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.     

环境水样中砷的化学形态分析

由于砷的化学形态不同,在环境中的毒性、分布、生物效应亦不相同,因而砷的形态分析在环境监测治理中有着不可忽视的重要作用.砷的形态分析     

有毒铜绿微囊藻对鱼和溞的毒性

用有毒铜绿微囊藻细胞及其从毒细胞中提取的毒素喂养和腹腔注射鱼类，结果表明：（1）微囊藻毒素MCYST－LR对所有实验过的鱼有毒害作用（LD_(50)为110－500μg／kg）．注射毒素24h后，鱼肝电镜超微结构观察均表现出肝损伤．（2）在受控条件下，当用有毒铜绿微囊藻作为食物喂养日鲢和罗非鱼时，鱼类能在以毒藻为唯一食物的环境中生活20d以上．白鲢和罗非鱼粪便的毒性比喂食藻类的毒性分别降低约2—4．5倍，其肝的超微结构现察仍有轻度损伤．（3）在培养液中加入15μg／mLMCYST－LR和用实验室纯培养的铜绿微囊藻作为食物培养枝角类时，均可使它们在48h死亡．以无毒微囊藻培养时则生长不良亦不怀卵，表明它不是枝角类合适的食物．     

苯并（a）芘诱导下岩虫CYP基因的表达特征

Rapid amplification of cDNA ends(RACE) and real-time polymerase chain reaction(RT-PCR) were carried out to analyze the CYP4 gene expression in polychaete Marphysa sanguinea exposed to benzo[a]pyrene(BaP) in this study. The full length of MsCYP4 cDNA was 2 470 bp, and it encoded 512 amino acids. The deduced amino acid sequence showed 47% identity with CYP4 F from frog Xenopus tropicalis and shared high homology with other known CYP4 sequences. To analyse the role of CYP4 in protecting M. sanguinea from BaP exposure, three BaP groups were established: 0.5, 5 and 50 μg/L. Polychaetes were sampled after 3, 7 and 12 d. At 0.5 μg/L, the effect of BaP on MsCYP4 gene expression increased with time prolonged. MsCYP4 gene expression curve showed Ushaped trend with time in 5 and 50 μg/L BaP groups. Therefore, MsCYP4 gene may play an important role in maintaining the balance of cellular metabolism and protecting M. sanguinea from BaP toxicity.     

北京西北城区一次重污染过程中PM10的氧化损伤能力研究

为评估大气重污染期间北京市可吸入颗粒物(PM_(10))的毒性,采集2016年3月份一次大气重污染过程中北京市大气PM_(10)样品,应用质粒DNA损伤评价法来研究其氧化损伤能力。结果表明,雾霾期间PM_(10)对DNA的损伤率高于雾霾逐渐消退时期,远高于雾霾前期清洁天,颗粒物对DNA损伤率随剂量的增加而增加。雾霾前后PM_(10)水溶样品的平均TD_(20)值表现为雾霾前清洁天(788.01μg/mL)雾霾消退后期(470.40μg/mL)雾霾期间(55.78μg/mL),说明氧化能力雾霾期间雾霾消退后期雾霾前清洁天。另外通过雾霾前后数据对比得到,暴露毒性指数TI大小顺序为雾霾期间(13 245.06)雾霾消退后期(1 658.87)雾霾前清洁天(254.08),说明雾霾期间PM_(10)对人体危害更大。     

纤粒矿物粉尘体外细胞毒性研究

采用体外细胞培养技术,观察兔肺泡巨噬细胞死亡率,用丙二醛（ＭＤＡ）的含量变化、乳酸脱氢酶（ＬＤＨ）及超氧化物歧化酶（ＳＯＤ）的活性变化来评价来自１２个矿６床的６种矿物的１２种结晶习性的矿物粉尘的细胞毒性,探讨其使巨噬细胞受损的机制。结果显示：沸石、硅灰石无细胞毒性,而其他的纤维状及片粒状矿物粉尘则表现出不同程度的细胞毒性,说明矿物粉尘的细胞毒性与矿物粉尘的形态有一定关系,但主要由矿物粉尘的特性所决     

工业废水和城市综合污水的环境风险管理

综述了国内外工业废水与城市综合废水的监控和环境风险管理进展。与发达国家比较,化学监测法是目前我国工业废水和城市综合污水监控的唯一手段,而且主要有赖于COD等极少参数,并不能有效监控复合有毒有机污染物的排放。采用生态毒性检测法,可弥补这一缺陷,满足环境风险管理要求。毒性鉴别评价鉴别出导致废水/污水生态毒性的关键有机毒物,是降低其环境风险的核心。还对生态毒性检测法应用于我国废水/污水排放的监控和环境风险管理前景做了评述。