The Ethical Conduct of Studies Involving Controlled Human Exposure to Environmental Pollutants

In recent years, the concern for human research subject protection has increased markedly in the United States. The nature of research subject participation in controlled-exposure environmental health research is such that the individual subject bears the risk of participation, while the benefits of such research accrue to society. Therefore, particular attention must be paid when designing studies to protect the health and safety of human research subject. This paper outlines principles for the appropriate selection of pollutants to which humans can be exposed, and the principles that should be used to protect the health and safety of human research subject.     

Modeling Human Exposure to Phthalate Esters: A Comparison of Indirect and Biomonitoring Estimation Methods

Humans are potentially exposed to phthalate esters (PEs) through ingestion, inhalation, and dermal contact. Studies quantifying exposure to PEs include “biomarker studies” and “indirect studies.” Biomarker studies use measurements of PE metabolites in urine to back-calculate exposure to the parent diester, while indirect studies use the concentration of the PE in each medium of exposure and the rate of intake of that medium to quantify intake of the PE. In this review, exposure estimates from biomarker and indirect studies are compiled and compared for seven PEs to determine if there are regional differences and if there is a preferred approach. The indirect and biomarker methods generally agree with each other within an order of magnitude and discrepancies are explained by difficulties in accounting for use of consumer products, uncertainty concerning absorption, regional differences, and temporal changes. No single method is preferred for estimating intake of all PEs; it is suggested that biomarker estimates be used for low molecular weight PEs for which it is difficult to quantify all sources of exposure and either indirect or biomarker methods be used for higher molecular weight PEs. The indirect methods are useful in identifying sources of exposure while the biomarker methods quantify exposure.     

Magnetic field from spot welding equipment—is the basic restriction exceeded?

A point measurement of the magnetic field (MF) near a typical spot welding machine showed that the magnetic flux density was above the ICNIRP reference level. To investigate if the basic restrictions were exceeded, the induced body currents in a full 3D human model were calculated. It was found that at an operator position of 34 cm away from the machine the maximum induced current density was below the ICNIRP basic restriction. But if the operator was closer to the machine, the basic restriction was exceeded. An important finding of the present article is that the basic restriction can be exceeded although the MF spatially averaged over the whole body is well below the reference level.     

The Importance of Human Data in the Establishment of Occupational Exposure Limits

The use of animal vs. human data for the purposes of establishing human risk was examined for four pharmaceutical compounds: acetylsalicylic acid, cyclophosphamide, indomethacin and clofibric acid. Literature searches were conducted to identify preclinical and clinical data useful for the derivation of acceptable daily intakes (ADIs) from which a number of risk values including occupational exposure limits (OELs) could be calculated. OELs were calculated using human data and then again using animal data exclusively. For two compounds, ASA and clofibric acid use of animal data alone led to higher OELs (not health protective), while for indomethacin and cyclophosphamide use of animal data resulted in the same or lower OELs based on human data alone. In each case arguments were made for why the use of human data was preferred. The results of the analysis support a basic principle of risk assessment that all available data be considered     

城市绿地暴露与人群健康效应研究

城市绿地是城市绿色基础设施和基于自然解决方案的主要载体,为人群提供了多种生态系统服务,关注人群健康和绿地布局的城市绿地暴露研究已经成为城市生态学、城市可持续发展等学科的前沿热点。目前国内外城市绿地暴露与人群健康研究仍处在兴起的初步发展状态,缺乏有效和公认的研究范式。尝试通过暴露科学的视角,研究城市绿地暴露及其人群健康效应的研究的热点领域:(1)从城市人群的绿地暴露特征来看,绿地暴露研究与现有旨在预防和减少环境污染暴露风险的传统环境健康研究的视角有显著不同,其目标是充分理解人群的绿地暴露特征及其产生健康效应的机制,鼓励和提高人群与绿地的有效和有益接触,服务于城市绿地和健康社区营造的科学规划和决策。(2)从城市绿地暴露的量化表征来看,现有的多种绿地暴露评价指标包括绿地可得性、绿地可及性和绿地可视性等多是表征了绿地的供给状况,并非直接的绿地暴露过程描述,未来可以结合城市人群的绿地暴露时空动态模式,参照总暴露数学方程来综合量化不同途径、访问周期、暴露时长等因素。(3)从城市绿地暴露的人群健康效应机制来看,现有绿地暴露的健康效应机制研究获得的通用理论性成果还不多,面临的挑战主要是:不同绿地健康效应研究采用的暴露特征指标不同,绿地暴露特征影响人群健康存在显著的尺度性,以及缺乏统一的绿地暴露健康效应调查方法。绿地在城市规划和建设中的作用尤其突出,但绿地的人群健康促进功能在我国城市规划和建设中还鲜有应用,作为城市生态学与环境风险、公共健康以及可持续发展的交叉前沿领域,相关成果将为指导健康导向的可持续城市/社区规划与建设提供直接的科学依据与理论支撑。     

Human body burdens of chemicals used in plastic manufacture

In the last decades, the availability of sophisticated analytical chemistry techniques has facilitated measuring trace levels of multiple environmental chemicals in human biological matrices (i.e. biomonitoring) with a high degree of accuracy and precision. As biomonitoring data have become readily available, interest in their interpretation has increased. We present an overview on the use of biomonitoring in exposure and risk assessment using phthalates and bisphenol A as examples of chemicals used in the manufacture of plastic goods. We present and review the most relevant research on biomarkers of exposure for phthalates and bisphenol A, including novel and most comprehensive biomonitoring data from Germany and the United States. We discuss several factors relevant for interpreting and understanding biomonitoring data, including selection of both biomarkers of exposure and human matrices, and toxicokinetic information.     

Hazard Assessment of Deer–Vehicle Collisions in Michigan

The relationship between deer–vehicle collision counts and vehicle miles traveled (VMT) is studied in this article using the Michigan (USA) crash database and categorized exposure data under different levels of data disaggregation. Negative binomial regression models were developed to establish the association between (human and deer) exposure and the frequency of deer–vehicle collisions. It is shown that VMT is nonlinearly correlated with the collision counts for most sets of circumstances except in rural areas. Observation of the association between the deer–vehicle collision count and the annual VMT across counties in Michigan reveals the unique characteristic of heteroskedasticity (i.e., variances of collision count are amplified with the increasing VMT). The regression results demonstrate that deer density stands out as the most significant exposure predictor in describing deer–vehicle collisions at the state level. It is recommended that differentiated exposure measurements for deer–vehicle collisions should be employed for three ecoregions in Michigan. Exposure predictors for deer–vehicle collisions appear to be more dependent on deer density in Michigan's Upper Peninsula and North Lower Peninsula ecoregions, while in the South Lower Peninsula ecoregion deer and human populations are equally important.     

控制人巨细胞病毒感染的策略

人巨细胞病毒（HCMV）感染对免疫受损人群危害极大,本综述了目前控制HCMV感染的策略,其中包括药物控制和免疫控制。阐述了使用药物控制HCMV感染的效果,疫苗在控制HCMV感染及引发疾病方面的作用及通过被动免疫控制HCMV感染的现状与进展。对这些策略的了解对控制HCMV感染具有重要意义。