Bioconcentration And Elimination Of Nitrobenzene By Aquatic Organisms(Algaes,Limnodilus Sp.,Crucian Carps)

Nitrobenzene(NB) is one of the dangerous chemicals in the world. Which has been reported to be mutagenic, teratogenic and carcinogenic, and is regarded as priority pollutants by Environmental Protection Agency of USA.In the paper, the law of bioconcentration and elimination of nitrobenzene by aquatic organisms (algaes,limnodilus sp.,crucian carps) is studied and to offer scientific information for effects of ecology and environment, including ecological risk assessment. The results are as follows:1.Through enriched culture in the culture condition of inorganic salt, the natural algaes in the Songhua River are done in the test. The concentration of NB added to the medium is 0.28mg/L. The results are as follows: both the rate of enrichment and release by algaes are rapid, after half hour reach the maximal enrichment (0.23mg/g dw), six hours behind reached the enrichment balance and the balance concentration is 0.12-0.15mg/g (dw); when the stabled balance reached, the biological enrichment index is 505.7; in fresh culture medium, it will takes one hour to reach the great release quality, the percentage is 25%.2.Nitrobenzene's enrichment and release in bodies of limnodilus sp. also be researched in this experiment when the concentration is 0.28mg/L and 0.0093mg/L. The result indicates that Nitrobenzene of different concentration released very rapidly and the curves are same approximately. In the concentration of 0.28mg/L, it takes one hour to reach the peak value (0.639mg/kg ww) of enrichment, the high concentration can keep stabilize for five hours, the BCF is 2.3, after six hours begin decline. In the concentration of 0.0093mg/L. Nitrobenzene's concentration in bodies of limnodilus sp. reaches upper level in two hours and keep stabilize, the BCF is 4.5, then the concentration begin decline. When transferred to fresh water, the release percentage exceeds 85% and needs 8 hours to release completely.3.Under the two concentration 0.586mg/L and 0.014mg/L, we researched enrichment and release of Nitrobenzene in bodies of crucian carps.. The result indicates that the enrichment rate is quite rapid, it takes six hours to reach the peak value when the concentration is 0.586mg/L and twenty-four hours when the concentration is 0.014mg/L. When the enrichment curve of high concentration team (0.586mg/L) reaches the stabilization, the BCF of each part in crucian carps.( branchia, bowels, muscle) is 7.34,3.87 and 2.57 respectively. But the enrichment curve of low concentration team (0.014mg/L) shows obvious apex shape, the BCF of each part in crucian carps.( branchia, bowels, muscle) is 10.43, 7.61, 5.82. The release rate is rapid in bodies of crucian carps. The percentage can reach 94% within 48 hours. The release accord with the first order kinetics reaction equation: + b. The enrichment ability have difference in a certain extent in different apparatus of crucian carps, branchia >bowels >muscle. So we can conclude that there is biotransformation during the process of biologic enrichment. i.e. there is enzyme catalysis reaction during the enrichment process.Simultaneously crucians were exposed to the same concentration (0.28±0.02 mg/L) the NB concentration in its bowels and muscle has no distinct difference without reference to feed the bait or not. But bait can influence the balance time and the metabolism rate.