Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima 739-8521, Japan; Department of Chemistry, Federal University of Technology, Akure, P.M.B 704, Ondo State, Nigeria.
Graduate School of Biosphere Science, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima 739-8521, Japan; Department of Environmental Sciences, Hazara University, Mansehra, Pakistan.
Sci Total Environ. 2020 Sep 1;733:139349. doi: 10.1016/j.scitotenv.2020.139349. Epub 2020 May 12.
Hydrogen peroxide (HO) is a reactive oxygen species formed in natural water. It is reportedly toxic to aquatic organisms with a predicted no-effect concentration (PNEC) of about 380 nM. In this study, a countrywide investigation of HO concentrations in selected rivers across Japan was conducted to identify rivers that pose toxicity concerns. Twelve rivers with a total catchment area of 13,646 km were selected from different prefectures. Spatial and temporal variation studies showed that the HO concentrations (avg. 320 nM, n = 111) varied by two orders of magnitude (range 21-2929 nM) across the rivers. The Yamato River in Osaka and Nara prefectures and the Kokubu River in Chiba Prefecture had the highest concentrations at 276-669 nM and 236-2929 nM, respectively. >75% of the data from the two rivers were either close to or exceeded the PNEC. Most of the results for the other rivers were less than the PNEC. There was a clear seasonal variation in the HO concentrations, with the highest values obtained in summer because of high solar irradiation. The HO concentration had the highest positive correlation (r = 0.61, p < 0.01, n = 111) with the product of dissolved organic carbon and solar radiation intensity, which suggests that these two factors in combination are important in determining the HO concentrations in river water. It was also observed that bigger rivers had lower HO concentration and vice-versa. This shows that the size of a river may influence its HO concentration. This study is the first countrywide survey of HO concentrations in different rivers and evaluation of their relationship with the PNEC. The data provide insight on the factors influencing the concentrations of HO in river water.
过氧化氢（HO）是天然水中形成的活性氧物质。据报道，它对水生生物具有毒性，预测无效应浓度（PNEC）约为 380 nM。在这项研究中，对日本选定河流中的 HO 浓度进行了全国范围的调查，以确定存在毒性问题的河流。从不同的县选择了 12 条总集水区面积为 13646 km 的河流。时空变化研究表明，河流之间的 HO 浓度（平均值 320 nM，n = 111）变化了两个数量级（范围 21-2929 nM）。大阪和奈良县的大和河以及千叶县的国府河的浓度最高，分别为 276-669 nM 和 236-2929 nM。这两条河的超过 75%的数据接近或超过了 PNEC。其他河流的大部分结果都低于 PNEC。HO 浓度存在明显的季节性变化，由于太阳辐射高，夏季获得的最高值。HO 浓度与溶解有机碳和太阳辐射强度的乘积呈最高正相关（r = 0.61，p <0.01，n = 111），这表明这两个因素的结合对确定河水中的 HO 浓度很重要。还观察到较大的河流具有较低的 HO 浓度，反之亦然。这表明河流的大小可能会影响其 HO 浓度。这项研究是对不同河流中 HO 浓度的首次全国性调查，并评估了它们与 PNEC 的关系。这些数据提供了有关影响河水中 HO 浓度的因素的见解。
