The "Bosco delle Querce" park ecosystem: mutagenicity tests in wild animals

The aim of this study was to evaluate the present biological risk for human users of the Bosco delle Querce park. The park was artificially created in place of the highly polluted TCDD area following the Seveso accident. Taki ng into account that: (1) we had little knowledge of the TCDD bioavailabili ty in loco after 20 years; (2) other contaminants may have been present in the studied area; and (3) TCDD can induce a broad range of effects by mecha nisms not yet well defined; we set out to study the biological damage to an imal life and to plant and animal cenosis by comparison to those of other u rban parks. We investigated the species composition and evolution of animal and plant cenosis; mouse, rabbit and housefly gametogenetic processes; TCD D-induced damage at the single-cell level by means of highly sensitive tech nique like a single-cell gel electrophoresis (COMET assay) capable of detec ting DNA structural damage on mouse and rabbit sperm and lymphocytes. Here, we present preliminary data. The qualitative and quantitative cytological composition of the stages of the seminiferous epithelium bore no signs of a lteration (the percentage of normally set-up tubules, the pachytene spermat ocytes/spermatid ratio and the Sertoli-spermatogonia and Sertoli-basal memb rane attachments). The percentages of abnormally shaped and aneuploid sperm have not significantly changed in Seveso mice and rabbits. The COMET assay on mouse sperm did not reveal structural damage to DNA. A survey of the 2n numbers of several wild mouse populations living in Northern Italy showed that the Seveso mice carry Robertsonially translocated chromosomes not yet described. The number of micronucleated polychromatic erythrocytes (micronu clei assay) in mouse and rabbit bone marrow was similar to that in controls . The gross anatomy analysis of 13 rabbit foetuses yielded no signs of alte ration; in particular, cleft palate was not detected. The structure and the meiotic behaviour of the housefly chromosomes was not completely regular; housefly fertility, however, looked normal. Since the long-term exposure to very low TCDD doses (doses that failed to induce maternal toxicity) profou ndly altered the reproductive patterns, the preliminary data we acquired in spired confidence about the safety for humans now using the park.