淋洗液对沿海滩涂设施土壤重金属的洗脱效应

为剖析不同淋洗液作用下土壤重金属的形态分布及淋洗效应,探究重金属活性钝化与总量消减调控技术,本文采用土柱模拟自然淋洗结合形态分析的方法,研究了不同浓度柠檬酸、EDTA和秸秆粉3种淋洗液对土壤Cd、Pb和Cr全量、形态分布及洗脱效果的影响.结果表明：盐碱环境下,柠檬酸和秸秆粉对土壤重金属的淋洗率不足1%,而EDTA对Pb和Cd的淋洗率分别达到24.62%和80.56%.形态分析结果表明：各处理对土壤Cd、Pb和Cr形态组成的影响程度表现为秸秆粉 > EDTA > 柠檬酸,EDTA和柠檬酸可增加酸溶态和可还原态含量进而促进重金属洗脱,但同时也提高了土壤有效态重金属含量并增加安全风险.秸秆粉对Cd和Pb的钝化效果最显著,促进其由其他形态向残渣态转化,但秸秆粉对Cr形态分布的影响较弱.     

基于热力数值模式的营口海域海冰单轴压缩强度分布规律

海冰灾害对冰区人类经济活动有着重要影响。本文基于2020/2021年冬季在将军石港观测的海冰温度与海冰盐度数据,结合海冰卤水体积参数化方案,给出基于海冰温度的海冰卤水体积分数评估公式;结合近67年的海冰温度计算结果,重现历年海冰单轴压缩强度演变过程,发现营口海域海冰单轴压缩强度呈减小趋势（0.0027 MPa/a）;分析海冰单轴压缩强度的概率分布,发现20世纪90年代后低强度海冰发生概率增大;评估营口海域20世纪60年代与近十年不同重现期下的单轴压缩强度,发现随着重现期的增大两个年份对应的力学强度差值也越来越大,且规范给出的重现期强度值小于上述计算结果。本文可为冰区经济活动的防灾减灾精细化管理提供科学支撑。     

Subcellular distribution op neurotoxic esterase activity in lamb and mouse brain

Abstract

Brain tissue samples of nice (7.5 g from 25 mouse brains and lamb (25 g) were homogenized and subcellular fractions prepared in order to assay the distribution of neurotoxic esterase (NTE) activity. The specific inhibitor, N,N‐diisopropylphosphorodiamidic fluoride (mipafox) was synthesized and purified. Maximum specific activity of NTE was reached in the microsomal fraction (110,000 g) while the enzyme activity in the soluble fraction (110,000 g) was extremely low. This subcellular distribution of NTE activity in mammal brains is an original contribution. Brain microsomal fraction is suggested to be a more reliable source for the highest activity of NTE. The specific activity of NTE of lamb brain was much higher than that of mouse brain. This night help interpretation of the characteristic species variation in susceptibility to NTE inhibitors which are known to be potent delayed neurotoxic agents.     

Phosphorus fractions and adsorption characteristics of floodplain sediments in the lower reaches of the Hanjiang River, China

The phosphorus fractions and adsorption characteristics of seven floodplain sediment samples collected in the lower reaches of China’s Hanjiang River were studied. Most phosphorus fractions showed a marked downstream increase in response to point-source inputs from urban areas. Total phosphorus (TP) contents in the sediments ranged from 603.68 to 945.25 mg.kg⁻¹. Inorganic phosphorus (IP) was the major component of TP, and calcium-bound phosphorus (Ca–P) was the major fraction of IP. The distribution characteristics of the phosphorus contents were affected by sediment grain size and hydrodynamic conditions. The maximum phosphorus adsorption capacities (Q _max) and the half-saturation concentration (k) were obtained using an improved Langmuir model. Native adsorbed exchangeable phosphorus content (w _NAP) and the zero-equilibrium phosphorus concentration value (c _EPC0) were subsequently calculated. The effects of sediment grain size, temperature, and disturbance on the phosphorus adsorption isotherms were also studied. The results showed that phosphorus adsorption on floodplain sediments was primarily chemisorption; the particle concentration effect played a more important role at a disturbance intensity of 150 r.min⁻¹ (on a shaker table) than at 100 r.min⁻¹.     

强制对流换热器表面CaCO3附着垢方解石及文石晶体质量分数变化分析

利用工业循环冷却水动态模拟循环装置,对模拟换热器壁面CaCO3附着垢晶体进行了XRD衍射分析表明,CaCO3附着垢晶体主要由方解石和文石两相所组成。结合方解石和文石晶体物相含量的XRD定量分析,分析了随着循环水流速增大,两者的质量分数变化关系。研究表明,当水流速度从0.401 m·s-1升高至1.338 m·s-1时,CaCO3附着垢中方解石和文石的质量分数分别呈现降低和增加趋势,且附着垢中文石的质量分数明显比方解石的质量分数偏高。从CaCO3晶体的生长以及CaCO3晶粒所受的附着力与水流剪切应力角度分析了上述变化的原因。     

Response of antioxidase in viscera of Pagrosuma Major larvae to water soluble fraction of hydrocarbons in No.0 diesel oil

ＩｎｔｒｏｄｕｃｔｉｏｎＡｑｕａｔｉｃｆａｒｍｓｌａｒｇｅｒｔｈａｎ 1 4ｋｍ2 ａｒｅｌｏｃａｔｅｄｉｎｔｈｅｎｏｒｔｈｅｒｎｐａｒｔｏｆＷｅｓｔＨａｒｂｏｒ,ＸｉａｍｅｎＭｕｎｉｃｉｐａｌｉｔｙｏｆＣｈｉｎａ.Ｔｈｅｓｅｆａｒｍｓａｒｅｕｎｄｅｒｇｒｅａｔｅｎｖｉｒｏｎｍｅｎｔａｌｓｔｒｅｓｓｏｗｉｎｇｔｏｒａｐｉｄｅｃｏｎｏｍｉｃｄｅｖｅｌｏｐｍｅｎｔ.Ｉｎｒｅｃｅｎｔｙｅａｒｓ,ｄｅｔｅｒｉｏｒａｔｉｎｇｆｒｅｓｈｗａｔｅｒｆｉｓｈｅｒｙ,ｃｏｎｃｏｍｉｔａｎｔｗｉｔｈｉｎｃｒｅａｓｉｎｇｍｏｒ…     

白土渣中润滑油回收技术的研究

研究开发了一种回收白土渣中润滑油的新技术--溶剂抽提技术.通过对润滑油回收量的综合比较,确立了实验所用的抽提溶剂及处理工艺的操作条件.结果表明:用石脑油馏分(60～90℃)抽提溶剂,最佳溶剂与白土渣投量比为1:1,抽提次数为2,温度为室温,搅拌时间为15min且回流液质量百分比为5%情况下,润滑油回收率为92%左右,并且可形成稳定的循环操作模式,为溶剂抽提法回收白土渣中润滑油的工业化应用提供了科学依据.     

黄河干流沉积物重金属的赋存形态特征及污染评价

重金属毒性强、在环境中不易降解,可通过食物链在人体累积,进而对流域生态环境及人类健康产生严重影响.2019年9月,沿黄河干流调查了14个断面,分析了沉积物中6种重金属（As、Cd、Cr、Cu、Pb和Zn）的总量及其赋存形态,采用地累积指数法、潜在生态风险指数法和风险评价编码法对沉积物重金属污染程度和生物有效性进行风险评价,采用主成分分析和冗余分析解析了重金属的主要来源.结果发现,重金属的含量平均值排序为：Cr>Zn>Cu>Pb>As>Cd,相对于各河段的背景值,Cd的超标率最高,达到85.7%.沉积物中As、Zn、Pb和Cu均以可氧化态为主,Cd以弱酸溶解态和残渣态为主,Cr则以残渣态为主.As、Cr、Cu、Pb和Zn的生物有效性均表现出上游最低,中游升高,下游降低的趋势.风险评价表明Cd是黄河干流污染风险级别最高的元素,极易对生态环境造成严重的威胁,应当优先防控,尤其是干流内蒙古段.PCA和RDA分析揭示了细颗粒泥沙和总有机质对重金属污染的主控作用,因此在黄河流域应重点防控随土壤侵蚀和泥沙迁移流失的重金属污染.     

室内人体行走引起颗粒物再悬浮的试验研究

室内人员活动是室内颗粒物再悬浮的重要因素,研究室内颗粒物再悬浮对评估室内空气质量有重要意义.以南开大学津南校区某公共教室为研究区域,通过现场试验研究了室内地面不同积尘负荷下,人员行走引起的PM_2.5再悬浮浓度及其扩散速率.结果表明:①不同时间间隔内的室内地面总颗粒积尘负荷不同,时间间隔为3、7、15 d时,室内PM_2.5积尘负荷分别为0.11、0.18、0.30 g/m2.②室内地面不同总颗粒积尘负荷下,在室内中心过道处行走时引起的PM_2.5再悬浮浓度约1 min后达到最高值,PM_2.5再悬浮浓度达到最高值的时间与地面不同总颗粒积尘负荷的关系不明显.③随着室内地面总颗粒积尘负荷的增加,人体行走引起的PM_2.5再悬浮浓度也会增加.当室内PM_2.5积尘负荷为0.30 g/m2时,行走路径中游坐姿1.1 m处与站姿呼吸平面1.5 m处的PM_2.5再悬浮浓度平均值分别为3.03、2.68 μg/m3,约是室内PM_2.5积尘负荷为0.18与0.11 g/m2时引起的PM_2.5再悬浮浓度平均值的2~3倍.④利用颗粒物传输模型对PM_2.5再悬浮进行量化分析发现,室内地面不同总颗粒积尘负荷的大小与PM_2.5再悬浮分数无关,PM_2.5再悬浮分数为2.2×10-8;室内PM_2.5积尘负荷为0.11、0.18、0.30 g/m2时,行走引起的再悬浮PM_2.5扩散速率分别为7.62×10-11、1.25×10-10、2.08×10-10 kg/s.研究显示,地面积尘负荷的大小会影响人体行走时颗粒物的扩散速率与室内PM_2.5浓度.