春季南海东沙岛硝酸盐干沉降通量、形成机制及其来源

硝酸盐是大气中主要的酸性离子,也是大气活性氮沉降主要的组成部分。中国目前对大气硝酸盐形成机制及其来源的研究主要集中在陆地区域,对海洋气溶胶的硝酸盐的形成机制及其来源的研究较少。本研究于2013年春季（3—5月）,在中国南海东沙岛共计采集了86个总悬浮颗粒（TSP）气溶胶样本,分析了TSP样品中NO₃⁻浓度、δ¹⁵N-NO₃⁻和δ¹⁸O-NO₃⁻值。结果表明：东沙岛春季TSP中浓度呈现逐月下降的趋势。基于浓度估算东沙岛春季NO₃⁻-N干沉降通量范围为(1.0±0.5)—(3.4±1.7) mg·d⁻¹·m⁻²（以N计,余同）。δ¹⁸O-NO₃⁻值在3月和4月（76.1‰±3.8‰和79.1‰±5.6‰）明显高于5月（67.0‰±7.5‰）,表明东沙岛3月和4月硝酸盐的形成路径不同于5月。贝叶斯同位素混合模型计算结果显示：N₂O₅参与的路径（N₂O₅+H₂O/Cl⁻和NO₃+VOCs）在3月和4月生成了37.2%和43.3%的硝酸盐,5月NO₂+OH路径是硝酸盐的主要形成路径,形成了80.2%的硝酸盐。δ¹⁵N-NO₃⁻值和气团后向轨迹表明,东沙岛春季不同月份TSP中NO₃⁻的来源不同,3月和4月以陆地源为主,5月主要受海洋源影响。     

三丁基锡对中国近海常见海洋微藻的毒性效应

研究三丁基氯化锡（TBT）对中国近海常见5种硅藻和甲藻（硅藻中丹麦细柱藻（Leptocylindrus danicus）、派格棍形藻（Bacilaria paxillifera）、聚生角毛藻（Chaetoceros socialis）,甲藻中微型原甲藻（Prorocentrum minimum）、简裸甲藻（Gymnodinium simplex））的毒性效应,考察了有机锡对浮游藻光合活性（Fv/Fm）、粒径、生长的影响。结果表明：派格棍形藻、聚生角毛藻、简裸甲藻的光合活性（Fv/Fm）受TBT影响较显著;微型原甲藻、丹麦细柱藻的光合活性受TBT影响较小。高质量浓度TBT胁迫下海洋微藻峰值粒径显著减小,低质量浓度TBT对峰值粒径影响不显著。低质量浓度TBT对派格棍形藻、聚生角毛藻、简裸甲藻、微型原甲藻均有较强的毒性作用,非检测毒性浓度（NDEC）分别为1.17、1.07、0.23、3.73μg.L-1,丹麦细柱藻对TBT具有很强耐受性,NDEC为112.62μg.L-1。     

基于机器学习的纳米材料生物效应研究的科学问题

纳米材料(nanomaterials,NM)作为一类新型的化学品,认识、控制其引起的不良环境健康风险是推广应用的重要前提。近些年,机器学习(machine learning,ML)作为一种数据驱动的研究方法,在环境、化学和材料等领域引起了广泛关注。从NM引起的细胞毒性、个体效应、蛋白冠与生态冠预测等几方面,介绍了ML的应用,并分析了应用过程中,数据集、描述符、ML方法、模型可解释性等方面存在的问题和解决方法。文章提出,数据提取与挖掘方法、新描述符、新模型、模型解释方法的创新与发展将能够促进ML在NM生物效应领域的应用。同时,随着ML的发展,ML有望能够预测新型的NM和复杂的效应,并揭示了相关原理。以梳理讨论ML在NM生物效应预测中面临的重要科学问题为重点,有助于后续研究者理清思路,解决该领域的难题,促进纳米产业健康可持续发展。     

2022年5—6月国内生产安全事故统计分析北大核心CSCD

统计了2022年5—6月国内发生的各种生产安全事故60起,其中包括交通事故、矿业事故、化工事故、市政事故和其他事故。统计表明,在60起事故中,交通事故占36.67%,矿业事故占10%,化工事故占20%,建筑事故占5%,市政事故占21.67%,其他事故占6.67%。60起事故共死亡144人。死亡人数的百分比分别为交通事故46.53%,矿业事故占8.33%,化工事故占18.75%,建筑事故占41.67%,市政事故占15.97%,其他事故占6.25%。2022年5—6月生产安全事故发生较多的4个省和自治区分别为山西(8起)、浙江(6起)、山东(4起)和辽宁(4起);死亡人数较多的5个省分别为山西(14人)、山东(12人)、甘肃(11人)和广东(10人)。     

Spatiotemporal patterns and other impacting factors on wheat production of Tibet,China北大核心CSCD

Wheat is the second-largest food crop in Tibet, China. Along with economic development, the pattern of wheat production in Tibet has changed dramatically, potentially affecting the balance of grain supply and demand, as well as food security. A clear understanding of the spatiotemporal patterns and other factors affecting wheat production can provide a necessary basis for the scientific management and efficient production of wheat. Based on the wheat yield from 1990 to 2020 in 74 county-level units of Tibet, this study analyzed the spatial and temporal change patterns of Tibetan wheat production and its impacting factors using the Gini coefficient, center of gravity move method, advantage index, exploratory spatial data analysis (ESDA), and geographically weighted regression model (GWR). Results showed that: (1) the total wheat production in Tibet rose from 1990 to 1999, fluctuated, and then decreased from 1999 to 2020. The production areas are mainly concentrated in the southern Tibetan Valley and counties in the Three Rivers region of eastern Tibet. (2) The spatial distribution and agglomeration pattern of wheat in Tibet is relatively stable, and the production center shows a slight fluctuation trend from west to east during the 1990-2020 time period. (3) Based on the comprehensive advantage index (CAI), Tibet’s wheat production in advantaged areas, slightly advantaged areas, slightly disadvantaged areas, and disadvantaged areas accounted for 13.5%, 8.1%, 9.5%, and 40.5% of the total production, respectively; indicating that the regional distribution of CAI exhibits spatial agglomeration rather than sporadic distribution. The patterns are HH (high-high), LH (low-high), and random; 29 hot spots are mainly distributed in Lhasa, Shannan, and Nyingchi, while the cold spots are mainly distributed in Xigazê and Ngari; and (4) the impacting factors on Tibet’s wheat production mainly include effective irrigation areas and agricultural mechanization level as positive factors, and regional gross agricultural product as the main negative factor. In addition, rainfall, other grain output, livestock inventory at the end of the year, and the number of non-primary industries also have an impact on wheat production. Wheat planting area in Tibet has been declining in recent years, thus exhibiting a significant pattern of spatial agglomeration. The three dominant factors affecting the emerging spatiotemporal pattern of wheat production in Tibet are the irrigation condition, mechanization, and local economic development levels. Based on the above conclusions, the study suggests building a high-yield wheat area consistent with local conditions by strictly protecting arable land, improving irrigation conditions, and increasing machinery investment. Depending on the counties of high-yield areas, Tibetan farmers and herders should cultivate the bases of wheat production and build a wheat base for local wheat consumption. © 2022 Science Press. All rights reserved.     

2022年9-10月国内生产安全事故统计分析

统计了2022年9—10月国内发生的各种生产安全事故37起,其中包括交通事故、矿业事故、化工事故、市政事故和其他事故。统计表明,在37起事故中,交通事故占40.54%,矿业事故占18.92%,化工事故占2.70%,市政事故占29.73%,其他事故占8.11%。37起事故共死亡115人。死亡人数的百分比分别为交通事故45.22%,矿业事故占23.48%,化工事故占6.09%,市政事故占22.61%,其他事故占2.61%。2022年9—10月生产安全事故发生较多的3个省和市分别为山西(5起)、上海(4起)和四川(3起);死亡人数较多的3个省分别为贵州(18人)、吉林(17人)和河北(14人)。     

氯/溴稳定同位素分析技术及其在环境科学研究中的应用

稳定同位素分析被认为是环境污染物溯源和转化途径探究的有效工具.针对氯/溴稳定同位素研究已经开发了一些较为可靠的分析技术,被广泛应用于氯乙烯、氯苯、溴酚、多溴二苯醚和有机氯农药等有机污染物的研究.本文综述了近年来氯/溴同位素分析技术的最新进展,介绍了稳定同位素分析技术在含氯/溴有机污染物的溯源分析和降解途径识别等方面的应...