Showing papers on "Water quality published in 1994"

Effects of land use on water quality and aquatic biota of three North Carolina Piedmont streams

Abstract: Three streams in the Piedmont ecoregion of North Carolina were studied to evaluate the effect of land use (forested, agricultural, urban) on water quality and aquatic biota. In comparison with the forested stream, there were few changes in water quality at the agricultural and urban streams. Suspended-sediment yield was greatest for the urban catchment and least at the forested catchment. Suspended-sediment concentrations during storm events followed this same pattern, but at low-moderate flows suspended-sediment concentrations were greatest at the agricultural site. Most nutrient concentrations were highest at the agricultural site, and the amount of ‘available’ dissolved nitrogen was elevated at both the urban and agricultural sites. High concentrations of metals (totals) in the water column were sometimes observed at all sites, but maximum average concentrations were recorded at the urban site (especially Cr, Cu, and Pb). Maximum sediment metal concentrations, however, were not found at the urban site, but were usually recorded at the forested site. Only minor differences were noted between fish communities of the forested and agricultural sites, although both abundance and average size of some species increased at the agricultural site. The fish community at the urban site was characterized by low species richness, low biomass, and the absence of intolerant species. Invertebrate taxa richness, a biotic index, and the number of unique invertebrate species (found at only one site) indicated moderate stress (Fair water quality) at the agricultural site and severe stress (Poor water quality) at the urban site. At the agricultural site, declines in taxa richness within intolerant groups were partially offset by increases within tolerant groups. The agricultural stream had the highest abundance values, indicating enrichment. The urban site, however, was characterized by low species richness for most groups and very low abundance values. Analysis of seasonal patterns suggested detritus was the most important food source for invertebrates in the forested stream, while periphyton was of greater importance in the agricultural stream. Dominant macroinvertebrate groups shifted from Ephemeroptera at the forested site, to Chironomidae at the agricultural site, and Oligochaeta at the urban site. There was little between-site overlap in dominant species (8–7%), indicating that land use strongly influenced the invertebrate community. Chemical and physical parameters measured at the three sites did not seem sufficient to account for all of the observed differences in the invertebrate communities, suggesting some unmeasured toxicity. Biological measurements, especially macroinvertebrates community structure, consistently indicated strong between-site differences in water and habitat quality.

Hydrologic and water quality impacts of agricultural drainage

Abstract: While some of the world's most productive agriculture is on artificially drained soils, drainage is increasingly perceived as a major contributor to detrimental off‐site environmental impacts. Howe...

Integration of a basin‐scale water quality model with gis

Abstract: Geographic Information Systems (GIS) have been successfully integrated with distributed parameter, single-event, water quality models such as AGNPS (AGricultural NonPoint Source) and ANSWERS (Areal Nonpoint Source Watershed Environmental Response Simulation). These linkages proved to be an effective way to collect, manipulate, visualize, and analyze the input and output date of water quality models. However, for continuous-time, basin large-scale water quality models, collecting and manipulating the input data are more time-consuming and cumbersome due to the method of disaggregation (subdivisions are based on topographic boundaries). SWAT (Soil and Water Assessment Tool), a basin-scale water quality model, was integrated with a GIS to extract input data for modeling a basin. This paper discusses the detailed development of the integration of the SWAT water quality model with GRASS (Geographic Resources Analysis Support System) GIS, along with an application and advantages. The integrated system was applied to simulated a 114 sq. km upper portion of the Seco Creek Basin by subdividing it into 37 subbasins. The average monthly predicted streamflw is in agreement with measured monthly streamflw values.

Riparian wetlands and water quality

Abstract: Because of wet soils adjacent to the streams, riparian buffers are frequently present between farming and urban activities on the uplands and small streams. These riparian areas have been shown to be very valuable for the removal of nonpoint-source pollution from drainage water. Several researchers have measured >90% reductions in sediment and nitrate concentrations in water flowing through the riparian areas. The riparian buffers are less effective for P removal but may retain 50% of the surface-water P entering them. I consider riparian buffers to be the most important factor influencing nonpoint-source pollutants entering surface water in many areas of the USA and the most important wetlands for surface water quality protection.

Drinking water quality

Abstract: Since 1990, California water utilities have been providing an annual Water Quality Report to their customers. This year’s report covers calendar year 2011 water quality testing, and has been prepared in compliance with regulations called for in the 1996 reauthorization of the Safe Drinking Water Act. The re-authorization charged the United States Environmental Protection Agency (USEPA) with updating and strengthening the tap water regulatory program.

The environmentally-sound management of agricultural phosphorus

Abstract: Freshwater eutrophication is often accelerated by increased phosphorus (P) inputs, a greater share of which now come from agricultural nonpoint sources than two decades ago. Maintenance of soil P at levels sufficient for crop needs is an essential part of sustainable agriculture. However, in areas of intensive crop and livestock production in Europe and the U.S.A., P has accumulated in soils to levels that are a long-term eutrophication rather than agronomic concern. Also, changes in land management in Europe and the U.S.A. have increased the potential for P loss in surface runoff and drainage. There is, thus, a need for information on how these factors influence the loss of P in agricultural runoff. The processes controlling the build-up of P in soil, its transport in surface and subsurface drainage in dissolved and particulate forms, and their biological availability in freshwater systems, are discussed in terms of environmentally sound P management. Such management will involve identifying P sources within watersheds; targeting cost-effective remedial measures to minimize P losses; and accounting for different water quality objectives within watersheds. The means by which this can be achieved are identified and include developing soil tests to determine the relative potential for P enrichment of agricultural runoff to occur; establishing threshold soil P levels which are of environmental concern; finding alternative uses for animal manures to decrease land area limitations for application; and adopting management systems integrating measures to reduce P sources as well as runoff and erosion potential.

Nutrient additions by waterfowl to lakes and reservoirs: predicting their effects on productivity and water quality

Abstract: Lakes and reservoirs provide water for human needs and habitat for aquatic birds. Managers of such waters may ask whether nutrients added by waterfowl degrade water quality. For lakes and reservoirs where primary productivity is limited by phosphorus (P), we developed a procedure that integrates annual P loads from waterfowl and other external sources, applies a nutrient load-response model, and determines whether waterfowl that used the lake or reservoir degraded water quality. Annual P loading by waterfowl can be derived from a figure in this report, using the days per year that each kind spent on any lake or reservoir. In our example, over 6500 Canada geese (Branta canadensis) and 4200 ducks (mostly mallards, Anas platyrhynchos) added 4462 kg of carbon (C), 280 kg of nitrogen (N), and 88 kg of P y-1 to Wintergreen Lake in southwestern Michigan, mostly during their migration. These amounts were 69% of all C, 27% of all N, and 70% of all P that entered the lake from external sources. Loads from all external sources totaled 840 mg P m-2 y-1. Application of a nutrient load-response model to this concentration, the hydraulic load (0.25 m y-1), and the water residence time (9.7 y) of Wintergreen Lake yielded an average annual concentration of total P in the lake of 818 mg m-3 that classified the lake as hypertrophic. This trophic classification agreed with independent measures of primary productivity,chlorophyll-a, total P, total N, and Secchi disk transparency made in Wintergreen Lake. Our procedure showed that waterfowl caused low water quality in Wintergreen Lake.

Wheat tillage and water quality in the Southern plains

Abstract: This study considers the impact of conventional-till (moldboard plow or sweeps) and no-till wheat ( Triticum aestivum L.) management practices on surface and groundwater quality. Concentrations and amounts of sediment, nitrogen (N), and phosphorus (P) in surface runoff, and associated nutrient levels in ground water were determined for seven dryland watersheds at two locations for periods up to 14 years. In general, annual surface runoff was similar for both tillage practices, ranging from 6 to 15 cm. Compared with conventional till, no-till reduced sediment, N, and P loss an average of 95%, 75%, and 70%, respectively. Concurrently, elevated levels of dissolved P (maximum 3.1 mg l −1 ) in surface runoff, and nitrate-N in ground water (maximum 26 mg l −1 ) were observed. About 25% more available soil water was in the no-till soil profiles, but this did not translate into increased grain yield. Instead, no-till grain yields were reduced an average 33% (600 kg ha −1 ) compared witj conventional till, which is attributed to a lower availability of surface applied fertilizer, and increasing cheat ( Bromus tectorum L.) and associated weed problems. From an overall agronomic and environmental standpoint, our results indicate that the management of no-till systems should include careful fertilizer placement and timing.

Hydrogeochemical assessment of groundwater in Moro area, Kwara state, Nigeria

Abstract: Detailed study of chemical analysis results of several groundwater samples (UNICEF-Assisted Water project, Kwara state, Nigeria) were carried out in an attempt to assess the quality and usability of groundwaters in the Moro area. Chemical analysis results indicate higher concentrations of Ca2+, Mg2+, and HCO3 − as compared to Na+, K+, Cl−, and SO4 2−. With exception of few locations where Fe is relatively higher, the concentrations of these ions together with other water quality parameters are all within permissible limits of the domestic and agricultural standards. On the basis of the analytical results, groundwaters in the study area are largely characterized as Ca-(Mg)-HCO3 type reflecting (possibly) young facies with limited migratory history. The occurrence of Ca-(Mg)-Na-HCO3 water type in certain areas is attributed to cation exchange processes. In addition, the observed scattered relationship between the TDS and the thickness of weathered horizons in the boreholes indicates the contribution of precipitation (recharge) to the ionic inputs in the groundwaters in addition to the weathering and dissolution processes.

Soil Processes and Water Quality

Abstract: Soil Processes and Water Quality (R. Lal and B.A. Stewart). The Management of Soil Phosphorous Availability and its Impact on Surface Water Quality (A. Sharpley and A. Halvorson). Impact of Nitrogen Fertilization of Pastures and Turfgrasses on Water Quality (R.M.C. Muchovej and J.E. Rechcigl). Impact of Soil N Management on the Quality of Surface and Subsurface Water (L.B. Owens). Animal and Municipal Organic Wastes and Water Quality (H. Kirchmann). Soil and Water Contamination by Heavy Metals (B.R. Singh and E. Steinnes). Water Quality Effects of Tropical Deforestation and Farming System on Agricultural Watersheds in Western Nigeria (R. Lal). Macropore Hydraulics: Taking a Sledgehammer to Classical Theory (E.L. McCoy, C.W. Boast, R.C. Stehouwer, and E.J. Kladivko). Water Quality Models for Developing Soil Management Practices (J.R. Williams, J.G. Arnold, C.A. Jones, V.W. Benson, and R.H. Griggs). Research Priorities for Soil Processes and Water Quality in the 21st Century (R. Lal and B.A. Stewart). Index.

Variations in stream water uptake by Eucalyptus camaldulensis with differing access to stream water

Abstract: The stable isotopes 2H and 18O were used to determine the water sources of Eucalyptus camaldulensis at three sites with varying exposure to stream water, all underlain by moderately saline groundwater. Water uptake patterns were a function of the long-term availability of surface water. Trees with permanent access to a stream used some stream water at all times. However, water from soils or the water table commonly made up 50% of these trees' water. Trees beside an ephemeral stream had access to the stream 40–50% of the time (depending on the level of the stream). No more than 30% of the water they used was stream water when it was available. However, stream water use did not vary greatly whether the trees had access to the stream for 2 weeks or 10 months prior to sampling. Trees at the third site only had access to surface water during a flood. These trees did not change their uptake patterns during 2 months inundation compared with dry times, so were not utilising the low-salinity flood water. Pre-dawn leaf water potentials and leaf 13C measurements showed that the trees with permanent access to the stream experienced lower water stress and had lower water use efficiencies than trees at the least frequently flooded site. The trees beside the ephemeral stream appeared to change their water use efficiency in response to the availability of surface water; it was similar to the perennial-stream trees when stream water was available and higher at other times. Despite causing water stress, uptake of soil water and groundwater would be advantageous to E. camaldulensis in this semi-arid area, as it would provide the trees with a supply of nutrients and a reliable source of water. E. camaldulensis at the study site may not be as vulnerable to changes in stream flow and water quality as previously thought.

Biological assessment of aquatic pollution: a review, with emphasis on plants as biomonitors*

Abstract: In a number of disciplines including ecology, ecotoxicology, water quality management, water resource management, fishery biology etc., there is significant interest in the testing of new materials, environmental samples (of water or sediments) and specific sites, in terms of their effects on biota. In the first instance, we consider various sources of aquatic pollution, sources typically associated with developed areas of the world. Historically, much water quality assessment has been performed by researchers with a background in chemistry or engineering, thus chemical analysis was a dominant form of assessment. However, chemical analyses, particularly of such materials as organochlorines and polyaromatic hydrocarbons can be expensive, and local environmental factors may cause the actual exposure of an organism to be little correlated with chemical concentrations in the surrounding water or sediments. To a large extent toxicity testing has proceeded independently of environmental quality assessment in situ, and the work has been done by different, and differently-trained researchers. Here we attempt to bring together the various forms of biological assessment of aquatic pollution, because in our opinion it is worth developing a coherent framework for the application of this powerful tool. Biotic assessment in its most primitive form involves the simple tracking of mortality in exposed organisms. However, in most natural environments it is extended, chronic exposure to contaminants that has the most wide-ranging and irreversible repercussions--thus measures of sub-lethal impairment are favoured. From an ecological standpoint, it is most valuable to assess ecological effects by direct study of in situ contaminant body burdens and impairment of growth and reproduction compared with 'clean' sites. A distinction is made here between bioindication and biomonitoring, and a case is made for including aquatic macrophytes (angiosperms) in studies of contaminant levels and effects in the biota. It is apparent that there is a concurrent need for laboratory-based testing of new industrial by-products before any are released in the environment, and such studies should aid the investigation of mechanisms and modes of toxicity, but environmental assessment, and tracking of improvements in environmental quality are most effectively achieved by active biomonitoring experiments.

Integrated laboratory and field approach for assessing impacts of heavy metals at the Arkansas River, Colorado

Abstract: This research employed an integrated laboratory and field approach to assess effects of heavy metals at the Arkansas River, a Colorado stream impacted by historic mining operations. Ambient metal levels, chronic toxicity, metal bioaccu-mulation by benthic organisms, and benthic community structure were examined at stations located upstream and downstream from California Gulch (CG), a U.S. Environmental Protection Agency Superfund site near Leadville, Colorado. Although each approach demonstrated effects of metals from CG, important differences among approaches were observed. Ambient metal concentrations and chronic toxicity tests conducted with Ceriodaphma dubia indicated reduced water quality at upstream and downstream stations. Because of temporal variability in metal levels, water samples collected for chronic toxicity tests did not reflect average exposure conditions. Instream monitoring of benthic communities was necessary to characterize metal impacts at the Arkansas River, but this approach had limitations. Levels of metals in periphyton and benthic invertebrates were significantly elevated at stations downstream from CG. Variation in metal levels among taxa and the absence of some taxa from some stations may limit the use of bioaccumulation studies for monitoring metal impacts. Benthic community structure was altered downstream from CG, but some metrics (e.g., species richness, abundance) were not affected by heavy metals because of the replacement of sensitive taxa by tolerant taxa. Because each of the approaches employed in this study provided different information on the degree of metal impacts, we recommend an integrated approach for assessing effects of metals on streams.

Monitoring of fecal pollution in coastal waters by use of rapid enzymatic techniques.

Abstract: Enzyme assays for 4-methylumbelliferyl-beta-D-galactopyranosidase and 4-methylumbelliferyl-beta-D-glucuronidase activities were used for rapid detection (25 min) of fecal water pollution and to determine the impact of sewage discharge in coastal waters. Two coastal areas were investigated: (i) an estuary characterized by a high degree of contamination downstream of a discharge from a sewage treatment plant and a low degree of water renewal and (ii) a fjord with a low degree of pollution and a high degree of water renewal. Statistical analysis showed that a global correlation curve could be used to estimate concentrations of culturable fecal coliform bacteria in the two coastal areas, although environmental factors important for cell physiology (e.g., salinity) varied at different sampling locations. The sensitivity limit for detection of 4-methylumbelliferyl-beta-D-glucuronidase activity corresponded to bacterial concentrations on the order of 10 to 100 CFU/100 ml. The 4-methylumbelliferyl-beta-D-galactopyranosidase assay was less sensitive because of a higher rate of substrate autohydrolysis. The detection limit corresponded to bacterial concentrations on the order of 100 to 1,000 fecal coliforms per 100 ml.

Watershed: The Role of Fresh Water in the Israeli-Palestinian Conflict

Abstract: This book explores the economic ecological and political issues of water quality quantity and distribution; solutions; and their role in the Israeli-Palestinian conflict. Chapters 1-3 focus on the setting in Israel and the Occupied Territories and describe the differences between the image and the reality the geography and climate and water supply and demand. Israel has average water availability comparable to North Africa. Water resources are plentiful in the Golan Heights area and the West Bank. Gaza is always short of water. Freshwater is obtained from Lake Kinneret large aquifers and smaller streams and aquifers. Most water comes from the Coastal and Mountain Aquifers. Despite infrastructure improvements in efficiency and increased use of recycled and saline water water supply has not kept pace with demand. Chapter 4 addresses the economic crisis of water shortages. Chapter 5 focuses on water quality and the ecological crisis. Chapter 6 discusses water distribution and the geopolitical crisis. The core problem is misallocation of water. Farmers pay too little for water. Accurate data are important to alleviating the three crises. Chapters 7-12 focus on solutions. Chapter 7 focuses on regional options for water management. Chapter 8 discusses water as a threat to security. Chapter 9 discusses the peace accord. Chapter 10 discusses Palestinian water management. Chapter 11 offers recommendations and establishes priorities. Economic efficiency conflicts with security needs and Israeli ideology. Shared water management conflicts with Palestinian desire for autonomy. There is a serious need for better governance.

Water quality monitor for a water purification system

Abstract: An improved water quality monitor is provided for use in a water purification system of the type having a reverse osmosis unit for producing relatively pure water from a tap water supply. The reverse osmosis unit supplies produced purified water to a reservoir for storage until dispensing, as by opening a faucet valve. An inlet shut-off valve closes to prevent tap water inflow to the reverse osmosis unit when the reservoir reaches a substantially filled condition. The water quality monitor includes electrodes in contact with the tap water and the produced purified water to obtain comparative conductivity readings which represent the performance level of the reverse osmosis unit in removing impurities from the tap water inflow. The monitor includes a test circuit responsive to movement of the inlet shut-off valve to take a conductivity reading at a point in time substantially after the shut-off valve opens to resume tap water inflow to the reverse osmosis unit, and substantially prior to shut-off valve closure when the reservoir reaches the filled condition. This conductivity reading is stored in memory for subsequent periodic display, for example, each time the faucet valve is opened, by energization of one or more indicator lights.

Quality of Runoff from Fescuegrass Plots Treated with Poultry Litter and Inorganic Fertilizer

Abstract: Recent application of either organic or inorganic fertilizers can promote increased runoff concentrations of nutrients, organic matter, and/or suspended solids. This experiment assessed the impacts of fertilizer treatment (control, poultry litter, and inorganic fertilizer) and simulated rainfalls (four events, on each at 7, 14, 36, and 68 d after application) on quality of runoff from fescuegrass (Festuca arundinacea Schreber) plots. Runoff was produced by simulated rainfall (50 mm h -1 ) and sampled at 0.08-h intervals during runoff (.)

Identification of tire leachate toxicants and a risk assessment of water quality effects using tire reefs in canals.

Abstract: Cover is important to aquatic habitat and fisheries often try to improve habitats by addition of natural and artificial material to improve cover diversity and complexity. Habitat-improvement programs range from submerging used Christmas trees to more complex programs. Used automobile tires have been employed in the large scale construction of reefs and fish attractors in marine environments and to a lesser extent in freshwater and have been recognized as a durable, inexpensive and long-lasting material benefiting fishery communities. Recent studies by the U.S. Bureau of Reclamation have quantified the importance of tire reefs to enhancing freshwater canal fisheries in the southwestern United States. These studies have demonstrated that fishes and aquatic macroinvertebrates are attracted to these structures, increasing species diversity, densities and biomass where reefs are placed in canals. However, the use of tire reefs in aquatic environments which have relatively small volumes compared to marine or reservoir environments has raised water quality concerns. Effects of tires on water quality have not typically been studied in the past because of the obvious presence of fishes and other aquatic organisms that make use of tire reefs; the implication being that tires are inert and non-toxic. Little information on effects of tiresmore » on water quality is in the literature. Stone demonstrated that tire exposure had no detrimental effects on two species of marine fish while results of Kellough's freshwater tests were inconclusive, but suggested that some factor in tire leachate was toxic to rainbow trout (Oncorhynchus mykiss). Nozaka et al. found no harmful substances leached from tire material soaked in fresh water. Because there are few data on toxicity associated with tires, this became the focus of our study. Toxicity Identification Evaluation (TIE) procedures developed by the EPA were used to evaluate water quality impacted by tires. 17 refs., 4 figs.« less

Global Water Resource Issues

Abstract: Foreword Preface Acknowledgements 1. Overview 2. Integrated water resources development and management 3. Water resources assessment 4. Protection of water resources, water quality and aquatic ecosystems 5. Impacts of climate change on water resources 6. Water and sustainable urban development 7. Water for sustainable food production and rural development 8. Drinking water supply and sanitation 9. Capacity building 10. Mechanisms for implementation and coordination at global, national and local levels References Index.

Anthropogenic heavy metal inputs to lowland river systems, a case study. The River Stour, U.K.

Abstract: Surface waters, sediments and interstitial waters were collected from 9 sites of the River Stour, UK, during June 1987. The aim was to identify the sources of EC List I (Hg, Cd) and List II (As, Cr, Cu, Ni, Pb, Zn) metals and metalloids to this lowland river system and to assess the magnitude of metal enrichment. The study reach spanned some 60 km, traversing rural and urban landscapes. Results indicate that the larger municipal sewage treatment works (STW), which receive industrial effluents, were the major source of metals, but smaller rural works also exerted some contaminative influences. Metal concentrations in bottom sediments, displayed 2–11 fold increases over catchment background levels with maximum loadings coinciding with discharges from the Great Cornard and Sudbury STWs. Elevations in water column metal concentrations were also apparent downstream of point source inputs, but concentrations were consistently below designated ‘Water Quality Standards’. Distance from the point source, sediment texture and hydrology appeared to be the main factors responsible for the observed distribution of metals within this river system.

National Standards and Guidelines for Pesticides in Water, Sediment, and Aquatic Organisms: Application to Water-Quality Assessments

Abstract: The effects of pesticides1 on water quality commonly are assessed by comparing measured concentrations of individual pesticide compounds in the environment with concentrations that have been determined to have potential adverse effects on humans, aquatic organisms, or other beneficial uses of water. Direct evaluation of the adverse effects of every pesticide present in a given hydrologic system is beyond the scope and budget of most water-quality studies. Many studies rely on standards or guidelines set by federal or state agencies or other institutions to indicate what concentrations may have adverse effects on human health, aquatic organisms, or wildlife. Such standards and guidelines generally are based on laboratory or field studies that document the effects of individual pesticides on specific aspects of water quality. Single-species toxicity tests (using a single species of a test organism) under various laboratory conditions are the most common type of study, whereas artificial ecosystem studies (using multiple species of a test organism) and field studies are relatively uncommon. Such studies rarely consider the effects of exposure to more than one chemical at a time.Technical information from such studies has been used by the U.S. Environmental Protection Agency (USEPA)2 in issuing national standards, such as drinking-water regulations (for example, see USEPA 1991a) and guidelines, such as ambient water-quality criteria for the protection of human health and aquatic organisms (for example, see USEPA 1980a) to meet its statutory requirements under the Safe Drinking Water Act (SDWA) and the Clean Water Act (CWA). The Food and Drug Administration (FDA) also has used its authority under the Federal Food, Drug, and Cosmetic Act (FFDCA) to set action levels (enforceable regulatory limits) for unavoidable residues of pesticides in foods (FDA 1990).