Abstract
The volume of treated sewage effluent (TSE) in public water bodies in Japan has increased over time. Therefore, it is critical that we understand the effect of TSE on water cycling, freshwater ecosystems, and conservation. However, it is difficult and expensive to implement studies and conservation activities on the large scales required using only researchers and government agency staff. Citizen science (i.e., engaging the public in scientific research) is increasingly being used to solve the challenge of large-scale environmental monitoring, especially in the United States and Europe. Citizen science is used less frequently in Japan. In 2014, we started a citizen science project to investigate the influence of different sewage treatment methods on the water quality of three rivers in the Sakai River basin in Yokohama City. The project involved the collaboration of citizens, universities, federal and local governments, and local communities. The project revealed that ammonium (NH4-N) and nitrate (NO3-N) concentrations and nitrogenous biochemical oxygen demand (N-BOD) differ among the effluents of the sewage treatment plants, suggesting different impacts on the water quality and BOD of each river.
