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Biological monitoring was carried out by assaying urinary dimethylated alkylphosphates [dimethyldithiophosphate (DMDTP), dimethylthio-phosphate (DMTP), and dimethylphosphate (DMP)] in 11 workers exposed to chlorpyrifos-methyl and azinphosmethyl during operations in a previously sprayed peach orchard. The subjects were divided into groups on the basis of the protective clothing worn. The results were compared with those of a reference group of 99 subjects not occupationally exposed to organophosphorus insecticides. The hand-wash liquid of the workers was also analyzed to evaluate skin contamination. Significantly higher levels of urinary excretion of alkylphosphates were found in all groups than in unexposed controls (Student's t test). A good correlation was found between quantities of the active ingredients on the hands and urinary excretion of total dimethylated alkylphosphates (r = 0.788) and of DMTP (r = 0.749) and DMP (r = 0.790) alone. The correlation between azinphos-methyl on the hands and urinary excretion of DMDTP was poor (r = 0.069). Under the working conditions investigated, the main route of absorption seems to be via the skin. Respiratory absorption, however, also appears significant in view of the difference in urinary excretion of dimethylated alkylphosphates found between subjects with and without face masks.

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The results of biological monitoring by assay of urinary 3,5,6-trichloro-2-pyridinol and alkylphosphates (DMP, DMTP) in groups of 9 and 2 workers exposed to chlorpyrifos-methyl during vine spraying and manual leaf thinning 5-11 d after spraying, respectively, are reported. The results are compared with those of a control group of 46 subjects not occupationally exposed to organophosphate insecticides. Significantly higher urinary excretion of metabolites (Mann-Whitney U-test) was found in both groups than in controls. Levels of 3,5,6-trichloro-2-pyridinol (mean +/- SD) were 15.9 + 10.6 nmol/g creatinine (n = 33) for controls, 92.4 + 162.5 nmol/g creatinine (n = 20) for manual workers, and 675.5 + 1110.8 nmol/g creatinine (n = 48) for workers spraying and mixing the insecticide. Levels of DMP (mean +/- SD) were 63.8 + 100.1 nmol/g creatinine (n = 42), 123.0 + 79.0 nmol/g creatinine (n = 20), and 577.2 + 1003.2 nmol/g creatinine (n = 61), respectively, for the same 3 groups. Levels of DMTP (mean +/- SD) were 153.4 + 164.4 nmol/g creatinine (n = 43), 489.3 + 288.3 nmol/g creatinine (n = 20), and 297.6 + 215.4 nmol/g creatinine (n = 61), respectively, for the same 3 groups. Good correlations were found between urinary excretion of 3,5,6-trichloro-2-pyridinol and DMP (r = .776 for manual workers; r = .775 for workers mixing and spraying the insecticide) or DMTP (r = .558 and r = .746, respectively for the same 2 groups). The peak of excretion of the three metabolites was found in urine samples collected the night after the spraying or leaf thinning operations.

Cases of polyneuropathy due to exposure to industrial solvents have been studied at several shoe factories in the province of Siena. After the screening of 654 employees 98 verified cases were detected. Of these, 16 were rated as moderate to severe, 45 as mild, and 37 were minimally involved but with characteristic electrodiagnostic abnormalities. Follow-up study in 53 patients showed that neurological signs and symptoms as well as electrodiagnostic abnormalities continued for years in several patients. In addition, after a year's observation, some patients showed signs of central nervous system dysfunction such as spasticity of the lower limbs and increased deep tendon reflexes. High percentages of commercial n-hexane were found in all the samples of glues and solvents collected from home-workers and from factories where cases of polyneuropathy occurred.