Scientific Information And Its Application - Linking Science And Policy For Urban Nonpoint Source Pollution In The Great Lakes Region

PLUARG (Pollution from Land Use Activities Reference Group) was one of the first significant acknowledgements of the need to move beyond point sources of pollution, to consider nonpoint sources, such as agricultural fields, paved roads, and even the atmosphere (PLUARG 1978). The study also reflected the dominant concerns of Great Lakes region residents in the 1970s, in its primary focus on eutrophication and toxic substances. By 1976 phosphorus loadings had exceeded recommended levels in every lake, with approximately 30 to 40 percent of this from municipal sewage and industrial effluents from urban areas (PLUARG 1978: 4). Other pollutants were also noted, including sediment, mercury, lead, pesticides and PCBs. Microorganisms were described as a potential health threat, and it was noted that between 1975 and 1977 there had been 18 beach closings in Canada due to bacterial levels (PLUARG 1978: 40). Nevertheless, PLUARG viewed microorganisms as primarily a small, local problem (PLUARG 1978: 19).

While devoting much of its attention, including recommendations for remedial action, to agriculture and forestry, PLUARG did consider urban development and its effects on water quality, noting that impervious surfaces such as roads and buildings alter regional hydrology, and that this has consequences in terms of nonpoint pollution. Developing urban land was identified as a significant source of several pollutants; in particular, it contributed per hectare nearly five times as much suspended solids as any other land use (Kellogg 1997). The study group also suggested that governments develop management plans for urban storm water runoff, to maintain natural stream flow and control the flow of sediment and toxics from commercial and industrial areas (PLUARG 1978: 5-6).

PLUARG noted that lack of research on urbanization had inhibited political action on this source of pollutants. Few studies had addressed pollution in coastal areas resulting from land use activities, and only a handful of studies had taken an "holistic approach" to water quality. In particular, PLUARG's final report noted the need for a more precise definition of pollution, for more research on the movement of phosphorus, heavy metals and other toxics from land use activities to water bodies, and for greater knowledge of tolerable waste loads in the Great Lakes (PLUARG 1978).

Some problems identified by PLUARG remain, including excess nutrient loads and contaminants, although aspects have been ameliorated. However, developments during the last decade have placed renewed emphasis on issues that PLUARG considered to be of only minor importance, such as microorganisms and sedimentation (IJC 2000: 30).

Most significant has been an orientation of concern from PLUARG's focus on agriculture and forestry, to the effects of urban areas. The first comprehensive effort to describe the quality of urban runoff-the Nationwide Urban Runoff Program-was undertaken soon after PLUARG was completed, in the early 1980s (Schueler and Caraco 2000: 11). The 1996 State of the Lakes Ecosystem Conference (SOLEC) concluded that urban growth and resulting nonpoint source pollution (tied especially to expansion of impervious surfaces) is a major source of stress on the Great Lakes ecosystem. This conclusion was subsequently reaffirmed by the Great Lakes Science Advisory Board (2000).

The major pollutants in urban waterways were summarized by the International Joint Commission (IJC 2000: 30):

One of the most significant developments in knowledge of the impacts of urban pollution has been elaboration of a broader understanding of its ecosystem context. Much of this understanding was codified in a recent report on the state of knowledge of American ecosystems, prepared by the Heinz Center for Science, Economics and the Environment. This report used 15 indicators to describe the environmental health of urban and suburban areas. Of these, seven are especially relevant to urban nonpoint source pollution and its impacts (Heinz Center 2002: 176):

Beyond placing urban nonpoint source pollution within an ecosystem context, recent research has identified new concerns. One example is groundwater quality. Although 8.2 million people within the Great Lakes region rely on groundwater as their primary source of drinking water, there are still significant unknowns regarding the effects of land use practices on these water supplies (Grannemann et al. 2000). However, one benefit of recent research employing a broader, ecosystem approach to urban nonpoint source pollution has been a better understanding of the relation between urbanization and groundwater quality. For example, research has elucidated the impact of road salt on Great Lakes water quality, and ultimately, on human health (Howard et al. 1993). The holistic approach of such research (i.e. linking human activity to groundwater pollution, and ultimately to Great Lakes ecosystem health) gives scientists avenues of research that may not be provided through less flexible methods.

As these evolving concerns and priorities suggest, scientists studying water quality must be responsive to changing circumstances. Several significant research issues of the 1960s and 1970s, such as lead contamination, had become virtually nonexistent by the 1990s. Meanwhile, other problems became major issues in nonpoint pollution prevention. For example, PLUARG documents virtually ignored the link between pet feces and elevated levels of microorganisms in Great Lakes water. This has since been recognized as a source of nonpoint pollution requiring additional research.

This illustrates how researchers must be prepared to adapt to new knowledge and changing political priorities in order to continue to provide relevant and meaningful information to decision makers. Given the diffuse sources of nonpoint pollution, and its diverse effects on the Great Lakes ecosystem, it is impossible to predict what issue will become the primary focus of future research. Flexibility in the content and methods of research will ensure that information generated is responsive to rapid urban and suburban change.

Urban pollution presents formidable challenges to researchers. In part, the challenge is one of inadequate information. According to the Heinz Center, available data are not yet adequate to serve as a basis for evaluating many aspects of the urban environment, including the significance of nonpoint source pollution. In particular, the quality of data on which the seven indicators noted above are based varies widely: extensive data are available for nitrate and phosphorus in streams, and some data exist for chemical contamination (although the benchmarks necessary to evaluate the significance of contamination have not been developed for many individual compounds, let alone for mixtures of chemicals or seasonal pulses of high concentrations). The status of animal communities in streams is difficult to evaluate (it involves comparison of each stream with an appropriate reference from within the same region, but outside the urban/suburban area), and is only done in a handful of states. Indicators for stream bank vegetation require further development to allow for national comparisons, and scientists are uncertain about how even to measure ecosystem services in urban ecosystems (Heinz Center 2002).

A particular challenge is posed by the need to identify specific sources of pollutants. There are countless such sources, and their significance varies with the season (Hirsch et al. 2001). While scientists are able to identify sources of pollutants in terms of general land use categories, identifying the specific pathways by which pollutants travel, as well as characterizing the significance of the frequency and intensity of activities that lead to production of pollutants, is much more difficult (Marsalek and Ng 1989). A great deal of research is required to determine the quantity of nutrients released from each source, and how they are transported from urban areas to lakes and streams. Some sources have been easier to track than others. For example, it is generally understood how and to what extent nitrous oxide (an airborne pollutant generated by burning fossil fuels) increases nitrogen available to aquatic life. In contrast, little is known regarding the significance of septic system overflows and lawn fertilizers to nutrient levels in water bodies. Although fertilized lawns have a higher concentration of phosphorus than any other source, no scientific studies have convincingly linked fertilization with higher levels of phosphorus in the Great Lakes (Barth 1995, Schueler and Caraco 2000: 13).

There are also several unknowns regarding urban nonpoint sources of toxic substances. Linking their presence to specific sources has been difficult, both because of the many possible local sources (e.g. lawns that receive pesticide applications), as well as the potential significance of atmospheric transport of contaminants from outside the Great Lakes Basin (IJC 2000: 14). While researchers have identified numerous toxic substances and have tracked their origin to general nonpoint sources, they have not been able to determine the relative significance of each source, or, in some cases, what pathway was followed to enter the Great Lakes. Analysis of contaminant loads in urban runoff is also hindered by the high cost of laboratory analyses, limiting available data (Tsanis et al. 1994).

There are also many new chemicals in the Great Lakes that scientists have yet to identify. As a recent IJC report noted, researchers extracting chlorinated hydrocarbon residue from Great Lakes fish and birds have only been able to identify 30 percent of their findings (IJC 2000: 15). A further complication is the potential for more reactive chemicals to bind with each other to form new, more potentially harmful mixtures. In addition, the release of pharmaceutical products into the Great Lakes environment is only now being noted as a potential public health concern.

Given the increased public attention being paid to pathogens, as a result of drinking water problems and beach closures, greater emphasis is being placed on researching their environmental and health consequences. But research is now just scratching the surface. Scientists have been able to identify several potential sources of bacteria, but there remain significant unknowns regarding their biology and pathways. Even the source of the bacteria in the 1993 Milwaukee outbreak has not been identified (Logan 2000). There are also methodological challenges to be solved: for example, sampling and microbiological testing procedures are not standardized throughout the Great Lakes, and there are no government guidelines for testing viruses at public beaches (Edsall and Charlton 1997: 90). The database for pathogens in tributaries discharging into the Great Lakes is poor (Logan 2000: 26).

The Great Lakes Science Advisory Board has summarized these shortcomings and their implications:

"Although we now have much better general information about the nature and importance of sources, most of this information is derived from inference and not from direct measurement. In fact, we have few direct measurements of loads, especially the detailed chemistry (for instance of phosphorus species) that may be relevant in assessing the effectiveness of proposed controls. As governments scale down their monitoring and surveillance efforts, these data are becoming scarcer and older. Without strong data, we lack proof of cause and effect relationships, and therefore cannot make sound management decisions with confidence.... The paucity of good data on nonpoint source loads and their impacts on environmental decisions has contributed to confusion about appropriate actions and endpoints, and is a major obstacle to further progress on commitments made in the Great Lakes Water Quality Agreement" (GLSAB 2000: 5-6; emphasis in original).

In response to these research needs the IJC has recommended a binational study of the effects of changes in land use on Great Lakes water quality (IJC 2000: 32).

The Heinz report also indicated the need for research on indicators of the effects of urban areas on water quality. Most of the seven indicators noted above need additional development, such as more specific definition, refined measuring methods, or better benchmarks for evaluating results (Heinz Center 2002).

There are several approaches to reducing the impacts of urban development, ranging from technologies applied at specific sites, to political innovations, such as smart growth, that may apply across an entire region. Each implies particular information and research needs.

Many techniques are available for managing nonpoint source pollutants, including storm water management practices that detain, retain, and treat pollutant-laden runoff: retention ponds, wetlands, filters and infiltration trenches, and open channels designed to replicate predevelopment stream hydrology and water quality (Schueler and Caraco 2000: 20). One challenge has been to find effective ways of controlling erosion from construction sites or roads. Measures such as erosion fences have proven effective, but scientists continue to examine other methods (Lampe et al. 1996). At best, stormwater management techniques can only remove up to 60 percent of phosphorus and 40 percent of nitrogen (GLSAB 2000: 4). Often they do much worse: many structural stormwater systems are now reaching the end of their useful lives, or are in any case poorly maintained, and so are unlikely to remove significant contaminants. More study is needed of the effectiveness of control technologies, particularly those, such as infiltration trenches and bioretention, for which little if any monitoring data exist (Schueler and Caraco 2000: 11). There is also a need to expand the tool kit of nonpoint source pollution control technologies, possibly through transfer of waste management technologies now used in municipal and industrial systems (GLSAB 2000: 10).

Schueler and Caraco (2000: 22) identify the following research needs for urban nonpoint control best management practices (BMPs):

Dozens of innovative efforts in managing urban nonpoint source pollution, particularly sediment, are underway across the region, as a result of support from the Great Lakes Basin Program for Soil Erosion and Sediment Control (Great Lakes Commission 2002).

Certain areas, such as wetlands, floodplains, steep slopes, mature forests, critical habitat areas, and shorelines are especially important in moderating the impact of urban nonpoint source pollution. Preventing development of these critical areas is an essential component of pollution control strategies. Buffer strips along streams are especially critical: a forested buffer provides shade, woody debris, leaf litter, streambank protection, and many other functions and services to the stream. However, a buffer alone cannot ensure effective water quality protection, since most runoff arrives at a stream by channel or drain pipe, effectively bypassing the buffer (Schueler and Caraco 2000: 19).

Pollution control strategies that rely on technology alone are inadequate. As has been noted, performance of these technologies will be compromised if they are poorly designed or maintained. They are also generally unable to prevent channel erosion, or remove bacteria effectively (Schueler and Caraco 2000: 15). Thus, they need to be placed within a broader context of watershed land use management. Several management strategies are available: reducing impervious surfaces, better site design, stream buffers, and protection of natural hydrologic features, such as wetlands. Effective regulatory actions include protection of floodplains and other natural features, as well as regulation for erosion and sediment control during subdivision development, and rules requiring maintenance and replacement of septic systems (IJC 2000: 31). Development plans that include a lower proportion of impervious land area, using smaller streets and fewer cul-de-sacs, are also important, as are cluster developments, in which housing is placed in close proximity on smaller lots, allowing a larger proportion of a subdivision to remain undeveloped (Kellogg 1997). All such efforts depend on considering the long-term impact of development on watershed streams during the planning process. Watershed plans also need to be produced on smaller scales, to ensure responsiveness to local conditions (Schueler and Caraco 2000: 22).

Many aspects of nonpoint source pollution control depend on initiatives by the public. This implies a need for effective dissemination of scientific information, on such matters as lawn care strategies that employ alternatives to pesticides, herbicides and fertilizers. Efforts to discourage toxic waste disposal down storm drains, or to encourage pet owners to clean up after their pets, also indicate a role for public education (Fortner et al. 1991). However, little is known about the effectiveness of public education in actually reducing pollutant loads (Schueler and Caraco 2000: 21).

An essential element in public education is providing information regarding not just impacts on the environment, but, more positively, about the contribution of effective watershed protection to human health and quality of life, and to the local economy, in the form of higher property values and a community that is more attractive to both residents and investors (Kellogg 1997). The objective would be to communicate a view of local environmental protection as an investment, not a cost.

Beyond disseminating information, public education should also encompass encouraging a role for the public in gathering information, through community-based environmental monitoring initiatives. Such initiatives can be important not only as sources of information, but in encouraging attitudes of local stewardship (see, for example, www.naturewatch.ca/english/).

Ultimately, control of urban nonpoint source pollution requires addressing unsustainable land use patterns, as technological or managerial solutions alone are inadequate. Smart growth initiatives, fostering more efficient land use through higher density development, provide one illustration of possible directions. The need for such initiatives illustrates how progress on more complex environmental problems depends on moving beyond narrow regulatory approaches, towards more innovative, dynamic collaborations among governments, the private sector, citizens' groups, universities and other organizations, ultimately embracing what is often referred to as "civic environmentalism," in which environmental protection is the joint responsibility of all members of a community (Shutkin 2000).

While civic environmentalism, as expressed through, for example, the decision to adopt smart growth patterns of development, is a political, not a scientific matter, the contribution of science to such a decision can be significant. This complex topic is examined more closely in the case study of the Oak Ridges Moraine.