FEATURE
Building a National Water Quality Monitoring Program A coordinated strategy is emerging to tackle monitoring at all geographic scales, from site specific to nationwide. MARY P O W E L L
P
lanning is now under way to establish a new national body—the National Water Quality Monitoring Council—that will be charged with integrating the many public and private water monitoring programs at all geographic scales into a coordinated effort to assess the quality of America's waters. Most current monitoring programs, although gathering valuable data for specific purposes such as compliance, were not designed to address integrated national needs. Significant information gaps exist, and data from local programs are often difficult to merge in order to address state, tribal, and national water quality concerns. As a result, there has been insufficient information to determine whether overall Clean Water Act (CWA) goals are being achieved or whether increasingly stringent point source treatment is yielding measurable nationwide environmental benefits. "To effectively manage and protect human health and natural resources and to support a sustainable economy with sufficient quantity and quality of water, it is essential to improve water quality monitoring so that we better understand the condition of the environment," says Elizabeth Jester Fellows, head of EPA's monitoring branch in the Office of Wetlands, Oceans, and Watersheds. Since 1992 Fellows has chaired a federal/state effort to evaluate water quality monitoring in the United States and recommend improvements. That three-year project—the Intergovernmental Task Force on Monitoring Water Quality (ITFM)—is the forerunner of the planned national council. Discussions on water-monitoring activities initiated in 1991 by EPA and the U.S. Geological Survey (USGS) identified pervasive problems, and ITFM was formed in 1992 to investigate them. The task force, a voluntary consortium of federal, state, and tribal agencies working with an advisory council representing municipalities, academia, and the private sector, surveyed existing water quality monitoring pro4 5 8 A • VOL. 29, NO. 10, 1995 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
grams, m a d e general r e c o m m e n d a t i o n s for improvement, and proposed a nationwide monitoring strategy. The strategy is intended to achieve a better return on public and private investments in monitoring, environmental protection, and natural resources management by expanding the base of information to a variety of users at multiple scales. Many of the task force's 1994 recommendations for an integrated, nationwide, voluntary strategy are already being implemented. In addition, ITFM working groups have developed guidance and tools for a nationwide effort. These include defining a monitoring framework to ensure that programs are flexible, watershed based, and comprehensive; identifying environmental indicators to measure whether nationwide goals and water quality uses designated by states and tribes are being met; and designing a program to achieve comparability for key methods nationwide through the use of performancebased methods. USGS, under its 1991 mandate from the Office of Management and Budget to operate a Water Information Coordination Program, housed ITFM and is planning to establish the Council to continue its work. Members of the ITFM partnership and advisory committee will be full members of the new Council; USGS and EPA will co-chair it. The Council will address the need for agency implementation of a consistent and coordinated strategy to provide a nationwide framework for water monitoring, according to Fellows. Although there has been greater coordination of water quality information in recent years, the historic fragmentation of monitoring efforts has made it difficult to answer such questions as "How clean are the nation's waters?" and "Are water quality conditions changing over time?" Recent technological developments, such as geographic information systems and the Internet, have provided the tools to locate, organize, and evaluate data and to gain new insights into hydrologie systems. New program objectives and integrated ap0013-936X/95/0929-458AS09.00/0 © 1995 American Chemical Society
The Emerging National Structure for Water Quality Monitoring
State and tribal teams provide collaboration and implementation of the individual state portion of the nationwide strategy. Composition and objectives of these teams vary depending on the needs of the particular state or tribe. The National Water Quality Monitoring Council will be composed of federal, state, tribal, interstate, local, and private representatives and will meet four times a year. With the support of working subgroups it initiates collaborations between members to implement the nationwide monitoring strategy, guidance, and tools for implementation.
proaches to resource management have changed monitoring needs and opened new avenues for institutional cooperation.
Beyond compliance monitoring As competition for adequate supplies of clean water has increased and concerns about public health and the environment have escalated, new demands are being placed on the infrastructure for water quality information. Tens of thousands of public and private organizations spend hundreds of millions of dollars a year on monitoring water quality for compliance with federal, state, and local regulations (i). Early in this century, water quality monitoring focused on health problems related to supply systems. In the past three decades, as control of water pollution became a major environmental priority, monitoring expanded rapidly. New bursts of monitoring by public and private entities began with each environmental law passed. Programs clustered around the implementation of the CWA; the Resource Conservation and Recovery Act; the Comprehensive Environmental Response, Cleanup, and Liability Act; the Safe Drinking Water Act; and many other laws at both federal and state levels. Many of these new laws required the regulated community to monitor the quality of discharges to
Additional regional or watershed teams provide interstate collaboration where needed. Composition and objectives depend on local needs. For example, a Southeast Regional Water Monitoring Council is forming with the states shown at left.
water. The resulting data demonstrate compliance with pollution control permits and provide part of the information used to estimate pollution loading from human sources into the environment. These compliance-monitoring efforts focus on welldefined sources of pollution, such as industrial facilities, sewage treatment plants, or waste disposal sites. The primary intent was to characterize the concentrations of pollutants at their sources. However, in the late 1980s, it became apparent that water quality protection and management goals could not be achieved without considering both point and nonpoint sources of pollution as well as habitat degradation. States and Native American tribes bear primary responsibility for monitoring within their borders. States and tribes monitor in varying degrees for status and trends, identification of emerging and existing problems, program design and management, evaluation of new or existing programs, and emergency response. In general, these efforts have concentrated on designing pollution prevention and control programs and ensuring compliance and program effectiveness. They currently provide relatively little information with which to evaluate ambient water quality conditions and trends. For example, Wisconsin has one of the most progressive overall state monitoring programs, yet of the 15,000 lakes in the state, VOL. 29, NO. 10, 1995 / ENVIRONMENTAL SCIENCE & TECHNOLOGY • 4 5 9 A
Federal ambient water monitoring programs Program, geographic scope
Media, constituents monitored
Objectives
Hydrologie Benchmark Network (Interior/USGS) Established 1964; national
Fifty-three surface-water stations in relatively pristine headwater basins. Nutrients, major ions, trace elements, sanitary bacteria, sediment concentration, and particle size.
Define baseline water quality conditions and the effects of atmospheric deposition on water quality.
National Stream Quality Accounting Network (Interior/USGS) Established 1972; national
Fresh and estuarine surface water. Nutrients, major ions, trace elements, radionuclides, sanitary bacteria, sediment concentration, and particle size.
Determine long-term trends in water quality and account for the mass movement of dissolved and suspended chemicals in the major river systems in the United States.
National Water Quality Assessment Program (Interior/USGS) Established 1991; national with regional and local study units
Fresh and estuarine surface water (water, sediment, and biota), groundwater. Inorganic and organic constituents in water, sediment, and biota.
Describe status and trends in water quality of representative parts of nation's streams and groundwater. Organized by watershed, investigates nonpoint source contamination and regionally defines relative contributions of major contamination sources.
National Trends Network (Interior/USGS) Established 1978; national
Atmospheric precipitation. Conductivity, pH, major cations and anions.
Determine the long-term trends in atmospheric deposition nationwide.
Biomonitoring of Environmental Status and Trends (BEST) Program (Interior/National Biological Service) Began development in 1992; currently being revised.
Lands under the stewardship of DOI and certain biological resources. Analytical chemistry of biota and media, biomarkers of exposure and effect, bioassays and toxicity tests, and measures of population and community structure.
To identify contaminant effects on lands and biological resources with an integrated ecosystem-based approach and to provide summary information to natural resource managers and the public for guiding conservation efforts.
National Status and Trends Program (NOAA) Includes Mussel Watch Project and Benthic Surveillance Project. Established 1984; national
Estuaries and near-coastal waters (sediments, mussels, oysters, fish); 70 toxic chemicals including trace elements, chlorinated pesticides, PCBs, petroleum hydrocarbons.
Monitor fish for indicators of contaminant effects; shellfish act as sentinel organisms to detect contamination levels; fish act as indicators of local pollution, and their exposure to toxic chemicals is linked through food chains to sediments.
Strategic Environmental Assessment Program (NOAA) Established 1979; national
Estuaries and near-coastal waters and their watersheds. Effects of human activities such as housing, shellfishing, pollutant loadings.
To provide consistent and complete information on human uses and their trends and those of selected marine resources.
Water Resources Monitoring Program (Tennessee Valley Authority) Established 1985; Tennessee Valley
Reservoirs and major streams. Physical, chemical, and biological variables; aquatic plant and mosquito populations.
Evaluate ecological health and suitability for recreation and human consumption offish. Draw attention to pollution problems, set cleanup goals, and measure the effectiveness of water quality improvement efforts.
Clean Water Act 305(b) (EPA, states) First report 1976; national compilation of state data
Surface, groundwater, wetland, estuarine, near-coastal, and drinking water. Many physical, chemical, and biological constituents. Intended: Surface water, near-coastal, forest, wetland, and agricultural ecosystems. Periodic surveys of biological, chemical, and physical constituents on statistically based sampling grid.
Evaluate whether the nation's waters are meeting water-quality standards and identify causes and sources of pollution.
Environmental Monitoring and Assessment Program (EPA) Established 1988; national
less than 2% are monitored for ambient conditions. Both the Wisconsin Department of Natural Resources and the Washington Department of Ecology estimate that compliance monitoring accounts for 80-90% of all monitoring in their states.
Compiling Clean Water Act data On the federal level, in the Clean Water Act of 1972 Congress ordered states to submit a biennial report to EPA describing the quality of all navigable waters in the state, an analysis of how those waters met the uses states set for them in water quality standards, the economic and social impacts of meeting CWA goals, and a description of nonpoint source pollution and controls. EPA compiles and analyzes the state reports and submits a national report to Congress. 4 6 0 A • VOL. 29, NO. 10, 1995 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
Monitor status and trends of ecological resources and develop innovative methods for anticipating emerging problems.
The states provide information on surface water and groundwater, wetlands, and drinking water according to CWA section 305(b) guidelines. EPA designs the guidelines in conjunction with states and tribes. For example, states report on total miles or surface area of rivers, lakes, coastal waters, and wetlands; miles or surface area assessed; the extent to which assessed waters meet designated uses as set forth in state water quality standards; and major constituents and sources of pollution. Information is also reported on groundwater quality and special concerns such as fish consumption bans. In Florida, monitoring data on surface water and groundwater have been administratively separated following the dictates of federal regulations. Rodney DeHan, manager of the state's groundwater pro-
gram, says, "It makes no sense in a state like Florida, where more than 92% of the base flow of streams comes from groundwater, to separate water into separate entities." Once the two data sets are joined, water resources can be managed by watershed, a direction that DeHan feels is essential to improving water quality. ITFM recently arranged for funding of a pilot project in northern Florida to create a threedimensional model of a tributary of the Suwannee River watershed, a critical step in assessing the health of watersheds and developing plans to manage those systems, according to DeHan. From a national perspective, however, the data that states include in their biennial 305(b) reports cannot outline statistical nationwide trends over time or easily be compared among states. State water quality standards vary, and states are not able to assess all of their waters within two years. Numerous federal, state, tribal, and local agencies have water-related responsibilities, in addition to private monitoring efforts. Other programs on the regional and interstate levels include the Chesapeake Bay Program and the Puget Sound Ambient Monitoring Program. On the local level, municipalities monitor the discharges from their sewage treatment plants and, if they have populations of more than 100,000, stormwater runoff. Private industry monitors its discharges and facilities under a variety of federal regulatory programs. The monitoring activities may be specified in federal or state permits, and permittees may conduct additional monitoring of their own. Hundreds of volunteer monitoring groups across the country also provide useful water quality data. Although some groups monitor for their own purposes or for educational reasons, many volunteer groups work closely with local, state, or federal programs to provide data. These groups increasingly use methods, quality assurance and quality control (QA/ QC), and other specifications that allow their data to be integrated into broader collection programs.
Data gaps remain The historical emphasis of monitoring programs on chemical-specific analyses has been important for determining loadings, assessing compliance, and measuring point source contributions. However, significant information gaps remain, and coordination of information gathering and sharing among programs is uneven. In addition, these efforts have left newer information needs unmet. For example, nonpoint source pollution, ecological conditions, and low-level chronic effects of multiple toxicants on aquatic biota or human health are contemporary environmental issues with little historical data. Problems associated with the lack of information have been aggravated by several factors. Important basic elements such as QA/QC of monitoring data and data interpretation are often assigned a lower priority than regulatory actions that are required by law. Many of the private-sector groundwater data are proprietary and will not be generally available. Data produced by existing monitoring programs do not always meet existing needs, particularly for ambient status and trends. Further, organizations may not be able to determine whether
they can use data generated by others, because QA/QC information is not documented and information is hard to access. Despite these limitations, federal nationwide monitoring programs have provided some useful information on status and trends in national water quality. For example, data from USGS indicate that fecal bacteria counts and total phosphorus concentrations decreased at a considerable number of monitoring stations across the United States during the 1980s (2-4). Data from the U.S. Fish and Wildlife Service (FWS) and the National Oceanic and Atmospheric Administration (NOAA) show that bioaccumulation of trace elements, pesticides, and trace industrial compounds has occurred at many locations in our rivers, estuaries, and near-coastal areas {5-11). Regional programs such as those of the Chesapeake Bay have indicated a substantial improvement in phosphorus concentrations since 1985 (12). A recent Centers for Disease Control study of the Midwest found much higher levels of biological contaminants in private wells than was previously known. However, these are singular occurrences, and individual agency programs cannot be readily aggregated to provide an overview of the country's water quality conditions. Congressional hearings in 1984 on the National Environmental Improvement Act noted that despite billions of dollars spent on monitoring, federal agencies could assess neither the status of ecological resources nor the overall progress toward legally mandated goals of mitigating or preventing ecological effects. The lack of documentation on the QA/QC of the data, lack of comparability among the different data collection methods used, and the difficulty of sharing automated information have contributed to this problem.
Renewed federal monitoring efforts Recognition of these limitations spurred federal action to develop new monitoring strategies that are based on federal, state, local, and private collaboration. Partly in response to the congressional hearings, NOAA, USGS, and EPA all initiated new nationwide monitoring programs (see sidebar). These programs met the specific objectives of their agencies and, in some cases, widened collaborative efforts. For example, the USGS National Water Quality Assessment Program (13) has a widely representative advisory board in each of its regional study areas. However, even with these newer programs, agreement is widespread that existing data cannot be added together to provide all the information needed to answer today's complex questions about the national or regional quality of water (14-20). Significant gaps in understanding of status and trends remain, and coordination among the various new programs still is uneven. For instance, the organizations that monitor water quality achieve their individual goals by measuring myriad environmental indicators; different agencies use different indicators to answer many of the same questions. Also, it remains the exception that data from different sources or time periods can be compared on a scientifically sound basis. Different agencies may use VOL. 29, NO. 10, 1995 / ENVIRONMENTAL SCIENCE & TECHNOLOGY • 4 6 1 A
Tools for national monitoring The Interagency Task Force on Water Quality Monitoring has identified and begun to develop tools and guidance needed to implement a national approach to monitoring. ITFM committees are currently working on the following areas. Committees Institutional framework. Design a structure for collaboration at all geographic scales. Products: Charter for permanent National Water Quality Monitoring Council, framework for monitoring programs. Chair: Bruce Baker, Wisconsin Water indicators. Recommend core nationwide indicators. Products: Criteria for indicator selection; recommended indicators to measure designated uses in wadeable rivers and streams; papers on ecoregions, biological reference conditions, and multimetric index calibration. Chair: Andrew Robertson, NOAA. Methods. Design a program to achieve comparability for key methods nationwide. Products: Charter for Methods and Data Comparability Board, policy paper on performance-based methods. Co-chairs: Russ Sherer, South Carolina; Herbert Brass, EPA Data management. Make water data easier to store, retrieve, and share. Products: Glossary of core minimum recommended
data elements, automated database of key water data systems, Internet home page for ITFM products and communication. Chair: Tom Yorke, USGS Assessment and reporting. Identify components of good water quality information reporting, work with national programs to produce such a report on the national scale. Products: Policy paper on target audiences, monitoring objectives and format characteristics for water quality reporting, annotated bibliography of selected outstanding water quality reports. Chair: Neil Carriker, TVA Groundwater. Ensure that ITFM products reflect the special needs of groundwater. Products: Framework for groundwater monitoring programs; matrix of groundwater indicators. Cochairs: Rodney DeHan, Florida; Charles Job, EPA Short-term focus groups Nationwide Aquatic Biological Integrity Special Assessment. Determine feasibility of nationwide pilot to gather data on aquatic biological integrity. Chair: Lynn Singleton, state of Washington Cost. Quantify amount spent on water quality monitoring in the United States. ITFM lead: David Pollison, Delaware River Basin
different field and laboratory methods, resulting in noncomparable data. Even if the same methods are used, different laboratories might select different analytical conditions and minimum reporting levels, rendering direct comparison of results difficult. Inconsistency in methods and lack of documentation include definition issues as well. No nationally accepted standard definitions exist for many water quality parameters. Different organizations may collect data using identical or similar methods, but identify them by different names, or use the same names for data collected by different methods. Currently, many federal agencies and most states store their water quality data in agency-specific data systems that other agencies cannot easily access or in files that are not yet automated. If others do access the data, in many instances the data cannot be used with confidence because the QA/QC information stored with the data may be incomplete or missing. For example, of the few nationwide water quality databases that exist, EPA's STORET, the Federal Data Reporting System for drinking water violations, and USGS's WATSTORE are technologically outdated, inflexible, and unable to meet the QA/QC and ecological data and information storage needs of new programs. These databases are currently being modernized. Lack of well-integrated data systems is also a problem at the state level, according to Lynn Singleton, program manager for environmental investigations and laboratory services in Washington state's Department of Ecology. "With poor data integration, addressing important societal questions is a challenge," says Singleton. A recent statewide effort to investigate environmental equity issues was difficult because the state lacked an integrated source of necessary information, according to Singleton. "We had to pull information from six or seven systems and thoroughly cross check the quality and compatibility of the data. We were eventually able to answer the questions, but it took months and months of ef4 6 2 A • VOL. 29, NO. 10, 1995 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
fort." Singleton is now heading up a cross-agency project to create just such an integrated data system for the state.
Database upgrade, pilot projects under way The ITFM effort has addressed these monitoring problems through a voluntary collaboration among different levels of government and the private sector. In general, the ITFM strategy focuses on filling existing information gaps to answer key questions of nationwide significance. All elements of the strategy can be implemented without changes in federal law, so the pending reauthorization of the CWA does not affect implementation of the ITFM strategy. Member agencies have already taken some steps to improve monitoring and achieve cost savings. Eight federal agencies, including the Smithsonian Institution, are negotiating to use and maintain a common automated taxonomic code. NOAA, USGS, EPA, and FWS have jointly purchased and are sharing remote-sensing land cover information needed for water assessment and management. EPA and USGS are both modernizing their national water quality data systems by using common data element names and reference tables. At the state level, ITFM has initiated intergovernmental pilot studies in three states to develop and test innovative concepts in monitoring programs. Arizona is focusing on data management and information sharing. Florida is developing a network that integrates surface water and groundwater monitoring in the Suwannee River basin. Wisconsin is comparing monitoring methods used by federal and state agencies and evaluating the differences in the results. In addition, statewide monitoring integration efforts are being established in Florida, Idaho, Maryland, Minnesota, New Jersey, and Wisconsin. Meetings have been held with a wide range of monitoring organizations and information users to begin the design of statewide strategies.
EPA, states, and tribes have used the ITFM mon itoring program framework to develop monitoring guidance for EPA water quality grants. The use of the framework throughout the nation is designed to im prove water quality information and the costeffectiveness of the programs. The Army Corps of En gineers also based its recent monitoring guidance on the ITFM monitoring framework. Although these and other components of the ITFM strategy are already being acted on, implementa tion of the full strategy will unfold over the next sev eral years. Data sharing and access through the In ternet, for example, will be available for major systems such as STORET, USGS's NWIS II, and various NOAA systems in the next two years. Joint training of EPA, USGS, and state staff in the eastern United States is being discussed this year for trace metals. In 1996, ITFM or the National Water Quality Monitoring Coun cil will concentrate on the following efforts: • Environmental indicators. Participate in devel oping a multiagency national water quality environ mental indicators report. At an EPA-sponsored work shop in June, 16 such indicators were identified that agencies could jointly use to characterize water qual ity nationwide. • Methods. Group and prioritize methods that most need nationwide comparability as the first ac tion of a new Methods and Data Comparability Board. • Information systems. Provide Internet access to a minimum of five disparate data systems in a geo graphic area as a first step to better system linkage. • Groundwater. Select a pilot area in which to test the recommended groundwater program frame work and indicators. • Ambient and compliance monitoring. Under take pilot programs, including federal, state, and pri vate monitoring, to demonstrate how ambient and compliance monitoring can work more effectively to gether in specified geographic areas. • Collaborative activities. Produce case studies of monitoring that use ITFM principles and tools as technical transfer documents. "With the accomplishments of the ITFM in cre ating partnerships, identifying problems, and devel oping a strategy and tools for implementation, the new national council has a solid foundation to build upon," Fellows believes. "Public and private organi zations now have an opportunity to change water quality monitoring and assessment so that it is more efficient and economical and allows for better man agement of our natural resources." From the state perspective, Washington's Single ton praises the ITFM effort and notes that the ini tial federal bias of the project "has gradually changed to a real appreciation of the role of the states. Just being able to meet with people from other agen cies and form professional relationships with them has been extremely valuable," he says. Transform ing the temporary ITFM into a permanent council with a network of state councils will continue this in teraction, Singleton believes. But communication is not enough, says Flori
da's DeHan. "You can meet and talk, but that only gets you so far. You need to do the pilot studies to answer the tough questions." The Suwannee River watershed project was funded at a modest $40,000 by ITFM, according to DeHan, but that allowed for new wells to be druled and for the creation of the 3-D watershed model. DeHan hopes that the new coun cil will continue to lend this type of financial and technical assistance that will lead states to adopt wa tershed approaches to environmental protection.
References (1) Ambient Water Quality Monitoring in the United States: First Year Review, Evaluation, and Recommendations; Inter governmental Task Force on Monitoring Water Quality: Washington, DC, 1992. (2) Smith, R. Α.; Alexander, R. B.; Wolman, M. G. Science 1987, 235, 1607-15. (3) Hern, J. D. In National Water Summary 1990-91 — Hydrologie Events and Stream Water Quality: U.S. Geo logical Survey Water Supply Paper 2400, 1991, 67-92. (4) Smith, R. Α.; Alexander, R. B.; Lanfear, K. J. In National Wa ter Summary 1990-91—Hydrologie Events and Stream Wa ter Quality: U.S. Geological Survey Water Supply Paper 2400, 1991, 111-40. (5) Schmitt, C. J.; Zajicek, J. L.; Ribick, M. A. Arch. Environ. Contam. Toxicol. 1985, 14, 225-60. (6) Schmitt, C. J.; Zajicek, ]. L.; Peterman, P. H. Arch. Envi ron. Contam. Toxicol. 1990, 19, 748-81. (7) Prouty, R. M.; Bunck, C. M. Environ. Monit. Assess. 1986, 6, 49-67. (8) National Status and Trends Program: A Summary of Data on Tissue Contamination from the First Three Years (19861988) of the Mussel Watch Project, National Oceanic and Atmospheric Administration, 1989; Technical Memoran dum NOS OMA 49. (9) O'Connor, T. R Coastal Environmental Quality in the United States; National Oceanic and Atmospheric Administra tion, National Ocean Service: Rockville, MD, 1990. (10) O'Connor, T. P.; Ehler, C. W. Environ. Monit. Assess. 1991, 17, 33-49. (11) Schmitt, C. J.; Brumbaugh, W. G. Arch. Environ. Con tam. Toxicol. 1990, 19, 731-47. (12) U.S. Environmental Protection Agency. Trends in Phos phorus in the Chesapeake Bay (1984-1990); Chesapeake Bay Liaison Office, Annapolis, MD; contract number 68WO-0043, 1991. (13) Leahy, Ρ Ρ; Thompson, T. H. U.S. Geological Survey Na tional Water Quality Assessment Program; U.S. Geolog ical Survey: Washington, DC, 1994; Open-File Report 9470. (14) National Research Council. National Water Quality Mon itoring and Assessment; National Academy Press: Wash ington, DC, 1987. (15) National Research Council. Managing Troubled Waters: The Role of Marine Environmental Monitoring; Na tional Academy Press: Washington, DC, 1990. (16) National Research Council. A Review of the USGS Na tional Water Quality Assessment Pilot Program; Na tional Academy Press: Washington, DC, 1990. (17) Surface Water Monitoring: A Framework for Change; Of fice of Policy, Planning, and Evaluation and the Office of Water. U.S. Environmental Protection Agency: Washing ton, DC, September 1987. (18) Knopman, D. S.; Smith, R. A. Environment 1993, 35(1), 17-41. (19) Fellows, E. J. Environment 1993, 35(5), 2-4. (20) Water Quality Monitoring in the United States—Final Re port of the Intergovernmental Task Force on Monitoring Water Quality, Intergovernmental Task Force on Moni toring Water Quality, U.S. Geological Survey: Washing ton, DC, 1995 (draft).
Mary Powell is an editor in the Environmental Protec tion Agency's Office of Pesticides program and a writer for ITFM.
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