施肥和秸秆覆盖对成都平原区农田氮和磷流失的影响

近年来由于氮、磷肥料过量施用造成了严重的污染问题和富营养化现象,而且这种污染问题在稻田区域更加明显.因此,采用田间小区试验方法,通过对2018年和2019年田间实地监测,在自然降雨条件下,对成都平原区不同施肥量以及秸秆覆盖对湿沉降和地表径流氮和磷的影响进行研究.结果表明,湿沉降氮养分主要以铵态氮存在,磷养分主要以可溶性总磷存在,氮和磷沉降主要发生在6～8月这3个月.地表径流量与降雨量呈正比,而地表径流氮养分浓度与降雨量呈反比.在2018年和2019年,增氮处理TR3总氮流失量分别为4.75 kg·hm^-2和2.68 kg·hm^-2,比常规处理TR1流失量增加26.73%和43.32%,是流失量最高的处理;减氮处理TR4总氮流失量分别为2.91 kg·hm^-2和1.37 kg·hm^-2,比常规处理TR1流失量降低了36.33%和26.74%,是流失量最小的处理.优化施肥处理TR2和减氮处理TR4能够有效降低地表径流磷素的流失,集中高强度降雨会降低地表径流总磷中颗粒态磷的含量.氮养分的流失主要集中于7～...     

矿山酸性废水中和渣制备建筑砌块

为了实现矿山酸性废水中和渣资源化,采用硅酸盐水泥(32.5R和42.5R)、铝酸盐水泥3种胶凝材料固化中和渣制备建筑砌块。在抗压强度和浸出毒性测定的基础上,通过X-射线衍射分析、热重分析等实验手段,探究了水泥矿物水化及其与中和渣中主要物质作用机理。研究结果表明,当m(水泥)∶m(干污泥)∶m(水)=1∶0.5∶0.75时,3种胶凝材料制备免烧砖的抗压强度均达到25 MPa以上,明显高于普通黏土烧结砖。     

微囊藻毒素的环境暴露、毒性和毒性作用机制研究进展

微囊藻毒素(MCs)是富营养化淡水水体中蓝藻的爆发性繁殖产生的最常见的藻毒素,因其分布广、结构稳定、毒性大引起了科学界的广泛关注。本文系统梳理了微囊藻毒素在我国水体中的污染现状和典型毒性效应及毒性作用机制。另外,针对目前藻毒素研究的不足提出了建议,可为有效降低环境中微囊藻毒素的潜在安全风险及深入研究其生态毒性效应提供支持。     

拟柱孢藻毒素生态毒性的研究进展和展望

随着全球变暖的加剧,拉氏拟柱胞藻（Cylindrospermopsis raciborskii）表现出从热带和亚热带地区向温带地区迁移和扩张的趋势。拟柱孢藻过度繁殖引发的主要生态环境问题是其有毒次级代谢产物—拟柱孢藻毒素（Cylindrospermopsin,CYN）的大量产生。这种蓝藻毒素水溶性很高,可长时间停留在水体中,对动植物和人类健康造成威胁。近年来,国际上对CYN的研究越来越多,研究范围也日趋广泛,而国内的相关研究却很少。本文根据现有的研究结果,介绍了CYN的分子结构和理化特性;总结了CYN可能对水生生物、土壤作物和人类健康造成的影响和危害,并对相应的致毒机理进行了归纳总结;最后对未来的研究内容和方向进行了展望。     

丹江口水库新增淹没区农田土壤重金属源解析

丹江口水库是南水北调中线工程水源地,研究新增淹没区农田土壤重金属分布、富集特征并解析其来源,对水库的水质安全保障具有重要意义.通过测定新增淹没区169个农田土壤样品中8种重金属（Cd、Cr、Cu、Ni、Pb、Zn、As、Mn）含量,对土壤重金属污染状况进行了分析.结果表明：Cr的平均含量（45.11mg/kg）均低于库区土壤环境背景值,而Cd的平均含量（1.04mg/kg）均高于背景值;除Cu外,Cd、Cr、Ni、Pb、Zn和As在丹库的空间变异性较强,变异系数分别为0.58、0.72、0.58、0.74、0.35、1.12;Cd和As是丹江口水库新增淹没区的主要污染元素,其中Cd的富集系数高达10.3,中度以上污染区为86.6%,As中度及以上污染区为2.6%;新增淹没区农田土壤重金属来源主要为自然源（Cr、Cu、Ni、Pb、Zn、Mn）、农业源（As）、工业和生活源（Cd）,贡献率分别为44.7%、15.9%和15.4%.     

Assessment of pollution of potentially harmful elements in soils surrounding a municipal solid waste incinerator,China

We assessed the contamination levels of Mn, Zn, Cr, Cu, Ni, Pb, As and Hg and the risks posed by these potentially harmful elements in top-soils around a municipal solid waste incinerator (MSWI).We collected 20 soil samples, with an average pH of 8.1, and another fly ash sample emitted from the MSWI to investigate the concentrations of these elements in soils. We determined the concentrations of these elements by inductively coupled plasma–optical emission spectrometer (ICP-OES), except for Hg, which we measured by AF-610B atomic fluorescence spectrometer (AFS). We assessed the risks of these elements through the use of geoaccumulation index (I _geo), potential ecological risk index (RI), hazard quotient (HQ _i ) and cancer risk (Risk _i ). The results showed that concentrations of potentially harmful elements in soil were influenced by the wind direction, and the concentrations of most elements were higher in the area northwest of the MSWI, compared with the area southeast of the incinerator, with the exception of As; these results were in accordance with those results acquired from our contour maps. According to the I _geo values, some soil samples were clearly polluted by Hg emissions. However, the health risk assessment indicated that the concentrations of Hg and other elements in soil did not pose non-carcinogenic risks to the local populations. This was also the case for the carcinogenic risks posed by As, Cr, and Ni. The carcinogenic risk posed by As was higher, in the range 6.49 × 10^–6–9.58 × 10^–6, but this was still considered to be an acceptable level of risk.

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邻苯二甲酸二乙基己酯(DEHP)对马氏珠母贝(Pinctada martensi)血细胞免疫功能及氧化应激效应的影响

邻苯二甲酸二乙基己酯(DEHP)是一种持久性的有机污染物(POPs),具有潜在毒性、致癌性。选取马氏珠母贝(Pinctada martensi)为研究对象,研究DEHP对其血淋巴细胞免疫功能和脂质过氧化水平的影响。将成年马氏珠母贝暴露于不同浓度(0.5、2.0、8.0、16.0 mg·L-1)的DEHP中,暴露14 d后测定血细胞数目(THC)、吞噬能力(phagocytic activity)、细胞膜稳定性(cell membrane stability)、脂质过氧化程度(LPO)和总谷胱甘肽含量(T-GSH)的变化。结果显示,血细胞数目随DEHP浓度的升高而降低,呈明显的剂量-效应关系,最低可见效应浓度(LOEC)0.5 mg·L-1。细胞膜稳定性和吞噬活力均随DEHP浓度的升高,呈现先升高后降低的变化趋势,其LOEC值分别小于2和8 mg·L-1。细胞中丙二醛(MDA)含量随染毒浓度增加逐渐升高,在8 mg·L-1浓度组达到最高值,之后降低,与之相应的脂质过氧化水平也呈现先升高后降低的变化趋势,LOEC2 mg·L-1。8mg·L-1浓度组的总谷胱甘肽含量与对照组相比存在显著差异性(p0.05),LOEC8 mg·L-1。研究结果表明:DEHP染毒14 d对马氏珠母贝血淋巴细胞免疫功能有明显的影响,同时还会诱导机体产生氧化应激效应,在所测试的指标中,血细胞计数对DEHP的胁迫最敏感(LOEC0.5 mg·L-1),细胞膜稳定性和脂质过氧化水平的敏感性次之(LOEC2 mg·L-1)。     

Cation exchange resin supported nanoscale zero-valent iron for removal of phosphorus in rainwater runoff

Self-made cation exchange resin supported nanoscale zero-valent iron （R-nZVI） was used to remove phosphorus in rainwater runoff. 80% of phosphorus in rainwater runoff from grassland was removed with an initial concentration of 0.72 mg. L-1 phosphorus when the dosage of R-nZVl is 8 g per liter rainwater, while only 26% of phosphorus was removed when using cation exchange resin without supported nanoscale zero-valent iron under the same condition. The adsorption capacity of R-nZVI increased up to 185 times of that of the cation exchange resin at a saturated equilibrium phosphorous concentration of 0.42 mg. L-1. Various techniques were implemented to characterize the R-nZVI and explore the mechanism of its removal of phosphate. Scanning electron microscopy （SEM） indicated that new crystal had been formed on the surface of R-nZVI. The result from inductive coupled plasma （ICP） indicated that 2.1% of nZVI was loaded on the support material. The specific surface area was increased after the load of nanoscale zero-valent iron （nZVI）, according to the measurement of BET-N2 method. The result of specific surface area analysis also proved that phosphorus was removed mainly through chemical adsorption process. X-ray photoelectron spectroscopy （XPS） analysis showed that the new product obtained from chemical reaction between phosphate and iron was ferrous phosphate.     

电镀污泥中重金属酸浸条件试验

酸浸条件的选择是资源化利用和安全处置电镀污泥中重金属元素的关键。以盐城市某企业含铜镍电镀污泥为研究对象,考察了酸浸条件对重金属铜镍的浸出率的影响。结果发现:硫酸浸出效果优于盐酸和硝酸,其最佳浓度为1.5 mol/L;污泥粒径越小,其重金属浸出率越高;升高浸取温度可以显著提高浸出率。正交实验结果表明:固液比为1∶15及45℃条件下,1.5 mol/L的硫酸溶液对粒径为100目的电镀污泥中铜、镍2 h后的浸出率分别达到97.59%和91.60%。     

Diel and seasonal methane flux across water–air interface of a subtropic eutrophic pond

Abstract

Methane, which is an important greenhouse gas, has received less attention regarding its flux in ponds. Small ponds, whose area only occupies approximately 8.6%, comprise the bulk of CH₄ efflux from lakes and ponds on a global scale. However, temporal and spatial variability, as well as consequences of CH4 fluxes from ponds, remains unknown. The aim of this study was to examine using 4 field experiments diel methane (CH₄) fluxes from a subtropic eutrophic pond in different seasons. For the eutrophic pond, the mean CH₄ efflux for all seasons was 1.772?mg/m²/h, and CH₄ emissions in summer were approximately three-fold higher than total of winter, spring, and autumn. Methane diffusive emissions were positively correlated with water temperature, dissolved oxygen (DO) and air temperature but negatively related to pH and to the difference between water temperature and air temperature. The diel diffusive CH₄ flux among different seasons varied significantly. The CH₄ bubble flux did not differ markedly in winter, spring and autumn, but the quantity in summer was significantly different from all other seasons. Bubble is the main pathway for CH₄ emissions. The CH₄ ebullition flux accounts for 66, 71, 97 and 98% of the total in winter, spring, summer and autumn, respectively. On an annual scale, the CH₄ ebullition flux accounts for 77% of the total fluxes (diffusive?+?ebullitive). Our results show that further investigations need to be carried out to probe temporal variability of CH₄ fluxes in ponds located in different climate zones for better understanding of the global carbon budget, which is critical to predict future climate changes.