Hair lead concentration in the Lebanese population: phase 1 results.

Phase 1 of this cross-sectional study aimed to compare hair lead concentrations and establish the determinants of hair lead levels in 149 occupationally exposed individuals versus 177 non-occupationally exposed controls in the Lebanese population. In addition to a standardized questionnaire, lead concentration was measured by atomic spectrophotometry. A 5-6-fold difference in hair lead concentration was found between occupationally exposed and non-exposed individuals (23.60 ppm versus 4.33 ppm). Professional exposure, particularly working in petrol refining and gasoline stations, had the highest correlation with lead exposure. In non-exposed individuals, male sex, non-Lebanese nationality and urban worksite correlated with higher hair lead concentration.

Hair lead concentration in the Lebanese population: phase 1 results

Phase 1 of this cross-sectional study aimed to compare hair lead concentrations and establish the determinants of hair lead levels in 149 occupationally exposed individuals versus 177 non-occupationally exposed controls in the Lebanese population. In addition to a standardized questionnaire, lead concentration was measured by atomic spectrophotometry. A 5-6-fold difference in hair lead concentration was found between occupationally exposed and non-exposed individuals [23.60 ppm versus 4.33 ppm]. Professional exposure, particularly working in petrol refining and gasoline stations, had the highest correlation with lead exposure. In non-exposed individuals, male sex, non-Lebanese nationality and urban worksite correlated with higher hair lead concentration

Behavior of triadimefon in two Lebanese soils.

The retention and fate of triadimefon fungicide were studied under two environmental conditions. Field studies were conducted on two soils, a sandy loam soil (Fanar) and a clay soil (Raouda). Fanar is a wet coastal area while Raouda is a dry agricultural area of the Bekaa plain located at an elevation of 870 m above sea level. Triadimefon was applied with a jet sprayer at 267 g a.i.ha(-1) and 200 g a.i.ha(-1) at Fanar and Raouda, respectively. Reconstituted soil columns (600 x 30 mm) glasses, were used to study the fungicide movement and metabolism in the two soils. Analyses of triadimefon and its metabolites were carried out using gas chromatography (GC) and high performance liquid chromatography (HPLC). The results indicated a weak reversibility of the adsorbed fraction in the clay soil. Clay is considered an important factor in triadimefon adsorption. Triadimefon mobility in the sandy-loam soil was relatively high in comparison with behavior in the clay soil where about half of the applied fungicide was detected in the upper 25 cm of soil, six days after treatment. Rapid degradation of triadimefon to triadimenol was observed in the two soils. The observed half-life was 8 days in sandy-loam and 13 days in clay soils.

Improved method for determination of polynuclear aromatic hydrocarbons in pharmacopoeial paraffin and mineral oils.

An improved method has been developed for quantitative determination of polynuclear aromatic hydrocarbons (PAHs) in pharmacopoeial paraffin and medicinal white oil samples. This new method combines 2 liquid-liquid partition and adsorption chromatography procedures with a 2-step purification on Sephadex LH 20 and liquid chromatography with fluorometric determination. Selective elution of PAHs results in absence of background fluorescence. The minimum detectable level ranges from 0.2 ppt for benzofluoranthene isomers to 200 ppt for acenaphthene. Recoveries of PAHs added at 7 ppm varied from 92.1 to 111.4%. When a variety of medicinal white oil samples were analyzed by this improved method, 27 PAHs were identified, including 11 suspected carcinogens. Their identities were confirmed by capillary gas chromatography.

Capillary gas chromatographic determination with electron capture detector of beta-propiolactone in biological materials.

A method has been developed for the determination of beta-propiolactone by derivatizing it to the volatile N-hexyl-3-heptafluorobutanoyloxypropanamide, which can be separated and identified by a capillary CP-Sil 8 column, and detected by an electron capture detector (ECD). First, beta-propiolactone is reacted with N-hexylamine to yield N-hexyl-3-hydroxypropanamide. The fluorobutanoyl ester derivative is next prepared by using heptafluorobutyric acid anhydride in the presence of trimethylamine. The method is very sensitive, simple, and specific, and can be used to detect and quantitate residual beta-propiolactone in lyophilized biological materials. The limit of detection is 0.2 ppm beta-propiolactone in a 50 mg sample; however, because of variability at low levels, the limit of quantitation is 1 ppm. Detector response was linear for 2-500 mg beta-propiolactone. Recoveries were 98% or greater from lyophilized vaccines spiked at the 2-20 ppm level. No side products or interference peaks were observed in the derivatization reaction.

High performance liquid chromatographic determination of clocapramine in feed and plasma.

A high performance liquid chromatographic method is described for the determination of clocapramine in animal feed and plasma. Samples are made alkaline and then extracted with chloroform containing opipramol as internal standard. For plasma samples, the organic phase is evaporated to dryness under a stream of nitrogen, and the residue is dissolved in dichloromethane-methanol. Extracts are chromatographed on silica gel with dichloromethane-methanol-ammonia (100 + 10 + 0.25) as eluant, and quantitated using an internal standard. Within-day precision for plasma extracts (n = 15) was 3.39, 5.7, and 4.13% at 5, 10, and 15 mg clocapramine/L plasma, respectively, and day-to-day precision was 4.6, 6.8, and 4.4% at the same levels. The detection limit was 0,5 mg/L. Recovery from feed over the concentration range 2-6 g/kg was greater than 96%.