中国环境镉接触人群低骨密度及肾功能不全的研究

25年前,Ambio曾载文提出应警惕环境镉污染引起的健康效应.1998年在中国进行了这方面的研究,评价了因食用大米而接触镉人群的前臂骨密度(BMD)和肾功能,发现尿镉(CdU)或血镉(CdB)高的绝经后妇女及血镉(CdB)高的男性,BMD均有所下降.在CdB或CdU与肾功能不全(视黄醇结合蛋白排泄增加)之间也发现了明显的、有统计学意义的剂量-效应关系及剂量-反应关系.第一次报道了日本以外的亚洲地区镉接触人群中存在骨不良效应.本文的意义在于阐明了亚洲的环境镉接触人群中仍存在着与肾和骨(镉的比较严重的有害效应)的联合效应,也讨论了一些欧洲镉接触人群的骨效应.     

Determination of germanium in urine and its usefulness for biomonitoring of inhalation exposure to inorganic germanium in the occupational setting

The present study aimed to assess whether urinary germanium concentration can be used as a biomarker of inhalation exposure to airborne dust from metallic germanium (Ge) or GeO2 in the occupational setting. A novel hydride generation-based method coupled with fow-injection graphite furnace atomic absorption spectrometry (HG/FI-GFAAS) was developed for the determination of urinary germanium. It was found that urinary germanium concentration could be reliably determined by a standard additions method after thorough digestion of the urine and careful pH adjustment of the digest. The limit of detection (LOD) in urine for the HG/FI-GFAAS method was 0.25 microg Ge L(-1). In Belgian control male subjects, the urinary germanium concentration was below this LOD. In 75 workers currently exposed to inorganic germanium compounds, respirable and inhalable concentrations of germanium in the aerosols were measured on Monday and Friday at the job sites using personal air samplers. Spot-urine samples were collected on the same days before and after the work shift. The germanium concentrations of respirable dust correlated very well with those of inhalable dust and represented 20% of the inhalable fraction. Workers exposed to metallic Ge dust were on average ten times less exposed to germanium than those whose exposure involved GeO2 (3.4 versus 33.8 microg Ge m(-3)). This difference was reflected in the urinary germanium concentrations (3.4 versus 23.4 microg Ge g(-1) creatinine). Regression analysis showed that the concentration of germanium in the inhalable fraction explained 42% of the post-shift urinary germanium concentration either on Monday or on Friday, whereas in a subgroup of 52 workers mainly exposed to metallic germanium dust 57% (r = 0.76) of the Monday post-shift urinary germanium was explained. Urinary elimination kinetics were studied in seven workers exposed to airborne dust of either metallic Ge or GeO2. The urinary elimination rate of germanium was characterised by half-times ranging from 8.2 to 18.1 h (on average 12 h 46 min). The present study did not allow discrimination between the germanium species to which the workers were exposed, but it showed fast urinary elimination kinetics for inhalation exposure to dust of metallic Ge and GeO2. It pointed out that urine samples taken at the end of the work shift can be used for biological monitoring of inorganic germanium exposure in the occupational setting.     

Dietary exposure of juvenile common sole (Solea solea L.) to polybrominated diphenyl ethers (PBDEs): Part 1. Bioaccumulation and elimination kinetics of individual congeners and their debrominated metabolites

The uptake and elimination of six PBDE congeners (BDE-28, -47, -99, -100, -153, -209) were studied in juvenile common sole (Solea solea L.) exposed to spiked contaminated food over a three-month period, then depurated over a five-month period. The results show that all of the studied PBDEs accumulate in fish tissues, including the higher brominated congener BDE-209. Several additional PBDE congeners were identified in the tissues of exposed fish, revealing PBDE transformation, mainly via debromination. The identified congeners originating from PBDE debromination include BDE-49 and BDE-202 and a series of unidentified tetra-, penta-, and hepta- BDEs. Contaminant assimilation efficiencies (AEs) were related to their hydrophobicity (log K_ow) and influenced by PBDE biotransformation. Metabolism via debromination appears to be a major degradation route of PBDEs in juvenile sole in comparison to biotransformation into hydroxylated metabolites.     

Lung retention and bioavailability of arsenic after single intratracheal administration of sodium arsenite,sodium arsenate,fly ash and copper smelter dust in the hamster

Arsenic is present in airborne particulate material released by coal-fired power plants and non-ferrous metal smelters. We have assessed whether the physico-chemical properties of arsenic in such particles play a role in its lung retention and uptake by the body. Female hamsters were given a single intratracheal instillation of fly ash or copper smelter dust suspensions (at doses of 50 or 100 g As kg^–1) or identical amounts of soluble tri- and pentavalent arsenic, in the presence or absence of an inert dust material (tungsten carbide). The concentration of the element was measured in a 24 hour urine sample collected on the 1st, 2nd and 6th day after treatment and arsenic remaining in lung tissue was determined at the end of the same time periods. Both lung retention and urinary As excretion indicate a prolonged contact of the lung tissue with particulate As in contrast to soluble As salts. In addition to the effect of solubility described here, more research is needed to determine the effect of particle size and lung loading on retention, as well as the potential differences in the lung inflammatory response using arsenic-rich particulates from various sources.     

Cellular metabolism of arsenic studied in mammalian cellsin vitro

The cytotoxicity of trivalent and pentavalent inorganic arsenic was studied in cultured mouse fibroblasts. Concentrations of As(III) in the M range and approximately 10-fold higher concentrations of As(V) led to a reduction of cellular proliferation and viability with a concomitant increase of LDH release and stimulation of lactate production. Cells pretreated with a low As(III) concentration were less sensitive to toxic doses of As(III) or As(V).Uptake of As(III) by the cells was greater than that of As(V). Both forms of inorganic arsenic were converted intracellularly to monomethylarsonic (MMA) and dimethylarsinic (DMA) acids, which were subsequently released into the culture medium. In As-pretreated cells, which proved more resistant to As toxicity, biotransformation of inorganic to MMA and DMA was increased.     

Low bone density and renal dysfunction following environmental cadmium exposure in China

This paper presents the main findings of a study on health effects of environmental cadmium pollution in China, performed in 1998, i.e. approximately 25 years after the first warnings of such effects were published in Ambio. Forearm bone mineral density (BMD) and renal dysfunction were assessed in population groups exposed to cadmium via rice. Decreased BMD was found in postmenopausal women with elevated urinary cadmium (CdU) or cadmium in blood (CdB) and among men with elevated CdB. Also, clear and statistically significant dose-effect and dose-response relationships were found between CdB or CdU and renal dysfunction (increased excretion of retinol-binding protein). This is the first report of bone effects among Cd-exposed population groups in Asia outside Japan. The report is also of interest since it demonstrates that bone effects, a comparatively severe adverse health effect of Cd, in combination with renal dysfunction, still occurs in environmentally exposed population groups in Asia. Recent reports on bone effects in Cd-exposed population groups in Europe are discussed.