厌氧条件下土壤中有机氯降解动力学模型及其参数优化——以五氯酚（PCP）为例

研究厌氧条件下土壤中有机氯降解动力学模型及其参数优化方法,对阐明有机氯降解的动力学反应机制具有十分重要的理论意义。文章以厌氧条件下土壤中五氯酚（PCP）降解为例,归纳介绍了两类用于描述土壤中PCP降解动力学过程的模型：一类模型是不考虑微生物生长的基质降解模式,以一级动力学模型最有代表性,但这类模型多数情况下没有或没有完全体现环境因素对PCP降解的抑制作用;另一类模型是考虑微生物生长的基质降解模式,以Monod动力学模型使用最普遍,但这类模型只在微生物生长的指数期适用,对延迟期、稳定期和衰亡期需经扩展才可应用。logistic动力学模型可广泛用于以上两类模型,是可以近似地描述微生物经适应过程和共代谢作用而致有机氯降解的简单模型。文章还总结了有机氯降解非线性模型参数的优化方法,并对其优缺点进行了分析和比较。针对目前土壤中有机氯降解动力学模型及其参数优化研究中存在的问题,对今后的研究方向进行了展望。     

除草剂绿草定-2-丁氧基乙酯的土壤降解特性

采用室内模拟试验方法,研究了绿草定-2-丁氧基乙酯在不同土壤中的降解特性.结果表明,绿草定-2-丁氧基乙酯在土壤中迅速降解,酸性土壤中其降解趋势遵循一级动力学模型,中性和碱性土壤中其降解动态不能用一级动力学模型进行简单的拟合;绿草定-2-丁氧基乙酯在土壤中的降解机制主要为化学水解作用,降解生成绿草定和丁氧基乙醇;土壤pH和土壤有机质含量是影响其土壤降解速率的主要因素,pH值越高,有机质含量越高,其土壤降解速率越快.     

一级动力学反应方程参数估计中若干问题的讨论

在农药的环境行为研究中,常用一级动力学反应方程来模拟农药的降解或残留。本文论述了用线性回归分析法估计一级化学动力学方程参数时存在的初始浓度飘移和非本义最优化问题,讨论了与此相关联的试验设置、安全间隔期、分段模拟和试验数据处理等问题,提出了解决问题的初步设想。     

一级动力学反应方程参数估计中若干问题的讨论

在农药的环境行为研究中,常用一级动力学反应方程来模拟农药的降解或残留。本文了用线性回归分析法估计一级化学这方程参数时存在的初始浓度多和非本义最优化问题。讨论了与此相关联的试验设置、安全间隔期、分段模拟和试验数据处理等问题,提出了解决问题的初步设想。     

城市污泥中邻苯二甲酸酯的好氧降解规律研究

为评价邻苯二甲酸酯类环境激素在环境中的滞留情况,妥善解决城市污泥的处理处置问题,对城市污泥中6种邻苯二甲酸酯的好氧生物降解规律进行了研究。结果表明,邻苯二甲酸酯的好氧生物降解性随烷基链含碳数的增加而降低;其好氧降解过程可用一级动力学模型描述;其好氧生物降解速率常数与烷基链含碳数、降解半衰期与烷基链含碳数、降解速率常数与正辛醇—水分配系数之间存在良好的相关性。     

白腐菌去除氯代酚动力学研究

使用Volterra模型描述 2 ,4-二氯酚体系中白腐菌生长动力学 ,建立氯代酚去除部分偶联型动力学方程 ,描述了生物降解体系中降解菌与目标化合物的反应历程 ,利用动力学方法初步探讨批次反应时生物吸附在氯代酚去除过程中的作用     

氯虫苯甲酰胺在甘蓝和土壤中的残留及消解动态

参照《农药残留试验准则》,采用田间试验方法,研究了济南和杭州两年两地的氯虫苯甲酰胺在甘蓝和土壤中的消解动态和最终残留。结果表明,氯虫苯甲酰胺最终残留在甘蓝、土壤中的质量分数分别是〈0.297 mg.kg-1,〈0.097 mg.kg-1;在甘蓝、土壤中的降解均符合一级动力学方程,降解半衰期分别为7.2～8.9 d和6.9～10.7 d;统计分析表明,两地区甘蓝中的残留消解行为无显著性差异,土壤中的残留消解行为差异性显著,土壤性质的不同是影响消解过程的主要因素。文章为制定该农药在甘蓝上最大残留限量标准和合理使用准则以及风险评估提供了科学依据。     

白腐菌去除氯化酚动力学研究

使用Volterra模型描述2,4-二氯酚体系中白腐菌生长动力学,建立氯代酚去除部分偶联型动力学方程,描述了生物降解体系中降解菌与目标化合物的反应历程,利用动力学方法初步探讨批次反应时生物吸附在氯休酚去除过程中的作用。     

手性有机磷农药在土壤中对映体选择性降解特征

马拉硫磷和丙溴磷是2种常用的有机磷杀虫剂,均有一个手性中心存在2个对映体.采用室内避光培养的方法,在对映体水平上研究了马拉硫磷和丙溴磷在2种土壤中的降解情况.结果表明,2种农药在土壤中的降解均较快,马拉硫磷和丙溴磷的降解半衰期分别为:黄土中3.5 h和21.5 h,红土中4.3 h和29.4 h.进一步的手性测定表明2种农药的降解均存在一定的对映体差异,丙溴磷对映体的选择性明显高于马拉硫磷,在2种土壤中马拉硫磷的左旋对映体降解快于右旋对映体,丙溴磷的右旋体降解快于左旋体.研究有助于深入认识2种有机磷农药在环境中的归趋,并对其生态风险性进行更合理的评估.     

三唑酮在油菜-土壤生态系统中的降解与建模

为评价三唑酮可湿性粉剂在土壤-油菜生态系统中使用后的残留行为和环境安全性,进行了2 a大田试验,并比较了指数模型、GM(1,1)灰色模型、阻滞动力学模型对三唑酮降解规律的描述。结果表明:3种模型的拟合结果均达到统计学意义上显著相关;对三唑酮在土壤和油菜中降解行为模拟结果最好的分别为GM(1,1)模型和阻滞动力学模型;三唑酮在土壤中2 a的半衰期分别为3.48和4.38 d,油菜植株中分别为1.98和3.78 d,其降解受温度影响较大。     

Bacterial degradation of monocrotophos and phyto- and cyto-toxicological evaluation of metabolites

The bacterium Serratia marsescens strain JAS16 was isolated from agricultural soil which had prior exposure to monocrotophos for three years. The strain JAS16 tolerated up to 1200 mg L^–1 monocrotophos and degraded the insecticide (1000 mg L^–1) at a degradation rate constant of 136 d^?1 (DT₅₀ = 3.7 d). In soil, the degradation rate constant was 105 d^?1 (DT₅₀ = 4.8 d). A schematic pathway is being proposed from the degraded products derived from gas chromatography--mass spectrometry (GC-MS). The phytotoxicity of degradation products to Vigna radiata, Vigna unguiculata, and Macrotyloma uniflorum and the genotoxicity to Allium cepa roots were found to be low. A cost-effective powder-based formulation was achieved with the isolate. The isolate remained viable during the storage and also multiplied with a higher colony forming units (CFU) load g^–1 for over a period of seven weeks of storage.     

ETU mineralization in soil under influence of organic carbon content,temperature, concentration,and depth

The mineralization of ¹⁴C‐ETU was measured by the evolution of ¹⁴CO₂ and described with a mathematical model consisting of two terms — one term describing the immediate mineralization of ¹⁴C‐ETU and another term describing the first order degradation of humus and/or biomass, where ¹⁴C had been built in. The influence of pesticide concentration, depth of soil, and incubation temperature showed combined interaction effects on the amount of ¹⁴CO₂ formed during the process and on the degradation rate of the pesticide. With the addition of soil extract, a combined effect between concentration and addition of organic extract was seen for the degradation rate, while a three‐way interaction between depth, concentration and organic extract was seen for the formation of ¹⁴CO₂. Degradation of ¹⁴C‐ETU can thus not be described only through investigations of one single of the mentioned parameters.     

Study on degradation process of famotidine hydrochloride in aqueous samples

The kinetics of famotidine (FAM) transformation under the influence of various factors, important from the environmental point of view, was investigated in aqueous solutions. The degradation processes using UV, H₂O₂, UV/H₂O₂, H₂O₂/Fe²⁺, and UV/H₂O₂/Fe²⁺ were studied. Direct photolysis and H₂O₂-assisted photolysis showed a pseudo-first-order kinetics, while the Fenton and the photo-Fenton processes fit second-order kinetics. The provided experiments proved a high resistance of FAM to direct photolysis. Its stability depends highly on the pH of the reaction solutions. The rate of FAM direct photolysis in acidic solutions was almost negligible. The reaction rate of FAM photolysis at pH 8–9 was 3.7 × 10^?3 min^?1 with DT₅₀ about 3 h 7 min. It was found that the presence of H₂O₂ in the reaction environment enhances the rate of photolysis of FAM. The observed rates of reaction were 5.1 × 10^?3 min^?1 and 3.7 × 10^?3 min^?1 in acidic and basic solutions, respectively. The used Fenton systems appeared to be the most efficient in FAM removal. The rate of reaction depends on concentration of Fe²⁺ and H₂O₂. It was observed that the presence of UV-light enhances the reaction rate by two to six times in comparison to the classical Fenton system. Additionally, FAM behavior in natural water under solar irradiation was examined. The irradiation experiments were carried out in batch experiments with simulated sunlight.     

Structural effect on photocatalytic degradation of metallised azo dyes in aqueous TiO2 suspension

Three metallised azo dyes were investigated under TiO₂‐photocatalytic and photosensitised conditions in aqueous buffering solutions. The degradation follows apparent first‐order kinetics. The size and strength of intramolecular conjugation determine the light‐fastness of the investigated dyes. Compared with ¹O₂ produced in photosensitised process, the more powerful *OH radicals in TiCO₂ photocatalytic process are highly reactive towards the investigated azo dyes. And as a result, the TiO₂‐photocatalysis makes little less distinction in the degradation kinetic data of the azo dyes compared with the photosensitised degradation of them.     

Temperature,salinity, and prey effects on polyp versus medusa bud production by the invasive hydrozoan<Emphasis Type="Italic"> Moerisia lyonsi</Emphasis>

Hydrozoan species are renowned for flexible asexual reproduction, which may predispose them to be successful invaders. Polyps of the invasive hydrozoan Moerisia lyonsi (Boulenger, 1908) have very high rates of asexual production of both polyp and medusa buds. In order to determine how environmental factors affect asexual reproduction in M. lyonsi, the quantitative relationships between polyp bud and medusa bud production were studied in a 31-day laboratory experiment during August 2001. The combined effects of prey (4, 8, 12, 16 Acartia tonsa copepods polyp^–1 day^–1), temperature (20°C, 29°C), and salinity (5, 15, 25) were tested on the development times for polyp buds (DT_p) and medusa buds (DT_m), the total asexual reproduction rate (ARR, no. buds polyp^–1 day^–1), and the ratio of medusa bud to total bud production (R_m). Greater food consumption significantly and directly enhanced ARR and R_m and shortened DT_p and DT_m. A lower temperature (20°C) and higher salinity (25) reduced food consumption, lengthened development times, and decreased ARR and R_m, with opposite effects for the higher temperature (29°C) and lowest salinity (5). The patterns of variation of these reproductive parameters are more complex. DT_m was most sensitive and was significantly and directly affected by all three measured factors. In addition to food consumption, direct effects were seen by temperature on DT_p and by salinity on R_m. ARR was directly affected only by food consumption. Overall, DT_p, DT_m, and R_m were more sensitive to environmental differences than was ARR. More favorable conditions enhanced medusa bud production. The adaptive reproductive processes and their significance for the maintenance and dispersal of M. lyonsi are discussed.Communicated by J.P. Grassle, New Brunswick     

氨基甲酸酯类农药对蛋白核小球藻联合毒性作用特点及机制

氨基甲酸酯类农药广泛应用于农业生产中,其在环境中的残留及其对非靶标生物的毒性作用引起关注。以5种氨基甲酸酯类农药包括残杀威、灭多威、抗蚜威、涕灭威和呋喃丹为研究对象,以蛋白核小球藻为受试生物,应用微板毒性分析法系统测定每种农药及其五元混合物对蛋白核小球藻在不同暴露时间(12、24、48、72和96 h)的生长抑制作用,并同步分析农药对蛋白核小球藻的生理特性如叶绿素含量、蛋白质含量、超氧化物歧化酶(SOD)活性和脂质过氧化物丙二醛(MDA)含量的影响。结果表明,5种农药对蛋白核小球藻的浓度-效应均具有明显的时间依赖性,农药抗蚜威在中低浓度促进绿藻生长,呈现非单调J型浓度-效应曲线(CRC)特征,其余4种农药的CRC呈现经典S型;以半数效应浓度的负对数(p EC50)为毒性大小指标,5种农药在96 h时毒性大小为:呋喃丹(p EC50=3.43)残杀威(p EC50=2.76)抗蚜威(p EC50=2.12)灭多威(p EC50=2.11)涕灭威(p EC50=1.89)。浓度为EC50的5种农药处理后的蛋白核小球藻中叶绿素和蛋白质含量随暴露时间的延长而减少,但不同农药处理的绿藻中叶绿素和蛋白质含量减少率随暴露时间延长变化趋势稍有不同; SOD酶活性随着暴露时间延长逐渐下降,MDA含量逐渐增加,这说明藻细胞受到破坏,脂质过氧化的损害程度超过细胞修复能力,SOD活性被抑制,细胞的抗氧化能力下降,藻细胞内的H2O2不断积累,导致MDA含量升高。五元混合物对蛋白核小球藻的毒性也具有一定的时间依赖性,并表现出刺激作用,即hormesis现象,且混合物毒性与组分浓度比具有良好的线性相关性;暴露于混合物的小球藻均在96 h出现了刺激效应,其叶绿素与蛋白质含量随暴露时间延长不断增加,SOD活性不断升高,MDA含量不断减少;五元混合物均在96 h呈现出拮抗作用,且与混合物的浓度和组分浓度比相关。     

Photochemical reaction of nitro-polycyclic aromatic hydrocarbons: effect by solvent and structure

Photochemical degradation of 1-nitropyrene, 2-nitrofluorene, 2,7-dinitrofluorene, 6-nitrochrysene, 3-nitrofluoranthene, 5-nitroacenaphthene, and 9-nitroanthracene was examined in CHCl₃, CH₂Cl₂, DMF, DMF/H₂O (80/20), CH₃CN, or CH₃CN/H₂O (80/20). The degradation mostly follows the first order kinetics; but a few follow second order kinetics or undergo self-catalysis. The photodegradation rates follow the order: CHCl₃ > CH₂Cl₂ > DMF > DMF/H₂O > CH₃CN > CH₃CN/H₂O. DMF is an exceptional solvent because three of the seven compounds undergo self-catalytic reaction. 9-Nitroanthracene, which has a perpendicular nitro group, is the fastest, while the more compact 1-nitropyrene and 3-nitrofluoranthene are the slowest degrading compounds.     

Photocatalytic degradation of the herbicide cinosulfuron in aqueous TiO<Subscript>2</Subscript> suspension

The photocatalytic degradation of a sulfonylurea herbicide, cinosulfuron, has been studied in TiO₂ aqueous suspensions. A first order kinetic law was found. The influence of the initial concentration of cinosulfuron and of the initial radiant flux on the kinetics were evaluated. The identification of the intermediate products was based on high performance liquid chromatography coupled with mass spectrometry analyses (HPLC-MS). The mineralization of cinosulfuron was traced using ion chromatography and total organic carbon (TOC) measurements. These results indicate that the photocatalytic degradation of cinosulfuron leads to CO₂, NO₃ ⁻ and SO₄ ²⁻ as final products, and in addition cyanuric acid (C₃H₃O₃N₃), confirming previous results on triazinic ring-containing compounds. Electronic Publication     

评估斑马鱼胚胎毒性试验在农药危害筛选中的应用

考虑到人类社会中大量使用化学物质,想要准确有效地评估这些化学物质对人类和生态受体的潜在风险,研发有效的手段和方法是至关重要的。鱼胚胎急性毒性试验是其中一种工具,已表现出与幼鱼急性毒性标准试验的预测结果高度吻合,而幼鱼试验对资源消耗更多。然而,也有证据表明,对于某些类型的化学物质,包括神经毒素,鱼类胚胎的敏感性低于幼鱼。本文利用已发表的斑马鱼胚胎毒性数据,与3种常用检测用鱼幼鱼(虹鳟鱼、蓝鳃太阳鱼、羊鲷)的半致死浓度50%(LC₅₀)数据进行比较,研究了鱼类胚胎对农药危害评估的效用。在将农药视为单因素的情况下,斑马鱼胚胎和幼鱼毒性数据相关性较差,差异显著(r²=0.28;p2=0.64;p 精选自Glaberman, S., Padilla, S. and Barron, M. G. (2017), Evaluating the zebrafish embryo toxicity test for pesticide hazard screening. Environmental Toxicology and Chemistry, 36: 1221–1226. doi: 10.1002/etc.3641
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3641/full