环境浓度下的混合抗生素对普通小球藻的联合毒性

近年来,抗生素已成为一类备受关注的新型环境污染物。为了探究这类化合物对各类生物的毒性效应,本实验以红霉素(ERY)、恩诺沙星(ENR)、磺胺甲恶唑(SMX)这3种常见的抗生素作为代表,研究其单独作用和两两联合作用对普通小球藻的生长、蛋白合成及丙二醛(MDA)含量的影响。结果表明:ERY、ENR和SMX对小球藻的96 h-EC50分别为85.7、124.5和1 672.7μg·L~(-1),且3种抗生素两两联合时对小球藻的毒性作用类型均为协同作用。此外,当暴露于环境浓度的抗生素时,无论是单独加药还是联合加药,除ERY处理组的小球藻的蛋白合成被轻微抑制外,其他各处理组的蛋白含量与对照组相比,均展现出低剂量刺激效应。对于MDA产量,ENR处理组的MDA含量与对照组无显著差异,其他各处理组均高于对照组;故环境浓度下的ENR并没有对小球藻造成明显的氧化损伤,而其他2种抗生素则对小球藻造成了氧化损伤。该研究为低浓度混合抗生素在淡水环境中联合暴露的生态风险评估提供了科学依据。     

Effects of different types of biochar on the properties and reactivity of nano zero-valent iron in soil remediation

• Biochar enhanced the mobility and stability of zero-valent iron nanoparticles. • Particle performance was best when the BC:nZVI mass ratio was 1:1. • Bagasse-BC@nZVI removed 66.8% of BDE209. The addition of nano zero-valent iron (nZVI) is a promising technology for the in situ remediation of soil. Unfortunately, the mobility and, consequently, the reactivity of nZVI particles in contaminated areas decrease due to their rapid aggregation. In this study, we determined how nZVI particles can be stabilized using different types of biochar (BC) as a support (BC@nZVI). In addition, we investigated the transport behavior of the synthesized BC@nZVI particles in a column filled with porous media and their effectiveness in the removal of BDE209 (decabromodiphenyl ether) from soil. The characterization results of N₂ Brunauer–Emmett–Teller (BET) surface area analyses, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) indicated that nZVI was successfully loaded into the BC. The sedimentation test results and the experimental breakthrough curves indicated that all of the BC@nZVI composites manifested better stability and mobility than did the bare-nZVI particles, and the transport capacity of the particles increased with increasing flow velocity and porous medium size. Furthermore, the maximum concentrations of the column effluent for bagasse–BC@nZVI (B–BC@nZVI) were 19%, 37% and 48% higher than those for rice straw–BC@nZVI (R–BC@nZVI), wood chips–BC@nZVI (W–BC@nZVI) and corn stalks–BC@nZVI (C–BC@nZVI), respectively. A similar order was found for the removal and debromination efficiency of decabromodiphenyl ether (BDE209) by the aforementioned particles. Overall, the attachment of nZVI particles to BC significantly increased the reactivity, stability and mobility of B–BC@nZVI yielded, and nZVI the best performance.     

Industrial land expansion in rural China threatens environmental securities

• China’s rural industrial land (RIL) area quadrupled from 1990 to 2015. • RIL expansion cost 9% of China’s crop production and threatened human/ecosystem safety. • The underprivileged population bears a disproportionally large share of the risks. China’s rural industrialization has been a major driver for its rapid economic growth during the recent decades, but its myriad environmental risks are yet to be fully understood. Based on a comprehensive national land-use data set, our study shows that the area of China’s rural industrial land (RIL) quadrupled during 1990–2015, reaching 39000 km² in 2015, comparable to urbanization in magnitude but with a much greater degree of landscape fragmentation which implies stronger ecological and environmental impacts. About 91% of the protected areas in the central China were within 50 km from rural industrial land, thus exposed to industrial disturbances. Accelerated rural industrial land expansion, particularly in regions under high geo-hazard risks, led to dramatically increased environmental risks, threatening the safety and health of both rural industrial workers and residents. Moreover, negative effects from rural industrial land expansion could partially offset the crop production growth in recent decades. The underprivileged rural population in the west bears a disproportionally large share of the increased environmental risks. China urgently needs to design and implement sustainable policies to restrict and reshape its rural industrialization. This study aims to inspire policy makers and researchers to rethink the current model of industrial expansion and improve rural industrial land planning, which is important for achieving the sustainable development goals of China.     

膜生物反应器无剩余污泥排放的研究

本文介绍了以膜生物反应器为基础的剩余污泥产量最少或无剩余污泥产生的最新的污水处理理论和技术。从技术微生物基本生命活动的物质转化概念和细胞产生和平衡的理论,提出了确定维持微生物基本生命活动的物质转化系数的方法,从理论与实验上计实了膜生物反应器无剩余污泥排放的可能性。     

利用含油碳酸钙污泥制备橡胶填充剂

本文以中原油田含油碳酸钙污泥为研究对象,根据高分子理论化学和橡胶工程理论,论证了油田含油碳酸钙污泥开发含油橡胶填充剂的理论基础。经粉体加工,将含油碳酸钙污泥制备成实验用橡胶填充剂。通过橡胶工程实验及产品测试,结果表明,与正在使用的普通碳酸钙和纳米碳酸钙填充剂相比,含油碳酸钙污泥制备的填充剂对橡胶制品的性能没有明显的影响;在分散性、橡胶网状分子的交联性、磨耗、回弹性等方面,较普通碳酸钙和纳米碳酸钙的填充效果稍优。     

Lactate oxidation in pyrite suspension: a Fenton-like process in situ generating H2O2

Pyrite is a common mineral at many mining sites. In this study, the mineral pyrite was studied as a Fenton-like reagent for environmental concerns. We selected lactate as a model target molecule to evaluate the Fenton-like catalytic efficiency of pyrite upon organic oxidation. A complete set of control experiments in both aerobic and anaerobic atmospheres unequivocally established that the pyrite in aqueous solution could spontaneously in situ generate OH and H₂O₂, serving as a Fenton-like reagent to catalyze the oxidation of lactate to pyruvate with no need for additional H₂O₂. We called it the pyrite-only Fenton-like (PF) reagent. Monitoring concentration changes of lactate and pyruvate with the time indicated that the pyrite mediated the favorable pyruvate formation at pH 4.5, 60 °C, under air atmosphere. The PF reaction could be stimulated by visible light illumination. Under the optimum conditions, up to 50% of lactate was degraded within 10 d. The results suggest that pyrite and its Fenton-like processes may be potentially practical in wastewater treatment.     

Quantifying the Effects of Conservation Practices on Soil,Water, and Nutrients in the Loess Mesa Ravine Region of the Loess Plateau,China

A large number of soil and water conservation programs have been implemented on the Loess Plateau of China since the 1950s. To comprehensively assess the merits and demerits of the conservation practices is of great importance in further supervising the conservation strategy for the Loess Plateau. This study calculates the impact factors of conservation practices on soil, water, and nutrients during the period 1954–2004 in the Nanxiaohegou Catchment, a representative catchment in the Loess Mesa Ravine Region of the Loess Plateau, China. Brief conclusions could be drawn as follows: (1) Soil erosion and nutrient loss had been greatly mitigated through various conservation practices. About half of the total transported water and 94.8 % of the total transported soil and nutrients, had been locally retained in the selected catchment. The soil retained from small watersheds do not only form large-scale fertile farmland but also safeguard the Yellow River against overflow. (2) Check dam was the most appropriate conservation practice on the Loess Plateau. In the selected catchment, more than 90 % of the retained soil and water were accomplished by the dam farmland, although the dam farmland occupied only 2.3 % of the total area of all conservation measures. Retention abilities of the characteristic conservation practices were in the following order: dam farmland > terrace farmland > forest land and grassland. (3) The conservation practices were more powerful in retaining sediment than in reducing runoff from the Loess Plateau, and the negative effects of the conservation practices on reducing water to the Yellow River were relatively slight.     

Splenocyte apoptotic pathway in mice following oral exposure to cerium trichloride

With their widespread application in agriculture, industry, culture, medicine, and daily life, lanthanide compounds are being brought into the ecological environment and human body through food chains. It is important to know the acute and chronic effects of lanthanides on the environment, nature balance, and the human body after their entry into bodies and the environment. Lanthanides have been demonstrated to cause spleen apoptosis and decreased immunity of mice, but very little is known about the molecular aspects of these mechanism. In order to understand the spleen apoptotic mechanism induced by intragastric administration of 2, 10 and 20 mg kg(-1) body weight CeCl(3) for consecutive 60 d, we investigated the cerium accumulation, apoptosis, the expression levels of the apoptosis-related cytokines into apoptosis-related genes and proteins. The results demonstrated that cerium had obvious accumulation in the mouse spleen, leading to the significant increase of the spleen indices and splenocyte apoptosis. Furthermore, CeCl(3) could effectively activate caspase-3 and -9, decrease the Bcl-2 the levels of gene and protein, and increase the levels of Bax, and cytochrome c genes and their protein expressions, and promote reactive oxygen species production. It implied CeCl(3)-induced apoptosis in the mouse spleen via intrinsic pathway. Our findings suggest the need for great caution to handle the lanthanides for workers and consumers.     

基于GIS的广西农业暴雨洪涝灾害风险评估

以自然灾害风险评估理论和方法为指导,遥感本底数据、气象数据、基础地理信息数据、社会经济数据为基础数据,构建广西农业暴雨洪涝灾害风险评估指标体系,采用层次分析及加权综合法建立农业暴雨洪涝灾害风险评估模型;借助GIS技术,计算广西农业暴雨洪涝灾害致灾因子危险性、孕灾环境敏感性、承灾体易损性、防灾减灾能力及综合风险指数,并对广西农业暴雨洪涝灾害进行风险区划,采用相关分析法将广西农业暴雨洪涝灾害风险结果与广西历史暴雨洪涝灾情数据进行对比验证,研究结果表明,农业暴雨洪涝风险分布结果与洪涝灾情损失的空间分布基本吻合,南部沿海的风险性最强,西部风险性最小。