Study of zinc pollution in river water: Average mass balance based on irrigation schedule
Pertiwi Andarani, Kuriko Yokota, Makoto Saga, Takanobu Inoue, Yoshitaka Matsumoto
Abstract
Abstract Aichi Prefecture, which has a dense industrial area, is one of the sites in Japan where the levels of zinc are elevated. However, currently, there is no clear evidence of the source of zinc in this prefecture. This study aims to assess zinc concentration and load in a river and identify the main sources of zinc pollution. We conducted a 20‐month survey to identify the temporal and spatial variation of zinc in river water, particularly in the Aizumame River. Using Flame Atomic Absorption Spectrometry, the total fraction of zinc concentrations was determined for nine sampling stations (five points in the mainstream and four points in the tributaries). The results show that the average of zinc concentration was lower during the irrigation period than in the non‐irrigation period. However, the load during the irrigation period was higher. During irrigation, the river discharges were higher resulting in a lower concentration. The highest zinc concentration was 0.139 mg/L in June 2017. Based on this study, the main zinc source was identified from industrial areas which on average contributed about 3,400 g/day into the mainstream. These results became more evident during the non‐irrigation period when only industrial discharges contributed zinc load into the mainstream.