Columba livia as a sentinel species for the assessment of urban air genotoxicity.

This study explored the comet assay as a possible tool to assess genotoxicity in erythrocytes of Columba livia to detect genotoxic effects induced by exposure to urban air pollution. Fieldwork was conducted between June 2004 and June 2005 in the city of Milan, Italy, by sampling pigeons in different areas almost twice a week. Six air contaminants-CO, PM10, NO(2), O(3) (ozone), SO(2), and C6H6-plus polycyclic aromatic hydrocarbons (PAHs) in fine particles, temperature, and ultraviolet index, were considered. Genotoxicity levels, expressed as %DNA migrated, tail moment, and damage index (DI), were always higher in wild pigeons than in pigeons living indoors (controls). Animals exposed to urban air showed significant differences from season to season, and the genotoxic parameters presented the highest values in summer (45.30% +/- 1.40% %DNA migrated, 12.73 +/- 0.80 tail moment, and 22.30 +/- 0.15 x DI x 10(-1)); regression analyses showed a positive relation between DI and O(3) concentrations (P < 0.001). The use of the comet assay DI parameter as a rapid assessment of incipient genotoxic risk by pollution, as measured in C. livia living in urban areas, is also discussed.

Influence of compost amendment on microbial community and ecotoxicity of hydrocarbon-contaminated soils.

The influence of a high quality compost amendment on two soils contaminated with diesel oil and polycyclic aromatic hydrocarbons, PAHs, respectively, was evaluated, with respect to contaminant biodegradation, microbial community composition and soil toxicity and genotoxicity. For each of the two soils, two 20-kg biopiles were set up, one without amendments and one compost-amended. GC/FID analyses revealed that compost was effective in enhancing biodegradation of diesel oil and of four-ring PAHs. It also influenced microbial community composition, as inferred by ARDRA analyses and partial sequencing of 16S rDNA of clones from libraries constructed from each soil sample. Microtox analyses on soil aqueous saline extracts and Solid Phase Tests showed some toxicity reduction due to compost addition, while the Comet assay, performed on coelomocytes of earthworms exposed to contaminated soils, did not show genotoxicity reduction. In general, the use of compost amendment to hydrocarbon-contaminated soils in a bioremediation process proved to be effective for depletion of contaminants and reduction of toxicity.

Porphyrin pattern and methemoglobin levels in Columba livia applied to assess toxicological risk by air pollution in urban areas.

The study has explored two conservative biomarkers, porphyrin pattern in guano and methemoglobin levels in blood of Columba livia, in order to assay their potential use for monitoring toxic effects induced by exposure to urban air pollution. Fieldwork was conducted between October 2003 and June 2005 in the city of Milan, Italy, by sampling the pigeons in different areas almost twice a week. Six air contaminants, CO, PM10, NO(2), O(3), SO(2), and C(6)H(6), plus polycyclic aromatic hydrocarbons (PAHs) in fine particles, temperature, and UV index, were considered. Protoporphyrins from pigeon excreta sampled outdoors were always higher than in indoor animals, particularly in winter. A positive correlation (p < 0.001) of protoporphyrin with PAHs was observed. In terms of the values of methemoglobinemia, animals exposed to urban air showed significant differences from season to season but only in summer and autumn did the outdoor pigeons show higher values than indoor animals. In summer, a regression model with a positive correlation between O(3) and benzene was determined (p < 0.01). The use of Columba livia as a sentinel for urban air pollution as well as for detecting complex interactions between contaminants in the urban air pollutant mixture was discussed.