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(22-16) CITYFISH: Effects on chub (Leuciscus cephalus) of chronic exposure to sub-lethal levels of complex pollutant mixtures in an urban river in Italy. McKenzie, D.2, Agradi, E.3, Rocco, R.1, Stopelli, B.1, Regondi, S.3, Taylor, E.2, Ceradini, S.*,1, 2 School of Biosciences, Birmingham, United Kingdom.3 Institute of Pharmacological Sciences, Milano, Italy.1 CESI, Segrate (MI), Italy. ABSTRACT- The CITYFISH project aims to establish links between the chemical and ecological quality of urban rivers and the population biology, biochemical and physiological status of resident fish species. Two sites on the River Lambro (Lombardy, Italy) were identified which were similar in their hydrological characteristics but which differed in chemical and ecological quality. Levels of bioavailable polyaromatic hydrocarbons and heavy metals, measured by passive samplers, were higher at an urban site (Brugherio) than at an upstream site (Merone). Brugherio had a lower extended biotic index and reduced diversity of fish species relative to Merone. Wild chub (mass approx. 150g) were collected at Merone and exposed in wire cages to the prevailing water conditions at each site for 3 weeks, in May and September 2001. Their exercise performance was then assessed, as an indicator of their physiological status. In both June and September, chub at Brugherio exhibited impaired swimming performance, their capacity to repeat a swim test was significantly less than that of fish at Merone. Performance of fish at Merone was similar to that of laboratory-acclimated chub maintained for 3 weeks in clean biofiltered water. Impaired performance of fish from Brugherio was a consequence of reduced aerobic scope and ability to allocate energy to power exercise. Tissues of the fish caged at each site were analysed for the expression of biochemical and molecular biomarkers of pollutant exposure. In September 2001, liver EROD activity and metallothionein levels were significantly higher at the Brugherio site. An absence of such differences in June may have been because the animals were in their breeding season. The results indicate that links can be drawn between the chemical quality of a water body and the species richness, physiological status, and ecotoxicological biomarker expression, of its resident fish populations. Key words: leuciscus cephalus, chemical pollution, swimming performance, biomarkers |
