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Purtse jõgi on olnud põlevkivitööstuse poolt mõjutatud juba eelmise sajandi keskpaigast alates ja aegade jooksul muutus jõgi „surnud“ jõeks. Alles 21. sajandi algusest on jõe olukord hakanud paranema. Töö üldiseks eesmärgiks oli uurida, kas jõe setted avaldavad toksilist mõju jões elavatele lõhilastele. Spetsiifiliseks eesmärgiks oli vaadata, kas reostunud ala kaladel on polütsükliliste aromaatsete süsivesinike (PAH) sisaldused kõrgemad kui reostamata alal ning uurida vererakkude näitajate abil, kas domineerivad genotoksilised või tsütotoksilised mõjud. Uurimisobjektideks olid lõhilased (Salmonidae), kelle sappides määrati PAH metaboliitide sisaldused fluorestsentsmeetodil, mikroplaadilugeja abil ning vere punaliblede kahjustused määrati mikroskoobi all. PAH metaboliitide tulemused olulist statistilist erinevust ei näidanud. Vererakkude erütrotsüütide kahjustustes ilmnes statistiline erinevus reostunud ning reostamata alade vahel. Reostunud kaladel oli vererakkude mikrotuumade esinemissagedus suurem kui reostamata alal (p-0,0307). Tööst selgub, et kalade vererakkude näitajad toovad reostunud ja reostamata alade vahelise erinevuse üsna selgelt välja ning sobiva tehnoloogia kasutamisel oleks setete eemaldamine Purtse jõest vajalik kalade ja inimeste tervise huvides. The Purtse River has been affected by the oil shale industry since the middle of the 20th Century. Over the years, the river became a „dead“ river. But since the beginning of the current Century, the situation has been improved. The general aim of this work was to investigate whether the river sediments have a toxic effect on salmonids. The specific obejective was to find out whether the fish from the polycyclic aromatic hydrocarbons (PAHs) polluted area of the river contained more PAH metabolites than the fish from an unpolluted area. Another specific goal was to examine through the blood cell abnormalities whether the cytotoxic effects or genotoxic effects on fish dominated. Concentrations of PAH metabolites in Salmonids biles were determined by fluorescent method using a microplate reader. The blood samples were taken and fixed and the red blood cell abnormalities were examined under a microscope. No statistically reliable difference in PAH metabolites between the fishes from the polluted and unpolluted area were found. Damages of blood cells showed a statistically significant difference between the contaminated and uncontaminated areas. The micronuclei test showed the difference with p-value of 0,0307 indicating that the number of blood cells with micronuclei in contaminated fish was much higher. The study reveals that the fish blood parameters are good biomarkers to show toxicity of sediments and, if there was a good technology, removal of the contaminated sediments would be beneficial for fish and humans. |
