Naslov
Assessment of genotoxic potency of sulfate-rich surface waters on medicinal leech and human leukocytes using different versions of the Comet assay

Autori
Mihaljević, Zlatko ; Ternjej, Ivančica ; Stanković, Igor ; Ivković, Marija ; Želježić, Davor ; Mladinić, Marin ; Kopjar, Nevenka

Izvornik
Ecotoxicology and environmental safety (0147-6513) 74 (2011), 5; 1416-1426

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Hirudo medicinalis; pollution; sulfate; gypsum; comet assay; genotoxicity

Sažetak
The aim of present study was to investigate how the exposure to sulfate-rich surface waters affects the levels of primary DNA damage in haemocytes of leech Hirudo medicinalis. Samples of surface water were collected at two sites near gypsum factory (Knin, Croatia) and two reference sites. In the laboratory they were subjected to detailed chemical analysis and used in the toxicity testing. For that purpose, previously acclimatized individuals of H. medicinalis were sub-chronically (for 28 days) exposed to tested water samples. The levels of primary DNA damage were evaluated using the alkaline Comet assay in haemocytes collected at 7th, 14th, 21st and 28th day of exposure and compared with their baseline values. Genotoxic potency of the water sample with the highest sulfate concentration was further evaluated using the alkaline, neutral and hOGG1 modified Comet assay on human peripheral blood leukocytes exposed ex vivo for 30 minutes. The purpose was to explore which mechanisms are responsible for the DNA damage. Chemical analysis revealed that sulfate concentrations in two water samples collected in Mali kukar Lake (1630 mg/L SO4) and in Kosovčica River (823.3 mg/L SO4) exceeded the WHO and US EPA defined limits for sulfate in drinking water. Increased levels of metals were found only in water sample collected in Mali kukar Lake. However, out of 65 elements analyzed, only nickel and titanium exceed the value legally accepted in Croatia for drinking water. The levels of DNA damage estimated by the alkaline Comet assay in the haemocytes of medicinal leech increased with the duration of exposure to two sulfate-rich water samples. Since haemocytes sensitively responded to treatment, they could be used for the biomonitoring purposes. As observed on treated human peripheral blood leukocytes, all versions of Comet assay were effective in the detection of DNA damage which was measured in samples with sulfate concentrations equal or higher to levels legally accepted for drinking water. Based on the obtained results, we assume that genotoxicity was a consequence both of direct (single- and double strand DNA breaks) and indirect effects (oxidative damage) caused by combined effects of all contaminants present in the water samples tested. Our results point out the need of an in situ monitoring and purification of gypsum mine water, prior to its release in the natural environment.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA