Showing papers on "Water quality published in 1998"

Tracing nitrogen sources and cycling in catchments

Abstract: Publisher Summary This chapter focuses on the uses of isotopes to understand water chemistry.I Isotopic compositions generally cannot be interpreted successfully in the absence of other chemical and hydrologic data. The chapter focusses on uses of isotopes in tracing sources and cycling of nitrogen in the water-component of forested catchment, and on dissolved nitrate in shallow waters, nutrient uptake studies in agricultural areas, large-scale tracer experiments, groundwater contamination studies, food-web investigations, and uses of compound-specific stable isotope techniques. Shallow waters moving along a flowpath through a relatively uniform material and reacting with minerals probably do not achieve equilibrium but gradually approach some steady-state composition. The chapter also discusses the use of isotopic techniques to assess impacts of changes in land-management practices and land use on water quality. The analysis of individual molecular components for isotopic composition has much potential as a method for tracing the source, biogeochemistry, and degradation of organic liquids and gases because different materials have characteristic isotope spectrums or biomarkers.

Agricultural Phosphorus and Eutrophication: A Symposium Overview

Abstract: Phosphorus in runoff from agricultural land is an important component of nonpoint-source pollution and can accelerate eutrophication of lakes and streams. Long-term land application of P as fertilizer and animal wastes has resulted in elevated levels of soil P in many locations in the USA. Problems with soils high in P are often aggravated by the proximity of many of these areas to P-sensitive water bodies, such as the Great Lakes, Chesapeake and Delaware Bays, Lake Okeechobee, and the Everglades. This paper provides a brief overview of the issues and options related to management of agricultural P that were discussed at a special symposium titled, “Agricultural Phosphorus and Eutrophication,” held at the November 1996 American Society of Agronomy annual meetings. Topics discussed at the symposium and reviewed here included the role of P in eutrophication; identification of P-sensitive water bodies; P transport mechanisms; chemical forms and fate of P; identification of P source areas; modeling of P transport; water quality criteria; and management of soil and manure P, off-farm P inputs, and P transport processes.

Water Pollution Control: A Guide to the Use of Water Quality Management Principles

Abstract: Policy and Principles. Water Quality Requirments. Technology Selection. Wastewater as a Resource. Legal and Regulatory Instruments. Economic Instruments. Financing Wastewater Management. Institutional Arrangements. Information Systems. Framework for Water Pollution Control. The Ganga, India. Shanghai Huangpu River, China. The Pasig River, Phillipines. Nigeria. The Witbank Dam Catchment. The Upper Tiete Basin, Brazil. The Mezquital Valley, Mexico. Lerma-Chapala Basin, Mexico. The Danube Basin. Moscow Region, Russia. Cyprus. Kingdom of Jordan. Sana'a, Yemen.

Characterization of Highway Runoff in Austin, Texas, Area

Abstract: Water quality of highway runoff in the Austin, Texas, area was determined by monitoring runoff at three locations on the MoPac Expressway. Daily traffic volumes, surrounding land uses, and highway drainage system types were different at each site. The concentrations of constituents in runoff at all sites were similar to median values compiled in a nationwide study of highway runoff quality. A grassy swale at one site was effective in reducing the concentrations of most constituents in runoff. The lower runoff coefficient at this site is attributable to infiltration of runoff into the grassy swale. The pollutant loads discharged from the pipe draining the swale were lower than those observed at the sites where runoff drained directly from the pavement. A first flush effect (i.e., higher pollutant concentrations at the beginning of an event) was evident during selected events, but was generally limited to a small volume. The overall effect was negligible when all monitored events were considered.

Drinking water in developing countries

Abstract: Safe drinking water remains inaccessible for about 11 billion people in the world, and the hourly toll from biological contamination of drinking water is 400 deaths of children (below age 5) This paper reviews the general guidelines for drinking water quality and the scale of the global problem It reviews the various water disinfection technologies that may be applicable to achieve the desired quality of drinking water in developing countries It then summarizes financing problems that deter extending access to safe drinking water to the unserved population and identifies feasible policy positions for enhancing availability of drinking water in these countries

Solar disinfection of drinking water contained in transparent plastic bottles : characterizing the bacterial inactivation process

Abstract: series of experiments is reported to identify and characterize the inactivation process in operation when drinking water, heavily contaminated with a Kenyan isolate of Escherichia coli, is stored in transparent plastic bottles that are then exposed to sunlight. The roles of optical and thermal inactivation mechanisms are studied in detail by simulating conditions of optical irradiance, water turbidity and temperature, which were recorded during a series of solar disinfection measurements carried out in the Kenyan Rift Valley. Optical inactivation effects are observed even in highly turbid water (200 ntu) and at low irradiances of only 10 mW cm 2 . Thermal inactivation is found to be important only at water temperatures above 45 °C, at which point strong synergy between optical and thermal inactivation processes is observed. The results confirm that, where strong sunshine is available, solar disinfection of drinking water is an effective, low cost method for improving water quality and may be of particular use to refugee camps in disaster areas. Strategies for improving bacterial inactivation are discussed.

Environmental Soil and Water Chemistry: Principles and Applications

Abstract: WATER CHEMISTRY AND MINERAL SOLUBILITY. Physical Chemistry of Water and Some of Its Constituents. Solution/Mineral-Salt Chemistry. SOIL MINERALS AND SURFACE CHEMICAL PROPERTIES. Soil Minerals and Their Surface Properties. Sorption and Exchange Reactions. ELECTROCHEMISTRY AND KINETICS. Redox Chemistry. Pyrite Oxidation Chemistry. Reaction Kinetics in Soil-Water Systems. SOIL DYNAMICS AND AGRICULTURAL-ORGANIC CHEMICALS. Organic Matter, Nitrogen, Phosphorus and Synthetic Organics. COLLOIDS AND TRANSPORT PROCESSES IN SOILS. Soil Colloids and Water-Suspended Solids. Water and Solute Transport Processes. The Chemistry and Management of Salt-Affected Soils and Brackish Waters. LAND-DISTURBANCE POLLUTION AND ITS CONTROL. Acid Drainage Prevention and Heavy Metal Removal Technologies. SOIL AND WATER: QUALITY AND TREATMENT TECHNOLOGIES. Water Quality. Soil and Water Decontamination Technologies. Appendix. Suggested and Cited References. Index.

Contribution of bedrock nitrogen to high nitrate concentrations in stream water

Abstract: Concentrations of nitrate in stream water throughout the world are reported to be elevated relative to natural background levels. This enrichment is commonly attributed to anthropogenic activities such as atmospheric emissions1, livestock feeding2, agricultural runoff3,4, timber harvesting practices5 and domestic/industrial effluent discharge4,6. Here we show that bedrock containing appreciable concentrations of fixed nitrogen contribute a surprisingly large amount of nitrate to surface waters in certain California watersheds,o an extent that even small areas of these rocks have a profound influence on water quality. As 75% of the rocks now exposed at the Earth's surface are sedimentary in origin7, and as these rocks contain about 20% of the global nitrogen inventory8, ‘geological’ nitrogen may be a large and hitherto unappreciated source of nitrate to surface waters. Such a natural nitrate source may be especially significant given that nitrate contamination at very low levels can contribute to surface water eutrophication9, may cause infant methaemoglobinaemia (‘blue baby’ syndrome)6 and has been implicated in certain cancers6. In addition, geological nitrogen may be a source of the ‘missing’ nitrogen noted in several biogeochemical studies of ecosystem nitrogen budgets1.

Water distribution system and diarrheal disease transmission: a case study in uzbekistan

Abstract: Deteriorating water treatment facilities and distribution systems pose a significant public health threat, particularly in republics of the former Soviet Union. Interventions to decrease the disease burden associated with these water systems range from upgrading distribution networks to installing reverse osmosis technology. To provide insight into this decision process, we conducted a randomized intervention study to provide epidemiologic data for water policy decisions in Nukus, Uzbekistan, where drinking water quality is suboptimal. We interviewed residents of 240 households, 120 with and 120 without access to municipal piped water. Residents of 62 households without piped water were trained to chlorinate their drinking water at home in a narrow-necked water container with a spout. All study subjects (1583 individuals) were monitored biweekly for self-reported diarrheal illness over a period of 9.5 weeks. The home chlorination intervention group had the lowest diarrheal rate (28.8/1,000 subjects/month) despite lack of access to piped water in their homes. Compared with the two groups that did not receive the intervention this rate was one-sixth that of the group with no piped water (179.2/1,000 subjects/month) and one-third that of the households with piped water (75.5/1,000 subjects/month). More than 30% of the households with piped water lacked detectable levels of chlorine residues in their drinking water, despite two-stage chlorination of the source water, and were at increased risk of diarrhea. Forty-two percent of these municipal users reported that water pressure had been intermittent within the previous two days. The dramatic reduction in diarrheal rates in the home-chlorination intervention group indicates that a large proportion of diarrheal diseases in Nukus are water-borne. The home-chlorination group had less diarrhea than the group with piped water, implicating the distribution system as a source of disease transmission. Taken together, these epidemiologic data would support the hypothesis that diarrhea in the piped water group could be attributed to cross-contamination between the municipal water supply and sewer, due to leaky pipes and lack of water pressure. Relatively inexpensive steps, including chlorination, maintaining water pressure, and properly maintaining the distribution system, rather than reverse osmosis technology, should reduce diarrheal rates.

Agricultural phosphorus and water quality: a U.S. Environmental Protection Agency perspective

Abstract: Pollution of lakes, rivers, and estuaries from agricultural sources of P is a major water quality problem in the USA. This paper explains the regulatory and nonregulatory programs developed by the U.S. Environmental Protection Agency (USEPA) to implement its legal mandate to control water pollution from these sources. The Clean Water Act defines concentrated animal feeding operations as point sources of pollution that are required to obtain permits to discharge into waters of the USA. All other agricultural sources are considered nonpoint and are not regulated under federal law. The USEPA provides grant money to the states to develop and implement nonpoint source programs. The Coastal Zone Act Reauthorization Amendments of 1990 requires coastal states to adopt nonpoint management measures that are backed by enforceable policies and mechanisms. For water bodies that continue to be impaired despite the basic implementation of these laws and other programs, states are required to develop a total maximum daily load (TMDL). The TMDL process is the quantitative basis for reaching water quality standards. The USEPA is putting a new emphasis on controlling nutrient pollution sources to meet the goal of the Clean Water Act.

Comparison of Membrane Filtration and Multiple-Tube Fermentation by the Colilert and Enterolert Methods for Detection of Waterborne Coliform Bacteria, Escherichia coli, and Enterococci Used in Drinking and Bathing Water Quality Monitoring in Southern Sweden

Abstract: A total of 338 water samples, 261 drinking water samples and 77 bathing water samples, obtained for routine testing were analyzed in duplicate by Swedish standard methods using multiple-tube fermentation or membrane filtration and by the Colilert and/or Enterolert methods. Water samples came from a wide variety of sources in southern Sweden (Skane). The Colilert method was found to be more sensitive than Swedish standard methods for detecting coliform bacteria and of equal sensitivity for detecting Escherichia coli when all drinking water samples were grouped together. Based on these results, Swedac, the Swedish laboratory accreditation body, approved for the first time in Sweden use of the Colilert method at this laboratory for the analysis of all water sources not falling under public water regulations (A-krav). The coliform detection study of bathing water yielded anomalous results due to confirmation difficulties. E. coli detection in bathing water was similar by both the Colilert and Swedish standard methods as was fecal streptococcus and enterococcus detection by both the Enterolert and Swedish standard methods.

Evaluation of Water Quality Factors in Storm Runoff from Paved Areas

Abstract: Continuous water quality measurements of storm runoff into a single road inlet have been carried out at two experimental catchments in Belgrade, Yugoslavia, and Lund, Sweden. Both sites were equipped with similar instrumentation for measurements of overland flow, turbidity, pH, conductivity, and temperature. The data were recorded at 10-s time intervals during rainfall events. To measure suspended solids concentration, turbidity meters were calibrated in conditions very similar to the real world. A detailed description of the field-measuring facilities used in the Belgrade catchment and the results of the measurements from both sites are presented. After detailed examination of possible errors in measurement, only the reliable data were used for statistical analysis. Event mean, extreme, and aggregated values were analyzed. The results indicate that the antecedent dry weather period length has only a minor effect upon road sediments wash-off, but it has an influence upon conductivity. The "first-flush effect" of suspended solids appears only in a limited number of events. Cross-correlation coefficients of rainfall, overland flow, and water quality were calculated for each event, taking into account the time lag between observed characteristics. These coefficients showed that suspended solids loading rate is influenced by rainfall intensity and overland flow rate. The results presented in this paper have been used in development of the physically based wash-off model published by Deletic and colleagues.

Computational Methods in Water Resources XII

Abstract: Water quality surface and subsurface transport microbial and reactive processes heterogeneity multiphase flow sedimentation optimization techniques. (Part contents).

Climate change and water resources in Britain.

Abstract: This paper explores the potential implications of climate change for the use and management of water resources in Britain. It is based on a review of simulations of changes in river flows, groundwater recharge and river water quality. These simulations imply, under feasible climate change scenarios, that annual, winter and summer runoff will decrease in southern Britain, groundwater recharge will be reduced and that water quality - as characterised by nitrate concentrations and dissolved oxygen contents - will deteriorate. In northern Britain, river flows are likely to increase throughout the year, particularly in winter. Climate change may lead to increased demands for water, over and above that increase which is forecast for non-climatic reasons, primarily due to increased use for garden watering. These increased pressures on the water resource base will impact not only upon the reliability of water supplies, but also upon navigation, aquatic ecosystems, recreation and power generation, and will have implications for water quality management. Flood risk is likely to increase, implying a reduction in standards of flood protection. The paper discusses adaptation options.

Soil: the environmental source of Escherichia coli and Enterococci in Guam's streams

Abstract: We have previously documented that faecal indicator bacteria (Escherichia coli, faecal coliform, enterococci) recommended by the U.S. Environmental Protection Agency (USEPA) to establish recreational water quality standards are naturally found in high concentrations in the surface and subsurface of soils in Hawaii. Rain, the source of all streams in Hawaii, washes the soil sources of faecal bacteria into all the streams of Hawaii, at concentrations which consistently exceed the USEPA recreational water quality standards. The objective of this study was to test the hypothesis that faecal bacteria are able to establish themselves in the soil environments of tropical islands by conducting the same study in Guam, a tropical pacific island with warmer temperatures and higher humidity than Hawaii. The same methods and study design used in Hawaii was used in Guam. The results of the study conducted in Guam revealed that all streams contain consistently high concentrations of faecal coliform, E. coli, and enterocci which exceeded the old USEPA recreational water quality standard of 200 faecal coliform/100 ml as well as the new water quality standards of 126 E. coli/100 ml or 33 enterococci/100 ml. These same faecal indicator bacteria were recovered in high concentrations in surface and subsurface (18-36 cm depth) soil samples in Guam. Limited coastal water analysis showed that most coastal marine waters contain low concentrations of faecal bacteria but coastal waters impacted by stream run-off showed elevated levels of faecal bacteria. The results of this study support the hypothesis that environmental conditions in the tropical areas of the world can support the growth and establishment of populations of faecal bacteria in the soil. Thus, soil becomes an environmental, non-faecal source of faecal indicator bacteria. These results indicate that USEPA water quality standards may not be directly applicable to tropical island environments.

Forms and concentration of phosphorus in drainage water of twenty-seven tile-drained soils

Abstract: In most mineral soils, P leaching is rarely viewed as an important environmental issue. However, P accumulation and decreased P sorption capacities in surface horizons of long-term fertilized soils may increase downward P movement. The objective of this study was to measure the concentration and characterize the P forms in drainage waters from nine soil series widely differing in clay content. Twenty-seven sites were sampled in 1994 and 1995 from an intensively cropped area of the province of Quebec, Canada. Drainage waters were characterized for their total P (TP), dissolved reactive P (DRP), dissolved organic P (DOP), and total particulate P (TPP) contents. The Quebec surface water quality standard of 0.03 mg TP L¹ was exceeded in 14 out of 27 sites in 1994 but only in 6 out of 25 sites in 1995. Of the 14 sites exceeding 0.03 mg TP L⁻¹ in 1994, 10 were clayey soils. Under these circumstances, more than 50% of the TP was as TPP whereas DOP forms represented <30%. In 1995, TPP forms accounted for, on average, <50% of TP and DOP accounted for more than 40% of the TP concentrations. This study suggests that flat clayey soils of medium to rich P status may be particularly at risk of exceeding water quality standards in subsurface runoff. Phosphorus losses in particulate form may be important in subsurface runoff from clayey soils when weather conditions favor rapid flow through cracks or macropores. Contribution of the Soils and Crops Research Centre no. 565.

Data from selected U.S. Geological Survey National Stream Water Quality Monitoring Networks

Abstract: A nationally consistent and well-documented collection of water quality and quantity data compiled during the past 30 years for streams and rivers in the United States is now available on CD-ROM and accessible over the World Wide Web. The data include measurements from two U.S. Geological Survey (USGS) national networks for 122 physical, chemical, and biological properties of water collected at 680 monitoring stations from 1962 to 1995, quality assurance information that describes the sample collection agencies, laboratories, analytical methods, and estimates of laboratory measurement error (bias and variance), and information on selected cultural and natural characteristics of the station watersheds. The data are easily accessed via user-supplied software including Web browser, spreadsheet, and word processor, or may be queried and printed according to user-specified criteria using the supplied retrieval software on CD-ROM. The water quality data serve a variety of scientific uses including research and educational applications related to trend detection, flux estimation, investigations of the effects of the natural environment and cultural sources on water quality, and the development of statistical methods for designing efficient monitoring networks and interpreting water resources data.

Non-living soil organic matter: what do we know about it?

Abstract: Summary. Non-living soil organic matter is a small but critical component of soils contributing to soil structure, fertility and a range of other chemical, physical and biological functions. Although considerable work has contributed to our knowledge of its distribution, chemical structure, mineral associations and turnover, there is still little information on which fractions or pools of non-living soil organic matter are implicated in various soil functions and to what extent. This review paper summarises some of what is known about the distribution, chemistry, mineral associations and soil structure, turnover and the measurement of non-living soil organic matter, with particular emphasis on Australia. It also discusses some of the difficulties in using current methods for describing the function of this material in soil.

Towards water security: political determination and human adaptation crucial

Abstract: Although high-level attention has been drawn to the escalating world water problems, few changes are noticeable in terms of actual management of the water resource. Politicians continue to be misled by the apparent simplicity of water. The environment-oriented community tends to focus only on problems arising from man-induced side-effects, and most people tend to take water for granted. The double challenge of providing adequate water supplies and meeting increasing food requirements of expanding populations, in addition to already existing water management problems, requires special attention. In addition, the intensifying pollution of water systems will have to be dealt with. Considerable human adaptation to physical realities as well as ingenious action are needed. There is a brief discussion of the risk of hydrocide, a condition of serious water-quality degradation where available water is no longer sufficient, or cannot be used for the purposes needed. However, the main focus of the paper is on water quantity issues, highlighting the confusion arising from different methods of assessing water scarcity. Levels of regional water scarcity predicaments are discussed in terms of distinct regional clusters. Attention is drawn to the limitations of dry climate regions to achieve food self sufficiency, and the emerging need in many areas to import food; related trade and price aspects are also discussed. A distinction is made between efficiency of use and efficiency of allocation. The need for a global ethic regarding upstream–downstream water-sharing is stressed, especially in cases of consumptive (evaporative) use of water for cultivating crops, which may deplete river flows available to downstream users. In conclusion, four key concerns are highlighted that call for global consensus.

The Role of Biological Indicators in a State Water Quality Management Process

Abstract: State water quality agencies are custodians of water quality management programs under the Clean Water Act of which the protection and restoration of biological integrity in surface waters is an integral goal. However, an inappropriate reliance on chemical/physical stressor and exposure data or administrative indicators in place of the direct measurement of ecological response has led to an incomplete foundation for water resource management. As point sources have declined in significance, the consequences of this flawed foundation for dealing with the major limitations to biological integrity (nonpoint sources, habitat degradation) have become more apparent. The use of biocriteria in Ohio, for example, resulted in the identification of 50% more impairment than a water chemistry approach alone and other inconsistencies of a flawed monitoring foundation are illustrated in the national 305(b) report statistics on waters monitored, aquatic life use attainment, and habitat degradation. Biological criteria (biocriteria) incorporates the broader concept of water resource integrity to supplement the roles of chemical and toxicological approaches and reduces the likelihood of making overly optimistic estimates of aquatic life condition. A carefully conceived ambient monitoring approach comprised of biological, chemical, and physical measures ensures all relevant stressors to water resource integrity are identified and that the efficacy of administrative actions can be directly measured with environmental results. New multimetric indices, such as the IBI, ICI, and BIBI represent a significant advancement in aquatic resource characterization that have allowed the inclusion of biological information into many States water quality management programs. Ohio adopted numerical biocriteria in the Ohio water quality standards regulations in May 1990 and, through multiple aquatic life uses that reflect a continuum of biological condition, represents a tiered approach to water resource management. Biocriteria provide the impetus and opportunity to recognize and account for natural, ecological variability in the environment, something which previously was been lacking in state water quality management programs. The upper Great Miami River in Ohio illustrates a case study where bioassessment data documented the efficacy of efforts to permit, fund, and construct municipal treatment systems in restoring aquatic life. In contrast, in the Mahoning River similar administrative actions were inadequate to restore aquatic life in an environment with severe sediment contamination and impacts from combined sewer overflows. A biocriteria-based goal of restoring 75% of aquatic life uses by the year 2000 in Ohio has led to the use of biological data to identify trends and forecast the status and the causes and sources of impairment to Ohio streams, an effort that should affect the strategic focus of our water resource management efforts. A biocriteria-based approach has profoundly influenced strategic planning and priority setting, water quality based permitting, water quality standards, basic monitoring and reporting, nonpoint source assessment, and problem discovery within Ohio EPA.

Sedimentation of Prairie Wetlands

Abstract: Many wetlands in the prairie pothole region are embedded within an agricultural landscape where they are subject to varying degrees of siltation. Cultivation of wetland catchment areas has exacerbated soil erosion; wetlands in agricultural fields receive more sediment from upland areas than wetlands in grassland landscapes and hence are subject to premature filling (i.e., they have shorter topographic lives). Associated impacts from increased turbidity, sediment deposition, and increased surface water input likely have impaired natural wetland functions. Although trapping of sediments by wetlands is often cited as a water quality benefit, sediment input from agricultural fields has potential to completely fill wetlands and shorten their effective life-span. Thus, the value placed on wetlands to trap sediments is in conflict with maximizing the effective topographic life of wetlands. Herein, we provide an overview ofsedimentation, identify associated impacts on wetlands, and suggest remedial management strategies. We also highlight the need to evaluate the impact of agricultural practices on wetland functions from an interdisciplinary approach to facilitate development of best management practices that benefit both wetland and agricultural interests. The prairie pothole region (PPR) occurs in a topographic, hydrologic, and land use setting that exacerbates the accumulation and retention of sediments in wetlands. Sediment retention by wetlands is often described as a water quality benefit (e.g., Botto and Patrick 1978; Kuenzler 1990). However, excessive sediment input from erosion of agricultural soils has potential to severely impact PPR wetlands; sediment is the major pollutant of wetlands, lakes, rivers, and estuaries in the United States (Baker 1992; USEPA 1995). Wetlands in the PPR are embedded within an agricultural landscape where cultivation of wetland catchment areas (i.e., the area that contributes surface runoff to the wetland basin) has greatly altered surface runoff dynamics and hydrologic inputs to groundwater. Grasslands that once protected prairie soils from erosion and moderated surface runoff have been converted to cropland. Consequently, wetlands in agricultural fields receive