IMPACT ASSESSMENT MODEL FOR CLEAR WATER FISHES EXPOSED TO EXCESSIVELY CLOUDY WATER1

ABSTRACT: A new type of empirical model described here enables real time assessment of impacts caused by excessive water cloudiness as a function of (a) reduced visual clarity (excessive cloudiness) and (b) duration of exposure to cloudy conditions, in fisheries or fish life stages adapted to life in clear water ecosystems. This model takes the familiar form used in earlier suspended sediment dose effect models where z is severity of ill effect (SEV), x is duration of exposure (h), y is black disk sighting range (y BD, m)—a measure of water clarity, a is the intercept, and b and c are slope coefficients. As calibrated in this study the model is Severity of ill effect is ranked on a 15‐step scale that ranges from 0 to 14, where zero represents nil effect and 14 represents 100 percent mortality. This model, based on peer consultation and limited meta analysis of peer reviewed reports, accomplishes the following: (a) identifies the threshold of the onset of ill effects among clear water fishes; (b) postulates the rate at which serious ill effects are likely to escalate as a function of reduced visual clarity and persistence; (c) provides a context (the “visual clarity” matrix, with its cell coordinates) to share and compare information about impacts as a function of visual clarity “climate” (d) demonstrates changes in predator prey interactions at exposures greater than and less than the threshold of direct ill effects; (e) calibrates trout reactive distance (cm) as function of water clarity in the form where y represents reactive distance (cm) and x represents visual clarity (black disk sighting range, cm), and where a and b are intercept and slope respectively, such that (f) identifies black disk sighting range, in meters, and its reciprocal, beam attenuation, as preferred monitoring variables; and (g) provides two additional optical quality variables (Secchi disk extinction distance and turbidity) which, suitably calibrated as they have been in this study, expand the range of monitoring options in situations in which the preferred technology—beam attenuation equipment or black disk sighting equipment—is unavailable or impractical to use. This new model demonstrates the efficacy of peer collaboration and defines new research horizons for its refinement.     

铝阳极电凝聚处理活性黑KN-B染料模拟废水

对铝阳极电凝聚处理活性黑KN-B模拟废水进行了初步的实验研究.考察了电流密度、初始pH值、电解质浓度及种类、温度、染料浓度等因素的影响.结果表明,在一定实验条件下,活性黑KN-B模拟废水的脱色效率可达到88%;电流强度、染料浓度、电解液初始pH值、氯化钠电解质浓度、温度对染料溶液脱色效率的影响明显,而硫酸钠电解质浓度对脱色效率的影响不显著;在电凝聚处理过程中,主要作用机理是吸附网捕占主导地位;活性黑KN-B在阴极上发生了还原反应.     

Atmospheric Deposition of Reactive Nitrogen on Turf Grassland in Central Japan: Comparison of the Contribution of Wet and Dry Deposition

The atmospheric deposition of reactive nitrogen on turf grassland in Tsukuba, central Japan, was investigated from July 2003 to December 2004. The target components were ammonium, nitrate, and nitrite ions for wet deposition and gaseous ammonia, nitric and nitrous acids, and particulate ammonium, nitrate, and nitrite for dry deposition. Organic nitrogen was also evaluated by subtracting the amount of inorganic nitrogen from total nitrogen. A wet-only sampler and filter holders were used to collect precipitation and the atmospheric components, respectively. An inferential method was applied to calculate the dry deposition velocity of gases and particles, which involved the effects of surface wetness and ammonia volatilization through stomata on the dry deposition velocity. The mean fraction of the monthly wet to total deposition was different among chemical species; 37, 77, and 1% for ammoniacal, nitrate-, and nitrite-nitrogen, respectively. The annual deposition of inorganic nitrogen in 2004 was 47 and 48 mmol m⁻² yr⁻¹ for wet and dry deposition, respectively; 51% of atmospheric deposition was contributed by dry deposition. The annual wet deposition in 2004 was 20, 27, and 0.07 mmol m⁻² yr⁻¹, and the annual dry deposition in 2004 was 35, 7.4, and 5.4 mmol m⁻² yr⁻¹ for ammoniacal, nitrate-, and nitrite-nitrogen, respectively. Ammoniacal nitrogen was the most important reactive nitrogen because of its remarkable contribution to both wet and dry deposition. The median ratio of the organic nitrogen concentration to total nitrogen was 9.8, 17, and 15% for precipitation, gases, and particles, respectively.     

活性粉末混凝土双向拉压强度试验研究

活性粉末混凝土具有超高强度、高韧性、高耐久性及高温度适应性等特点,为一种新型的混凝土材料。通过科学的方法建立一套处于平面应力状态的活性粉末混凝土构件(如受弯构件的弯剪段)的安全设计,双向拉压应力状态下的强度准则是必需的。采用15个“8”字形试件,选取了5个不同拉压应力比工况,进行了强度试验,其试验结果表明不同拉压应力比工况的试件,其破坏形态均为拉断型破坏;随着拉应力的增大,活性粉末混凝土的抗压强度随之减小。依据试验结果,建立了活性粉末混凝土双向拉压应力状态下的实用强度准则,对于处于平面应力状态的活性粉末混凝土构件的安全设计具有较强的实用价值。     

Cytotoxicity of lambda-cyhalothrin on the macrophage cell line RAW264.7

The wide use and wide-spectrum toxicity of synthetic pyrethroids (SPs) insecticides make them an emerging ecotoxicological concern. Some previous studies showed that SPs possessed cytotoxicity in some immune cells such as human lymphocytes and rat bone marrow. However, the cytotoxicity of SPs to macrophages, which are crucial to innate immunity, has not been explored. In the present report, we investigated a new pyrethroid insecticide, lambda-cyhalothrin (LCT), which may increase the generation of reactive ...     

三苯基甲烷类染料氧化酶基因(tpmD)在大肠杆菌中的无诱导表达

为了解决嗜水气单胞菌DN322对鱼类的潜在致病性问题,有必要克隆表达该菌的三苯基甲烷染料脱色酶基因tpmD.通过PCR方法获得该基因,并与脱色希瓦氏菌S12的NAD(P)H脱氢酶基因启动子和用于荧光标记的编码CCPGCC的碱基序列融合,将有启动子和无启动子的融合基因片段分别连接到质粒pMD18-T中,转化大肠杆菌E.coli DH5α和E.coli BL21.结果发现,有启动子的融合基因能被E.coil在不加诱导物IPTG的条件下高效正确表达,脱色酶活性甚至超过基因供体菌DN322.将上述两株大肠杆菌工程菌株在自然水体中进行孔雀石绿污染小试处理,60d内在每个350mL反应体系中累积共投加大于10000mg的孔雀石绿,脱色率一直保持在92%以上;细菌数量最后增加了5～10倍.研究结果证明,基因工程菌在不加营养物的条件下也有很强的脱色活性和长期的存活能力;在tpmD基因3'端加入的用于螯合双砷荧光染料的18bp编码氨基酸碱基序列不影响此基因的表达和酶的脱色活性,这将赋予此工程菌可示踪性.     

Chitosan and chemically modified chitosan beads for acid dyes sorption

The capabilities of chitosan and chitosan-EGDE (ethylene glycol diglycidyl ether) beads for removing Acid Red 37 (AR 37) and Acid Blue 25 (AB 25) from aqueous solution were examined. Chitosan beads were cross-linked with EGDE to enhance its chemical resistance and mechanical strength. Experiments were performed as a function of pH, agitation period and concentration of AR 37 and AB 25. It was shown that the adsorption capacities of chitosan were comparatively higher than chitosan-EGDE for both acid dyes. This is mainly because cross-linking using EGDE reduces the major adsorption sites -NH3+ on chitosan. Langmuir isotherm model showed best conformity compared to Freundlich and BET. The kinetic experimental data agreed very well to the pseudo second-order kinetic model. The desorption study revealed that after three cycles of adsorption and desorption by NaOH and HCl, both adsorbents retained their promising adsorption abilities. FT-IR analysis proved that the adsorption of acid dyes onto chitosan-based adsorbents was a physical adsorption. Results also showed that chitosan and chitosan-EGDE beads were favourable adsorbers and could be employed as low-cost alternatives for the removal of acid dyes in wastewater treatment.     

Effect of functional groups on sludge for biosorption of reactive dyes

The sludge, which was collected from a biological coke wastewater treatment plant, was used as a low-cost adsorbent in the removal of reactive dyes (methylene blue (MB) and reactive red 4 (RR4)) from aqueous solution. The pH of dye solution played an important role on the dye uptake. As the solution pH increase, the MB uptake increased, while the RR4 uptake decreased. The maximum uptake of RR4 by protonated sludge was 73.7 mg/g at pH 1, and the maximum uptake of MB by sludge was 235.3 mg/g at pH 9. Three functional groups, including carboxyl, phosphonate, and amine group, were identified by potentiometric titration, fourier transform infrared (FT-IR) spectrometry, and X-ray photoelectron spectroscopy (XPS). The anionic functional groups, phosphonate and carboxyl group, were identified as the binding sites for the cationic MB. Amine groups were identified to bind RR4. The main mechanism of the reactive dyestuffs adsorption is electrostatic interaction.     

废弃农林生物质在废水处理中环境友好利用的研究进展

农林废弃物是一种重要的、廉价丰富的、尚没有得到充分利用的生物质资源,其利用受到越来越多的关注。本文综述近年来国内外利用废弃农林生物质环境友好处理各种废水的现状。重点阐述了废弃农林生物质作为吸附剂对印染、重金属等工业废水的处理以及通过改性手段来提高农林生物质处理效果的研究进展。