Grantee Research Project Results
2000 Progress Report: The Impact of Lawn Care Practices on Aquatic Ecosystems in Suburban Watersheds.
EPA Grant Number: R828007Title: The Impact of Lawn Care Practices on Aquatic Ecosystems in Suburban Watersheds.
Investigators: Armbrust, Kevin L. , Williams, James B. , Black, Marsha C. , Keeler, Andrew G. , Meyer, Judith L. , West, Dee , Shuman, Larry , Noblet, Raymond , Gragson, Ted
Institution: University of Georgia
Current Institution: University of Georgia , Alpharetta Environmental Services , Mississippi State University , Peachtree City Developmental Services
EPA Project Officer: Packard, Benjamin H
Project Period: March 1, 2000 through February 28, 2003
Project Period Covered by this Report: March 1, 2000 through February 28, 2001
Project Amount: $893,849
RFA: Water and Watersheds (1999) RFA Text | Recipients Lists
Research Category: Watersheds , Water
Objective:
The working hypothesis of this project is that homeowner beliefs, values, and socioeconomic status will determine loads and ecological impacts of turf care chemicals (pesticides and nutrients) in aquatic ecosystems in suburbanized watersheds. The specific objectives of this investigation are to:- Measure the loading to streams and temporal trends in concentrations of turf care products and biological indicators of stream ecosystem health in creeks receiving storm water drainage from residential neighborhoods of different socioeconomic status.
- Compare the cultural models of lawn and lawncare held by "experts" and "homeowners" in order to determine their points of commonality and divergence, and establish the systematic nature of internal and contrastive variation.
Progress Summary:
The progress during the past year is presented below by each objective.Objective 1. In support of Objective 1, this first year's activities and accomplishments have focused in two major areas: (1) development of methods and environmental behavior data for turf pesticides and nutrients as well as biological indices against specific pesticides, and (2) monitoring of water and sediment for pesticides, nutrients, metals, and biological impacts in suburban and reference streams.
Monthly samples have been taken for nine dates starting in July 2000, and the last one in March 2001. Both water and sediment samples were taken for each of two reference sites and four residential sites. Methods have been developed to analyze turf pesticides used in both water and sediment by GC/MS with negative chemical ionization or LC/MS/MS in MRM mode. Pesticides monitored include the herbicides 2,4-D, dicamba, pendimethalin, prodiamine, atrazine, simazine, prometon, and oxadiazon; the insecticides carbaryl, malathion, diazinon, chlorpyrifos, and trichloropyridinol; and the fungicide chlorothaloinil and its degradation product hydroxychlorothalonil. This spring, the herbicide dithiopyr, the insecticides imidacloprid and fenvalerate, and the fungicides propiconazole and flutonil will be added to the screen. Runoff experiments on outdoor turf plots have shown that the potential for runoff of these products is inversely proportional to their soil adsorption coefficients. Chemicals most frequently detected in water were oxadiazon and hydroxychlorothalonil. In sediment, oxadiazon, hydroxychlorothalonil, and chlorpyrifos were most frequently observed. All were detected at low ppb levels in sediment and at low part-per-trillion (ppt) levels in water. Laboratory degradation experiments with hydroxychlorothalonil indicated that it should be degraded by sunlight in surface water systems.
Water samples are analyzed for NO3-N, NH4-N, soluble P, turbidity, total suspended solids, total organic carbon, Zn, Cu, and As. Sediments are analyzed for Zn, Cu, and As. To date, all samples have been analyzed for the nutrients and general water quality parameters. Sediments have been analyzed for Zn for the first eight dates and methods currently are under development for Cu and As. Nitrate and ammonia levels are relatively low for the entire data set with a slight increase in nitrate-N in the March sampling. Soluble P was higher in July and August than later in the fall and winter. Turbidity and total suspended solid data were well correlated and generally low but were higher in the March sampling after several spring rains. The total organic carbon values are relatively constant. There were no discernable patterns for the different types of sites (reference versus residential).
As leaf litter is decomposed in streams it provides a critical basal resource for stream food webs. Hence, we have measured leaf litter breakdown rates in eight streams in suburban Atlanta: golf course and upstream reference in Alpharetta, two reference (pre-suburbanization) streams in Peachtree City, and four streams flowing through developments with different home values in Peachtree City (two high, one intermediate, and one lower). Tulip-poplar (Liriodendron tulipifera) leaves were collected as they fell from trees in autumn 2000, placed in coarse mesh bags in the streams, and retrieved at intervals. Leaf breakdown rates were not significantly different in the reference and golf course streams although the study site had somewhat higher nutrient and pesticide metabolite concentrations (MacGregor, et al., 2001). Preliminary calculations of leaf breakdown rates did not detect any differences among the streams in Peachtree City (Herbert, et al., 2001), but additional analyses are essential before reaching conclusions. Analyses that currently are in progress include sediment accumulated in leaf packs, aquatic insects colonizing leaf packs, and fungal biomass and spores in leaf packs. Ongoing analyses also include measures of algal biomass and continuous temperature and discharge measures in the six streams in Peachtree City.
Biomonitoring is a process whereby responses to chemical contaminants are quantified in situ at the cellular, physiological, and ecological levels to characterize health risks to resident organisms. Bivalves often are used for biomonitoring because of their widespread distribution and abundance in study areas, sedentary habits, and ability to bioaccumulate pollutants without excessive mortality. We are actively measuring sensitive cellular and physiological stress responses in freshwater clams (Corbicula fluminea) and mussels (Utterbackia imbecillis) to determine if lawn care chemicals are having adverse effects on organisms in streams receiving residential and golf course runoff.
Presently, we have completed the field component of clam deployments in six Peachtree City, GA, streams (June 2000 ? August 2000) and at three locations in Camp Creek, Alpharetta, GA (February 2001 ? April 2001). For Peachtree City deployments, approximately 75 percent of the tissue analyses have been completed, and three new biomarkers have been added to our original research plan (superoxide dismutase, catalase, and lipid peroxidation). Furthermore, laboratory toxicity tests on larval mussels (glochidia) were conducted with commercial formulations of five commonly used lawn care chemicals to assess mixture interactions and biomarker sensitivity.
Preliminary data from laboratory toxicity tests suggest that the toxicity of atrazine, glyphosate, carbaryl, diazinon, and copper is additive for equitoxic mixtures (95 percent CI = -0.60 to 1.88) and environmentally realistic mixtures (95 percent CI = -0.10 to 0.48), and that biomarkers may be a sensitive and rapid assessment method (i.e., increases in DNA damage were observed at 1/5 NOEC values). Preliminary data from Peachtree City clam deployments suggest that clams deployed at R2, H1 and H2 were stressed (i.e., had decreased condition index values and/or elevated superoxide dismutase activity). While sites R2 and H2 had elevated OH-chlorthalonil concentrations in the water, additional water, sediment, and tissue chemistry data will be needed to evaluate the chemical etiology of the observed stress. These analyses will be conducted during the next reporting period.
The toxicities of three commonly detected insecticides in the Peachtree City, GA, streams?carbaryl, chlorpyrifos, and malathion?have been evaluated in the laboratory using laboratory-reared black fly larvae, Simulium vittatum IS-7, in a 48 hour static orbital shaker bioassay. LC50 values for each insecticide were established and used in determining the toxic effect of these insecticides as mixtures. Results of the 48 hour LC50 tests reported as the median with fiducial limits, have shown chlorpyrifos to be the most toxic to black fly larvae [LC50 = 0.43 µg/L (0.39-0.48)] followed by carbaryl [LC50 = 28.95 µg/L (27.29-30.58)], and malathion [LC50 = 84.76 µg/L (68.94-105.94)]. The toxicity of these chemicals as mixtures was analyzed using the toxic unit (TU) approach. Toxicity was shown to be greater than additive for the ternary mixture of chlorpyrifos/carbaryl/malathion [LC50 = 0.57TU (0.47-0.66)], and the binary mixtures of chlorpyrifos/malathion [LC50 = 0.72 TU (0.60-0.83)], and carbaryl/malathion [LC50 = 0.78 TU (0.70-0.85)]. The binary combination of chlorpyrifos and carbaryl was shown to be additive [LC50 = 0.98 TU (0.90 -1.05)]. These results indicate that increased toxicity may be elicited in these streams where all three chemicals are present.
Along with the laboratory assays, quarterly (summer, fall, winter, spring) macroinvertebrate collections were conducted in the Peachtree City, GA, streams and the stream at a golf course in a North Atlanta, GA, suburb using the EPA's Rapid Bioassessment Protocol for Wadeable Streams and Rivers to determine effects of insecticide runoff on the invertebrate communities. Samples have been sorted and currently are being identified. Once identifications have been completed, the data will be incorporated into biological indices and metrics to determine if there are differences in the macroinvertebrate communities between study and reference streams.
Objective 2. The premise of this research is that beliefs, values, and practices about lawn and lawn care are structured according to cultural models representing the knowledge needed to be a functioning member of one's society or social group. The level of agreement or disagreement on beliefs, values, and practices about lawn and lawn care are expected to display clear social patterns of variation between homeowners, environmental custodians, horticultural writers, and lawn care professionals. Because "knowing better" does not always lead to "behaving correctly" this research not only focuses on the beliefs and values about fertilizer application rates, mower blade height, species composition, but also focuses on the behavior that puts such principles into practice.
This research takes an integrated systems approach to determine the impact that turf care chemicals used on residential lawns have on non-target aquatic ecosystems, and the factors affecting the cultural beliefs and values guiding homeowner decisions about lawn care influencing chemical movement to aquatic ecosystems. Year one activities were as follows:
Bibliography - A comprehensive bibliography of articles, books, and other materials relevant to the research was assembled from the literature with citations entered to a citation database and reference articles copied and filed for consultation. The nature of this research and the social science approach taken are sufficiently novel so there is no ready synthesis to draw on: relevant literature is widely dispersed in different fields and domains of inquiry. The bibliography provides both the foundation to our approach and the context for our results.
Homeowner-Lawn Survey - Two preliminary surveys were implemented in the targeted watersheds, a face-to-face survey of homeowners and an observational survey of lawns. Questions and observations on these surveys were specific to the project area as well as drawn from an earlier state-wide survey (carried out by a different group). The purpose of our surveys was to assess the representativeness of the study population in light of previous results and to initially characterize the population for subsequence activities. The results are being used to design the suite of interview questions we will use during Year 2 in face-to-face interviews with homeowners on their lawn management practices and experts on lawncare generally (i.e., "exploratory interviews"), and the observations we will make on lawns.
City Ordinances and Active Ingredients - We obtained the recently approved city ordinances and identified chapters and articles related to lawns, grass, landscaping, etc. This information was then coded and entered into a text database to be analyzed for content and used in subsequent interviews with environmental custodians and lawncare professionals. The ordinances represent the legal and social framework within which homeowners are expected to act and which environmental custodians are expected to uphold. The active ingredient list with corresponding trade and product names is the starting point for knowing exactly what additives homeowners apply to their lawn, as well as the common link between the chemistry and practice of lawn care.
Mapping - A GIS spatial and attributes database was assembled from widely disparate pieces of information drawn from various state and county offices. The database now includes a classification of city land use, neighborhood boundaries, individual property information (parcel boundaries, real estate market value and tax information), and physical environment and infrastructure (elevation, hydrology, roads, sewer, etc.). In this project, full integration will be achieved through the temporal and spatial association of sampling. Determining the spatially explicit properties of observed behavior and expressed beliefs is critical to our success.
Future Activities:
At the present time the project is on track and there are no expected changes in the project schedule. For Objective 1, over the next year samples will continue to be collected and analyzed for pesticides, nutrients, and general water quality parameters. In addition, autosamplers will be deployed at the four residential sites and possibly at the reference sites in Peachtree City to analyze both pesticides and nutrients in stormwater runoff. Storm events likely will be monitored in the summer to catch the majority of insecticide applications and the fall to catch fall pre-emergent herbicide applications. During the next reporting period, assay results will be provided from the Alpharetta study and the deployment study at Peachtree City will be repeated. Laboratory experiments with clams to investigate if environmental stressors (elevated temperatures, low dissolved oxygen, and food quality) can affect lawn care chemical toxicity also will be conducted. A continuation of the sampling, sorting, and identification of macroinvertebrates will be the focus for the remainder of the project, as will be the preparation of manuscripts for publication of data.For Objective 2, the major activities for the next reporting period are to gather direct information on: (1) lawns associated with houses and behavioral information on owner management strategies, and (2) group-representative information on beliefs, values, and cultural models. Two graduate student assistants will be working full time and two additional graduate students will be working part time during the summer of 2001, with the principal investigator to map lawns, recruit lawn-diary participants, and conduct exploratory and explanatory interviews of individuals identified with the four groups. At the completion of this intensive period of information gathering, statistical and graphical methods will be used to evaluate individual and aggregate responses appropriate to the conditions of this research.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 71 publications | 17 publications in selected types | All 17 journal articles |
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Type | Citation | ||
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Armbrust KL, Peeler HB. Effects of formulation on the run-off of imidacloprid from turf. Pest Management Science 2002;58(7):702-706 |
R828007 (2000) |
not available |
Supplemental Keywords:
lawns, lawn care, suburbia, cultural models, policy, watersheds, ecological effects, dose-response, mixtures, pesticides, aquatic toxicology, macroinvertebrates, black flies., RFA, Scientific Discipline, Toxics, Geographic Area, Water, Ecosystem Protection/Environmental Exposure & Risk, Hydrology, Nutrients, Water & Watershed, Ecosystem/Assessment/Indicators, pesticides, State, Ecological Effects - Environmental Exposure & Risk, Southeast, Ecology and Ecosystems, Watersheds, fate and transport, nutrient transport, anthropogenic stress, aquatic ecosystem, nutrient supply, ecological effects, ecological exposure, contaminant transport, valuation of watersheds, suburban watersheds, stream ecosystems, bioavailability, river inputs, runoff, watershed sustainablity, Georgia (GA), Atlanta, Georgia, socioeconomics, chemical transport, ecological impacts, stormwater drainage, aquatic ecosystems, lawn care practices, pesticide runoff, bioindicators, homeowner beliefs, nutrient cycling, water quality, ecological indicators, herbecides, public policy, lawn care, community values, land useRelevant Websites:
http://anthro.dac.uga.edu/ Departmental website with relevant background on the investigator and a selected publication list
http://coweeta.ecology.uga.edu/ Project site for NSF-sponsored research project the investigator is tied to with related aspects to the current project.
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.