Luigi Di Lorenzo

Significance of urinary arsenic speciation in assessment of seafood ingestion as the main source of organic and inorganic arsenic in a population resident near a coastal area

In order to characterize the different sources of exposure to arsenic (As), urinary excretion of total As, the sum of inorganic As+MMA+DMA determined by the hydride generation-atomic absorption spectrophotometry technique, and the species As3, As5, monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and arsenobetaine were determined in 49 workers at a steel foundry, with presumed occupational exposure to As, and 50 subjects from the general population, all males. No evidence of occupational exposure to As resulted from environmental monitoring performed in the foundry, although the analysis of minerals used as raw materials showed the presence of As, particularly in fossils and fine ores. The urinary concentrations of As3, MMA, DMA, the sum of inorganic As+MMA+DMA and total As were not different in the two groups, while arsenobetaine appeared significantly higher in the controls than in the workers. The different species of urinary As were all significantly correlated. Urinary excretion of As3 was associated with the consumption of mineral water and with residence in an industrial zone, while MMA, DMA, arsenobetaine, the sum of inorganic As+MMA+DMA and total As urinary excretion were associated with the consumption of crustaceans and/or shellfish 3 days or less before urine collection. Multiple regression analysis confirmed these results. In conclusion, in populations with a high consumption of seafood, living in areas characterized by coastal/marine As pollution, only speciation of As can identify a prevalent role of environmental sources, like the consumption of seafood contaminated by As, in determining urinary As excretion, and exclude an occupational origin of the exposure.

Acute radiodermatitis from accidental overexposure to X-rays

Approximately 2 weeks after accidental overexposure to X-ray radiation, a worker developed acute radiodermatitis on fingers of both hands. Exposure simulation indicated that total ionizing radiation absorbed by his fingers amounted to about 20 Gy. After 2 years, acute radiodermatitis evolved to chronicity of lesions with presence of atrophic skin, teleangiectasia, alopecia, and dyskeratosis on three right-hand fingers. Cytogenetic dosimetry of peripheral blood lymphocytes, performed 2 months after acute radiation, showed an increase of micronuclei (7% vs. 1 +/- 0.4% according to laboratory reference data). The increase was ascribed to the high dose of ionizing radiation absorbed by circulating lymphocytes in the vessels of overexposed tissues. The cytogenetic examination was repeated 27 months after acute irradiation; it was found that the percentage of micronuclei had been restored to within reference levels. The possibility of using cytogenetic dosimetry, following acute partial exposure to X-rays, not just as an indicator of previous exposure, but also as an indicator of the absorbed radiation dose is examined. Lastly, the possible stochastic effects that may set in on the skin of the affected fingers and the need for periodically monitoring the evolution of chronic skin lesions, are discussed.