Natural siliceous dust and human health： Pathways, toxicity, and impact

Fine atmospheric dust includes mineral particles and aggregates, fibrous minerals and fibrous organic material. Generation, dislodgement and transport （deflation） of natural dust with the finer （〈4 microns） components suspended as silt-size aggregates, is widespread in and adjacent to the world＇s drylands, as well as deriving from volcanic vents. Silica is a highly fibrogenic agent in lung tissue. Long-term inhaling of siliceous dusts can lead to a number of fibrotic lung diseases, including natural （non-occupational） pneumoconioses （notably silicosis, but including asbestosis and others）. Different polymorphs of silica show different levels of toxicity in interaction with lung tissue. Particles with highly active surfaces may release radicals, causing cell damage. Some types of inhaled particulates are degraded by macrophages, but many are highly resistant and persist in the lungs, some stimulating fibroblastic cells to deposit collagen. Silicosis is an inflammation of the lung commonly caused by silicate mineral particles, leading to fibrosis. Three types are recognized： nodular pulmonary fibrosis （simple or chronic silicosis）, acute silicosis, and accelerated silicosis. Generally, finer particulates have greater oxidative capacity than the coarser fractions. They contain more reactive oxygen species, their greater bioreactivity making them more toxic to pulmonary tissue. Nevertheless, inhalation of large dust particles （〉 10μm） may constitute a health risk if the mineralogy is toxic, regardless of where the grains lodge in the respiratory system. Dust may absorb harmful gases, disease-generating bacteria and carcinogenic hydrocarbon compounds. Silica-related respiratory disease may also an exacerbate cardiac problem, and epidemiology suggests a link with tuberculosis. Quantification of dust loading and exposure requires study of spatial and temporal patterns, supported by meteorological analysis, airflow modeling and satellite-borne imagery. Some acute, short-term health impacts have been assessed using atmospheric and health records both before and after a dust storm or by comparison of populations within and outside such events. Analysis of the size, shape, mineralogy and geochemistry of ambient dust particulates provides information on natural dust sources, dust concentrations, and potential particulate toxicity, as well as providing a datum for assessment of human exposure levels.     

Methylmercury and human biomarkers： Questioning the evidence

Methylmercury （MeHg） is a powerful neurotoxicant in humans. In terms of biomarkers of MeHg exposure, hair and blood have long been used in epidemiological studies as the biomarkers of choice. In fact, total hair mercury （Hg） content as well as organic blood Hg concentrations reflects exposure to organic Hg from food consumption. Extensive studies, establishing a constant and linear relation between MeHg intake versus Hg levels in hair and blood, were conducted by governmental officials to establish guidelines on safe levels of MeHg exposure, which were translated into threshold daily fish consumption rates （usually expressed as μg MeHg per kg bodyweight）. Nowadays, in most epidemiologic studies blood or hair mercury （Hg） level is commonly used as a valid proxy to estimate human exposure to methylmercury （MeHg） through fish consumption without relating this signal to actual fish consumption patterns among populations. Human variability in mercury toxicokinetics was identified and measurement error has been pointed out to be a substantial contributor to observed variability, particularly where dietary information is retrospective and self-reported. However, experimental evidence indicates that significant variability among individuals may exist in the biokinetics of mercury. Also recent findings from previous population-based studies through COMERN initiative also revealed that MeHg metabolic processes might greatly vary across populations. In fact, it is unlikely that the magnitude of the difference measured between observed and expected levels of mercury, given the reported intake, can be entirely explained by laboratory measurement errors or reporting bias.     

加强煤炭资源开发管理 促进煤炭工业健康发展——在全国煤炭工作会议上的发言

《国务院关于促进煤炭工业健康发展的若干意见》意义重大,影响深远。国家发展改革委召开的这次会议非常必要,十分及时。刚才,张晓强副主任作的报告非常重要,涉及我部工作的,我们一定抓好落实。下面,我简要汇报一下国土资源部在煤炭资源管理方面所做的工作,以及下一步贯彻落实国务院精神的有关措施。一、煤炭资源管理的基本情况改革开放以来,煤炭工业为国民经济和社会发展作出了重大贡献。在今后相当长的时期内,煤炭仍将是我国的主体能源,煤炭工业的健康发展直接关系到我国的能源安全。目前,由于市场需求的拉动,煤炭价格持续走高,煤炭资源的…     

工程质量安全监督与行业发展司2005年工作要点

要始终贯穿一条主线，推进形成两种机制，紧紧抓住三项重点，重视提高四种能力，抓好五个薄弱环节。以切实保障人民群众生命财产安全和促进建筑业持续健康发展为主线；推进形成建筑市场自行调节机制和各方主体自我管理机制；紧紧抓住城市公共安全、施工安全和工程质量安全三项重点；积极培育并提高应急管理能力、工程质量安全和施工安全监管能力、     

保障饮水安全维护生命健康

我国是地方病流行较为严重的国家，地方病分布广泛，受害人口较多。由于自然环境影响。地方性砷中毒、地方性氟中毒、克山病、大骨节病以及地方性甲状腺肿等．在“老少边穷”地区及部分农村地区仍很严重。无疑，地方病严重影响了当地人民群众的生命健康和正常生活．并严重阻碍了建设小康社会的步伐。     

城市大气环境边界层观测试验

城市大气环境边界层观测试验工程提出了城市区域大范围大气污染"空气穹隆"动力过程三维结构,首次揭示出北京周边地形"山谷风"与城市"热岛"效应相互作用对城市大气环境影响的综合特征.试验采用卫星遥感-地面观测相结合的技术方案,揭示北京周边地区污染贡献及其气溶胶远距离输送轨迹特征,提出建立北京及其周边地区点-面结合、卫星遥感-地面观测相结合立体综合监测网的设计新方案.该项目被世界气象组织专家组工作会议评为国际城市大气环境观测优秀示范计划,项目研究成果于2002年作为特邀撰稿发表于美国<环境与健康>(SCI),研究成果在北京市及有关省市推广应用.     

矿产资源对人体健康的影响及其对策--以四川省为例

随着社会的发展,人类对矿产资源的需求量日益增大.而某种程度上,一些国家或地区的环境污染状况,总是与这些国家和地区的矿产资源的富集程度、开发和利用水平相关联,以下就四川省矿产资源对人体健康影响及其对策加以分析.1 四川省矿产资源和人口密度分布特点四川境内分布的矿产资源中22种元素和矿种对人体健     

饮水与健康

人天天都在喝水,但是为什么要喝水,许多人却知之甚少。 水是构成一切生物体的基本成分。不论是动物还是植物,均以水维持最基本的生命活动。人可数天无食,不可一天无水,所以,水是生命之源泉,水也是人类最必需的营养素之一。人的体重约50％～70％是水分。含水量随年龄、性别及身体状况的不同而异。脑组织大约含85％的水,血液大约含有90％的水,水是人     

农药污染对人体健康的危害及防治

我国是使用农药最早的国家之一，有着十分悠久的历史，农药用于防治农林牧业病、虫草害、鼠害和其他有害生物是调节植物生长的药物及加工制剂。大量的事实表明，农药在防治病虫害、保护庄稼生长方面的作用不容置疑。从不使用农药的自然农业发展到使用农药的现代农业，农药做出了一定的贡献。据统计，世界粮食因为农药的实用，产量相对增长，但如果不使用农药，因为病、虫、草害的影响，粮食将减少1／3[1]。由此可见，农药在人类农业史中起了十分重要的作用。但是由于农药是一种化学制剂，长期大量使用，会对环境生物安全和人体健康产生不利的影响。农药怎样污染环境和对人体健康产生危害，笔者就这一问题加以论述。