新旧版GB6566《建筑材料放射性核素限量》比较研究

为了方便检测机构、消费者和企业理解掌握新版GB6566-2010标准内容,笔者对与旧标准相比的主要变化、标准具体内容进行了归纳整理,并对实际应用中应注意的问题加以解析。     

Occurrence and behaviour of nonylphenol and octylphenol in Nanming River, Guiyang City, China

Occurrence, variation and behaviour of nonylphenol (NP) and octylphenol (OP) were studied in surface water and groundwater in Guiyang, Guizhou Province, southwestern China. Discharge of wastewater from Guiyang City was the main source of alkylphenols (APs) entering the aquatic environment. The concentrations of NP and OP in river water ranged from 40 to 1582 ng L(-1) and from below the lowest limit of detection (LOD) to 67 ng L(-1), respectively. NP and OP were also detected in groundwater. Both NP and OP exhibited spatial and temporal variations in river water and groundwater. It was found that concentrations of NP and OP in river water was low upstream and dramatically increased downstream, and higher concentration of NP was found in winter compared to that in summer. Proportions of NP and OP were trapped by suspended particulate matter (SPM), which accounted for 7.6-50.0% and 3.4-25.6% of their total concentration in the river water system, respectively. Seasonal changes in water flow were responsible for the temporal variations of APs. To determine the behaviour of APs along the river, a mass balance equation based on chloride was used. The results showed that a mixing process was the predominant factor to determine upstream APs concentrations; while the discharge of wastewater controlled the concentrations of APs downstream. Considering the adverse effect of APs on organisms, combined effect modeling was used to assess the toxicity to fish. It was found that the predicted mixture effect for APs in river water on fish vitellogenin induction was low upstream and medium downstream, respectively.     

Matrix-bound phosphine and phosphorus fractions in paddy soils

Phosphine (PH(3)) is a natural gaseous carrier of phosphorus (P) in its geochemical cycles, and it might be important to the P balance of natural ecosystems. Paddy fields are thought to be one of the main sources responsible for the production and emission of PH(3) in to the environment. The relationships between matrix-bound PH(3) (MBP) and different P fractions, as well as selected metals were investigated to explore the possible production of MBP and its link to P cycle in the paddy soils. MBP range from 20.8 (-1) to 502 ng kg(-1) with an average of 145 ng kg(-1). Concentrations at the milk stage are significantly higher than at the jointing stage. The total P range from 333 mg kg(-1) to 592 mg kg(-1). Average P fractions decrease in the order: Ca-P (69.9%) > Organic P (16.5%) > occluded P (6.50%) > Fe-P (5.93%) > dissolved P (0.80%) > exchangeable P (0.32%) > Al-P (0.02%). Different levels of nitrogen fertilizer have little effect on the contents of MBP, P fractions and metals. A significant positive correlation between MBP and Ca-P (p = 0.002), as well as between MBP and Ca (p = 0.008) could be observed, suggesting that Ca-P mainly affects the production of MBP in the paddy soils. It is suggested that soil MBP is strongly linked to Ca-P fertilizer use because soil spiked with P-fertilizer produced an additional 758 ± 142 ng of MBP per kg of soil, compared to only 81.7 ± 12.3 ng of MBP per kg of unspiked soil. No correlations are found between MBP and other P fractions, or between MBP and Al, Fe and Mn.     

Mobilization and plant accumulation of prometryne in soil by two different sources of organic matter

Prometryne is a selective herbicide of the s-triazine chemical family. Due to its weak absorption onto soil, it readily leaches down through the soil and contaminates underground water. Application of organic manure to soil has become a widespread practice as a disposal strategy to improve soil properties. In this study, we demonstrated the effect of pig manure compost (PMC) and lake-bed sludge (SL) on the sorption/desorption, mobility and bioavailability of prometryne in soil using comprehensive analysis approaches. Downward movement of prometryne was monitored in the packed soil column. Addition of PMC or SL decreased considerably the mobility and total concentration of prometryne in the soil leachate. Bioavailability analyses with wheat plants revealed that addition of the organic matter reduced accumulation of prometryne in tissues and increased plant elongation and biomass. These results indicate that the organic amendments are effective in modifying adsorption and mobility of the pesticide in soil.     

环珠江口近地面夜间臭氧上升现象：基于垂直观测的两个个例研究

利用广州塔的O₃观测资料、风廓线雷达和转动拉曼温廓线激光雷达探测的垂直环境气象等观测资料,结合ERA5的近地面风场,对2017年5月6—7日(Case I)和2019年10月1—2日(CaseⅡ)两个典型个例从垂直混合与水平输送的角度进行特征与成因分析.O₃的垂直观测结果表明,夜间残留层可储存日间混合层内的高浓度O₃气团.从垂直混合与水平输送的分析结果表明,残留层O₃的垂直混合及高浓度O₃气团的水平输送是夜间地表O₃的重要来源：夜间存在垂直风切变或边界层抬升,均可加强O₃的垂直混合;珠三角地区背景风表现为在早上偏北风和晚上转换为偏南风,广州与佛山地表O₃浓度上升最显著.此外,夜间O₃浓度上升事件可造成夜间及凌晨O₃ 8 h滑动平均值持续高值,对空气质量和大气氧化性造成一定影响.     

基于模糊数学的场地重金属污染风险综合评价

在传统土壤评价方法的理论基础上,参考模糊数学的架构,建立了由风险因素集、风险评价集、隶属度函数、评估矩阵和权重系数组成的评价模型,最终形成了一套场地重金属污染风险的综合评价方法.选取安徽铜陵某冶炼厂作为研究场地,分析场地土壤中重金属的污染情况并验证该评价模型的科学性.结果表明,研究场地内表层土壤重金属含量平均值分别为As(1382mg/kg)、Cd(64.9mg/kg)、Cu(4973mg/kg)、Pb(3403mg/kg),As和Pb污染严重.相比于传统土壤评价方法,综合评价方法考虑重金属的人体健康风险、地下水迁移风险和生态风险3个方面,插值后不同风险所占面积比例为安全(25.3%)、低风险(5.86%)、中风险(9.00%)、高风险(59.9%).与内梅罗指数法对比,综合评价风险结果中的高风险区域面积下降了9.50%,而中风险、低风险和安全区域的面积则分别上升了约3.54%、3.83%和1.20%,整体风险有所降低.与传统土壤评价方法对比,基于模糊数学模型的综合评价方法不局限于重金属总量单一因素对土壤污染风险水平的限制,根据场地实际情况及土地二次利用途径对其进行更加详细的污染风险评...     

零秒脱落连接器可靠性设计及指标验证

目的 实现零秒脱落连接器高可靠的要求。方法 在产品设计中系统地开展可靠性设计与分析工作,进行设计方案优选以及设计方案优化,提高连接器的固有可靠性水平。通过分析确定连接器的薄弱环节及其可靠性特征量,并据此制定可靠性试验方案,验证连接器可靠性水平。结果 通过对可靠性试验数据进行评估,在规定的试验条件下,零秒脱落连接器发射任务可靠度的单侧置信下限值满足规定的可靠性指标要求。结论 通过将可靠性设计与分析工作融入产品工程设计过程中,在设计阶段有效地确保了连接器固有可靠性的实现。可靠性试验方案合理、可行,有效地降低了样本数量及试验成本。为相似产品的可靠性设计验证工作积累了工程经验。     

莱州湾西南部岸线变迁对海域水动力影响的数值研究

20世纪70年代以来,盐田、养殖围堤、港口堤坝建设等开发活动使莱州湾西南部岸线变迁尤为显著,从而引起了海湾水动力环境的改变。为探究近50年莱州湾水动力环境对海湾西南部岸线变迁的响应,本文建立二维数值模型,研究莱州湾西南部3个时段岸线变迁对海湾潮流、纳潮量和水交换的影响。结果表明,1968－2020年莱州湾西南部流速变化以减小为主,流速变化较大的区域主要位于盐田或养殖围垦区和新建港口附近海域。近50年,莱州湾纳潮量呈逐年减小趋势,大潮、中潮、小潮和全潮平均纳潮量分别减少5.85%、7.28%、8.85%和6.47%,围填海是导致纳潮量减小的主要原因。1968－2010年莱州湾整体的水交换能力有所提高,2010－2020年则相差很小;从局部看,1990－2020年港口附近海域的水交换能力均显著降低。     

南京城市大气氨-铵的高频演化及其气粒转化机制

本研究于2018年秋季利用在线气体和气溶胶组分监测仪以高时间分辨率连续测定南京市大气中的气体(主要是NH_3)与二次无机气溶胶(主要是NH_4~+、NO_3~-和SO_4~(2-))浓度,借此研究污染和非污染期城市大气NH_3和NH_4~+的演化规律,进而探讨NH_3-NH_4~+气粒转化过程中的化学机制.结果表明,观测期间NH_3和NH_4~+浓度的平均值(±1σ)分别为(15. 3±6. 7)μg·m-3和(11. 3±7. 8)μg·m-3,且日变化在污染和非污染事件中呈现出显著的差异.综合在线观测的NH_3和NH_4~+浓度数据,通过计算潜在源贡献因子,分析了NH_3和NH_4~+的潜在贡献源区在重污染过程受长距离污染传输影响较小,证明城市也是NH_3排放的重要热点地区.进一步分析发现,NH_3-NH_4~+的气粒转化是影响NH_3和NH_4~+日变化的主要驱动因子.具体体现在:低温、高湿(温度在7. 5～12. 5℃,湿度在50%～90%)时,NH_3和NH_4~+的气固转化速度较快,NH_3与酸性物质反应生成更多的NH_4~+,使得(NH4)2SO4和NH4NO3的形成从而导致污染事件的加剧.研究结果有助于厘清城市大气NH_3的来源和转化机制及其对颗粒物的潜在贡献.     

新乡市夏冬季节PM2.5稳定碳同位素特征分析

为了探究新乡市PM_(2.5)中δ~(13)C比值的季节性变化特征及其对污染来源的指示作用,于2017年夏冬季节采集PM_(2.5)有效样品91个,并测定了样品中的总碳、水溶性离子和稳定碳同位素比值(δ~(13)C).夏季和冬季的TC浓度平均值分别为11.78μg·m~(-3)和26.6μg·m~(-3).夏季δ~(13)C比值为-27.70‰～-25.22‰其中前14 d的δ~(13)C比值波动较大平均值为-26.96‰,而后16d的δ~(13)C比值相对稳定,平均值为-25.69‰,而且前半月和后半月火点数具有较大差异同时K_(nss)~+浓度与TC质量浓度显著相关(R~2=0.62,P0.01)这说明夏收季节生物质燃烧可能对δ~(13)C比值有显著影响.新乡地区冬季RH与TC/PM_(25)质量比值的显著负相关(R~2=0.68,P0.01),揭示了在霾增长初期以SOA增长为主,而污染期以SIA贡献为主.冬季采样期δ~(13)C比值为-26.72‰～-23.49‰,对霾发展过程中稳定同位素组成的研究发现在霾增长过程中δ~(13)C比值以富集为主,而在霾清除阶段δ~(13)C比值以贫化为主.