Ambient nitrogen oxides exposure and early childhood respiratory illnesses

Acute respiratory infections are common in children below 5 years and recent studies suggest a possible link with air pollution. In this study, we investigated the association between ambient nitrogen oxides (NO_x) and bronchitis or upper airway inflammation.This longitudinal study was conducted in Teplice and Prachatice districts, Czech Republic. Children were followed from birth to 4.5 years of age. Data were compiled from medical records at delivery and at follow up, and from self-administered questionnaires from the same two time points. Air pollution monitoring data were used to estimate exposure over five different averaging periods ranging from three to 45 days prior to an episode. To quantify the association between exposure and outcome, while accounting for repeated measure correlation we conducted logistic regression analysis using generalized estimating equations.During the first 2 years of life, the adjusted rate ratio for bronchitis associated with interquartile increase in the 30-day average NO_x was 1.31 [95% confidence interval (CI): 1.07, 1.61] and for two to 4.5 year olds, it was 1.23 (95% CI: 1.01, 1.49). The 14-day exposure also had stable association across both age groups: below 2 years it was 1.25 (95% CI: 1.06, 1.47) and for two to 4.5 years it was 1.21 (95% CI: 1.06, 1.39). The association between bronchitis and NO_x increased with child's age in the under 2 years group, which is a relatively novel finding.The results demonstrate an association between NO_x and respiratory infections that are sufficiently severe to come to medical attention. The evidence, if causal, can be of public health concern because acute respiratory illnesses are common in preschool children.     

The Water Table: The Shifting Foundation of Life on Land

Hyperarid, arid, and semi-arid lands represent over a third of the Earth’s land surface, and are home to over 38 % of the increasing world population. Freshwater is a limiting resource on these lands, and withdrawal of groundwater substantially exceeds recharge. Withdrawals of groundwater for expanding agricultural and domestic use severely limit water availability for groundwater dependent ecosystems. We examine here, with emphasis on quantitative data, case histories of groundwater withdrawals at widely differing scales, on three continents, that range from the impact of a few wells, to the outcomes of total appropriation of flow in a major river system. The case histories provide a glimpse of the immense challenge of replacing groundwater resources once they are severely depleted, and put into sharp focus the question whether the magnitude of the current and future human, economic, and environmental consequences and costs of present practices of groundwater exploitation are adequately recognized.     

Conversion of a Missouri River Dam and Reservoir to a Sustainable System: Sediment Management1

Abstract: A present and future challenge for water resources engineers is to extend the useful life of our dams and reservoirs. Ongoing reservoir sedimentation in impoundments must be addressed; sedimentation in many reservoirs already limits project benefits and effective project life. Sustainability requires that incoming sediment be moved downstream past the impounding dam. We use Lewis and Clark Lake, the most downstream of the six Missouri River main stem reservoirs, to demonstrate how a reservoir in advanced stages of its project life could be converted to a sustainable system with local benefits exceeding costs by a factor of 1.5. Full consideration of benefits would further enhance project justification. The proposed strategy involves four phases that will take about 50 years to complete. Cost estimates for this potential project range from the quantitative to the plausible, but it is clear that the results justify a full engineering, environmental, and economic study of this model project. If implemented, the project will create scientific knowledge and develop technologies useful for achieving sustainability at many other reservoirs in the Mississippi River basin and beyond.     

酞酸酯对人与环境的危害

酞酸酯是一种增塑剂，随着时间的推移，可由塑料中转移到外环境，现已成为地球上最为广泛存在的环境污染物。该文较系统地介绍了酞酸酯的理化性质，毒性和致癌作用，以及其对环境的影响，环境行为，动物的吸收，分布、代谢和排泄等等，最后还对酞酸酯的有关毒性评价作了部分介绍。     

乌鲁木齐市PM2.5 中重金属污染特征及健康风险评估

为探究乌鲁木齐大气细颗粒物(PM2.5)中重金属的污染水平、来源、健康风险及其变化趋势,对乌鲁木齐市典型区域2020年各季节PM2.5中重金属的质量浓度进行了连续监测.研究结果表明,2020年,乌鲁木齐市大气ρ(PM2.5)年均值超过我国《环境空气质量标准》(GB 3095-2012)二级标准限值(35 μg/m3),冬季PM2.5中重金属质量浓度最高,夏季最低;其中质量浓度较高的重金属为铜(Cu)、铬(Cr)、锌(Zn)、锰(Mn).1#(交通要道区)、2#(工业集中区)、3#(农业区)3个监测点大气PM2.5中重金属总质量浓度分别占ρ(PM2.5)的1.57％,2.48％,0.68％;不同监测点位重金属质量浓度表现为2#＞1#＞3#.1#、2#、3#监测点大气PM2.5中重金属的主要来源有燃煤源、工业源、交通源.Cr对不同人群的致癌风险(ILCR)＞10-4,存在致癌风险;镍(Ni)、镉(Cd)对不同人群的ILCR为10-6～10-4,存在一定的致癌可能,处于可接受水平.Mn、Cr的危险系数(HQ)＞1,存在非致癌风险;其余重金属对不同人群的HQ＜1,非致癌风险可忽略;7种重金属的HQ表现为儿童＞成年男性＞成年女性.     

厌氧填埋垃圾降解阶段指标体系的建立

以厌氧填埋场中垃圾的降解过程为依托点,从渗滤液的水质特征和填埋气的组成两个方面筛选出判断指标,最后建立判断填埋垃圾降解阶段的指标体系.结果表明,ρ(BOD5)/ρ(COD)可以反映出渗滤液的可生化性,从而间接反映出填埋垃圾所处的降解阶段,是判断填埋垃圾降解阶段的重要定量指标.     

西北江下游河流底栖动物群落健康评价

2020年12月在西北江下游河流设置11个采样点,调查底栖动物群落结构,应用底栖动物完整性指数(B-IBI)评价河流健康状况,并分析B-IBI值与环境因子的关系.结果表明,参照点位的B-IBI值在0.59～4.00之间,处于中等—优状态;受损点位的B-IBI值在0～0.82之间,处于很差—良好状态,其中较差和很差状态占比为87.5％.氨氮浓度与B-IBI值呈现极显著的负相关性,降低水污染负荷是促进底栖动物群落恢复健康的有效途径.在水质已经实现好转的基础上,可通过营造河底卵石生境来促进底栖动物群落恢复,同时也应加强河岸带的修复.     

生态健康、生态风险、生态安全概念辨析

在人类活动影响下,生态系统退化的速度越来越快,作为衡量生态系统存在状态的生态健康、生态风险、生态安全评价日益受到重视。然而,目前对于3个概念的界定不够明晰,在评价过程中指标体系混淆混用,致使理论研究也固步不前,影响了对实践的指导意义。生态健康、生态风险、生态安全的联系体现在评价主体的一致性和生态安全评价需要以生态健康评价、生态风险评价为基础;而三者的区别体现在内涵、评价对象以及评价的指标体系3个方面。     

Human Impacts on Drainages of the Mesa Central, Mexico, and Its Genetic Effects on an Endangered Fish, Zoogoneticus quitzeoensis

Abstract:  The Mesa Central of Mexico is of special conservation interest due to its high richness of freshwater fish species, of which the goodeines are one of the most representative groups. Through an integrated approach, we determined conservation priorities for goodeine populations. We based our recommendations on the genetic diversity (variation in five microsatellite DNA loci) in 10 populations of Zoogoneticus quitzeoensis and on an analysis of ecological (e.g., presence of exotic species), social (e.g., political situation), and environmental (e.g., pollution) information for 52 historical occurrence points for species in the genus Zoogoneticus . Patterns of genetic erosion and genetic diversity indices were closely associated with human impact. Recent bottleneck events were most evident in the populations from remnants of the lakes drained at the beginning of the twentieth century. We identified seven operational conservation units (OCUs), all of which should be conserved because they contain unique portions of the total variation of the species. Special attention needs to be given to increase genetic variability, recover population sizes, and reestablish contact among populations within OCUs. It is imperative to create an integrative and effective approach for the recovery and conservation of the freshwater fish diversity of Central Mexico that is based on social and natural sciences.