雾霾重污染期间北京居民对高浓度PM2.5持续暴露的健康风险及其损害价值评估

开展短期内高浓度空气污染造成的人体健康风险评价以及健康经济损失研究,对推进城市大气污染防控,保证人民群众的健康水平具有重要的科学价值和实际意义.研究选择2013年1月发生的北京市雾霾重污染事件,采用泊松回归模型评价全市居民对10~15日高浓度PM2.5暴露的急性健康损害风险,并采用环境价值评估方法估算人群健康损害的经济损失.结果表明,短期高浓度PM2.5污染对人群健康风险较高,约造成早逝201例,呼吸系统疾病住院1 056例,心血管疾病住院545例,儿科门诊7 094例,内科门诊16 881例,急性支气管炎10 132例,哮喘7 643例.相关健康经济损失高达4.89亿元(95%CI:2.04~7.49),其中早逝与急性支气管炎、哮喘三者占总损失的90%以上.建议应针对不同人群不同健康终点的健康风险进行健康预警并开展及早医学干预,以降低类似空气重污染事件给居民健康带来的风险和损失.     

石化企业苯类物质非密闭操作过程的职业暴露分析

采用职业卫生学调查和职业暴露风险评估方法,对选定的苯类物质非密闭操作过程较集中的芳烃装置进行职业暴露分析和评估,为石化企业苯类物质的健康风险控制提供依据。     

上海崇明地区大气分形态汞污染特征

2014年3月~2015年2月对上海崇明东滩湿地公园的气态零价汞(GEM)、活性气态汞(RGM)和颗粒态汞(PBM)分别进行了为期1a的连续监测.GEM、RGM和PBM的年平均浓度分别为(2.75±1.13)ng·m~(-3)、(13.39±15.95)pg·m~(-3)和(21.89±40.42)pg·m~(-3),明显高于对应北半球背景值浓度.GEM浓度在夏季最高(3.65 ng·m~(-3)),受自然源排放影响较大,秋冬季较低,受人为源排放影响较大;RGM浓度在春季最高,冬季最低,主要受风速风向的影响;PBM浓度在秋冬季节明显高于其他季节,受秋冬季节较多的细颗粒物重污染过程的影响.GEM和PBM浓度均夜间较高,白天较低,主要受空气气团混合作用影响.RGM浓度在下午较高,主要是由于GEM在下午的光氧化作用加强,利于RGM的生成.GEM和PBM浓度在偏西风向上浓度较高,受上海、江苏等地人为源排放影响较大.RGM浓度在东南风向上浓度明显高于其他方向,这是因为RGM主要来源为人为排放,其浓度受风速影响较大,东南风向上平均风速较小,持续的弱风及停滞的空气不利于RGM的扩散.     

长期暴露下纳米二氧化钛对典型淡水藻体砷累积与生物转化的影响

以铜绿微囊藻(Microcystis aeruginosa)和斜生栅藻(Scenedesmus obliquus)为研究对象,通过室内培养实验,研究了长期暴露下纳米二氧化钛(nano-TiO_2)对五价砷[As(Ⅴ)]在典型淡水藻体中累积与生物转化的影响.结果表明不同藻类对无机砷的吸收和转化能力差异很大.长期暴露下斜生栅藻累积的砷(As,以DW计,下同)高达(819.66±11.25)μg·g-1,比铜绿微囊藻累积的As[(355.95±8.31)μg·g-1]高2倍多.Nano-TiO_2可增加藻体对As的吸收累积,降低了培养基中As的含量.同时,nano-TiO_2可增加藻体对As(Ⅴ)的生化转化;其中,铜绿微囊藻中有机砷以二甲基砷(DMA)为主,而斜生栅藻中有机砷以一甲基砷(MMA)为主.另外,长期暴露下nano-TiO_2处理的铜绿微囊藻和斜生栅藻向培养基释放的甲基砷小于对照组,表明长期暴露中的nano-TiO_2不能促进藻体内甲基砷的释放.研究结果可促进nano-TiO_2与As相互作用时生态风险的理解.     

Bridging the gap between green behavioral intentions and employee green behavior: The role of green psychological climate

How do employees' perceptions and interpretations of organizational policies, practices, and procedures affect the enactment of their behavioral intentions? In a daily diary study, we examined the between‐persons relationship of corporate environmental strategy and pro‐environmental or “green” psychological climate; and whether green psychological climate moderates the within‐person relationship of employees' daily green behavioral intentions and their green behavior on the following day. To test our hypotheses, we collected survey data from 74 employees across 10 workdays. Results showed that corporate environmental strategy is positively related to green psychological climate that, in turn, moderates the relationship between green behavioral intentions and next‐day employee green behavior. Specifically, we found the relationship to be positive only when employees perceive a positive green psychological climate. We discuss implications of our findings for future research on employee green behavior and for organizations interested in encouraging employee green behavior. Copyright © 2017 John Wiley & Sons, Ltd.     

Limitations in the determination of maximum residue limits and highest residues of pesticides: Part I

The pesticide usages are controlled by comparing residue concentrations in treated commodities to legally permitted maximum levels (MRLs) determined based on supervised trials designed to reflect likely maximum residues occurring in practice following authorised use. The number of trials available may significantly affect the accuracy of estimated maximum residues. We conducted a study with synthetic lognormal distributions with mean of 1 and standard deviations of 0.8 and 1.0, which reflect the residue distributions observed in practice. The likely residues in samples were modelled by drawing random samples of size 3, 5, 10 and 25 from the synthetic populations. The results indicate that the estimations of highest residues (HR), used for calculation of short-term intake, and the MRLs, serving as legal limits, are very uncertain based on 3–5 trials indicated by the calculated HR_0.975/HR_0.025 and MRL_0.975/MRL_0.025 ratios of 12 and 9, and 13 and 10, respectively, which question the suitability of such trials for the intended purpose. As the 95% range of HR and MRL rapidly decreases with number of trials, ideally ≥15 but minimum 6–8 trials should be used for estimation of HR and MRL according to the current typical practice of Codex Alimentarius.     

Exposure to inhaled THM: Comparison of continuous and event-specific exposure assessment for epidemiologic purposes

Trihalomethanes (THMs) (chloroform, bromoform, dibromochloromethane, and bromodichloromethane) are the most abundant by-products of chlorination. People are exposed to THMs through ingestion, dermal contact and inhalation. The objective of this study was to compare two methods for assessing THM inhalation: a direct method with personal monitors assessing continuous exposure and an indirect one with microenvironmental sampling and collection of time–activity data during the main event exposures: bathing, showering and swimming. This comparison was conducted to help plan a future epidemiologic study of the effects of THMs on the upper airways of children. 30 children aged from 4 to 10 years were included. They wore a 3M^™ 3520 organic vapor monitor for 7 days. We sampled air in their bathrooms (during baths or showers) and in the indoor swimming pools they visited and recorded their time–activity patterns. We used stainless steel tubes full of Tenax^® to collect air samples. All analyses were performed with Gas Chromatography and Mass Spectrometry (GC-MS). Chloroform was the THM with the highest concentrations in the air of both bathrooms and indoor swimming pools. Its continuous and event exposure measurements were significantly correlated (r_s = 0.69 p < 0.001). Continuous exposures were higher than event exposures, suggesting that the event exposure method does not take into account some influential microenvironments. In an epidemiologic study, this might lead to random exposure misclassification, thus underestimation of the risk, and reduced statistical power. The continuous exposure method was difficult to implement because of its poor acceptability and the fragility of the personal monitors. These two points may also reduce the statistical power of an epidemiologic study. It would be useful to test the advantages and disadvantages of a second sample in the home or of modeling the baseline concentration of THM in the home to improve the event exposure method.     

EXPOSURE ASSESSMENT OF POPULATIONS USING ENVIRONMENTAL MODELING,DEMOGRAPHIC ANALYSIS,AND GIS1

ABSTRACT: Simulation of ground-water flow and fate of contaminants in the subsurface environment constitutes a major phase of most environmental assessment and site remediation studies. These simulation studies yield information on spatial and temporal distributions of contaminants in the subsurface media. An important use of this information is to conduct exposure assessment studies. Spatial and temporal distributions of both chemical concentrations and exposed populations render this integrated exposure analysis task rather difficult. Geographic Information Systems (GIS), on the other hand, provide a platform in which layered, spatially distributed databases can be manipulated with ease, thereby simplifying exposure analysis tasks significantly. In this paper, we describe procedures that combine the simulation models and demographic databases under a GIS platform to automate the exposure assessment phase of a typical health assessment study. Procedures developed herein significantly simplify the post-processing phase of the analysis, and render the overall task more ‘user friendly.’ A site-specific application is included as a demonstration of the proposed process.     

MODELING FECAL COLIFORM CONTAMINATION IN THE RIO GRANDE1

This study examines sources of fecal coliform in Segment 2302 of the Rio Grande, located south of the International Falcon Reservoir in southern Texas. The watershed is unique because the contributing drainage areas lie in Texas and Mexico. Additionally, the watershed is mostly rural, with populated communities known as “colonias.” The colonias lack sewered systems and discharge sanitary water directly to the ground surface, thus posing an increased health hazard from coliform bacteria. Monitoring data confirm that Segment 2302 is not safe for contact recreation due to elevated fecal coliform levels. The goal of the study was to simulate the observed exceedences in Segment 2302 and evaluate potential strategies for their elimination. Fecal coliform contributions from ranching and colonia discharges were modeled using the Hydrologic Simulation Program‐Fortran (HSPF). Model results indicated that the regulatory 30‐day geometric mean fecal coliform concentration of 200 colony forming units (cfu) per 100 milliliters is exceeded approximately three times per year for a total of 30 days. Ongoing initiatives to improve wastewater facilities will reduce this to approximately once per year for 14 days. Best management practices will be necessary to reduce cattle access to streams and eliminate all exceedences. The developed model was limited by the relatively sparse flow and fecal coliform data.     

General prevention and risk minimization in LCA A combined approach

Methods for life cycle assessment of products (LCA) are most often based on the general prevention principle, as opposed to the risk minimization principle. Here, the desirability and feasibility of a combined approach are discussed, along with the conditions for elaboration in the framework of LCA methodology, and the consequences for LCA practice. A combined approach provides a separate assessment of above and below threshold pollution, offering the possibility to combat above threshold impacts with priority. Spatial differentiation in fate, exposure, and effect modelling is identified to play a central role in the implementation. The collection of region-specific data turns out to be the most elaborate requirement for the implementation in both methodology and practice. A methodological framework for the construction of characterization factors is provided. Along with spatial differentiation of existing parameters, two newly introduced spatial parameters play a key role: the sensitivity factor and the threshold factor. The practicability of the proposed procedure is illustrated by an example of its application. Providing a reasonable data availability, the development of separate LCA characterization factors for the respective assessment of pollution levels above and below environmental threshold values seems to be a feasible task that may add to LCA credibility.