Polycyclic aromatic hydrocarbons mainly originate from the incomplete combustion of fossil fuels such as petroleum, natural gas and coal. Also, biomass burning has attracted much attention due to its mutagenic, allergenic and carcinogenic properties. Anthracene, a three-ringed polycyclic aromatic hydrocarbon, is widely known as a common hazardous ubiquitous environmental pollutant. Anthracene is used to make dyes, plastics and pesticides. The present study aims to evaluate the risks of Anthracene to fish using a micronucleus (MN) assay; the test has been used successfully as a mutagenic assay. Ninety fishes were adapted and acclimated to the laboratory conditions for one week before starting the experiment, then were exposed to (7.5mg/L, 10mg/L, and 12.5mg/L) of Anthracene for 72 hours. Results demonstrated that the LD50 of Anthracene in fish was (10 mg/L). Based on the values of LC50, the fish were then exposed for 72 h to three concentrations of sub-lethal Anthracene (2.5 mg/L, 5 mg/L and 7.5 mg/L) and control (0.00 mg/L) after (72 hours, 10 days, 20 days). Peripheral blood samples smears were collected from each group, the sample was stained by Giemsa stain, and frequencies of MNs were counted. The study showed an increase in micronuclei with concentration and period. In conclusion, it can use of the micronucleus assay in erythrocytes of fish as a sensible index for the assessment and evaluation of aquatic environmental pollution Keywords: PAH; Anthracene; Micro nucleus assay; Carp.

The Microorganisms: yeast Sporobolomyces yunnanensis, Rhodotorula mucilaginosa and Kluyveromyces marxianusin growth of 184× 106 ± 15 cell\ml, and bacteria Pseudomonas aeruginosa and Bacillus cereus in the growth of 9 – 15× 108 ± 5 cell\ml, and algae Chlorella vulgaris in the growth of 45 × 105 ± 5 cell\ ml were selected as a bio filter to reduce organic and nonorganic pollutants from wastewater by COD, TOC, TN and TP concentrations of 455, 151, 9.5 and 31 ppm in treatment period 4, 6 and 18 hr. and pH of 7-8 in 25 Co as a Batch culture system. The yeasts showed ability to reduce COD concentration by 50-64% in 18 hr. treatment period, and the bacteria showed the ability to reduce COD, TOC, TN and TP concentrations by 59-69%, 57-66%, 53-63% and 40-55% in 18 hr. treatment period. At the same time, algae showed efficiency in reducing TN and TP by 81, 82%. The selective microorganisms showed high efficiency as a biofilter to reduce pollutants concentrations from wastewater in three serial steps by a treatment period of 6 hr in each step with a high ability to reduce COD, TOC, TN , and TP concentrations by 83, 91, 100, and 100% in 18 hr. treatment period. Ultimately, this study demonstrated the high efficiency of the multiple biofilters consisting of bacteria, yeasts, and algae in reducing the concentration of pollutants in sewage wastewater. Keyword. Multiple biofilters, Bacteria, Yeast, Algae, COD, TOC, TN.