title: The use of bioassays for the risk assessment of toxic leachates: an experimental study.
abstract: Solid wastes from the oil-shale industry produce leachates containing toxic compounds such as heavy metals and persistent polycyclic aromatic hydrocarbons (PAH). The hazard to the environment represented by waste leachates depends not only on their chemical composition, but also on the mobility and bioavailability of toxic contaminants in soils. We evaluated the applicability of bioassays for toxicity assessment of the bioavailable fraction of heavy metals and PAH in soils, in experiments with samples of four different soil types (Rendzina, Brown pseudopodzolic, Typical brown, Sodpodzolic), the pH of which ranged from 6.2 to 7.2. The toxicity of the bioavailable fraction of the soil contaminants was assessed with the dehydrogenase enzyme activity assay, and with a Toxkit microbiotest with the crustacean, Thamnocephalus platyurus, after treatment of the soil samples with an artificial solution containing chromium (III), lead (II), copper (II), cadmium (II) and pyrene. The test results confirm those of earlier experiments, which characterised the sorption potential of investigated soils for the same compounds. Both tests turned out to be sufficiently sensitive, and hence can be recommended as effective and useful tools for the assessment of the bioavailable fraction of soil contaminants.
authors.affiliation: National Institute of Chemical Physics and Biophysics, Tallinn, Estonia. natalja@kbfi.ee
authors.forename: Natalya
authors.initials: N
authors.lastname: Irha
authors.forename: Irina
authors.initials: I
authors.lastname: Blinova
mesh_terms: D000818:Animals; D001681:Biological Assay; D001682:Biological Availability; D003445:Crustacea / Q000187:drug effects / Q000254:growth & development; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents / Q000378:metabolism; D007220:Industrial Waste / Q000009:adverse effects* / Q000032:analysis; D007928:Lethal Dose 50; D019216:Metals, Heavy / Q000633:toxicity; D010078:Oxazines / Q000378:metabolism; D010088:Oxidoreductases / Q000187:drug effects / Q000378:metabolism; D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity; D018570:Risk Assessment / Q000379:methods*; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity*; D023382:Toxicity Tests, Acute; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*; D014966:Xanthenes / Q000378:metabolism
chemical_list: D007202:Indicators and Reagents; D007220:Industrial Waste; D019216:Metals, Heavy; D010078:Oxazines; D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D014966:Xanthenes; C005843:resazurin; D010088:Oxidoreductases