Iwashita Masato, Shimamura Tadashi
School of Allied Health Sciences, Kitasato University 1-15-1 Kitasato, Sagamihara, Kanagawa 228-8555, Japan.
Sci Total Environ. 2003 Aug 1;312(1-3):167-79. doi: 10.1016/S0048-9697(03)00251-1.
We investigated long-term variations in dissolved chemical species in water sampled from the Sagami River and its tributaries, Japan. The samples were taken monthly from May 1993 to April 2000 at 28 sampling sites in the Sagami River system. In this paper, we concentrate on 17 sites in the upper catchment. Twenty-four major to trace elements (Li, Mg, Al, Ca, V, Mn, Fe, Co, Ni, Cu, Zn, As, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, W, Tl, Pb, U) were determined by using conventional Q-pole ICP-MS with direct nebulizalion. Water flux was measured from 1995. The data for most species were subjected to fast Fourier transformation (FFT) to extract dominant periodicities, their magnitudes, and their phases. Clear seasonal variations were observed for Al, V, As, Rb and Cs at some sampling points, especially in the tributaries. The seasonal variations may be due to either anthropogenic causes, such as irrigation or wastewater discharge, or natural causes, such as water temperature, pH, redox condition, water flux, or activity of microorganisms. We found no correlation with pH. Water temperature may not be a main controlling factor, although the seasonal variability would be correlated with it. Hydrologic factors may have only minor effects. We suggest that most of the seasonal variation might be correlated with the irrigation of rice paddies. It was difficult to identify all the causes of the seasonal variability. To investigate interannual trends, we used centered 12-month moving averages to eliminate seasonal variations. The water quality of the uppermost streams was generally constant, being controlled by springs on Mt. Fuji. However, in 1993 and 1998, V, As, Rb, Cs and U were depleted briefly, possibly by dilution by overflow from Lakes Kawaguchi and Yamanaka. Hydrologic factors may be more important for interannual variability than seasonal variability. Some heavy trace elements (Zn, Ni, Cd and Sb) showed very irregular variations with high concentration peaks. These elements were discharged from either factories or abandoned mine tailings.
我们调查了从日本相模川及其支流采集的水样中溶解化学物质的长期变化情况。这些样本于1993年5月至2000年4月期间每月在相模川水系的28个采样点采集。在本文中，我们重点关注上游集水区的17个站点。使用具有直接雾化功能的传统Q极电感耦合等离子体质谱仪测定了24种主要和微量元素（锂、镁、铝、钙、钒、锰、铁、钴、镍、铜、锌、砷、铷、锶、钼、银、镉、锑、铯、钡、钨、铊、铅、铀）。自1995年开始测量水流量。对大多数物种的数据进行了快速傅里叶变换（FFT），以提取主要周期、其幅度和相位。在一些采样点，特别是支流中，观察到铝、钒、砷、铷和铯有明显的季节变化。这些季节变化可能是由于人为原因，如灌溉或废水排放，也可能是自然原因，如水温、pH值、氧化还原条件、水流量或微生物活动。我们发现与pH值没有相关性。水温可能不是主要控制因素，尽管季节变化会与之相关。水文因素可能只有轻微影响。我们认为大部分季节变化可能与稻田灌溉有关。很难确定季节变化的所有原因。为了研究年际趋势，我们使用了12个月中心移动平均值来消除季节变化。最上游溪流的水质总体稳定，受富士山泉水控制。然而，在1993年和1998年，钒、砷、铷、铯和铀短暂减少，可能是被河口湖和山中湖的溢流稀释所致。水文因素对年际变化可能比季节变化更重要。一些重微量元素（锌、镍、镉和锑）显示出非常不规则的变化，有高浓度峰值。这些元素是从工厂或废弃矿尾矿中排放出来的。
