title: Cytogenetic index and functional genome alterations in Chironomus piger Strenzke (Diptera, Chironomidae) in the assessment of sediment pollution: a case study of Bulgarian and UK rivers.
abstract: The genotoxicity of trace metals in the sediments from a number of polluted sites on UK and Bulgarian rivers to Chironomus piger was assessed by an examination of genome instability as demonstrated by structural and functional changes to the salivary glands chromosomes. Based on the metal assays, the sediments were characterized to range from 'extremely' to 'strongly contaminated'. The cytogenetic index calculated on the basis of somatic structural chromosome alterations in the polytene chromosomes indicates a high level of pollution (0.07-0.06 in Bulgarian and 0.10-0.13 in UK stations). Exposure of C. piger to contaminated sediments resulted in a high level of chromosome damage as indicated by a somatic index of between 1.96 and 4.0. The transcription mechanism of the Balbiani rings and nucleolar organizer was damaged as their activity was either partially or completely suppressed. We have demonstrated that the C. piger genome is a sensitive sublethal indicator of sediment contamination, and is a highly suitable candidate for ecotoxicological monitoring of running waters.
authors.affiliation: Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, boulv. Tzar Osvoboditel 1, Sofia 1000, Bulgaria. Electronic address: michailova@zoology.bas.bg.
authors.forename: P
authors.initials: P
authors.lastname: Michailova
authors.affiliation: Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, boulv. Tzar Osvoboditel 1, Sofia 1000, Bulgaria.
authors.forename: J
authors.initials: J
authors.lastname: Ilkova
authors.affiliation: Department of Geography, The University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: A P
authors.initials: AP
authors.lastname: Dean
authors.affiliation: Faculty of Life Sciences, University of Manchester, Oxford Road, M13 9PT Manchester, UK.
authors.forename: K N
authors.initials: KN
authors.lastname: White
mesh_terms: D000818:Animals; D002031:Bulgaria; D002683:Chironomidae / Q000187:drug effects / Q000235:genetics*; D002869:Chromosome Aberrations / Q000139:chemically induced; D020732:Cytogenetic Analysis; D004784:Environmental Monitoring / Q000379:methods*; D004787:Environmental Pollution / Q000032:analysis*; D049750:Genome, Insect; D019015:Geologic Sediments / Q000032:analysis*; D007814:Larva / Q000235:genetics; D019216:Metals, Heavy / Q000633:toxicity; D045483:Rivers / Q000737:chemistry*; D012469:Salivary Glands / Q000187:drug effects / Q000473:pathology; D006113:United Kingdom; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical
keywords: Chironomus piger; Monitoring of running waters; Pollution; Polytene chromosome alterations; Trace metals