Grantee Research Project Results
2001 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 , Peachtree City Developmental Services , Alpharetta Environmental Services
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, 2001 through February 28, 2002
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: (1) measure loading to streams, 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; and (2) compare the cultural models of lawn and lawncare held by "experts" and "homeowners" to determine their points of commonality and divergence, and establish the systematic nature of internal and contrastive variation.
Progress Summary:
In support of the first objective mentioned above, the first year's activities and accomplishments focused on monitoring water and sediment for pesticides, nutrients, metals, and biological impacts in suburban and reference streams.
Analysis for pesticides, nutrients, and general water quality parameters is essentially complete on monthly samples starting in July 2000, and ending at present in March 2002, totaling 21 dates at six sites. For pesticides, results were similar to those from the previous year, and also to those obtained by the National Water-Quality Assessment (NAWQA) program conducted by the United States Geological Survey (USGS). At least one pesticide was detected in any sample. In general, pesticide concentrations in water were in the low part-per-trillion range, while those in sediments were in the part-per-billion range. In sediments, the only pesticides detected were chlorpyrifos, chlorothalonil, and dithiopyr. The most commonly detected pesticides in water were the fungicide chlorothalonil and its degradation product, hydroxychlorothalonil, the insecticide chlorpyrifos, and the herbicides oxadiazon and dithiopyr. Concentrations and frequencies of detection were generally higher at sites downstream from golf courses; however, a greater diversity of pesticides was detected at sites receiving only runoff from residential lawns. The number of pesticides detected per sample appeared to be correlated by the size of the drainage area, rather than by socioeconomic class. For nutrients, the analyses completed for water are nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), soluble phosphate-phosphorus (PO43- -P), turbidity, total suspended solids, and dissolved organic carbon (DOC). The metal analyses for water (Zinc (Zn), Copper (Cu), and Arsenic (As)) are completed for March 2001 through December 2001, totaling 10 dates at six sites. Sediment samples are being analyzed by the Environmental Protection Agency (EPA) Total Recoverable Elements method. Sediment samples analyzed for Zn are complete from July 2000 to August 2001, totaling 14 dates at six sites. Sediment analyses for Cu and As are complete from July 2000 to February 2002, totaling 20 dates at 6 sites.
Nitrate-N values are all below about 0.5 milligrams per liter (mg/L). All sites showed a gradual increase in NO3-N concentrations from November 2000 to June 2001, and then decreased to a low during September through November. The values increased again by January 2002. The NH4-N concentrations followed a similar pattern as NO3-N with more fluctuations in the values. Ammonium-N concentrations were lowest from September to November 2001. All NH4-N concentrations were below 0.1 mg/L. There were no discernable differences among sites for NO3-N; however, NH4-N concentrations were somewhat different, especially for a small peak in March 2001. Phosphate-P concentrations were 15 micrograms per liter (µg/L) at the highest peak, which came in March 2001. There were some differences among the sites at that time, but very few differences otherwise. Values for phosphate-P concentrations were mostly below 5 µg/L. Turbidity was usually low with the exception of some very high values at single sites on three occasions. Several sites showed an increase in turbidity in March 2001, which corresponded to increases in phosphate-P and NH4-N at the same sites. As expected, total suspended solids were well correlated with turbidity. The DOC concentrations were generally near 10 mg/L with a small peak at all sites in February 2001, and a larger peak for three sites in May 2001. The DOC concentrations were at a low at all sites for July and August 2001.
There were more consistent differences among the six sites for metals in the sediments than for any of the water quality data. Concentrations of Zn, Cu, and As were consistently higher at Smokerise than for other sites, and Zn was also higher at Stony Brook. These two sites represent the high-end neighborhood watersheds. Cu was especially higher at Smokerise than for the other sites. The Cu source is unknown, but soil samples taken from the Smokerise watershed were much higher in Cu and As using the same EPA test than at two of the other locations. Soil Zn has not yet been analyzed. Metals in the water were very low and were consistent across sites and dates with one exception. Cu and As were higher for the high-end Smokerise site for May 2001. This increase corresponded to a high DOC concentration on that date at that site.
Tulip-poplar leaves were collected as they fell from trees during autumn 2000. Fifty air-dried, 8 gram leaf packs in coarse mesh bags were assembled and placed in the six streams in Peachtree City, GA, in November 2000. Packs were removed at intervals, and weight loss was determined. We also measured other variables that can influence leaf breakdown rates: temperature, water velocity, and accumulation of sediment, fungal biomass, and invertebrate abundance in leaf packs. Others measured stream nutrient and pesticide concentrations on this project. Leaf breakdown rates were not significantly different among streams, although regressions of leaf breakdown rate versus stream velocity and versus impervious surface cover in the watershed were significant. Breakdown rate increased with increasing velocity and impervious surface cover, suggesting that physical abrasion of leaves is important in accelerating leaf breakdown in these streams. Pesticide and nutrient concentrations differed little among streams during the time of this experiment, although sediment accumulation in the leaf packs differed among streams. Preliminary analysis suggests that fungal biomass continues to increase during the first two months of breakdown with little difference among streams.
We also are sampling benthic algae seasonally in these streams. The highest benthic algal biomass was observed in spring 2001, but there were no significant differences between streams. Algal species are currently being identified, and tolerance indices are being calculated. These should be completed by fall 2002. We will compare stream rankings based on algal indices with rankings based on invertebrate indices and biomarkers.
During fall 2001, laboratory microcosms were used to examine the effects of common fungicides (flutolanil, chlorothalonil, and hydroxychlorothalonil) on leaf breakdown rates and fungal biomass. Concentrations of fungicides used were such that the lowest concentrations were comparable to those found in the study streams, and the highest concentrations corresponded to those found in a stream draining a golf course. Preliminary analyses indicate that the fungicides did not significantly reduce leaf breakdown rates. Further analysis of leaf weights and fungal and bacterial biomass is necessary to confirm the reduction of these rates.
Pragmatic methods are needed to assess the adverse effects of chemical contaminants on aquatic organisms during environmental exposures. Cellular endpoints or biomarkers of chemical toxicity that are predictive of detrimental effects at the organismal, population, and community level may offer efficient and sensitive methods for monitoring biological resources. Because oxidative stress is a common mechanism of toxicity through which diverse chemicals exert adverse effects, we are evaluating biomarkers of oxidative stress (glutathione, catalase, superoxide dismutase, lipid peroxidation, and DNA damage) and condition indices in clams exposed in situ to suites of lawn care chemicals. To date, we have completed the field component of clam deployments in six Peachtree City, GA streams (summers 2000 and 2001), and at three locations in Camp Creek, Alpharetta, GA (winter/spring 2001). Furthermore, we have completed all of the biomarker analyses for Peachtree City streams except for DNA damage. Present data show that clams from contaminated sites exhibit transient signs of oxidative stress (i.e., elevated superoxide dismutase and catalase activity) at 4 weeks but not at 8 weeks. Furthermore, data show that glutathione depletion and effects on condition index occur late in exposures. Clams may be able to compensate for adverse cellular effects, but the energy required for amelioration will eventually affect organismal health. Annually, we have observed that streams during wet seasons have lower temperatures, higher dissolved oxygen concentrations, lower organic seston concentrations, higher alkalinity and hardness, and higher contaminant concentrations. Clams from streams during wet seasons displayed biomarker response patterns and condition indices that appear to be worse than clams from streams during dry years. Together, this research highlights that chemical contamination of streams and the corresponding adverse effects on aquatic organisms may vary year to year in response to changes in climatic conditions.
Macroinvertebrate collections for Year 1 in the Peachtree City, GA, streams and the stream at the Golf Club of Georgia in Alpharetta, GA, have been sorted and identified. The data will be incorporated into biological indices to determine if there are differences among reference and study streams when year two sampling and identifications are complete. Year 2 sampling has been completed for both the Peachtree City and Alpharetta sites. Samples currently are being sorted and identified in our laboratory.
As with Year 1, we were not able to collect the number of black fly larvae needed to determine how well black fly populations predict overall stream health. Artificial substrates were placed into all six streams in Peachtree City and were successfully colonized by black flies. However, the number of larvae collected was well below 50, the minimum number we desired. Consequently, we have de-emphasized this aspect of the project, due to the lack of adequate numbers for analysis.
To compensate for the lack of information produced from the black fly field data, we are supplementing laboratory experiments assessing the effects of pulsed exposures of chlorpyrifos, carbaryl, and malathion, singly and as mixtures, on black fly larvae, Simulium vittatum IS-7, survival, growth, and pupation rates. Based on preliminary data, individual chemicals exposed to S. vittatum IS-7 for a 2 hr pulse at 1 ppm on day 0, 1, 2, 3, 5, 7, and 9, of larval development appear to have no effect on survival, growth, or pupation rates. These tests will be repeated and statistically analyzed to determine if any effects are significant.
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 the behavior that puts such principles into practice.
This research takes an integrated systems approach to determine the impact of turf care chemicals used on residential lawns, their effect 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 two activities were as follows:
We completed 23 interviews with "experts" (i.e., aesthetic guardians, environmental custodians, and lawn care professionals) active in Peachtree City. Those individuals interviewed were identified by homeowners or through public listing services as individuals who have direct experience and knowledge about the research site. All interviews ranging from 45 to 120 minutes in duration were transcribed and coded for initial analysis using the software program NVivo. Preliminary analysis is complete. In addition to interviews, a total of 21 proxy documents (i.e., reports, flyers, work policies, etc.) were obtained in the course of these interviews that provide context or additional insight on the content of the interview.
All geographic information system (GIS) coverages compiled in the previous year were converted to a common global projection system. Micro-watershed boundaries were derived for the entire city based on USGS 30-meter digital elevation model (DEM), with particular attention to the areas where water sampling is being carried out; in addition, boundaries were finalized for neighborhood, founding dates, and property values. From the finalized property values and micro-watershed coverages, a potential list of homeowner interviewees stratified into high and low value homes within each watershed being sampled were generated.
An interview protocol for homeowners was developed based on the preliminary
results from expert interviews and any additional information obtained. For
example, information at the "Grow and Mow Expo" (Atlanta, February
2002), and interviews with area retailers addressed: (1) knowledge, appearance,
and information regarding lawn care; (2) decision making and practice of lawn
care; (3) personal information including education, home modifications, and
major landscaping. These topics were incorporated into our interview protocol
with homeowners.
A lawn-care additives (i.e., fungicides, bactericides, herbicides, growth regulators,
insecticides, miticides, nematicides) database was developed. This database
includes information on the nine active ingredients already recorded in water
sampling at the research site, as well as information on nine additional active
ingredients that various experts thought were significant. The database includes
nomenclature, related products, related brand names, biological action, user
guidelines, and marketing information.
We carried out an initial evaluation of the historical development of landscape design of research site. In Peachtree City, a limited set of interviews was conducted with several principals in the real estate firms that coordinate the layout and building activities in neighborhoods. Design documents and correspondence associated with the founding of the city were also reviewed. In addition, a comprehensive literature search was conducted of architectural and landscape design, corresponding to the period of founding and development of the research site.
Future Activities:
At the present time, the project is on schedule and there are no expected changes in project schedule.
Monthly samples of pesticides will continue to be collected through June. For nutrients, monthly water and sediment samples will continue to be taken throughout the coming summer and fall, even though no biological assessments are planned. At present, there are not enough data to determine annual patterns. Also, the source of the high Cu at the Smokerise site will be investigated. 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 will likely be monitored in the summer to catch the majority of insecticide applications and the fall to catch fall pre-emergent herbicide applications.
During summer and fall 2002, we intend to complete the analyses of the relationship between leaf breakdown rate and possible controlling factors: temperature, water velocity, nutrient and pesticide concentrations, sediment accumulation, fungal biomass, and aquatic invertebrates in leaf packs. Future research will include measuring contaminant body burdens in field-exposed clams, in vitro studies of the mechanism by which lawn care chemicals produce oxidative stress and chronic laboratory exposures of clams to a mixture of lawn care chemicals. A continuation of the sorting and identification of macroinvertebrates in addition to the pulsed insecticide exposure experiments will be the focus for the remainder of the project. We will also be preparing manuscripts for publication of our data.
The major objectives for the next reporting period are to: (1) conduct and transcribe four "expert" interviews; (2) conduct and transcribe homeowner interviews; (3) conduct a comprehensive set of interviews with city planners, designers, and builders associated with the research site as part of the study of the evolution of land
Journal Articles on this Report : 6 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. Influence of soil binding potential on pesticide runoff. GTA Today, July/August, 2001. |
R828007 (2001) R828007 (Final) |
not available |
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Armbrust KL. Pesticide runoff from turf. Through the Green, July/August, 2001. |
R828007 (2001) R828007 (Final) |
not available |
|
Shuman LM. Phosphate and nitrate movement through simulated golf greens. Water, Air, and Soil Pollution 2001;129(1-4):305-318. |
R828007 (2001) R828007 (Final) |
not available |
|
Shuman LM. Runoff of phosphorus from simulated golf fairways. Turfgrass Trends 2001;10:1-4. |
R828007 (2001) R828007 (Final) |
not available |
|
Shuman LM. Nitrogen and phosphorus loss from greens and fairways. USGA Green Section Record 2001;39:17-18. |
R828007 (2001) R828007 (Final) |
not available |
|
Shuman LM. Pesticide and nutrient fate: phosphorus leaching from golf greens. Through the Green, May/June, 2002, p. 38. |
R828007 (2001) R828007 (2002) R828007 (Final) |
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/ Exit
http://coweeta.ecology.uga.edu/ Exit
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.