geogenic (rock-water interaction) and anthropogenic sources and domestic sewage. Findings of factors, cluster analysis (CA) and correlation matrix (CM) were also found to be consistant with the PCA results. It has been evident from the statistical analysis that the major groundwater quality is significantly influenced by EC, TDS, Cl and Na due to the inland salinity caused by seawater intrusion. Results of the study are expected to provide insights into taking effective action for groundwater quality protection by decision-makers on the Tuticorin coast of southern Tamil Nadu.

Patterns in groundwater quality: Selected observations in Iowa

Groundwater quality in Iowa varies with depth, location, ownership of well, time of sampling, and geologic features. Samples from deep wells (>30.48 m or 100 ft) are highly mineralized with sulfates and carbonates (calcium and magnesium), whereas the mineral content in samples from shallow wells (<30.48 m or 100 ft) is relatively much lower. Nitrate as a percent of dissolved solids is negligible in samples from deep wells and reaches as high as 3 to 5% in samples from shallow wells. Shallow wells, in particular non-public wells, are highly susceptible to nitrate contamination (with an average concentration of 27.8 mg/l) compared with any other category of wells studied. In shallow non-public wells, the concentration of nitrate from recent geologic deposits (31.61 mg/l) is more than twice the level found in corresponding public wells from similar deposits (13.35 mg/l). Shallow non-public wells are also subject to sharp seasonal fluctuations, with a peak nitrate concentration of 55.81 mg/l in the month of May, possibly because of spring runoff from agricultural and other surface sources. These observations are further supported by the results of nitrate analyses from a large number (over 44,000) of private wells in Iowa. Eighteen percent of these private wells were found to exceed the maximum contaminant level of 45 mg/l nitrate (NO3 −). A higher proportion of the shallow wells (<30.48 m or 100 ft) exceed the maximum contaminant level of 45 mg/l (3867 out of 13,625 or 28.4%). It is proposed that the observed variability in groundwater quality be used as a first step in developing a strategy for strengthening state-wide groundwater quality monitoring programs. Strong state-wide programs would be of considerable assistance to policy makers in the resolution of major groundwater quality issues.