乌鲁木齐不同功能区昼间臭氧浓度变化特征分析

为了研究乌鲁木齐市昼间的近地层大气臭氧浓度变化特征,利用靛蓝二磺酸钠分光光度法(IDS法)对乌鲁木齐市不同功能区在采暖期前期、采暖期与采暖期后期昼间的小时臭氧浓度进行监测,分析与温度、太阳辐射、相对湿度的相关性。结果表明:乌鲁木齐市不同功能区昼间的小时臭氧浓度变化具有明显的"单峰型"变化规律,从早上09:00开始,臭氧浓度明显上升,最高的小时臭氧浓度出现在午后,其中,交通区、工业区昼间的小时臭氧浓度较高。不同时间段臭氧总平均浓度依次为采暖期前期>采暖期后期>采暖期,不同时间段昼间的小时臭氧浓度变化与太阳辐射、温度呈显著的正相关性,与相对湿度呈显著的负相关性。     

基于多种预测模型的玉米低温冷害预测集成模型

引入大气环流特征量因子、500hPa高度场因子、太平洋海温因子以及预报量本身的均值周期因子等四类因子的低温冷害预测子模型来建立玉米低温冷害预测集成模型。利用该集成模型预报下一年温度等级时，将上一年的实况资料输入预测模型，滚动预测，克服了统计模型预报时效短的缺点，且试报准确性高，无错报。     

新毒性试验生物萼花臂尾轮虫的特性试验

研究了萼花臂尾轮虫Ｂｒａｃｈｉｏｎｕｓ ｃａｌｙｃｉｆｌｏｒｕｓ ２４ｈ标准化急性毒性试验的可行性和优越性。应用轮虫休眠卵，在２５℃、３０００ｌｘ的强光照下进行孵化，吸取孵化后３ｈ内的幼体，进行２４ｈ（暗相）急性毒性试验。研究表明，Ｃｕ、Ｈｇ、ＮａＰＣＰ、ＳＤＳ、Ｃｄ、Ｚｎ、Ｎｉ、ＮＨ３对Ｂ．ｃａｌｙｃｉｆｌｏｒｕｓ的２４ｈ ＬＣ５０值分别为０．０２２、０．０４３、１．３０、１．４７、１．７７、１     

氯代苯类化合物对江水细菌的毒性及QSAR研究

采用细菌生长抑制实验,测定了18种氯苯类化合物对长江水中混合细菌的毒性,得到24 hIC₅₀值,-1gIC₅₀为3.65～4.32,其中,毒性最弱的是氯苯,毒性最强的是1,2,4-三氯苯.选用分子连接性指数法对毒性数据进行定量结构活性关系(QSAR)研究.结果表明,氯苯类化合物对江水细菌的毒性与苯环上取代基的种类、数目和位置有关,价分子连接性指数0XV和7X_CHV能够很好地描述氯苯类化合物对江水细菌的毒性.方程-1gIC₅₀=0.8390XV-25.3727X_CHV+0.802的稳健性很好,该模型的预测值与毒性实测值之间的相关系数达0.948.      

Microbiological degradation of polycyclic aromatic hydrocarbons: Anthracene,benzo(K)fluoranthene,dibenzothiophene, benzo(H) quinoline and 2‐nitronaphthalene

Biodegradation experiments of various polycyclic aromatic hydrocarbons were studied with mixed bacteria culture under aerobic conditions. An easy‐to‐handle clean‐up procedure was developed for PAH and their metabolites simultaneously as well as a gc‐ms‐method to identify and quantify these compounds.

Anthracene and dibenzothiophene are completely degradable in an aqeous system, whereas biodegradation of benzo(k)fluoranthene and benzo(h)quinoline is possible only in an oil‐in‐water‐system with dodecane as cosubstrate. No degradation of nitronaphthalene was observed in aqueous systems. New metabolites are 2,3‐dihydroxybenzothiophene, hydroxybenzothiophenecarbonic acid and benzothiophenequinone for dibenzothiophene and hydroxyfluoranthenic acid for benzo(k)flouranthene. Whereas the former metabolites are degradable under the experimental conditions, the latter accumulates during the degradation experiment.

The results are important for microbiological wastewater treatment, since knowledge of biodegradation processes is indespensable for the successful treatment of PAH‐containing wastewater.     

生活与工业污水混合处理系统中关键毒物追踪

以常州市城北污水处理厂的进水和A^2O出水为研究对象，采用毒性鉴别评价（T IE）程序，对关键毒物进行了追踪。结果表明，进水对大型蚤（Daphnia magna）具 有24h急性毒性，经过A^2O系统的处理，出水已不显示24h急性毒性；因曝气可去除废水毒性，C18固相提取亦可去除废水毒性，据此判断进水中存在的主要毒物 为挥发性非极性有机化合物。进出水的GC／MS图谱显示，处理前后有机物浓度大大降低，关键毒物基本去除。     

Biodegradation of starch-poly(β-hydroxybutyrate-co-valerate) composites in municipal activated sludge

Injection-molded composites were prepared by blending PHBV⁵ with native cornstarch (30% and 50%) and with cornstarch precoated with PEO as a binding agent. These composites were evaluated for their biodegradability in municipal activated sludge by measuring changes in their physical and chemical properties over a period of 35 days. All composites lost weight, ranging from 45 to 78% within 35 days. Interestingly, the extent and rate of weight loss were quite similar in PHBV composites with no starch, with 30% starch, and with 50% starch. Weight loss was slowest in PHBV blends prepared with PEO-coated starch. For all samples, the weight loss was accompanied by a rapid deterioration in tensile strength and percentage elongation. The deterioration of these mechanical properties exhibited a relative rate of PHBV>starch-PHBV>PEO-coated starch-PHBV. Changes in starch/PHBV composition after biodegradation were quantified by FTIR spectroscopy. Increasing the starch content resulted in more extensive starch degradation, while the PHBV content in the blends became less susceptible to hydrolytic enzymes.The mention of firms names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over firms or similar products not mentioned. All programs and services of the U.S. Department of Agriculture are offered on a nondiscriminatory basis without regard to race, color, national origin, religion, sex, marital status, or handicap.     

Calculation of carbon balances for evaluation of the biodegradability of polymers

Establishing carbon balances has been proven to be an applicable and powerful tool in testing biodegradability of polymers. In controlled degradation tests at a 4-L scale with the model polymer poly(h0581m471k0q2772/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-hydroxybutyrate) (PHB), it was shown that the degree of degradation could not be determined with satisfactory accuracy from CO₂ release alone. Instead, the course of degradation was characterized by means of establishing carbon balances for the degradation of PHB withAcidovorax facilis and a mixed culture derived from compost. Different analytical methods for determining the different carbon fractions were adapted to the particular test conditions and compared. Quantitative determination of biomass and residual polymer were the main problems in establishing carbon balances. Amounts of biomass derived from protein measurements depend strongly on assumptions of the protein content of the biomass. Selective oxidation of biomass with hypochlorite was used as alternative, but here problems arose from insoluble metabolic products. Determination of soluble components with the method of chemical oxygen demand (COD) also includes empirical assumptions but seems acceptable if the dissolved carbon fraction is in the range of some 10% total carbon. Results confirm both analytical assays and theoretical approaches, in ending up at values very close to 100%, within an acceptable standard deviation range under test conditions comparable to standard test practice.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.     

2种杀虫剂对日本沼虾的急性毒性

研究了毒死蜱和硫丹对日本沼虾(Macrobrachium nipponense)的毒性作用.根据预试验确定2种杀虫剂对日本沼虾的急性毒性试验浓度,测定沼虾24和48 h的半致死浓度p(LC50),在0～48 h的ρ(LC50)值范围内设定6个浓度梯度,对日本沼虾进行24 h胁迫试验以测定耗氧量和排氨量.毒死蜱和硫丹对日本沼虾的24和48 hρ(LC50)分别为5.03、2.01和8.47、4.02 μg·L-1,其安全质量浓度分别为0.096和0.272 μg·L-1,表明日本沼虾对毒死蜱的敏感性明显高于硫丹.随着2种杀虫剂浓度的逐渐升高,日本沼虾的耗氧量和排氨量均呈现下降趋势,表明日本沼虾采用相同的适应方式来抵御2种杀虫剂对其基础代谢的胁迫,表现为被动的忍耐.     

2016～2020年成都市控制PM2.5和O3-8h污染的健康效益评价

细颗物(PM_2.5)和臭氧是我国主要的大气污染物,严重危害人群健康.为评估成都市大气污染防治行动实施期间PM_2.5和臭氧对人群健康的影响,首先,利用流行病学中的广义相加模型和非线性分布滞后模型估算了2014～2016年成都市PM_2.5和臭氧最大8 h滑动平均(O_3-8h)浓度变化对居民疾病死亡影响的暴露-反应关系系数(β),在此基础上,采用环境风险和环境价值评估法估算2016～2020年成都市PM_2.5和O_3-8h浓度暴露水平变化的健康收益.结果表明：(1)2016～2020年成都市的ρ(PM_2.5)年均值呈逐年下降趋势,从63μg·m^-3降至40.92μg·m^-3,年均下降率约为10.14%;与之相反,ρ(O_3-8h)年均值从155μg·m^-3升至169μg·m^-3,年均增长率约为2.23%.(2)成都市PM_2.5...