Development and application of quantitative methods for monitoring dermal and inhalation exposure to propiconazole

Quantitative methods to measure dermal and inhalation exposure to the fungicide propiconazole were developed in the laboratory and applied in the occupational exposure setting for monitoring five farm workers' exposure during pesticide preparation and application to peach crops. Dermal exposure was measured with tape-strips applied to the skin, and the amount of propiconazole was normalized to keratin content in the tape-strip. Inhalation exposure was measured with an OVS tube placed in the worker's breathing-zone during pesticide handling. Samples were analyzed by GC-MS in EI+ mode (limit of detection 6 pg microl(-1)). Dermal exposure ranged from non-detectable to 32.1 +/- 22.6 ng per microg keratin while breathing-zone concentrations varied from 0.2 to 2.2 microg m(-3). A positive correlation was observed between breathing-zone concentrations and ambient air temperature (r2 = 0.87, p < 0.01). Breathing-zone concentrations did not correlate with dermal exposure levels (r2 = 0.11, p = 0.52). Propiconazole levels were below limit of detection when rubber gloves, coveralls, and full-face mask were used. The total-body propiconazole dose, determined for each worker by summing the estimated dermal dose and inhalation dose, ranged from 0.01 to 12 microg per kg body weight per day. Our results show that tape-stripping of the skin and the OVS can be effectively utilized to measure dermal and inhalation exposure to propiconazole, respectively, and that the dermal route of exposure contributed substantially more to the total dose than the inhalation route.

A comparative study of initiation and development of embryogenic callus from haploid embryos of several barley cultivars. II. Cytophotometry of embryos and callus

Cells of haploid barley embryos (Hordeum vulgare L. 'Bruce', 'Perth', and 'Klages') and callus cells originating from embryos were cytophotometrically examined to determine the ploidy level. Specific embryo tissues regularly exhibited predictable ploidies and smaller embryos had a higher percentage of haploid cells than larger embryos of the same age. The predominantly haploid cells of the scutellar epidermis of the embryo initiated callus which generally, at least initially, was haploid. Monitoring of the ploidy evolution of these haploid calli showed that over a 6-month period each line exhibited its own unique rate of polyploidization, although lines of the same cultivar showed similar trends. Accumulation of cells at the diploid level was often a characteristic of these cultures.