Showing papers on "Water quality published in 1989"

AGNPS: A nonpoint-source pollution model for evaluating agricultural watersheds

Abstract: A computer model to analyze nonprofit-source pollution and to prioritize potential water quality problems in rural areas is described. The event-based model uses geographic cells of data units at resolutions of 0.4 to 16 ha to represent upland and channel conditions. Within the framework of the cells, runoff characteristics and transport processes of sediment, nutrients, and chemical oxygen demand are simulated for each cell and routed to the outlet. This permits the flow at any point in the watershed to be examined. Upland sources contributing to a potential problem can be identified and prioritized where remedial measures could be initiated to improve water quality most efficiently.

The occurrence of disinfection by-products in US drinking water

Abstract: Data were gathered on the presence of disinfection by-products (DBPs) in drinking water and on the impact of treatment processes on DBP formation and control. Thirty-five water treatment facilities were selected to provide a broad range of source water qualities and treatment processes. Trihalomethanes were the largest class of DBPs detected (on a weight basis) in this study, with haloacetic acids being the next most significant DBP fraction. Formaldehyde and acetaldehyde, by-products of ozonation, were also demonstrated to be produced by chlorination. Cyanogen chloride was found to be preferentially produced in chloraminated water.

WHO guidelines for drinking-water quality.

Abstract: s, 61: 4784 (1964). 5. MONIER-WILLIAMS, G. W. A/umimum in food. London, Ministry of Health, 1935 (Reports on Public Health and Medical Subjects). 6. SYLVESTER, R. 0. ET AL. Factors involved in the locatiOn and operation of an aluminium reduction plant. Proceedings of the 22nd Industrial Waste Conference. Lafayette, IN, Purdue University, 1967, pp. 441-454. 7. RIDGWAY, J. ET AL. Water quality changes-chemical and microbiological studies. In: Water distrzbution systems. Medmenham, England, Water Research Centre, 1979. 8. AINSWORTH, R. G. ET AL. Deposits, corrosion products and corrosion mechanisms in iron mains. In: Water distribution systems. Medmenham, England, Water Research Centre, 1979. 9. AINSWORTH, R. G. ET AL. The introduction of new water mto old distribution systems. Medmenham, England, Water Research Centre, 1980 (TR 146). 10. VozAR, L. Content of aluminium in the diet and its biological action. Voprosy pitanija, 21: 28 (1962). II. ZooK, E. G. & LEHMANN, J. Total diet study: content of ten minerals-aluminium, calcium, phosphorus, sodium, potassium, boron, copper, iron, manganese and magnesium. Journal of the AssociatiOn of Official Agricultural Chemists, 48: 850 (1965). 12. GABOVICH, R. D.

Climate change, hydrology, and water resources

Abstract: Growing atmospheric concentrations of carbon dioxide and other trace gases are leading to climatic changes with important implications for the hydrologic balance and water resources. These “greenhouse gases” are expected to alter the radiative balance of the atmosphere, causing increases in temperature and changes in many other climatic variables. Recent hydrological research strongly suggests that this so-called “greenhouse effect” will alter the timing and magnitude of runoff and soil moisture, change lake levels, and affect water quality. Such changes raise the possibility of environmental and socioeconomic dislocations, and they have important implications for future water resources planning and management. This paper reviews state-of-the-art research into the implications of climatic changes for the hydrologic cycle and for water resources and discusses the implications of such changes for future water planning and management.

Impact of timber harvesting and production on streams: A review

Abstract: Timber harvesting operations have significant effects on both water quantity and water quality. The effects on water quantity have been well documented both in Australia and elsewhere. The effects on water quality are less widely appreciated, and include elevated concentrations of dissolved salts, suspended solids and nutrients, especially during peak flow periods. Several Australian studies have failed to measure peak flow transport of suspended solids, or have measured it inadequately, thus severely underestimating transport. The major short-term effects of timber harvesting on the aquatic biota result from increased sediment input into streams or increased light through damage to, or removal of, the riparian vegetation. Sediment which settles on, or penetrates into, the stream bed is of more concern than suspended sediment, and can lead to long-term deleterious changes to fish and invertebrate populations. Increased light causes an increase in stream primary production which may increase invertebrate densities, and alter community composition. These biological consequences have not yet been adequately investigated in Australia. Longer-term effects, as yet not investigated in Australia, include changes to stream structure as the regrowth forest has fewer large logs to fall into the stream. These large logs play a major role as habitat and retention structures in streams. There has been no attempt to evaluate the effects of timber production activities, including pesticide use and fuel reduction burning, on the Australian stream biota. Likewise, although buffer zones are widely advocated as a protection measure for streams in Australia, there have been no studies to evaluate their effectiveness.

Environmental Fate of Alachlor and Metolachlor

Abstract: Recent revelations on ground water contamination by pesticides have caused public concern and emotion about the quality of drinking water, which have led to renewed pesticide monitoring and research and the call for stricter health advisories and water quality standards. The toxicological significance to humans and domestic, wild, and aquatic animals of such high use compounds as alachlor and atrazine is receiving close examination.

Nitrate in ground water in the United States.

Abstract: Many activities of modern society, including agricultural land use, contribute nitrate contamination to ground water. Natural background areas commonly show 10 mg/L, at least seasonally. Expanded use of nitrogen fertilizers has profitably increased agricultural production, but it has also had an adverse impact on water quality in many areas. In responsive ground-water settings, nitrate concentrations have increased concurrent with the increased use of N-fertilizers. Wells and ground water exhibiting nitrate contamination have been noted in every state in the USA. The major areas exhibiting problems with nitrate contamination of ground water are: 1. areas of widespread grain production (particularly corn), marked by intensive row-cropping and heavy fertilization; 2. areas with locally intensive animal feeding and handling operations; and, 3. areas of irrigation and fertilization of vegetable and specialty crops, particularly shallow-rooted vegetable crops on sandy soils. Ground water contributes to the nitrate contamination of surface waters through base-flow to streams and lakes. Nitrate loads have increased in many streams, particularly from the midwestern grain-belt eastward, since 1974, in spite of reductions in point-source loads. These increases were highly correlated with many measures of agricultural activity. Nitrate concentrations in ground water typically show significant variability in many dimensions: with depth, spatially, and over time; and these variations are often inter-related. Recognition of this variability is important to understand the extent of the problem and to design programs to mitigate it. At present, nitrate contamination is only evident in shallow portions of the ground-water flow system. This is, in part, a function of time; relative to the dimensions of the ground-water system. In many areas, particularly in deeper portions of the ground-water system the impact of recent nitrate leaching may not be noted for several decades.

Global freshwater quality : a first assessment

Abstract: Introduction water quality in perspective natural characteristics of water bodies anthroprogenic impacts on water quality pathogens in fresh water biodegradable organics and oxygen balance suspended matter in rivers and lakes eutrophication in lakes and reservoirs nitrates salts in surface and ground waters heavy metals organic micro-pollutants acidification river case study - Danube lake case study - Great Lakes reservoir case study - Lake Nasser ground water case study anthropogenic impacts study - lake sediments global water quality assessment conclusions and recommendations.

Viability of Giardia cysts suspended in lake, river, and tap water

Abstract: Numerous waterborne outbreaks of giardiasis have occurred since 1965, yet little or no information has been reported on the viability of Giardia cysts in different aquatic environments. We have studied the viability of Giardia muris cysts suspended in lake, river, and tap water, while also monitoring water temperature, dissolved oxygen, pH, and other water quality parameters. Fecal pellets containing G. muris cysts were placed in glass vials covered with filter paper and exposed to (i) lake water at 15 ft (ca. 4.6 m) and 30 ft (ca. 9.2 m), (ii) river water, (iii) tap water, and (iv) distilled water stored under laboratory conditions. At 3, 7, 14, 28, 56, and 84 days, two vials from each environment were removed, and cyst viability was determined by (i) fluorogenic dye exclusion, (ii) production of giardiasis in an animal, and (iii) cyst morphology by Nomarski microscopy. In the fall, the cysts suspended at 30 ft in lake water remained viable for up to 56 days whereas cysts stored at 15 ft were nonviable after day 28. The G. muris cysts exposed to river water remained viable up to 28 days as determined by the production of giardiasis in mice. G. muris cysts suspended in tap water showed no signs of viability after 14 days, while cysts serving as controls (exposed to refrigerated distilled water) remained viable for up to 56 days. In the winter, Giardia cysts suspended in either lake or river water were viable for 56 to 84 days whereas cysts exposed to tap water were nonviable by day 14.(ABSTRACT TRUNCATED AT 250 WORDS)

Measuring the Benefits of Improvements in Water Quality: The Chesapeake Bay

Abstract: Federal, state, and local government agencies have joined forces in the ambitious and expensive task of improving the water quality of the Chesapeake Bay. Clean-up efforts will be devoted to three major problems: nutrient over enrichment, toxic substances, and the decline of submerged aquatic vegetation. Although the beneficiaries are ultimately human, criteria for judging the Bay's water quality have been primarily biological and physical. This paper addresses the question of the human values from the Bay. How do people use the Bay and how much are they willing to pay for the changes in water quality that improve their use? With a variety of methods and data sources, we estimate the annual aggregate willingness to pay for a moderate improvement in the Chesapeake Bay's water quality to be in the range of $10 to $100 million in 1984 dollars.

Delivery of sediment and pollutants from nonpoint sources: A water quality perspective

Abstract: In a 1984 report to Congress, the U.S. Environmental Protection Agency (EPA) concluded that nonpoint pollution was a leading cause of the nation's remaining water quality problems. Half of the states specified that nonpoint pollution was a significant water quality problem, and nearly every state reported some kind of water quality problem related to these sources. Research suggested that lakes, including the Great Lakes; reservoirs; and estuaries, such as the Chesapeake Bay, were particularly vulnerable to nonpoint pollution. Recognizing the need for a massive, federal nonpoint pollution cleanup program, the EPA administrator called for redirecting existing federal, state, local, and private resources to assess nonpoint source problems of national significance ( 45 ). Managers of nonpoint pollution abatement programs must identify land and define those land use activities that pose the most severe threat to receiving waters, so-called “hazardous land” (34). To define hazardous lands, information is needed on the strength of the pollution source and on attenuation of pollutants between the source and receiving water body. Sediment delivery characteristics In the 1950s, researchers studying sediment deposition in reservoirs noted that the quantity of sediment deposited in and passed through reservoirs was smaller than the upland erosion potential …

A survey of constructed wetlands for acid coal mine drainage treatment in the Eastern United States

Abstract: The oxidation of pyritic minerals, exposed to oxygen and water during the mining of coal, results in the formation of acid mine drainage (AMD), which is characterized by low pH and high concentrations of dissolved sulfate, iron, and other metals. Federal and State regulations require that discharges from coal surface mines meet water quality criteria. Toward that end, chemical treatment of AMD, usually with soda ash briquettes, lime, limestone, or sodium hydroxide, is effective but expensive. Recently, man-made wetlands have been proposed as a low-cost, low-maintenance alternative to chemical treatment of AMD. To assess the status of man-made wetland treatment of AMD in the eastern U.S., a survey was conducted by the U.S. Office of Surface Mining, Reclamation, and Enforcement. As of May 1988, 142 wetlands had been constructed for AMD treatment. In 50% of the constructed wetlands, treatment efficiencies (reductions in concentration) for H+, acidity, Fe, Al, Mn, and SO4 2 of at least 68, 67, 81, 48, 34, and 8%, respectively, were obtained. However, over 11% of the constructed wetlands yielded greater concentrations in the effluent from the wetland than were present in the influent AMD for one or more of these 6 chemical parameters. Treatment efficiency generally was not correlated with design criteria (e.g., area of wetland, depth of the organic substrate in the wetland, AMD flow rate, metal loading rates). Also, treatment efficiency was generally not affected by either the type of organic substrate used in wetland construction or the addition of lime and/or fertilizer to the constructed wetland. The effectiveness of wetland treatment of AMD is not only extremely variable, but also presently not predictable.

Water Quality Benefits from the Conservation Reserve Program

Abstract: The Conservation Reserve Program, a land retirement program designed to remove from production 40 to 45 million acres of highly erodible cropland, may generate an estimated $3.5 to $4 billion in water quality benefits. Potential benefits include lower water treatment costs, lower sediment removal costs, less flood damage, less damage to equipment which uses water, and increased recreational fishing. Benefits were estimated with a set of procedures that approximated the physical, chemical, biological, and economic links between soil erosion and water use.

Nitrogen management and ground water protection.

Abstract: Dedication. List of Contributors. 1. Ground Water Quality Concerns About Nitrogen (R.F. Follett, D.J. Walker). Introduction. Health concerns. Human toxicity. Economic concerns. Economic concepts. Problem nature and implications for solution. Public policy options. Resource conservation concerns and issues. References. 2. Sources of Nitrate to Ground Water (D.R. Keeney). Introduction. Nitrogen cycling. Natural sources of nitrate. Geologic nitrogen. Forests. Forage and pasteral agriculture. Waste materials. Animal wastes. Sewage sludge and effluent. Septic tanks. Row crops agriculture. Irrigated agriculture. Summary. References. 3. Nitrate in Ground Water in the United States (G.R. Hallberg). Introduction. Nitrate, agriculture and ground water. Nitrate and water quality: a national overview. Comparisons with state data. Surface water and ground water. Nitrate distribution and variability. Depth distribution. Spatial variability and depth distribution. Spatial variability: land use and local sources. Temporal variations. Depth and time. Denitrification and time. Nitrate variability among wells. Summary and conclusions. References. 4. Ground Water Nitrate in Other Developed Countries (Europe) - Relationships to Land Use Patterns (S. Juergens-Gschwind). Introduction. Impact of bare land. Impact of forestry. Impact of grassland. Cut grassland (meadowland). Grazed grassland. Impact of arable crops. Depending on crop type. Depending on type of soil. Depending on rainfall and irrigation. Depending on temperature. Depending on ground water level and drainage. Depending on rate, timing and form of fertilizer use. The impact of horticulture. Intercropping and green manuring. Irrigation. Home and hobby gardens. References. 5. Nitrate Transport and Leaching Mechanisms (W.A. Jury, D.R. Nielson). Introduction. Nitrate transport mechanism. Convection. Diffusion. Hydrodynamic dispersion. Removal and reaction mechanisms. Plant uptake. Denitrification. Spatial variability and the transport problem. Models for characterizing leaching. Process models. Stochastic models. Spatial variability and the modeling problem. Uncertainty in modeling transport to ground water. Summary and conclusions. References. 6. Proper Accounting for N in Cropping Systems (J.F. Power, F.E. Broadbent). Introduction. Crop N requirements and yield goals. Contrubitions to residual soil N. Soil tests and residual nitrates. Management practices and N accounting. Mineralization and immobilization. Organic-inorganic interchange of N in soils. Kinetics of immobilization and mineralization. Factors influencing immobilization. Influence of environmental factors on immobilization and mineralization. Predicting N mineralization. Conceptual models of mineralization and immobilization. Conclusions. References. 7. Fertilizer Nitrogen Management (G.A. Peterson, W.W. Frye). Introduction. Importance of N fertilizer to agriculture. Amount of fertilizer-N to apply. Yield goals. Soil tests. Soil sampling.

Targeting the Conservation Reserve Program to Maximize Water Quality Benefits

Abstract: There is a growing desire on the part of environmental and conservation groups to see agricultural programs that remove cropland from production, or that require soil and input conservation, be used to protect or improve water quality. Such programs could become powerful tools for addressing an important source of water pollution. One such program is the Conservation Reserve Program (CRP). Many environmental groups are looking upon the CRP as a way of retiring from production cropland which is contributing to water quality problems. Senators Robert Dole and Wyche Fowler have each proposed expansions of the CRP specifically to address water quality issues. The Environmental Protection Agency is encouraging states either to incorporate the CRP into their plans to meet the nonpoint source pollution requirements of the 1987 Water Quality Act, or to develop their own CRP-like programs. Most discussions of how to approach the problem of nonpoint source pollution involve targeting programs to problem watersheds. For example, Section 319 of the 1987 Water Quality Act requires states to identify priority watersheds for treatment of nonpoint source pollution problems. Such targeting implies there exist criteria upon which areas can be ranked for the purpose of implementing water quality improvement measures. The criteria selected are

Water Disinfection by Solar Radiation: Assessment and Application

Abstract: Edited version of the project technical report entitled: Solar ultravioletradiation : assessment and appreciation for drinking-water disinfiection

Water purifying and dispensing system

Abstract: A vending or dispensing system for providing purified water in response to a customer request is described. The water dispensing system has a water reservoir or tank containing first stage purified water and is provided with a subsystem for circulating water from the reservoir through a microbial sterilizer on at least a periodic basis for a predetermined period of time to maintain water quality within the tank. In one aspect, the water is passed through the microbial sterilizer before entering the tank for the first time as first stage water. Additional features described to insure water purity include flushing or rinsing the lines between a first stage water purification mechanism and the water reservoir prior to topping off the reservoir with purified water, and providing control mechanisms for ensuring that sump liquid cannot be suctioned back into the system. The purification mechanism, of which there may be more than one, may include, but is not limited to, an activated carbon filter, an ion exchange resin bed, a reverse osmosis (RO) filter and the like. The microbial sterilizer may include such equipment as one or more or multi-stage ultraviolet (UV) sterilizers. In one embodiment, the entire system is operated by a microcontroller in response to user commands.

Stormwater detention: For drainage, water quality, and CSO management

Abstract: Storage in Sewer Networks. Tunnel Storage. Calculation Methods for Detention Facilities. Overview of Several Computer Models. Wetlands.

A Water Quality Index for River Management

Abstract: The theoretical basis underlying the development of a new series of water quality indices is outlined. The main features of their development are the incorporation of legally adopted water quality standards and criteria and the inclusion of information on potential water use and toxic determinands directly within their structural format. Thus an indication of a change in the economic potential of a river through a gradual change in water quality (and hence water use) can be obtained. The General Water Quality Index (WQI) has been applied to all the data for an annual or longer time series as a means of detecting cycles and trends in river water quality. An examination of the lowest determinand ratings for each data set highlights the specific determinand(s) responsible for these deteriorations. A 5 percentile WQI score has been calculated for the time series of data and 90 per cent upper and lower confidence limits calculated around this score. The results of these applications indicate the ability of the index accurately to reflect both changes in water quality and potential water use.

Northern pike (Esox lucius L.) and aquatic vegetation, tools in the management of fisheries and water quality in shallow waters

Abstract: Species and size composition of fish communities in shallow stagnant waters appear to be associated with the type, abundance and pattern of the vegetation. Man-induced impacts as eutrophication, and suppression of vegetation for reasons of water quantity management or angling pleasure may induce irreversible changes in the aquatic ecosystem. Water quality management should aim at restoring former pike habitat. Submerged weeds are important to that effect. These habitats are characterized by relatively low densities of fish stocks. Stocking of bream and carp interferes strongly with these objectives. With respect to fish stocks, interests of water quality and fishery management may be opposed.

Testing for Trend in Lake and Ground Water Quality Time Series

Abstract: The detection of gradual trends in water quality time series is increasing in importance as concern grows for diffuse sources of pollution such as acid precipitation and agricultural non-point sources. A significant body of literature has arisen dealing with trend detection in water quality variables that exhibit seasonal patterns. Much of the literature has dealt with seasonality of the first moment. However, little has been mentioned about seasonality in the variance, and its effect upon the performance of trend detection techniques. In this paper, eight methods of trend detection that arise from both the statistical literature as well as the water quality literature have been compared by means of a simulation study. Varying degrees of seasonality in both the variances and the means have been introduced into the artificial data, and the performances of these procedures are analyzed. Since the focus is on lake and ground water quality monitoring, quarterly sampling and short to moderate record lengths are examined.

Threats to the World's Water.

Abstract: Water is in short supply in many regions; almost everywhere increasing amounts of organic waste and industrial pollutants threaten its quality. Only international cooperation in the integrated management of water resources can ameliorate the situation. Agriculture is usually the main drain on the water supply. Problems associated with overirrigation, increased population, and organic and industrial wastes are described. The paper explains the global water cycle; illustrates the uneven distribution of water among the oceans, ground water, ice caps, glaciers, lakes, and soil moisture; and gives data on the global water consumption from 1950 to 1980. Recommendations for water management are given.