Objectives-An epidemiological study of 90 male pesticide applicators licensed in New York was conducted to investigate the effect of exposure to organophosphate pesticides on the peripheral nervous system.

Polychlorinated biphenyls are wide pollutants readily detected in environmental and human specimens. DNA adduction occurs through the corresponding quinones. Polychlorinated biphenyls are first metabolized to arene oxides, which can be further oxidized to dihydroxy metabolites by microsomal cytochrome p450s. The catechol and hydroquinone products are further oxidized by peroxidases to quinones, which are electrophilic and capable of reacting with DNA to form adducts. DNA adduction is initiated by Michael addition preferentially to guanosine followed by stabilization through enolization. Another nucleophilic attack forms a five-membered ring, which aromatizes by dehydration to form the final adduct. This report describes the characterization and quantitative study of DNA adducts formed from lower chlorinated PCB-derived quinones. Quantitative study by HPLC/ESI-MS/MS and (32)P-postlabeling-HPLC gave the adduct levels in the range of 3-1200 adducts per 10(8) nucleotides. These results demonstrate that increasing chlorine substitution is associated with lower yields of DNA adduct. Although (32)P-postlabeling is more sensitive than HPLC/ESI-MS/MS for the quantitative analysis of DNA adducts, modification levels were severely underestimated by the (32)P-postlabeling assay as compared to the HPLC/ESI-MS/MS assay.

Photodissociation of i-pentanal ((CH3)2CHCH2CHO; 3-methylbutanal) and t-pentanal ((CH3)3CCHO; 2,2-dimethylpropanal) in the 280−330 nm region was investigated at 5 nm intervals by using dye laser photolysis in combination with cavity ring-down spectroscopy. Absorption cross-sections of i-pentanal and t-pentanal were obtained. Both aldehydes exhibited a broad absorption band peaking at 295 nm, with maximum absorption cross-sections of (5.90 ± 0.22) × 10-20 and (4.26 ± 0.07) × 10-20 cm2, respectively, for i-pentanal and t-pentanal. The formation yield of the HCO radical from photolysis of i-pentanal and t-pentanal was determined by monitoring HCO absorption at 613.8 nm. Except for 325 and 330 nm photolysis of i-pentanal, the HCO yield was found to be independent of aldehyde pressure (2−12 Torr) and total pressure (20−400 Torr). For the photodissociation of t-pentanal, the HCO yield was also determined in the 0.5−2 Torr range and was found to increase with t-pentanal pressure. The variation of HCO radical yield with photolysis wavelength was determined. The peak HCO yields from t-pentanal and i-pentanal photolysis were 0.92 ± 0.11 and 0.40 ± 0.08 at 315 nm, respectively, where uncertainty reflects experimental scatter only. The difference in the peak HCO yield from t-pentanal and i-pentanal photolysis was attributed to the opening up of the Norrish II channel for i-pentanal. End products from closed-cell photolysis of i-pentanal and t-pentanal were investigated at 290, 310, and 330 nm by using HPLC. Acetaldehyde was found to be a product from the photodissociation of i-pentanal/N2 mixtures. Photolysis rates of i-pentanal and t-pentanal to form HCO were calculated for two representative atmospheric conditions (noontime at sea level and 40° N latitude on January 1 and on July 1) and were compared to those obtained from acetaldehyde photolysis.