Effect of Contaminants on the Genome of Some Species of Genus Chironomus (Chironomidae, Diptera) Live in Sediments of Dunajec River and Czorsztyn Reservoir

Abstract

The effect of contaminants on the genomes of Chironomus plumosus L. and Chironomus bernensis Wülker, Klötzli species was studied in the Dunajec River (station 1) and in the littoral of Czorsztyn Reservoir (stations 2 and 3). According to the index of geoaccumulation, the sediments were polluted by cadmium (Cd) and chromium (Cr). Cd concentrations at stations 1, 2, and 3 were 0.71, 0.56, and 1.27 μg g −1 , while Cr concentrations were 841.5, 186.9, and 40.7 μg g −1 , respectively. The pH of sediments ranged from 6.7 to 7.

Chironomids (Diptera) and their salivary gland chromosomes as indicators of trace-metal genotoxicity

“…The level of NOR activity decreased to the intermediate level in 43% of the cells. The centromere regions were in a heterozygous depressed state in 50% of the larvae collected from the two trace-metal-polluted Polish stations (Michailova et al 2009c), while this phenomenon was not observed in larvae from the Bulgarian station (Ilkova 2004). In the industrialand urban-waste-contaminated Finnish stations, no somatic aberrations were found (S index = 0).…”

“…The S indexes were 0.10 in the Bulgarian station (estimated from data in Ilkova 2004). The S indexes were 0.5 and 0.8 in the two Polish stations (estimated from data in Michailova et al 2009c). The levels of activity of BR 2 /BR 3 were analyzed only in the Bulgarian station, where in ∼80% of the cells both BRs significantly decreased their activity levels to levels of complete depression (Ilkova 2004).…”

“…At Santena, the somatic aberrations consisted in deficiencies only (S index = 0.07). A Waksmund there were various types of somatic aberrations (S index = 0.9, estimated from data in Michailova et al 2009c). A dark knob in heterozygous state was observed at the telomere of chromosome G in larvae from both stations (33.3% of the cells in larvae from Waksmund and 2.8% of cells in larvae from Santena).…”

“…Therefore we need to study this phenomenon better in order to understand which environmental factors bring it on. In one third of the already studied populations (Ilyinskaya 1995), accessory "B" chromosomes have been found in very variable numbers (Zhimulev 1998;Camacho et al 2000;Michailova & Mettinen 2000;Ilkova 2004;Michailova et al 2009c). It would be interesting to perform an analysis of the causes of the appearance and the variations in the numbers of B chromosomes in populations of this species.…”

“…A dark knob in heterozygous state was observed at the telomere of chromosome G in larvae from both stations (33.3% of the cells in larvae from Waksmund and 2.8% of cells in larvae from Santena). The difference in the genome reactions to the sediments at the two stations may be related to the differences in the concentrations of some trace metals in their sediments (Petrova & Michailova 2002;Michailova et al 2009c). NOR reactions were studied only in larvae from Santena.…”