Arsenic water quality indicator

For this study, we consider four types of water non-impacted (arsenic below detection limit), low (greater than the detection limit and less than 10 pg/l As), moderate (10-100 p.g/1 As), and high (greater than 100 pg/1 As). Typical of water quality data, the data set is censored and as such, the concentrations reported for most constituents are not normally distributed (Gibbons, 1994). Because of this limitation, box plots (Fig. 6) are used to evaluate and compare the water quality results. The distributions of concentrations were compared for iron, sulfate, pH, alkalinity, nickel, zinc, manganese and specific conductance (SC). The box plots should be viewed with consideration of sample size, which is indicated on Fig. 6. 

The loss in weight is dependent upon the quality of the arsenic oxide and glycerol used. If these are dry, the weight loss should be as indicated. The lower figure is equivalent to 1 mole of water for each mole of glycerol. 

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