Description

This management measure involves limiting the impact of pesticides on water quality by educating residents and businesses on alternatives to pesticide use, and on proper pesticide storage and application techniques. Pesticides in stormwater runoff directly affect the health of aquatic organisms. Their presence in drinking water also threatens human health. Insecticides, such as diazinon and chloropyrifos, are of greatest concern because even at low levels they can harm aquatic organisms (CWP, 1999 and Schueler, 1995). A recent U.S. Geological Survey of urban streams found that some of the more commonly used household and garden insecticides occurred at higher frequencies and concentrations in urban streams than in agricultural streams (USGS, 1999). The study also found that insecticide concentrations frequently exceeded USEPA guidelines for protecting aquatic life.

Homeowners applying insect and weed killer to their lawns and gardens are the biggest source of pesticides contaminating urban streams. Every year, they apply an average of 5 to 7 pounds of pesticides to their well-maintained lawns (Schueler, 1995). Pesticide pollution prevention plans try to limit the adverse effects of insecticides and herbicides. They do this by providing information on chemical-free alternative pest control techniques and by explaining how to determine appropriate pesticide dosages. As part of their outreach message, lawn care and landscaping management programs often include information on proper pesticide use.

Applicability

EPA estimates that nearly 70 million pounds of pesticides are applied to urban lawns each year. Table 1 compares surveys on residential pesticide use in eleven different areas of the country, broken down by insecticides and herbicides use. It appears that pesticide application rates vary greatly, ranging from a low of 17 percent to a high of 87 percent, but climate is an important factor in determining insecticide and herbicide use.

Table 1. A comparison of eleven surveys of residential insecticide and weedkiller use

Insecticides appear to be applied more widely in warm weather climates, where insect control is a year-round problem (such as in Texas, California, and Florida). In warm weather areas, between 50 and 90 percent of residents reported that they had applied insecticides in the last year. This compares to 20 to 50 percent reported in colder regions, where hard winters help keep insects in check. By contrast, herbicide application rates tend to be higher in cold weather climates, where it is used to kill weeds that arrive with the onset of Spring (60 to 75 percent in the Michigan, Wisconsin, and Minnesota surveys).

Design Considerations

A popular way for program managers to educate residents and businesses on alternatives to chemical pesticides is integrated pest management (IPM). Employing a holistic approach to pest control, IPM examines the interrelationship between soil, water, air, nutrients, insects, diseases, landscape design, weeds, animals, weather, and cultural practices before selecting an appropriate pest management plan. The goal is not the elimination of pests. Rather, IPM programs seek to manage pests at an acceptable level while avoid environmental disruptions. IPM programs combine preventative practices with non-chemical and chemical pest controls to minimize pesticide use and to promote natural pest control. Non-chemical pest controls employ good bugs to eat pests. Cultural pest controls include handpicking individual pests and removing diseased plants. Bug zappers and paper collars are examples of mechanical pest controls. Each method reduces the need for chemicals. When pesticides are needed, IPM programs urge users to try less toxic products like insecticidal soaps. A central concept of IPM, reducing herbicide use, is driven by rising tolerance levels among certain weed species. See USEPA's Integrated Pest Management and Food Production fact sheet or Integrated Pest Management at Iowa State University website for more information on IPM.

Many lawn care and landscaping management programs include education on proper pesticide use. This is most often accomplished though informational brochures and fact sheets on pesticide use in the home and garden. Informational packets include tips on identifying pest problems, selecting environmentally friendly treatment approaches, less-toxic chemical pest control products, and proper pesticide mixing, application rates and cleanup procedures. Program managers can consult cooperative extension programs and university agricultural programs for more information regarding water quality-friendly pest control techniques.

Limitations

The greatest limitation program managers face is the public's perception that no alternatives to pesticides exist. Surveys suggest that the public is well aware of the potential environmental dangers of pesticide use. In several surveys, residents ranked pesticides as the leading cause of neighborhood pollution (Elgin DDB, 1996). Despite this, pesticide use remains high in many urban areas (see Table 1). The time homeowners need to learn about alternative pest control techniques may limit program effectiveness. Many residents prefer the ease of spraying a chemical on their lawns to other pest control techniques they perceive as more time intensive and less reliable. Managers should recognize that IPM programs have their own limitations, including questions about the effectiveness of alternative pest control techniques.

Effectiveness

Cooperative extension and university agricultural programs across the county have studied the effectiveness of alternative pest control techniques, both at limiting pesticide use and at protecting water quality. A national report synthesizing these findings remains to be conducted, however. Despite this, recent studies on insecticides present in stormwater confirm the need for pesticide control programs. Based on results from recent urban stream sampling, the USGS concluded that the presence of insecticides in urban streams may significantly obstruct their restoration (USGS, 1999). Table 2 examines eight studies on stormwater runoff and insecticide concentrations. It provides an example of how insecticides persist even after their use is discontinued.

Research on diazinon use in the San Francisco Bay region also confirms the need for pest control programs. Studies reveal that diazinon use even among just a few individual homes in a watershed can produce harmful diazinon levels in urban streams (CWP, 1999). Due to diazinon's solubility, current stormwater and wastewater treatment technologies cannot significantly reduce diazinon levels. The best tool for controlling diazinon use in urban watershed is through source control - educating residents and businesses on pesticide alternatives and on safe application methods.

An example of a successful IPM program is Eugene, Oregon's Grounds Maintenance Program. Begun in the early 1980s, the program includes all city public parks and recreation areas. The city uses a variety of IPM methods, including water blasting to remove aphids, insecticidal soaps, and the limited use of pesticides. The city has also adopted higher tolerance levels for certain weed and pest species, reducing the need to apply pesticides and herbicides. Since the program's inception, Eugene's pesticide use has plunged by more than 75 percent (Lehner et. al., 1999). Although exact cost savings haven't been calculated, the city's turf and grounds supervisor believes the IPM program has saved money while producing little citizen opposition.

Table 2: Banned or restricted insecticides found in stormwater runoff concentrations in µg/l (ppb) (Source: Schueler, 1995)

Cost Considerations

The cost of educating residents on proper pesticide use varies depending on the intensity of the effort. Some cities have begun partnerships that include training retail employees on IPM techniques, similar to those of lawn care and landscaping programs. In addition, the partnerships assemble promotional materials and displays on safer pesticide alternatives. Cost estimates must include expenditures of staff time for training and materials production. Since a number of good fact sheets on IPM and pesticide use are available through cooperative extension programs, managers should consider using these resources instead of creating new ones. Using master gardener volunteers to help train residents and store employees is another cost saving measure.

References

Aveni, M. 1998. Water-wise gardener program: Summary report. Unpublished data. Virginia Cooperative Extension. Prince William County, VA.

Bannerman, R. 1994. Unpublished data on diazinon concentrations and toxicity in stormwater ponds. Bureau of Water Management. Wisconsin DNR. Madison, WI.

California Environmental Protection Agency. 1995. Consumer Factsheet: Urban IPM. Department of Pesticide Regulation, Sacramento, CA.

Center for Watershed Protection (CWP). 1999. Diazinon sources in runoff from the San Francisco Bay region. Technical Note 106. Watershed Protection Techniques 3(1): 613-616.

Cohen, S., S. Nickerson, R. Maxey, A. Dupuy, and J. Senita. 1990. A groundwater monitoring study for pesticides and nitrates associated with golf courses on Cape Cod. Groundwater Monitoring Review 5: 166-173.

D'Andrea, M., and D. Maunder. 1994. Characterization of Urban Nonpoint Source Discharges in Metropolitan Toronto.

Dewbery and Davis. 1989. Toxicity of Sediments from BMP Ponds. Final Report. Prepared for Northern Virginia Planning District Commission. Annandale, VA. 26 pp.

De Young, R. 1997. Healthy Lawn and Garden Survey: Data Analysis Report. Rouge River National Wet Weather Demonstration Project. Oakland County, MI. 40 pp.

Dindorf, C. 1992. Toxic and Hazardous Substances in Urban Runoff. Hennepin Conservation District. Minnetonka, MN. 98 pp.

Elgin DDB. 1996. Public Awareness Study: Summary Report. The Water Quality Consortium. Seattle, WA. 24 pp.

Hippe, D, D. Wangsness, E. Frick, and J. Garret. 1994. Pesticide Monitoring in the Apalachicola-Chattahoochee-Flint River Basin. US Geological Survey. National Water Quality Assessment Program. Water Resources Investigation Report 94-118. Atlanta, GA.

Iowa State University. No date. Integrated Pest Management at Iowa State University. [www.ipm.iastate.edu/ipm/ ]. Last updated 12/13/04. Accessed 10/18/05.

Knox, G., A. Fugate, and G. Israel. 1995. Environmental Landscape Management Use of Practices by Florida Consumers. University of Florida Cooperative Extension Service. Bulletin 307. Monticello, FL. 26 pp.

Kroll, J., and D. Murphy. 1994b. Pilot monitoring for 14 pesticides in Maryland surface waters. Maryland Dept. of Environment. Chesapeake Bay Program Technical Report 93-020. 108 pp.

Kroupa and Associates. 1995. Westmorland Lawn Care Survey. Milwaukee, Wisconsin. 12 pp.

Lehner, P., G. Aponte Clarke, D. Cameron, and A. Frank. 1999. Stormwater Strategies: Community Responses to Runoff Pollution. Natural Resources Defense Council, New York, NY.

Metropolitan Washington Council of Governments. 1983. Urban Runoff in the Washington Metropolitan Area: Final NURP Report. Department of Environmental Programs. Washington, DC. 222 pp.

Morris, W., and D. Traxler. 1996. Dakota County Subwatersheds: Residential Survey on Lawn Care and Water Quality. Dakota County, Minnesota, Decision Resources, Ltd.

National Service Research (NSR). 1998. Pesticide Usage and Impact Awareness Study: Executive Summary. City of Forth Worth Water Department. Fort Worth Texas. 44 pp.

Scanlin, J., and A. Cooper. 1997. Outdoor Use of Diazinon and Other Insecticides: Final Draft. Alameda County Clean Water Program and Alameda County Flood Control and Water Conservation District. Oakland, CA. 20 pp.

Schueler, T. 1995. Urban pesticides: from the lawn to the stream. Center for Watershed Protection, Ellicott City, MD. Watershed Protection Techniques 2(1): 247-253.

Smith, J. 1996. Public survey used to estimate pollutant loads in Maryland. Technical Note 73. Watershed Protection Techniques 2(2): 361-363.

Swann, C. 1999. A Survey of Residential Nutrient Behaviors in the Chesapeake Bay. Widener-Burrows, Inc. Chesapeake Research Consortium. Center for Watershed Protection. Ellicott City, MD. 112 pp.

Thomas, P., and S. McClelland. 1994. NPDES monitoring Atlanta Georgia Region. In US EPA. 1983. Results of the Nationwide Urban Runoff Project. Final Report. Vol 1. U.S. Environmental Protection Agency, Office of Water, Washington, DC.

United States Geological Survey (USGS). 1999. The Quality of Our Nation's Waters Nutrients and Pesticides. U.S. Geological Circular #1225. [http://water.usgs.gov ].