Characterization of the monthly variation in (1 → 3)-β-d-glucan concentrations in university laboratories

We characterize the monthly variation in (1 → 3)-β-d-glucan concentration measured over the course of 1 year, and we evaluate the characteristics of size selection using a two-stage cyclone sampler. The (1 → 3)-β-d-glucan concentrations were measured in four bio-related laboratories. A total of 156 samples were collected using a new two-stage cyclone sampler. Analysis of (1 → 3)-β-d-glucan was performed using the kinetic Limulus amebocyte lysate assay. The study showed that airborne (1 → 3)-β-d-glucan concentrations were significantly higher in laboratory D (mean ± SD 1,105?±?1,893 pg/m³) and in the spring (5,458 pg/m³). The highest concentration of (1 → 3)-β-d-glucan occurred in the spring, particularly in May.     

Investigation of organic pollutants in wastewater-irrigated soil and its DNA damage and oxidative damage on mice

This work aimed to determine the DNA and oxidative damage on mice by mixtures of organic contaminants in wastewater-irrigated soil, in order to assess their usefulness as markers for this kind of pollution. Wastewater-irrigated soil samples in the vicinity of an industrial area in Tangshan, China were collected, and soil irrigated by underground water satisfying drinking water standards was used as control group. Organic pollutants were extracted from the soil using ultrasonic oscillation, and analyzed by gas chromatography–mass spectrometry (GC-MS). Meanwhile, DNA damage on mice was determined by the Comet assay after oral gavage with the extracts, and changes in total superoxide dismutase (T-SOD) activity, glutathione peroxidase glutathione, GSH peroxidase (GSH-P_X) activity and malondialdehyde content in serum of mice were investigated. The number of categories and concentrations of organic compounds in the wastewater-irrigated soil is more than those in groundwater-irrigated soil, as identified by the GC-MS. The toxicity test of mice showed that compared with reagent control group, the activities of T-SOD and GSH-P_X decreased; the tailing rate of peripheral blood lymphocyte of mice increased and was more than that of the control group. This shows that mammalian toxicity end points can be used to determine the joint toxicity of organic pollutants in soil. When there is no means to identify each and every pollutant in soil, it is feasible to evaluate the combined effects of various pollutants to determine the extent to which the soil is polluted.     

Factor analysis of H2S emission at a wastewater lift station: a case study

Odor and corrosion are common problems in domestic wastewater collection, transportation, pumping, and treatment processes. Based on the comparison among odorous compounds and onsite observations at a wastewater lift station, H₂S is more likely to have caused the odor and corrosion problems than methanethiol and other organic sulfides. The field data from both air and wastewater quality monitoring demonstrated that more H₂S (1 ppmv) was formed at a more negative redox potential, lower pH, and a higher temperature of wastewater. Since the lower detection level of most current analytical techniques is much greater than human’s smell and the reference concentration for adverse health effects, automatic monitoring on the threshold of H₂S formation provides a mechanism to trigger control techniques only when necessary for cost saving purposes. Based on Gibbs free energy, a more negative redox potential is required to form H₂S with an increase in pH and a decrease in temperature and SO ₄ ^2? concentration. However, pH effect is more significant than both temperature and SO ₄ ^2? concentration for H₂S formation. It is recommended that H₂S control techniques be started when the redox potential is below ?44 mV, the pH is lower than 5.6, and the temperature is higher than 11.5 °C to control H₂S below the reference concentration. Corroded concrete particles were examined by X-ray diffraction, which showed that the dominant crystal form was quartz.     

Sensitivity of isolated eggs of pond snails: a new method for toxicity assays and risk assessment

The concentration of heavy metals in the environment is normally low. We here address whether using the development of isolated pond snail Radix auricularia eggs would provide a more sensitive endpoint and whether the gelatinous matrix of the egg mass surrounding the eggs indeed protects the snail embryos. In the present study, artificial removal of the gelatinous matrix of egg masses greatly increased the sensitivity of developing eggs to a heavy metal (cadmium). The sensitivity of isolated eggs to cadmium was determined using several convenient endpoints, including mortality, hatching rate, and heart rate, with an acute toxicity test and a subchronic test. In the acute toxicity test, a 96-h LC₅₀ value of 58.26 μg/L cadmium was determined. In the subchronic toxicity test, sublethal effects in terms of a significant reduction in hatching rate could be found in the 25-μg/L treatment, and a significant decrease of heart rate was observed in both treatments (5 and 25 μg/L). The high sensitivity of isolated eggs indicates that such tests can be efficient for toxicity assays and risk assessment, although one needs to keep in mind that the ecologically relevant measure of toxicity will be how eggs are affected when they are still inside the egg mass.     

钙基磁性生物炭对Cr（VI）污染土壤钝化稳定化机制及微生物影响研究

生物炭改性材料因具有活性官能团众多、吸附效能高等优势被广泛应用于土壤重金属污染修复治理中.本研究以稻谷壳为原料,采用 共沉淀法及CaCO₃浸渍法制备了钙基磁性生物炭（Ca-Fe-B）,并使用电子扫描显微镜（SEM）、傅里叶红外光谱（FTIR）、X射线衍射分析（XRD）、X射线光电子能谱分析（XPS）进行表征.同时,通过梯度浓度Cr（VI）污染土壤实验考察Ca-Fe-B施入对土壤pH、Cr（VI）稳定化效果、土壤酶活性及微生物群落结构的影响,并阐述其钝化机理.结果表明：①Ca-Fe-B表面负载Fe₃O₄、γ-Fe₂O₃、Fe₃C及以方解石形式存在的CaCO₃,具有大量—OH、—O—C=O、Si—O—Si、C≡C及C≡N等官能团;②Ca-Fe-B可显著提升土壤pH,在Cr（VI）污染浓度为100、200、1000 mg·kg^-1时,90 d的 固定效率分别可达72.57%、67.07%及59.88%,并使土壤中部分可交换态Cr转化为可还原态及残渣态Cr;③Ca-Fe-B可促进土壤β-葡萄糖苷酶与几丁质酶酶活性,但磷酸酶对其响应不显著,也可显著提升土壤中Proteobacteria门菌相对丰度;④Ca-Fe-B表面形成Si—O—Ca—OH键可吸附Cr（VI）, Fe（Ⅱ）作为电子供体参与土壤Cr（VI）还原过程,并生成Cr₂O₃、Cr（OH）₃沉淀及（Cr_xFe_1-x）（OH）₃、Cr_xFe_1-xOOH络合沉淀,以—OH、 —C=C—、O—C=O为主的大量含氧官能团协同吸附络合土壤中的Cr（VI）.研究显示, Ca-Fe-B对Cr（VI）污染土壤具有良好的稳定性能,有望为土壤重金属污染修复提供一种新的研究思路和技术路线.     

Optimizing the atmospheric sampling sites using fuzzy mathematic methods

A new approach applying fuzzy mathematic theorems, including the Primary Matrix Element Theorem and the Fisher Classification Method, was established to solve the optimization problem of atmospheric environmental sampling sites. According to its basis, an application in the optimization of sampling sites in the atmospheric environmental monitoring was discussed. The method was proven to be suitable and effective. The results were admitted and applied by the Environmental Protection Bureau (EPB) of many cities of China. A set of computer software of this approach was also comuletelv comniled and used.     

Elemental sulfur effects on Pb and Zn uptake by Indian mustard and winter wheat

A pot experiment was conducted to investigate the influence of elemental sulfur to contaminated soil on plant uptake by a heavy metal hyperaccumulator, Indian mustard( Brassica juncea ) and a field crop, winter wheat( Triticum. aestivum). Elemental sulfur(S) with different rates was carried out, they were 0(S0 ), 20(S20 ), 40(S40 ), 80(S80 ), and 160(S160 ) mmol/kg respectively. Extra pots with the same rates of S but without plants were used for soil sampling to monitor pH and CaCl2-extractable heavy metal changes. The results showed that S enhanced phytoextraction of Pb and Zn from contaminated soil. Application S effectively decreased soil pH down to 1.1 as the most at the rate of Sl60. The concentrations of CaCl2-extractable Pb and Zn in soil and uptake of Pb and Zn by the plants were increased with soil pH decreased. A good correlation between CaCl2-extractable Pb/Zn and soil pH was found( Rpb^2 = 0.847 and RZn^2 = 0,991, n = 25). With S application, soil CaCl2-extractable Pb and Zn concentrations, concentration of Pb and Zn in plants and the amount of removal by plant uptake were significanfly higher than those without S. Under the treatment of S160, the highest CaCl2-extmctable Pb and Zn were observed, they were 4.23 mg/kg and 0.40 mg/kg, 2.7 and 2.0 times as that of the control(So ) respectively. At the highest rates of S( Sl~0 ), both Indian mustard and winter wheat reached the highest uptake of Pb and Zn. The highest Pb concentrations in wheat and Indian mustard were 32.8 mg/kg and 537.0 mg/kg, all 1.8 times as that of the control, and the highest Zn concentrations in wheat and Indian mustard were 215.5 mg/kg and 404.0 mg/kg, 2.4 and 2.0 times as that of the control respectively. The highest removals of Pb and Zn from the contaminated soil were 0.41 rag/pot and 0.31 nag/pot by Indian mustard in the treatment of S160 through 50 days growth.     

高浓度苯酚在石墨电极上电解特性的研究

研制了数据在线采集记录系统对高浓度苯酚在石墨电极上电解过程的循环伏安行为进行了研究。采用连续循环伏安法考察了体系电解的特点,并考察了支持电解质、扫描速率、苯酚的浓度对反应体系的影响。结果表明:峰电流密度与扫描速率的平方根及苯酚浓度呈线性递增关系,支持电解质的添加量在苯酚电解过程存在最佳值,多次扫描过程中峰电流密度有下降趋势。实验推断电解效率下降是由于电极表面被聚合物污染导致,这一现象对电解处理有机物种的系统控制过程具有重要意义。     

两级CSTR亚硝化启动及稳定运行试验研究

采用两级CSTR反应器对实际生活污水亚硝化的启动过程及稳定运行主要影响因素进行了研究.通过向生活污水里投加(NH₄)₂SO₄来提高进水氨氮浓度,并逐渐调整两级反应器的曝气强度至DO浓度分别为(1.5±0.12),(0.35±0.1) mg/L,历经45d即实现了亚硝化的启动,亚硝化率保持在90.3%以上,氨氧化率保持在91.2%以上.低氨氮生活污水运行时,通过第一级反应器中三组DO/ALR的效果对比,表明DO/ALR在1.2~2.0 mg O₂/(gN·d)时亚硝化效果最好.降低氨氮浓度以及增大HRT两种情况下导致ALR改变时,维持上述DO/ALR范围依然可以保证亚硝化的稳定.     

净化铁锰氨生物滤池内氨氮转化途径

为考察净化铁锰氨生物滤池内NH₄+-N的转化途径,利用氮素计量关系和沿程试验研究了净化铁锰氨生物滤池内产生TN_loss(氮损失)的原因和NH₄+-N转化途径. 结果表明,净化铁锰氨生物滤池内DO消耗异常,TN_loss不守恒,当进水ρ(NH₄+-N)平均值分别为1.262、2.296、3.111 mg/L时,NLR(氮损失率)分别能达到7.89%、12.91%、17.73%. 利用硝化反应和CANON(全程自养脱氮)方程式计算得出理论TN_loss和TDOC(理论耗氧量),与实际TN_loss和ADOC(实际耗氧量)的差值分别小于±0.030、±0.10 mg/L,各阶段NH₄+-N 通过CANON途径转化的比例分别为48.58%、60.77%、68.10%,硝化反应和CANON途径共同参与了NH₄+-N转化. 沿程试验结果表明,整个试验阶段,NO₂--N在滤层中均有积累,并在滤层厚度为10~18 cm内出现NO₂--N和NH₄+-N共存的现象,进一步证明CANON途径是净化铁锰氨生物滤池内产生TN_loss的原因.