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The flow cytometry (FC) has been used to detect Giardia cysts and Cryptosporidium oocysts quantitatively and instantaneously in this study. The experimental results showed that FC is potential to become a more precise method for the detection of Giardia and Cryptosporidium in water. This study also evaluated the staining efficiencies for three commercial antibodies. After staining Cryptosporidium oocysts with direct immunofluorescent antibodies in water samples, two populations were detected in the scatter-plots (FL1 versus SSC) of the FC. The Cryptosporidium oocysts and Giardia cysts are significantly separated from other particles while stained with direct immunofluorescent antibodies produced by Meridian Diagnostics and Waterborne Inc.

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This study assessed the aquatic toxicity of the River Keya during its passage through the Hsin Chu City, Taiwan. The River Keya receives effluent from the Union Wastewater Treatment Plant of Hsin Chu Science Industrial Park (UWTP-HCSIP) primarily covering more than 500 semiconductors-related high-tech industries. Although the effluent from the UWTP-HCSIP has met the current environmental regulations of Taiwan, the aquatic environment of the River Keya was frequently subjected to unknown interferences. The aim of present study was to assess the acute toxicity of the River Keya using Daphnia magna. Six sampling sites were arranged where four were at downstream from the confluence of the effluent from the UWTP-HCSIP to the River Keya, and the other two were at the upstream to serve as references. Daphnia magna was employed to test the static 24-h acute toxicity, and the data obtained were further analyzed using the Probit and Spearman-Karber statistical models. Results showed a significant increase of the electric conductivity, BOD 5 , and COD in those sampling sites downstream of the confluence point. The toxicity unit (TU) of the river water showed an increase-then-decrease fashion, and up to a 3-fold increase of TU was found downstream the UWTP-HCSIP effluent convergent to the River Keya. In comparison with the TU of the samples taken at the discharge point of the UWTP-HCSIP and the downstream of the convergence, the former is two times higher than the latter. These comparative results revealed that the aquatic toxicity effect is close related to the effluent from the UWTP-HCSIP, and a carry capacity of River Keya, especially for aquatic toxicity should be established.