Water Quality Analysis

2.5 METHODS OF WATER QUALITY ANALYSIS

Water quality data may be interpreted on the basis of the both individual analysis and sets of analysis from one sampling site or different sampling sites in an area or aquifer being examined. In the case of individual analysis, the first step is the exanimation to accuracy, followed by estimation of source, mass balance examination of the minerals that may have dissolved or precipitated. Collectively, water analysis may be compared and interpreted using areal plots, graphical methods, and statistical analysis. Statistical analysis are usually separated into those useful for qualitative comparisons, for example, stiff diagrams, and those designed to detect chemical tends or mixing such as Piper or Durov

Many authors have use different methods to classify groundwater in different parts of the world for different uses. These methods include classification based on Total Dissolved Solids, Handa’s classification, corrosivity ratio, Schoeller’s water type, Stufyzand water type, USSL classification, groundwater hardness, sodium absorption ratio, residual sodium carbonate, indices of base exchange, CaCO3 saturation indices, Gibb’s plot, Piper’s geochemical facies etc.

Water with high TDS indicates more ionic concentration, which is inferior and can cause physiological disorders to its user when used as drinking water (Subba Rao et al 2002). TDS is one of the important factors that determine the suitability of water for various uses. Carroll (1962) proposed a classification of groundwater based on the TDS. Salts of calcium, magnesium, sodium and potassium present in irrigation water may pose to be injurious to plants (Obiefuna and Sheriff, 2011). The authors went further to stress that salts from the major ions when present in excess quantities can affect the osmotic activities of the plants and may prevent adequate aeration. Accoding to WHO (2006) Classification of groundwater base on total dissolved solids is; 100000mg/l as brine

A Stiff diagram, uses four parallel, horizontal axes extending on each side of a vertical, zero axis. Four cations and four anions can thus be plotted on the left and right of the vertical axis, respectively. Concentrations are in meq/l, and the resulting points are connected to give an irregular polygonal pattern. The size of the pattern is approximately equal to the total ionic content. Classically, the pairs are sodium chloride, calcium-bicarbonate, magnesium, sulfate, and iron-carbonate. Usually the iron-carbonate line is small or nonexistent (Hounslow, 1995). Though the method is able to establish patterns, it is constrained by its inability to handle large volumes of data. To overcome this limitation, Yidana et al. (2010) showed that the stiff diagrams could be generated for water types after they have been