Enzyme-linked immunosorbent assays (ELISAs) are reported for the detection of atrazine and its principle metabolite in human urine. The ELISAs can be used with crude urine or following extraction and partial purification by methods described in this report. GC, MS, and HPLC techniques were used to confirm and complement the ELISA methods for qualitative and quantitative detection of urinary metabolites. A series of samples from workers applying this herbicide confirmed a mercapturic acid conjugate of atrazine as a major urinary metabolite. The mercapturate was found in concentrations at least 10 times that of any of the N-dealkylated products or the parent compound. Atrazine mercapturic acid was isolated from urine using affinity extraction based upon a polyclonal antibody for hydroxy-s-triazines and yielded products sufficiently pure for structure confirmation by MS/MS. In a pilot study monitoring applicators, a relationship between cumulative dermal and inhalation exposure and total amount of atrazine equivalents excreted over a 10-day period was observed. On the basis of these data, we propose that an ELISA for the mercapturate of atrazine could be developed as a useful marker of exposure.
ABSTRACT. Fogger application of pesticide in greenhouses canHand spraying with high-pressure, high-volume systems is the most common technique of pesticide application in greenhouse culture. However, fog or aerosol applications are feasible and often-used alternatives for enclosed structures. The motivations for fog application are the potential to increase spray deposition; improve pest control efficacy; and reduce application times, rates of active ingredients, and applicator exposure. A common fogging procedure in greenhouse operations is to apply the fog in late afternoon or early evening. This practice allows cultural workers to be absent from the greenhouse during and up to 12 to 16 h after application. Also, greenhouse vents may remain closed after application since nighttime temperatures are lower. Moreover, many applications are made by positioning the fogger within the greenhouse and allowing it to run unattended until the application is complete; the applicator can remain outside the structure during application. Anecdotally, fogging is often considered a hazardous application technique since the pesticide droplets are smaller and more concentrated than in conventional "wet" spraying techniques. Such reasoning may be valid; the potential inhalation hazard may exist. Practically, the potential hazard could be mitigated through establishment of appropriate re-entry intervals and use of respiratory protection with appropriate performance criteria for workers re-entering the structure.
LITERATURE REVIEWA comprehensive study (Brouwer et al., 1992) reviewed previous work (e.g., Lindquist et al., 1987) concerning airborne concentration of pesticide following low-volume and fog application in greenhouses. Brouwer observed that the number and scope of previous studies were limited and a lack of information on greenhouse environmental conditions and droplet size spectra from application equipment made comparisons between studies invalid. Brouwer experimentally determined airborne pesticide concentrations up to 10 h post-application. Volatile insecticide (dichlorvos, v.p. = 1600 mPa) and nonvolatile fungicide (thiophanate-methyl, v.p. < 0.001 mPa) were applied using a mist (nonthermal) blower with a droplet size volume median diameter of 21 µm. The decrease in airborne concentration was described by a log-linear (i.e., an exponential decay) function. Concentration of the dichlorvos decreased by 90% during the first 3 h postapplication; the greenhouse was then vented and no further data recorded. Concentration of the thiophanate-methyl decreased by 99% in the 3-h post-application.Exploratory studies of airborne pesticide concentration in greenhouses have been conducted in California by the Worker Health and Safety Branch, California Department of Pesticide Regulation (formerly California Department of Food-and Agriculture), California Environmental Protection Agency. Rech and Edmiston (1988) monitored concentration of permethrin following thermal fog application of 0.24 kg a.i./ha. Air concentrations measured 1, ...
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