Abstract
The algal growth potential (AGP) test is a useful tool for assessing the eutrophication of rivers and lakes. Nevertheless, the AGP test is relatively expensive because of its large scale. In this study, a microplate technique was used in the AGP test to develop a microscale version. The algal growth in the microplate wells was monitored by examining the relationship between the absorbance (450 nm) measured using a microplate reader and cell concentration. A high correlation was observed between absorbance and cell concentration. There were few differences between the microplate wells with respect to well position, suggesting that the effect of well position on algal growth is negligible. The microscale AGP test using a microplate was compared with the conventional flask-size AGP test. A high similarity between the two methods was observed. Therefore, the microscale AGP test is a simple and useful method for conducting AGP tests on many water samples. The change in AGP level in the Tama River was investigated. AGP level increased considerably after inflow of water discharged from sewage treatment plants (STPs). This study has demonstrated that STP discharge has a considerable effect on river water quality.
