United States Environmental Protection Agency National Exposure Research Laboratory Research Triangle Park, NC 27711 Research and Development EPA/600/SR-96/098 August 1996 Project Summary v>EPA Evaluation and Selection of Analytical Methods for Lawn- Applied Pesticides Marcia G. Nishioka, Marielle C. Brinkman, and Hazel M. Burkholder The work described in this report summarizes four different surveys that were conducted. The first two surveys were conducted to identify the lawn pesticides, including herbicides, insec- ticides, and fungicides, used in the Co- lumbus, Ohio area by professional lawn care companies and home owners, re- spectively. The third survey was con- ducted to identify through literature publications available methods for analysis of 12 different lawn-applied pesticides that were identified in the first two surveys. The fourth survey, a literature search, was conducted to identify the major soil metabolites of four herbicide acids. Data from the two literature searches have been ab- stracted and compiled into separate databases using Borland's Paradox (DOS) software. Methods reported in the literature may not be appropriate for anticipated EPA pesticide studies in track-in and intra-home redistribution. Published methods are not specific to the matri- ces of interest here (house dust, entryway soil, and polyurethane foam collected carpet and turf surface- dislodgeables). Potential interferences and co-extracted species such as hu- mic acids, aliphatic fatty acids, lipids, phenols, PAH and other combustion source-derived species are not ad- dressed. This Project Summary was developed by EPA's National Exposure Research Laboratory, Research Triangle Park, NC, to announce key findings of the re- search project that is fully documented in a separate report of the same title (see Project Report ordering informa- tion at back). Introduction Various pesticides have been identified in house dust and indoor air. In at least one case, the presence in the home of several pesticides (e.g. chlorpyrifos, diazinon, o-phenylphenol) was clearly due to indoor use of whole room foggers and sprays. The presence of other pesticides appeared to be due to infiltration and mi- gration into the home of pesticides that were originally applied to foundations, walkways, and gardens (e.g. permethrin, chlordane, heptachlor). Infiltration through foundation cracks probably explains the presence of chlordane indoors in many older homes and may be similar to radon infiltration. However, for pesticides such as permethrin, which are applied at sites distant from the foundation, track-in of con- taminated soil on shoes may explain the presence of these outdoor-applied pesti- cides in the home. House dust may be a more complex matrix than soil or plant material, as other human and combustion source-derived pollutants will be encountered (e.g. fatty acids, lipids, phenols, PAH, carpet addi- tives). The ease in applying standard soil analysis methods to house dust samples for outdoor applied pesticides will be com- promised further by pesticide levels that are expected to be significantly lower due to the dilution that occurs during any migra- tion process. Therefore, methods suitable for outdoor levels are unlikely to be suit- able for lower indoor levels in a specific matrix like house dust. ------- Conclusions The primary lawn-care pesticides ap- plied in the Columbus area are preemer- gence and post-emergence herbicides. The most frequently used preemergence herbicides are the dinitro-aniline deriva- tives pendimethalin, benfluralin, and triflu- ralin. The latter two are often combined in a mixture for application (trade name Team). The most frequently used post-emer- gence herbicides are the acid herbicides, dicamba, 2,4-dichlorophenoxyacetic acid (2,4-D), mecoprop (or MCPP), and 2-me- thyl-4-chloro-phenoxyacetic acid (MCPA). Dicamba, 2,4-D, and mecoprop are fre- quently combined for application (trade name Trimec, among others). Recent con- cern over possible adverse health effects from 2,4-D exposure has prompted sev- eral of the larger lawn-care companies to replace the 2,4-D with MCPA in the Trimec or Trimec-equivalent formulations. Applications of insecticides and fungi- cides vary widely in Columbus. These ap- plications depend on the particular com- pany and the general weather patterns. At least one company routinely applies an insecticide with herbicides. Mild winters and/or cool, wet weather increase the use of fungicides and insecticides. Other com- panies report that they have not applied fungicides in several years. A previous study of pesticides in house dust stated that house dust extracts caused significant problems for "in con- trol" GC quantification. Because problems of this nature were not identified in analy- ses of soil samples, we have to assume that soil and house dust are distinctly dif- ferent in composition and that the com- plexity of house dust extracts requires more rigorous analytical methods, espe- cially cleanup steps. Methods that have been reported in the literature cannot be recommended for anticipated pesticide studies in track-in and intra-home redistri- bution because they do not address the matrices of interest, do not provide suffi- cient cleanup steps, and, thus, do not have the requisite sensitivity. Published methods generally address the less com- plex matrices of soil and water. From the standpoint of analysis meth- odology alone, the published methods 1) allude to difficulties in dealing with co- extracted humic acids without providing solutions, 2) provide little or no sample cleanup, 3) detail excessive artifact forma- tion during derivatization steps, 4) obtain low recovery of analytes from clay-like soils, 5) provide insufficient detection lim- its, and/or 6) rely on relatively high-cost GC/MS analyses rather than lower-cost GC selective detector analyses. Appropriate trace analysis methods need to be developed for the herbicide acids, the dinitro-aniline herbicides and moderately polar insecticides/fungicides, and glyphosate in house dust, entry-way soil, and dislodgeable residues. These methods need to address cleanup of co- extracted humic acids, fatty acids, lipids, and other neutral co-extracted organics. Target detection limits of 10-100 ppb in dust and soil are anticipated for studies of the migration of lawn-applied pesticides. Extraction methods developed for dust and soil need to be compatible with the PUF polymeric structure, so that only a simple scaling factor is needed to adapt dust methods to PUF-collected surface- dislodgeables. Proposed analysis meth- ods for dust and soil are detailed in this report. The literature survey of herbicide acid soil metabolites indicated that major me- tabolites are either acidic or phenolic spe- cies. For the chlorophenoxy herbicide ac- ids (2,4-D, mecoprop, and MCPA) the dominant metabolite is the phenol that results after cleavage of the alkanoic side chain (e.g. 2,4-dichlorophenol from 2,4- D). Because of the similarity in polarity between herbicide and metabolite, both species may be analyzed using a single method. This approach is routinely used in studies of glyphosate, where both par- ent and its metabolite, aminomethyl- phosphonic acid, are monitored. Recommendations We recommend that the analysis meth- ods proposed in this report be evaluated for application to the respective pesticide classes with regard to recovery, precision, and accuracy in the three matrices of in- terest. The analysis methods should be evaluated for detection and quantification at trace (10-100 ppb) levels in house dust, high clay content entry-way soil, and PUF- collected surface dislodgeables. This report was submitted in partial ful- fillment of Contract No. 68-DO-007 by Battelle Columbus Operations under spon- sorship of the U.S. Environmental Protec- tion Agency. ------- Marcia Nishioka, Marielle Brinkman, and Hazel Burkholder are with Battelle, Columbus, OH 43201 Robert G. Lewis is the EPA Project Officer (see below). The complete report, entitled "Evaluation and Selection of Analytical Methods for Lawn-Applied Pesticides," (Order No. PB96-199559; Cost: $25.00, subject to change) will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: National Exposure Research Laboratory U. S. Environmental Protection Agency Research Triangle Park, NC 27711 United States Environmental Protection Agency National Risk Management Research (G-72) Cincinnati, OH 45268 Official Business Penalty for Private Use $300 BULK RATE POSTAGE & FEES PAID EPA PERMIT No. G-35 EPA/600/SR-96/098 ------- |