Assessing Japan’s Tama River Health Using Benthic Macroinvertebrates and Physico-Chemical Properties as Indicators of Water Quality
Abstract – Japan’s Tama river is an invaluable water resource for many living organisms including humans. Many ecological studies have shown that benthic macroinvertebrates can serve as bioindicators to assess the quality of water. Surprisingly there are currently no studies on macroinvertebrate-based health analysis that have been published pertaining to this river. In this study, the health of 2 sites of the Tama river in Japan was assessed using benthic macroinvertebrates, via the kick netting method, and measures of chemical/physical variables (nitrites, nitrates, pH, dissolved oxygen, ammonia, phosphate, temperature). The most abundant taxa for site 1 was the Trichopetera with a total of 72 specimens found, while the most abundant for site 2 was the Hirudinea, Caenidae Caenis, and Platyhelminthes with a total of 21, 19, and 15 specimens found respectively. The MCI, SQMCI, and Shannon Diversity Index were calculated and indicated that site 1 (upstream) had probable mild pollution and lower diversity, while site 2 (downstream) had probable moderate pollution/severe pollution despite having higher diversity. All chemical and physical variables were within healthy river standards besides nitrate, which was higher than the recommended amount for both sites. These findings can suggest that certain regions of the Tama river have mild-moderate pollution, suggesting the need for more in-depth studies on this natural resource.