近岸海域典型水体中镉的水生态风险评估

为了解我国近岸海域重金属污染现状,以镉为目标污染物,选择北部湾、渤海湾、杭州湾、辽东湾、闽江口、珠江口、长江口、黄河口等8个典型海湾、河口区域作为评估目标区域进行水生态风险评估。研究结果显示:北部湾、渤海湾、杭州湾、闽江口、长江口、珠江口、黄河口等7个海域水体中镉的暴露水平较低,从2005至2013年其急、慢性暴露的最高潜在影响比例均低于5%,且整体呈下降趋势。辽东湾水体中镉从2005至2013年对水生生物的最高潜在影响比例为28.67%(95%置信区间26.29%~30.06%),5%、10%、15%、20%超过率对应的潜在影响比例分别为18.95%(17.84%~20.23%)、12.51%(11.65%~13.61%)、8.26%(7.40%~9.15%)、5.45%(4.62%~6.16%),其在2005—2010年间呈现略微上升趋势,2010—2013年间呈现下降趋势。水体中镉暴露水平主要受入海河流污染物输入的影响,其中五里河、大凌河影响最强。     

蛋白组学分析揭示出阿特拉津对非洲爪蟾的生殖毒性源于其诱导生殖细胞凋亡并干扰紧密连接蛋白和代谢相关信号通路

阿特拉津可对雄性脊椎动物生殖系统造成不良影响,但其中分子机制尚不明了。本文作者将非洲爪蟾(Xenopus laevis)暴露于100 ppb的阿特拉津120 d,利用同位素标记相对和绝对定量(iTRAQ)技术检测了非洲爪蟾睾丸和卵巢中蛋白图谱的变化,结果显示100 ppb阿特拉津可影响爪蟾发育,延迟和阻碍雄性细精管的形成。组学分析显示,睾丸中143种以及卵巢中121种蛋白均表达异常,这些蛋白与细胞凋亡、细胞间紧密连接以及代谢途径相关。
精选自Xiuping Chen, Jiamei Wang, Haojun Zhu, Jiatong Ding and Yufa Peng. Proteomics analysis of Xenopus laevis gonad tissue following chronic exposure to atrazine. Environmental Toxicology and Chemistry: Volume 34, Issue 8, pages 1744–1750, August 2015. DOI: 10.1002/etc.2980
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.2980/full     

Spatial heterogeneity of lake eutrophication caused by physiogeographic conditions: An analysis of 143 lakes in China

In order to identify the effect of geographic characteristics on the variations of nutrient concentrations and the utilization efficiency of nutrients by phytoplankton, data from 143 lakes, from 2008 to 2010, including three very different types of topography, i.e., the first topography ladder(FTL), second topography ladder(STL), and third topography ladder(TTL), were statistically analyzed. Lakes in the FTL and STL, located at high elevation(above1000 m) and low longitudes(lower than 105° E), were sporadically oligotrophic, whereas lakes in the TTL were almost all mesotrophic and eutrophic. The trophic level index(TLI)became higher with the rise of longitude. Two turning points(5 and 15°C) on the curve of TLI as function of the average annual temperature(AAT) corresponded with the AAT in different lake regions in the STL and TTL. Because the responses of TLI to AAT differ significantly, there were variations of nutrient and algal biomass concentrations in different lake regions in the same type of topography ladder. According to the differences in utilization efficiency of total nitrogen or total phosphorus by phytoplankton, China could be partitioned into six lake regions. Scientific nutrient criteria for each lake region shall be established considering these differences in China.     

Offspring sex in a TSD gecko correlates with an interaction between incubation temperature and yolk steroid hormones

We incubated eggs of the Japanese gecko Gekko japonicus at three temperatures, and measured yolk testosterone (T) and 17??-estradiol (E2) levels at three time points in embryonic development (oviposition, 1/3 of incubation, and 2/3 of incubation), to examine whether maternal influence on offspring sex via yolk steroid hormone deposition is significant in the species. Eggs incubated at 24?°C and 32?°C produced mostly females, and eggs incubated at 28?°C almost a 50:50 sex ratio of hatchlings. Female-producing eggs were larger than male-producing eggs. Clutches in which eggs were incubated at the same temperature produced mostly same-sex siblings. Yolk T level at laying was negatively related to eggs mass, and yolk E2/T ratio was positively related to egg mass. Results of two-way ANOVA with incubation temperature and stage as the factors show that: yolk E2 level was higher at 32?°C than at 24?°C; yolk T level was higher, whereas yolk E2/T ratio was smaller, at 28?°C than at 24?°C; yolk E2 and T levels were higher at 2/3 than at 1/3 of incubation. Our data in G. japonucus show that: (1) maternal influence on offspring sex via yolk steroid hormone deposition is significant; (2) incubation temperature affects the dynamics of developmental changes in yolk steroid hormones; (3) influences of yolk steroid hormones on offspring sex are secondary relative to incubation temperature effects; and (4) offspring sex correlates with an interaction between incubation temperature and yolk steroid hormones.     

湿式电除尘器极配改进及性能测定

极配形式作为电除尘器的核心组成部分,对电晕放电特性的影响十分重要。电除尘器极配系统电晕放电性能可用伏安特性曲线来描述和判断。通过实验研究了电场风速、雾滴粒径和喷水量对湿式电除尘器电晕放电特性的影响。结果表明:电场风速对起晕电压和火花放电电压的影响不大;在相同的试验条件下,随着电场风速的增大,伏安特性曲线向下偏移;在相同的电压下,雾滴粒径越大,电晕电流越大,但火花放电电压却降低;在一定的电场风速下,随着喷水量的增大,伏安特性曲线有向上偏移的趋势,但火花放电电压比不喷水时要低得多。     

Comparison of dynamic adsorption/desorption characteristics of toluene on different porous materials

Four different types of adsorbents, SBA-15, MCM-41, NaY and SiO₂, were used to study the dynamic adsorption/desorption of toluene. To further investigate the influence of pore structure on its adsorption performance, two SBA-15 samples with different microspores were also selected. It is shown that microporous material NaY has the largest adsorption capacity of 0.2873 mL/g, and the amorphous SiO₂ exhibits the least capacity of 0.1003 mL/g. MCM-41 also shows a lower break through capacity in spite of the relatively small pore diameter, because it can not provide the necessary small geometric confinement for the tiny adsorbates. However, the mesoporous SBA-15 silica with certain micropore volume shows relatively higher adsorption capacity than that of MCM-41 silica. The presence of micropores directly leads to an increase in the dynamic adsorption capacity of toluene. Although NaY has the highest adsorption capacity for toluene, its complete desorption temperature for toluene is high (>350℃), which limits its wide application. On the contrary, mesoporous silica materials exhibits a good desorption performance for volatile organic compounds at lower temperatures. Among these materials mesoporous SBA-15 samples, with a larger amount micropores and a lower desorption temperature, are a potentially interesting adsorbent for the removal of volatile organic compounds. This behavior should been related with the best synergetic effect of mesopores and micropores.     

Ammonium removal pathways and microbial community in GAC-sand dual media filter in drinking water treatment

A GAC-sand dual media filter (GSF) was devised as an alternative solution for drinking water treatment plant to tackle the raw water polluted by ammonium in place of expensive ozone-GAC processes or bio-pretreatments. The ammonium removal pathways and microbial community in the GSFs were investigated. The concentrations of ammonium, nitrite and nitrate nitrogen were monitored along the filter. Total inorganic nitrogen (TIN) loss occurred during the filtration. For 1 mg ammonium removal, the TIN loss was as high as 0.35 mg, DO consumption was 3.06 mg, and alkalinity consumption was 5.55 mg. It was assumed that both nitrification and denitrification processes occur in the filters to fit the TIN loss and low DO consumption. During the filtration, nitritation, nitrification and nitritation-anaerobic ammonium oxidation processes probably occur, while traditional nitrification and denitrification and simultaneous nitrification and denitrification processes may occur. In the GSFs, Nitrosomonas and Nitrospira are likely to be involved in nitrification processes, while Novosphingobium, Comamonadaceae and Oxalobacteraceae may be involved in denitrification processes.     

Projection pursuit cluster model and its application in water quality assessment

One of the difficulties frequently encountered in water quality assessment is that there are many factors and they cannot be assessed according to one factor, all the effect factors associated with water quality must be used. In order to overcome this issues the projection pursuit principle is introduced into water quality assessment, and projection pursuit cluster(PPC) model is developed in this study. The PPC model makes the transition from high dimension to one-dimension. In other words, based on the PPC model, multifactor problem can be converted to one factor problem. The application of PPC model can be divided into four parts: (1) to estimate projection index function Q(a) ; (2) to find the right projection direction a ; (3) to calculate projection characteristic value of the i th sample zi, and (4) to draw comprehensive analysis on the basis of zi. On the other hand, the empirical formula of cutoff radius R is developed, which is benefit for the model to be used in practice. Finally, a case study of water quality assessment is proposed in this paper. The results showed that the PPC model is reasonable, and it is more objective and less subjective in water quality assessment. It is a new method for multivariate problem comprehensive analysis.     

Evaluating the short-term effect of ambient temperature on non-fatal outdoor falls and road traffic injuries among children and adolescents in China: a time-stratified case-crossover study

● A study assessing the temperature-injury relationship was conducted among students. ● The maximum risks of injury appeared at moderate temperatures. ● The temperature effect on outdoor falls was greater in older students. Although studies have suggested that non-optimal temperatures may increase the risk of injury, epidemiological studies focusing on the association between temperature and non-fatal injury among children and adolescents are limited. Therefore, we investigated the short-term effect of ambient temperature on non-fatal falls and road traffic injuries (RTIs) among students across Jiangsu Province, China. Meteorological data and records of non-fatal outdoor injuries due to falls and RTIs among students aged 6–17 were collected during 2018–2020. We performed a time-stratified case-crossover analysis with a distributed lag nonlinear model to examine the effect of ambient temperature on the risk of injury. Individual meteorological exposure was estimated based on the address of the selected school. We also performed stratified analyses by sex, age, and area. A total of 57322 and 5455 cases of falls and RTIs were collected, respectively. We observed inverted U-shaped curves for temperature-injury associations, with maximum risk temperatures at 18 °C (48th of daily mean temperature distribution) for falls and 22 °C (67th of daily mean temperature distribution) for RTIs. The corresponding odds ratios (95% confidence intervals) were 2.193 (2.011, 2.391) and 3.038 (1.988, 4.644) for falls and RTIs, respectively. Notably, there was a significant age-dependent trend in which the temperature effect on falls was greater in older students (P-trend < 0.05). This study suggests a significant association between ambient temperature and students’ outdoor falls and RTIs. Our findings may help advance tailored strategies to reduce the incidence of outdoor falls and RTIs in children and adolescents.     

固定污染源烟气中可凝结颗粒物监测技术现状及展望

随着国家对大气环境治理的推进,可凝结颗粒物(CPM)成为工业烟气防治的关键污染物。CPM在烟道高温环境中为气态物质,排入大气环境后快速凝结成颗粒态物质,对其进行准确测量是国内外的前沿技术挑战之一。通过研究分析CPM在烟气和烟羽中演化特征与监测技术现状,阐明CPM的概念、形成机制与排放特征,阐释已有的工业烟气CPM采集与分析方法及其存在的问题,并进一步对超低排放烟气中CPM的在线监测和质控技术提出展望。