POSSIBLE RELEVANCE OF PIGEONS AS AN INDICATOR SPECIES FOR MONITORING AIR-POLLUTION

Wild city pigeons were caught at four different locations in the Nethe rlands to represent areas of high (Amsterdam-high), moderate (Amsterda m-medium), and low (Maastricht and Assen) traffic density. It is assum ed that local ambient air pollution decreases as a function of traffic density. In these pigeons levels of polycyclic aromatic hydrocarbon ( PAH)-DNA adducts, oxidative DNA damage, and heavy metal residues were determined in kidney, lung, liver, and blood (no adduct analysis in bl ood). The contribution of leaded gasoline to total body lead content w as estimated by measuring concentrations of Pb and its isotopes in blo od. We also analyzed samples of ambient air particulate matter for PAH and heavy metal concentrations at the four different locations. Inter regional differences in heavy metals in ambient air particulate matter were reflected relatively well by pigeon body loads. The highest lead and cadmium concentrations in blood, kidney, liver, and lung were fou nd in the Amsterdam high traffic density area, followed by Amsterdam-m edium, Assen, and Maastricht. A high Pb concentration in blood coincid ed with relatively low Pb-246/Pb-207 values, indicating a high contrib ution of leaded gasoline to total blood Pb concentrations in pigeons f rom the Amsterdam high traffic density area. Significantly enhanced bl ood zinc values were found in pigeons from both locations in Amsterdam compared to pigeons from the other two areas. However, no differences in Zn tissue levels between the four different groups were found. Oxi dative DNA damage, determined as the ratio of 7-Hydro-8-oxo-2'-deoxygu anosine/deoxyguanosine, in pigeon liver was highest in Amsterdam-high, followed by Assen (low traffic density). Pb content, but not the Cd c ontent, was positively associated with oxidative DNA damage in liver t issue. In lung tissue, a negative correlation was found between oxidat ive DNA damage and Zn content. These results indicate that the carcino genic potential of Pb might be ascribed to oxygen radical formation, w hereas Zn plays a protective role against oxidative DNA damage. Places with high and medium traffic density could be clearly discriminated o n the basis of PAH levels in the ambient air. The PAH content in parti culate air samples was nob however, reflected in total PAH-related DNA adduct levels because no differences could be observed in tissue addu ct levels in pigeons from the four different locations. Our results in dicate that wild city pigeons fan be used as biological indicators of exposure to heavy metal pollution in outdoor air.