Evaluate Biodegradeation To Organic Compound By Compound-CO₂ In Sealed Vessels Test

Chemical pesticide is mainly organism exogenous material which is synthesized by human beings. Many pesticides themselves are not only poisonous to the mankind and other creature but also very difficult to degrade. It caused serious negative influence when the pesticide is used excessively in the agricultural production. Microbial degradation is not only one of the most important transformation mechanisms for organic chemicals, but also a key process for the chemical recycling in the environment. Hence, biodegradation rates play an important role in estimation of the environment fate and hazard of chemicals.According to the Organization for Economic Co-operation and Development guideline for the testing of chemicals No. 310 CO2 in Sealed Vessels which was protrusived in March 2006,International Standard ISO 14593 (adopted March 1999) and the US Environmental Protection Agency (EPA), Office of Prevention, Pesticides and Toxic Substances, (OPPTS) Method 835.3120, we established the method No 310 CO2 in Sealed Vessels and studied the main factors in detail which had influence to this method, also studied the activeness of active sludge determination method. In this text, we evaluated the toxicity,the ready biodegradability of Flumorph and acetochlor, 3,5-dichlorophenol,sodium benzoate and aniline being the used reference compounds.The results of the research showed that it was feasible to evaluate the ready biodegradability using CO2 in Sealed Vessels Test established in this lab. In this text, we use sodium benzoate as the reference compound, sodium benzoate had been biodegraded by 62.09% by day 4, it proved the test was feasible and activeness of active sludge satisfiesd the experimental request. Another reference compound, aniline had been biodegraded by 63.46% by day 7,it also conformed to the OECD experiment criterion requirement. As a result, we could consider both sodium benzoate and the aniline as the reference compound. we evaluated the ready biodegradability of Flumorph and acetochlor, they are not considered readily biodegradable. We got three conclusions through studying the three factors influence to this method.1. the degeneration rate of sludge sodium benzoate and the aniline are obviously different because the three inoculums -surface water,soil leachate and active are different in the number of inoculum and the kind. The activity of active sludge exceeds the soil leachate , the surface water is the worst. 2. when the concentration of inoculum exceeded 40mg/L, sodium benzoate had been biodegraded less than 60% by day 14. the result doesn't conformed to the OECD experiment criterion requirement about reference compound. 3. when the concentration of sodium benzoate was 5-40mgC/L, it's degeneration had been exceeded 60% after 14 d, the group 20mgC/L was the best in degeneration, it was85.35%, the degeneration rate of group 100mgC/L and 200mgC/L had been biodegraded less than 60% by day 14. We evaluated the toxicity of Flumorph and acetochlor to active sludge using Activated Sludge Respiration Inhibition Test, both of theirs EC50 exceeded 300mg/L. It showed that they had no toxicity to active sludge. In the study of the activeness of active sludge, we learned the activeness of active sludge was descending when the time of acclimatization was longer.