Pesticide-induced alterations of hemopoietic functions in Anabas testudineus inhabiting wetlands in agricultural landscape

The unrestricted use of agrochemicals in crop fields lowers the overall prospects of survival and yield of wetland fish species like Anabas testudineus. In the present study, the impact of different doses of SUMIDON-40, an organophosphate (OP) pesticide on the hematopoiesis of Anabas testudineus has been examined. The small lymphoid hemoblast and consequently the polychromatophilic erythroblasts decreased significantly at both sublethal and LC₅₀ dose-treated fish. The percentage of mature erythrocyte also fell significantly in the pesticide-treated groups. The erythropoietic efficiency was increased in fish exposed to sublethal dose but fell in fish exposed to LC50 dose. Among leucocytes, the percentage of neutrophils rose in Anabas testudineus in both treatment groups and percentage of macrophage decreased significantly only in LC₅₀ dose-treated group. The percentage of lymphocyte increased significantly in sublethal dose-treated groups. The overall leukopoietic efficiency, however, was elevated significantly in both treatment groups. These facts clearly indicated that pesticides affected the overall process of hematopoiesis in this fish species. Flow cytometric analysis of cell cycle in pronephric kidney cells confirmed changes in percentage of cell death and DNA synthesis following pesticide exposure. Data indicate that habitat deterioration from agrochemicals impedes the hematopoiesis in this species resulting in reduced tolerance in their usually hypoxic habitat environment.     

Hydroxyl radical generation by redox cycling of some chemotherapeutic antibiotics

The anticancer drugs: adriamycin, farmorubicin and mitomycin C greatly enhance the generation of hydroxyl radicals (HO^.) from H₂O₂ in the presence of Co(II) ions (CoCl2) at pH 7.4 and 8, as measured by the deoxyribose assay. Catalase, hydroxyl radical scavengers (mannitol, cysteine, glutathione, thiourea, lactic dehydrogenase) inhibited the degradation of deoxyribose confirming that HO‐radicals are responsible for the degradation of the carbohydrate.     

日本农村循环经济系统磷代谢分析——以北海道中札内村为例

在介绍日本农村循环经济模式特征的基础上,采用物质流分析方法,选取日本典型农村循环经济模式进行磷代谢分析。结果表明,大量的堆肥和直接还田改善了畜禽排泄物和农村生活对水体环境的影响,但对于减少种植业引起的磷排放未起到关键作用。建议在建设新农村的同时,有必要考虑农村生活-种植业-畜牧业一体化循环经济模式,扩大农村生活废弃物的再资源化量,以减少对系统外环境的污染。     

Nitrogen budget and its environmental loading in an urban ecosystem with the rapid urbanisation of China

A detailed nitrogen (N) budget has been developed for an urban ecosystem based on the method of material flow analysis. How increased human activity and urbanisation influences N cycling have also been analysed. Total N input and output in the urban ecosystem of Zhengzhou City (ZUE) was calculated at 304.8?Gg was 275.3?Gg year^?1, resulting in an N accumulation of 29.5?Gg year^?1. Industry and human life activities, which respectively accounted for 43.8% and 34.2% of total N inputs and 52.6% and 29.1% of total N outputs, were the core of N flow in the urban ecosystem. Humans activities mediated more than 98% N inputs into the ZUE, 73.2% of N was released into the atmosphere and 11.7% into hydrosphere. This very large volume of released N could contribute to regional problems. High energy consumption, insufficient wastewater treatment facility practices, and low N use efficiency are the primary causes of pollution. The major challenge ahead for the urban ecosystem is how to manage high-intensity N pollutant inputs to the urban ecosystems coupled with incomplete N cycling and removal. Based on the analysis of the N budget and loading, this study also proposes an N management strategy for the ZUE.     

Formation of N-nitrosodimethylamine (NDMA) by ozonation of dyes and related compounds

Formation of N-nitrosodimethylamine (NDMA) by ozonation of commercially available dyes and related compounds was investigated. Ozonation was conducted using a semi-batch type reactor, and ozone concentration in gas phase and the ozone gas flow were 10 mg L(-1) and 1.0 L min(-1), respectively. NDMA was formed by 15 min of ozonation of seven out of eight selected target compounds (0.05 mM) at pH 7. All the target compounds with N,N-dimethylamino functions were NDMA precursors in ozonation. The lowest and highest NDMA concentrations after ozonation of the target compounds were 13 ng L(-1) for N,N-dimethylformamide (DMF) and 1600 ng L(-1) for N,N-dimethyl-p-phenylenediamine (DMPD), respectively. NDMA concentrations after 15 min of ozonation of 0.05 mM methylene blue (MB) and DMPD increased with an increase in pH in its range of 6-8. The effects of coexisting compounds on NDMA concentrations after 15 min of ozonation of 0.05 mM MB and DMPD were examined at pH 7. NDMA concentrations after ozonation of MB and DMPD increased by the presence of 0.05 mM (0.7 mg L(-1) as N) nitrite (NO(2)(-)); 5000 ng L(-1) for MB and 4000 ng L(-1) for DMPD. NDMA concentration after MB ozonation decreased by the presence of 5mM tertiary butyl alcohol (TBA), a hydroxyl radical (HO.) scavenger, but that after DMPD ozonation was increased by the presence of TBA. NDMA concentrations after ozonation of MB and DMPD were not affected by the presence of 0.16 mM (5.3 mg L(-1)) hydrogen peroxide (H(2)O(2)). When 0.05 mM MB and DMPD were added to the Yodo and Tone river water samples, NDMA concentrations after 15 min of their ozonation at pH 7 increased compared with those in the case of addition to ultrapure water samples.     

Fe-Mn-sepiolite as an effective heterogeneous Fenton-like catalyst for the decolorization of reactive brilliant blue

A study of the decolorization of reactive brilliant blue in an aqueous solution using Fe-Mn-sepiolite as a heterogeneous Fenton-like catalyst has been performed. The Fourier transform infrared (FTIR) spectra of the catalyst showed bending vibrations of the Fe-O. The X-ray diffraction (XRD) patterns of the catalyst showed characteristic diffraction peaks of α-Fe₂O₃, γ-Fe₂O₃ and MnO. A four factor central composite design (CCD) coupled with response surface methodology (RSM) was applied to evaluate and optimize the important variables (catalyst addition, hydrogen peroxide dosage, initial pH value and initial dye concentration). When the reaction conditions were catalyst dosage= 0.4 g, [H₂O₂]= 0.3 mL, pH= 2.5, [reactive brilliant blue]_o = 50 mg·L⁻¹, and volume of solution= 500 mL at room temperature, the decolorization efficiency of reactive brilliant blue was 91.98% within 60 min. Moreover, the Fe-Mn-sepiolite catalyst had good stability for the degradation of reactive brilliant blue even after six cycles. Leaching of iron ions (<0.4 mg·L⁻¹) was observed. The decoloring process was reactive brilliant blue specific via a redox reaction. The benzene ring and naphthalene ring were first oxidized to open ring; these were then oxidized to the alcohol and carboxylic acid. The reactive brilliant blue was decomposed mainly by the attack of ·OH radicals including surface-bound ·OH radicals generated on the catalyst surface.     

广州市移动源现状及其污染控制管理对策

通过对广州市机动车辆构成状况和发展趋势、车流变化与氮氧化物变化关系以及各类车型污染排放分担率的分析,结果表明:在排放污染物的移动源中,小型车(出租车及其他小型车)和摩托车是一氧化碳、碳氢化合物的主要排放源;公共汽车等大型车是氮氧化物的主要排放源之一。并提出对广州市机动车污染控制应着重控制摩托车、小型车(特别是轿车,包括出租车)、公共汽车的污染排放。      

UASB+AF处理维生素C废水的研究

采用有效容积为６ｍ３的ＵＡＳＢ＋ＡＦ反应器处理维生素Ｃ高浓度有机废水,结果表明：稳定运行容积负荷可达１０—１２ｋｇＣＯＤ／（ｍ３·ｄ）ＣＯＤ去除率大于８０％,容积产气率大于３．０Ｎｍ３／（ｍ３·ｄ）,并具有启动速度快和较强耐冲击负荷的能力。     

明渠潮流中垂向紊动射流流场的数值模拟

选用ｋ－ε双方程紊流模型，对自由水面做“动”刚盖假设，建立了明渠潮流中垂向射流流场的数学模型，根据潮汐流动返复回荡的特点，对离散方程组的求解采用“跟踪扫描”逐行求解法，保护和加快了解的收敛，计算了５种不同回荡周期情况下射流流场的变化过程，预报回流区高度与实测值吻合。分析了潮汐非恒定性的影响，获得了一些有益的结论。     

闽南地区酸性雾水特征初探

1993年3～4月,在闽南地区进行了一次综合性酸雨集中观测,探讨其雾水特征如下:闽南地区雾水已严重酸化,其最低pH值达到2.91,是该地区酸性湿沉降的重要组成部分;雾水中有机酸根的贡献占总阴离子量9%;雾水含较多四价硫,并与甲醛反应形成络合物;雾水受到周围海洋的影响,Cl-有严重的亏损