EFFECTS OF CLIMATE VARIABILITY ON RIVERS: CONSEQUENCES FOR LONG TERM WATER QUALITY ANALYSIS1

ABSTRACT: Associations between the El Nino Southern Oscillation (ENSO) climate pattern and temporal variability in flow and 12 water quality variables were assessed at 77 river sites throughout New Zealand over a 13‐year period (1989 through 2001). Trends in water quality were determined for the same period. All 13 variables showed statistically significant linear regression relationships with values of the Southern Oscillation Index (SOI). The strongest relationships were for water temperature (mean R²= 0.20), dissolved reactive phosphorus (0.18), and oxidized nitrogen (0.17). The association with SOI varied by climate region. The observed patterns were generally consistent with known ENSO effects on New Zealand rainfall and air temperature. Trends in water quality variables for the periods 1989 through 1993, 1994 through 1998, and 1989 through 1998 were reasonably consistent with trends in SOI, even when the influence of river flow was removed from the data. This suggests that SOI effects on water quality are not necessarily a direct consequence of changes in flow associated with rainfall variation. In addition, both Baseline (32 upstream) and Impact (45 downstream) sites showed similar trends, indicating that changes in management were not directly responsible. We conclude that interpretation of long term water quality datasets in rivers requires that climate variability be fully acknowledged and dealt with explicitly in trend analyses.     

DATA ANALYSIS OF WATER QUALITY TIME SERIES IN LAKE ERIE1

ABSTRACT: A comprehensive data analysis study is carried out for detecting trends and other statistical characteristics in water quality time series measured in Long Point Bay, Lake Erie. In order to glean an optimal amount of useful information from the available data, the exploratory and confirmatory data anslysis stages are adhered to. To test a range of hypotheses regarding the statistical properties of the time series, a wide variety of both parametric and nonparametric techniques are employed. A particularly useful nonparametric method for discovering trends is the seasonal Mann-Kendall test.     

TRENDS IN LEAD CONCENTRATIONS IN MAJOR U.S. RIVERS AND THEIR RELATION TO HISTORICAL CHANGES IN GASOLINE-LEAD CONSUMPTION1

ABSTRACT: Declines in concentrations of dissolved lead occurred at nearly two-thirds of 306 locations on major U.S. rivers from 1974 to 1985. Declines in dissolved lead concentrations are statistically significant (p < 0.10) at approximately one-third of the sampling locations. Statistically significant increases in dissolved lead concentrations occurred at only 6 percent of the sites, but are clustered in the Texas-Gulf and Lower Mississippi regions. Possible explanations for the observed trends in lead concentrations are tested through comparisons with (1) records of lead discharges from major sources including leaded-gasoline consumption and municipal- and industrial-point source discharges, (2) trends in various water-quality constituents such as pH and total alkalinity, and (3) basin characteristics such as drainage area. Statistically significant declines in lead concentrations in streams and gasoline lead (i.e., the largest source of lead at these sites) are highly coincident for the 1979 to 1980 period at most sampling locations. The greatest amount of decline in gasoline lead occurred at sites showing statistically significant downtrends in stream concentrations of lead from 1974 to 1985. No more than 5 percent of the trends in stream lead are influenced by municipal- and industrial-point sources of lead. Factors that affect the transport of dissolved lead, including lead solubility, suspended sediment, and basin characteristics such as drainage basin size, are not significantly related to trends in dissolved lead. Trends in streamflow explain no more than 7 percent of the downtrends in concentrations of lead and may partly explain the frequent increases in lead concentrations in the Texas-Gulf and Lower Mississippi regions.     

活性污泥3号模型(ASM3)的发展与应用

IAWQ又于1999年推出ASM3,它不以水解作用为重点,更深入考虑了胞内存贮过程,并考虑环境因素对衰减过程的修正,把溶解性、颗粒性有机氮的降解与微生物的水解、衰减和生长结合在一起。带有EAWAG生物除磷模块的ASM3能预测除磷效果;通过校正的ASM3能预测脱氮除磷、污泥产量。     

Trend surface analysis of forest landscape pattern in Guandishan forest region of Shanxi,China

１ＩｎｔｒｏｄｕｃｔｉｏｎＡｌｍｏｓｔａｌｏｆｌａｎｄｓｃａｐｅｓａｒｅｓｐａｔｉａｌｙｈｅｔｅｒｏｇｅｎｅｏｕｓｍｏｓａｉｃｓｏｆｌａｎｄｃｏｖｅｒｏｒｈａｂｉｔａｔ（Ｆｏｒｍａｎ，１９９５）．Ｔｈｅｓｐａｔｉａｌａｒａｎｇｅｍｅｎｔｏｒｓｐａｔ...     

红枫湖、百花湖水污染趋势分析及控制对策

研究了贵州高原地区红枫湖和百花湖的水污染状况,结果表明湖水中TN、K-N、SD、DO、NO2-N和TP等 普遍超标,水质达不到功能区类别要求,并呈现水体富营养化现象。通过水污染的趋势分析,探讨湖水污染的原 因,提出相应的水污染控制对策。     

铝合金的半固态成形

半固态加工是金属材料成形领域中的一种新工艺。分析了铝合金半固态成形技术的现状及发展趋向。     

昆明市主要供水水源地水质现状及其趋势分析

对昆明市主要供水水源松花坝水库、大河水库、柴河水库作了水质现状和富营养化评价,结果为2005年松花坝水库水质为IV类,中营养;大河水库水质为Ⅲ类,中营养;柴河水库水质为Ⅲ类,富营养.分析了3个水源地2001～2005年污染指标变化趋势,根据污染分析提出了防治对策.     

絮凝剂的研究现状及发展前景

本文对当前国内外絮凝剂的研究现状及应用进行了总结，对于各类絮凝剂的历史发展进行了回顾，对絮凝剂的发展前景及趋势作了展望和预测。     

遥感技术在土壤污染中的应用研究进展

近年来遥感技术不断地拓展着应用的领域和范围，在土壤污染方面得到了广泛的关注和应用。传统土壤污染的研究存在许多弊端，需要耗费大量时间和精力。遥感技术具有建模范围大、实时性短的特点，它的出现使这些繁琐的过程更加简化。特别是近些年来图像处理手段和无人机遥感技术的发展，极大地提高了该技术的应用精度。本文从遥感技术在土壤污染状况的识别、反演、监管和风险评估等方面的应用出发，列举了遥感技术应用过程中常用的反演手段和方法，梳理了监管数据来源和监管对象。通过目前土壤污染与遥感技术结合的发展现状，较为全面地回顾了国内外遥感技术应用于土壤污染的发展历程，总结了遥感技术应用于土壤污染的各个方面的进展，并对该方面的未来发展趋势进行了展望。