Evaluation of a Water Analysis Kit ,

A Hach DR‐EL/2 Direct Reading Engineer's Laboratory Kit (Hach Chemical Co., Ames, Iowa) was evaluated by comparison to standard analytical methods. Results of Hach kit methods were highly correlated with concentrations of standard solutions. The y ‐intercepts ( a ) did not differ from 0 for most methods, but for 11 methods regression coefficients ( b ) differed from 1.0. For each of the 20 parameters, three natural water samples were analyzed seven times by Hach kit and by the standard method. Mean values obtained by the two analytical systems were usually significantly different and the standard method sometimes gave higher precision than the Hach kit. Nevertheless, the Hach kit usually gave close approximations of values obtained by standard methods. Comparisons also included analyses of a large series of natural water samples. Correlation coefficients between Hach kit and standard methods were often > 0.99. Although a = 0 for 14 methods, b = 1.0 for only 8 methods. Reliability of the Hach kit was adequate for general surveys of water quality, fisheries management decisions, and research requiring only approximate data on water quality.