生态补水对玄武湖水质的影响

分析南京玄武湖1997年-2010年的水质变化,以及生态补水与玄武湖水质变化的关系。结果表明,玄武湖于1998年实施生态补水,随着生态补水的持续运行和生态补水量的不断增加,玄武湖水质得以显著改善,其水质类别由生态补水前的劣V类水体转为V类水体,并接近于Ⅳ类水体,富营养化程度由重度富营养化水平转为轻度富营养化水平。目前玄武湖主要营养物质来源于生态补水,相关性分析显示各湖区TN浓度与生态补水中TN浓度呈显著相关关系。     

Blood mercury concentration among residents of a historic mercury mine and possible effects on renal function: a cross-sectional study in southwestern China

This cross-sectional study aimed to investigate blood mercury (B-Hg) concentration of residents living in the vicinity of Chatian mercury mine (CMM) in southwestern China and to assess the possible effects on renal function. It evaluates the effects of gender and age (children, <18 years; adults, 18–60 years; elderly, >60 years) on the B-Hg and serum creatinine (SCR) and serum urea nitrogen (SUN) levels. In the CMM, elevated levels were found for B-Hg, SCR, and SUN with mean values at 6.09 μg/L, 74.21 μmol/L, and 13.26 mmol/L, which were significantly higher than those in the control area, respectively. Moreover, the coefficients between paired results for B-Hg and SCR and SUN levels were positive at statistical significance (B-Hg vs. SCR, r?=?0.45, p?<?0.01; B-Hg vs. SUN, r?=?0.20, p?<?0.05). The aforementioned results revealed that mercury exposure can cause human renal function impairment. B-Hg, SCR, and SUN can also be useful biomarkers to assess the extent of mercury exposure among residents in areas with extensive mining activities. Furthermore, data analysis revealed that there was a tendency for higher B-Hg, SCR, and SUN levels in females than in males, and the levels of B-Hg, SCR, and SUN increased among the older residents. We conclude that females and the elderly in the mining area were more susceptible to mercury exposure, and therefore, they deserve further research.     

火灾发生率空间分异及影响因素研究

为了探究我国火灾空间聚集特征与影响因素的空间异质性,采用全局莫兰指数、局部莫兰指数、逐步回归模型、地理加权回归模型、地理探测器方法对我国地级市单元进行研究。研究结果表明:我国火灾发生率具有显著的聚集性;我国火灾发生率较低的“冷点”区域有1个,火灾发生率较高的“热点”区域有4个;人均GDP、城镇居民人均可支配收入、人口密度、年平均气温4 个因素的影响效应具有空间异质性。人均GDP与火灾发生率为正相关,另外3影响因素对火灾发生率的作用表现出正负2种相关关系;2因素交互作用要比单因素作用于火灾发生率时影响力更显著,各影响因素的交互作用类型有非线性增强型和双因子增强型2种。     

黄、渤海滨海带大气颗粒物时空分布与来源特征

PM10作为大气污染物监测的主要指标之一,探究大气PM10浓度对大气环境质量和人体健康评价具有重要意义。黄、渤海滨海带包括京、津和辽、冀、鲁、苏等工、农业大省,区域大气PM10污染的时空分布和来源特征具有复杂性和典型性。在锦州、北京、天津、烟台、青岛、连云港和盐城7个城市布设10个采样点,含7个城市点和3个农村点,开展为期一年的大气颗粒物的采样;同时,于冬季1月和夏季7月在锦州、天津和烟台进行合计60 d的加密采样,藉以确定研究区域大气PM10的时空分布和来源特征。结果表明,黄、渤海滨海带大气年均PM10总浓度为(129’18)"g·m~(-3),单月最低值出现在2015年7月盐城农村样点15"g·m~(-3),最高值为2015年3月北京城市点307"g·m~(-3)。盐城大气PM10浓度(城市点(85’27)"g·m~(-3)和农村点(66’35)"g·m~(-3))显著低于其他样点大气PM10浓度。渤海滨海带中西部的京(140’68"g·m~(-3))、津(169’60"g·m~(-3))两市大气PM10年均浓度显著高于东部的锦州(125’41"g·m~(-3))和烟台(109’31"g·m~(-3));而且黄海滨海带大气PM10年均浓度(114"g·m~(-3))显著低于渤海滨海带年均浓度(136"g·m~(-3)),总体上表现出西高东低、北高南低的特征。黄、渤海滨海带城市点和农村点年均浓度分别为(129’18)"g·m~(-3)和(112’30)"g·m~(-3);农村点春冬季大气PM10浓度和城市点浓度相当,无显著差异,夏秋季大气PM10浓度略低于城市浓度,表明农村地区大气颗粒物污染情况也较为严重,需受到关注。区域内PM10浓度季节变化整体表现为春冬高、夏秋低。利用多元回归分析初步判断黄、渤海滨海带PM10属于复合来源,大气PM10浓度约30%的变化与降水、人均能耗和沙尘天气相关。黄、渤海滨海带大气PM10浓度的昼夜变化不大,大气PM10浓度与气温呈现正相关,与风速和降水呈现负相关,表现为受各种气象因素综合作用的影响。     

Assessment of leaching behavior and human bioaccessibility of rare earth elements in typical hospital waste incineration ash in China

Leaching behavior and gastrointestinal bioaccessibility of rare earth elements (REEs) from hospital waste incineration (HWI) fly and bottom ash samples collected from Beijing and Nanjing Cities were assessed. In the same ash sample, the leaching concentrations of individual REEs determined by the Toxicity Characteristic Leaching Procedure (TCLP) were higher than those detected by the European standard protocol (EN-type test), thereby suggesting that the low pH value of leaching solution was an important factor influencing the leachability of REE. The REE bioaccessibility results, which were evaluated using the physiologically based extraction test (PBET), indicated that REEs were highly absorbed during gastric phase by dissolution; and subsequently precipitated and/or re-adsorbed in small intestinal phase. The relative amounts of the total REEs extracted by the TCLP method, EN-type test and PBET test were compared. In addition to the pH value of extraction solutions, the chelating role of REEs with organic ligands used in the PBET method was also an important parameter affecting REE adsorption in human body. Additionally, this study showed that REEs were extracted by these methods as concomitants of heavy metals and anions (NO₃ ^–, F^–, SO₄ ^2–, and Cl^–) from HWI ash, which probably caused the remarkably complex toxicity on human body by the exposure pathway.

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Application of phosphate solubilizing bacteria in immobilization of Pb and Cd in soil

Environmental Science and Pollution Research - In the present study, heavy metal (HM)-tolerant phosphate solubilizing bacteria (PSB) were isolated and their performance during the remediation of Pb...     

Effects of an iron-silicon material,a synthetic zeolite and an alkaline clay on vegetable uptake of As and Cd from a polluted agricultural soil and proposed remediation mechanisms

Economic and highly effective methods of in situ remediation of Cd and As polluted farmland in mining areas are urgently needed. Pot experiments with Brassica chinensis L. were carried out to determine the effects of three soil amendments [a novel iron-silicon material (ISM), a synthetic zeolite (SZ) and an alkaline clay (AC)] on vegetable uptake of As and Cd. SEM–EDS and XRD analyses were used to investigate the remediation mechanisms involved. Amendment with ISM significantly reduced the concentrations of As and Cd in edible parts of B. chinensis (by 84–94 % and 38–87 %, respectively), to levels that met food safety regulations and was much lower than those achieved by SZ and AC. ISM also significantly increased fresh biomass by 169–1412 % and 436–731 % in two consecutive growing seasons, while SZ and AC did not significantly affect vegetable growth. Correlation analysis suggested that it was the mitigating effects of ISM on soil acidity and on As and Cd toxicity, rather than nutrient amelioration, that contributed to the improvement in plant growth. SEM–EDS analysis showed that ISM contained far more Ca, Fe and Mn than did SZ or AC, and XRD analysis showed that in the ISM these elements were primarily in the form of silicates, oxides and phosphates that had high capacities for chemisorption of metal(loid)s. After incubation with solutions containing 800 mg L^?1 AsO₄ ^2? or Cd²⁺, ISM bound distinctly higher levels of As (6.18 % in relative mass percent by EDS analysis) and Cd (7.21 % in relative mass percent by EDS analysis) compared to SZ and AC. XRD analysis also showed that ISM facilitated the precipitation of Cd²⁺ as silicates, phosphates and hydroxides, and that arsenate combined with Fe, Al, Ca and Mg to form insoluble arsenate compounds. These precipitation mechanisms were much more active in ISM than in SZ or AC. Due to the greater pH elevation caused by the abundant calcium silicate, chemisorption and precipitation mechanisms in ISM treatments could be further enhanced. That heavy metal(loid)s fixation mechanisms of ISM ensure the remediation more irreversible and more resilient to environmental changes. With appropriate application rate and proper nutrients supplement, the readily available and economic ISM is a very promising amendment for safe crop production on multi-metal(loids) polluted soils.     

以水鸟保育为目标的水稻田构建技术及效果评估

海岸带自然湿地具有重要的水鸟保育价值。近年来,大规模的海岸带围垦造成了海岸带自然湿地的消失和质量退化,导致水鸟栖息地面积和质量的急剧下降,严重降低了水鸟的保育效果。海岸带自然湿地围垦后,部分转化为水鸟保育效果较差的工业模式水稻田。提升水稻田的水鸟保育效果,关键在于改善水稻田的构建技术。根据海岸带水稻田的种植管理模式和水鸟的生境选择特点,提出了一种以水鸟保育为目标的水稻田构建技术,以生态工程手段提升水稻田的水鸟保育效果。该技术的核心内容为在水稻田中构建水池单元,并设置生境小岛等功能组件,建立水稻田复合生态系统,实现多种种植和养殖。在满足水稻田生产管理需要的同时,为水鸟提供丰富的食物和适宜的多样性栖息场所。为验证该技术的水鸟保育效果,2013年夏季在崇明东滩依此技术构建了10 hm~2水稻试验田。2013年秋季至2014年春季,对比工业模式水稻田,各选取总面积10 hm~2的调查样方,开展一个完整年度的水鸟群落调查,每个季度调查5次,共计15次水鸟调查。水稻试验田共记录到水鸟34种,平均密度为41.87±6.62只/hm~2;工业模式水稻田共记录到水鸟12种,平均密度为2.08±0.45只/hm~2,水稻试验田的水鸟种类和密度均显著高于工业模式水稻田。结果表明,水稻田构建技术能够显著增加水稻田的水鸟种类和数量,提升水稻田的水鸟保育效果,从而弥补海岸带自然湿地缺失对水鸟造成的影响。水稻田构建技术可以为海岸带水稻田的水鸟保育工作提供了科学依据,同时为海岸带受损湿地的修复和水鸟栖息地的优化改造提供了参考案例。     

我国畜禽集约化养殖环境压力及国外环境治理的启示

集约化养殖是我国畜禽产业发展的必然趋势,但畜禽集约化养殖带来的环境污染也日益严重。通过测算近10 a来的全国畜禽养殖废弃物产生总量及废弃物中氮、磷养分的排放总量,以欧盟畜禽耕地承载负荷为标准,建立畜禽粪便土地负荷警报值等级,分析得出我国全国及各区域畜禽养殖的环境压力:从近5 a全国层面看,以氮养分测算的耕地负载警报值在0.7左右,且2009~2011年的警报值已经超过07,畜禽氮养分的耕地负荷已经开始对环境产生污染威胁;而以磷肥测算的耕地负载警报值已经超过1,对环境造成了较严重的污染威胁。从2010年具体区域情况看,以氮养分测算的耕地负载警报值超过07的达到17个省份,其中河南、湖南、广东、四川污染较严重,北京的畜禽养殖氮养分环境污染已经到严重的程度;以磷养份测算的耕地负载警报值已有21个省份超过1,北京和广东的耕地负载警报值已接近3,磷养分的环境污染已很严重。最后,探讨了发达国家畜禽养殖环境压力及环境治理措施对我国的启示     

丙烯酸酯类高吸油树脂的合成及其吸附性能

采用悬浮聚合法,以甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)为单体、二乙烯苯(DVB)为交联剂、过氧化苯甲酰(BPO)为引发剂,合成了一种丙烯酸酯类高吸油树脂。实验结果表明,在m(MMA)∶m(BA)=0.5、DVB加入量为0.8%、BPO加入量为1.2%的最佳条件下,树脂对氯仿的吸油率可达30.6 g/g,对氯仿、柴油、甲苯、废机油、花生油、丙酮等有机溶剂和油品的保油率可达90.0%以上。