Effects of Different Absorbing Medium on Microwave Remediation of Chlordane Contaminated Soil

Objective] This study almed to compare the effects of three absorbing medium on microwave degradation of chIordane in contaminated soiI under alkaline condition. [Method] SoiI sampIes were coI ected from the original site of a reIocated pesticide production enterprise as experimental materials, to investigate the effects of Cu2O, MnO2 and activated carbon powder as absorbing medium on soiI warming and removal rate of chIordane under alkaline condition with 20% moisture content. In addition, the effects of activated carbon as the optimal absorbing media on the removal rate of chIordane in contaminated soiI were analyzed, and the effects on the removal rate of chIordane in different weights of soiI sampIes were investigated. [Result] The effects of three different absorbing medium on the removal rates of chIordane demonstrated a descending order of activated carbon ＆gt; MnO2 ＆gt; CuO2. Under the same microwave condition, the removal rate of chIordane decreased with the increase of soiI weights, but the utiIization efficiency of microwave was improved continuousIy and tended to be stabiIized with the increase of soiI weights. [Conclu-sion] This study provided a theoretical basis for further Iarge-scale appIication in soiI remediation.

Enzymatic Degradation of Organochlorine Insecticide Chlordane by Phlebia brevispora

[ Objective ] This study aimed to clarify the mechanism of enzymatic degradation of organochlorine insecticide chlordane by the white rot fungus Pldebia brevispora. [ Method ] The degradation characteristics of chlordane were determined by the crude enzyme extracted from P. brevispora strain by pure culture, ultrasonic fragmentation and centrifuge separation. [ Result] About 33.2% and 10.4% of chlordane were degraded respectively by intracellular enzyme and extracellular enzyme within 20 min. At pH 5.0 and 3℃, the crude enzyme showed the greatest degradation activity （49.9%）, with its Michaelis-Mentn＇s constant （Km ） and maximum degradation rate （ Vmax ） of 3.49 and 8.38 ttmol/min, respectively. [ Conclusion] Extracellular enzyme can degrade chlordane through dehydrogenation or dehydrochlorination. Intracellular enzyme plays a major role in chlordane degradation. It can transform chlordane to some hydroxylated metabolites through hydroxylation or substitution of chlorine atom by hydroxyl group.

Impact of some chlorinated pesticides on the haematology of the fish Cyprinus carpio and Puntius ticto

The effects of pesticides on blood characteristics and histological changes in erythrocytes of the fish species Cyprinus carpio and Puntius ticto were studied. The fishes were exposed to sub lethal concentrations of different chlorinated pesticides namely aldrin, dieldrin, DDT, BHC and chlordane for 10, 20 and 30 d in continuous flow-through test. The LC 50 values were calculated based on acute toxicity tests and the sublethal doses were arrived at for chronic bioassay studies. Results showed an increase in haemoglobin content of both Cyprinus carpio and Puntius ticto in case of aldrin and dieldrin. Haemoglobin content reduced from an initial 13 g/100 ml to 8.07 and 10.15 g/100 ml in case of Cyprinus at the end of ten days exposure to aldrin and dieldrin respectively, and gradually increased to 8.7 g/100 ml and 10.15 g/100 ml after 20 d of exposure. The haemoglobin content after 30 d exposure to aldrin and dieldrin was 10.15 g/100 ml and 11.6 g/100 ml respectively. In case of Puntius ticto, the haemoglobin content in control fishes recorded was 12.8 g/100 ml while in case of fish exposed to aldrin, the haemoglobin content reduced initially on ten days exposure to 10.15 g/100 ml and increased to 11.6 g/100 ml and 13.0 g/100 ml during twenty days and thirty days exposure respectively. This trend was also observed with dieldrin in both the fishes studied. Red blood cells were also counted in case of all the pesticides and exposure periods with respect to Cyprinus carpio and Puntius ticto. Irrespective of the species and pesticide, the RBC counts uniformly showed decreasing trend with the increase in exposure period, while packed cell volume, PCV(%) showed increasing trend with respect to increase in exposure period in case of aldrin and dieldrin in both the fishes. But DDT, BHC and chlordane showed decreasing trend in PCV(%) values with increasing periods of exposure.