Seasonal variation of indoor radon in dwellings of Malwa region, Punjab

Indoor radon measurements in 105 dwellings belonging to 21 villages of Muktsar and Ferozepur districts of Malwa region, Punjab, have been carried out, using LR-115 type II cellulose nitrate films in the bare mode. The annual average indoor radon value in the study area varies from 76.25 to 145.50 Bq m⁻³, which is well within the recommended action level [ICRP, 1993. Protection against radon at home and work. Annals of ICRP, ICRP Publication, p. 65]. Seasonal variation of indoor radon shows high values in winter and low values in summer. The winter/summer ratio of radon concentration has been computed for all 105 dwellings. The winter/summer ratio of indoor radon ranges from 0.84 to 1.89 with an average of 1.46. The indoor radon values obtained in the present investigation are more than the world average of 40 Bq m⁻³     

First-trimester prenatal diagnosis of the nijmegen breakage syndrome and ataxia telangiectasia using an assay of radioresistant dna synthesis

Prenatal diagnosis was performed in two pregnancies at risk of the Nijmegen breakage syndrome. In one pregnancy, an affected fetus was diagnosed by demonstration of radioresistant DNA synthesis, using autoradiographic detection of incorporated tritiated thymidine in cultured chorionic villus cells. The diagnosis was confirmed in fetal skin fibroblasts. In the other case, the fetus appeared unaffected. Using the same procedure, unaffected fetuses were predicted from chorionic villus cells in two pregnancies at risk of ataxia telangiectasia, which is another genetic disorder showing the feature of radioresistant DNA synthesis. The present biochemical method for prenatal detection of Nijmegen breakage syndrome and ataxia telangiectasia can be used as a simplified alternative to the cytogenetic procedures reported earlier for ataxia telangiectasia.     

焦化区苯污染状况及风险评价研究

采用顶空气相色谱法对焦化厂附近不同距离采集的土壤样品中苯含量进行了检测,分析了气象、地理位置等因素对苯含量的影响.结果表明,苯浓度值大小为南>北>东>西,在距离焦化厂200m左右处出现最大值,检测结果与当地风向(主导风向为南风)具有较好的相关性;采用大气污染扩散模型对焦化厂附近空气中的苯浓度和最大落地距离进行了计算,结果与土壤中苯的检出规律具有一致性.通过呼吸暴露法对焦化区居民进行了健康风险和泄漏风险评价结果表明,焦化厂的苯产生源直接排放会对附近居民造成严重的安全隐患(Risk=0.008,略小于警戒线0.01),而经过治理后对当地居民造成的致癌风险会大大减小(Risk=0.001);发生苯泄漏时,在E-F稳定度下,距离焦化区最近的村庄1处的浓度值超过中国居住区大气中有毒物质的最高允许浓度11.7倍,具有较大的风险性.     

Influence of groundwater recharge and well characteristics on dissolved arsenic concentrations in southeastern Michigan groundwater

Arsenic concentrations exceeding 10 μg/l, the United States maximum contaminant level and the World Health Organization guideline value, are frequently reported in groundwater from bedrock and unconsolidated aquifers of southeastern Michigan. Although arsenic-bearing minerals (including arsenian pyrite and oxide/hydroxide phases) have been identified in Marshall Sandstone bedrock of the Mississippian aquifer system and in tills of the unconsolidated aquifer system, mechanisms responsible for arsenic mobilization and subsequent transport in groundwater are equivocal. Recent evidence has begun to suggest that groundwater recharge and characteristics of well construction may affect arsenic mobilization and transport. Therefore, we investigated the relationship between dissolved arsenic concentrations, reported groundwater recharge rates, well construction characteristics, and geology in unconsolidated and bedrock aquifers. Results of multiple linear regression analyses indicate that arsenic contamination is more prevalent in bedrock wells that are cased in proximity to the bedrock-unconsolidated interface; no other factors were associated with arsenic contamination in water drawn from bedrock or unconsolidated aquifers. Conditions appropriate for arsenic mobilization may be found along the bedrock-unconsolidated interface, including changes in reduction/oxidation potential and enhanced biogeochemical activity because of differences between geologic strata. These results are valuable for understanding arsenic mobilization and guiding well construction practices in southeastern Michigan, and may also provide insights for other regions faced with groundwater arsenic contamination.     

中国癌症与土壤环境中铊元素的关系

利用土壤环境中铊元素资料７６９个数据,癌死亡调查资料７８７０８０例,研究了胃癌,食管癌,肝癌,宫颈癌,肺癌、大肠癌、白血病、鼻咽癌、乳腺癌死亡率与人群生存区土壤环境中铊元素的关系。     

COMARE 11th report: an alternative interpretation

The 11th report of COMARE (Committee on Medical Aspects of Radiation in the Environment) established that the incidence of some childhood cancers, including leukaemia, is inversely related to population density in England, Wales and Scotland, and is particularly high in Buckinghamshire. Using a photographic archive survey, the present paper notes that population density is also inversely related to overhead wire domestic electricity supply in Buckinghamshire. Factors associated with domestic electricity supply may be relevant to the geographical distribution of some childhood cancers.     

Chronic risk assessment of exposure to volatile organic compounds in the atmosphere near the largest Mediterranean industrial site

This study focuses on characterising the risk of exposure to volatile organic compounds (VOCs) by means of inhalation in people living in the vicinity of the largest chemical production site in the Mediterranean area. Eighty-six VOCs were initially selected for this study based on their adverse environmental and health effects. The monitoring campaign was conducted for 276 days in three different locations around the chemical site. The analytical method used for the characterisation was based on European standard method EN-14662-2, which consists of the active sampling of air for 24 h in charcoal tubes, followed by extraction with carbon disulphide and GC-MS analysis. Forty-four VOCs with toxicological data available concerning their carcinogenic and non-carcinogenic health effects were quantified during the monitoring campaign. None of the quantified VOCs showed average concentrations exceeding their chronic reference concentrations and, therefore, no non-carcinogenic health effects are expected as a result of this exposure. However, the global average cancer risk due to VOC exposure in the area (3.3 × 10^− 4) was found to be above the values recommended by the WHO and USEPA.The influence of the analytical method was also evaluated by comparing cancer risk estimates using a thermal desorption (TD) method based on method EN-14662-1. The results of the 24-h samples for the solvent extraction method were compared with the average of 12 daily samples of 2-h for the TD method for 24 sampling days. Although the global estimated lifetime cancer risk was statistically comparable for both methods, some differences were found in individual VOC risks.To our knowledge, this is the first study that estimates the carcinogenic and non-carcinogenic risks posed by the inhalation of VOCs in people living near a chemical site of this size, and compares the estimated cancer risk obtained using two different standard analytical methods.     

PM2.5 chemical composition and health risks by inhalation near a chemical complex

Particulate matter (PM_2.5) samples were collected in the vicinity of an industrial chemical pole and analysed for organic and elemental carbon (OC and EC), 47 trace elements and around 150 organic constituents. On average, OC and EC accounted for 25.2% and 11.4% of the PM_2.5 mass, respectively. Organic compounds comprised polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, anhydrosugars, phenolics, aromatic ketones, glycerol derivatives, aliphatic alcohols, sterols, and carboxyl groups, including aromatic, carboxylic and dicarboxylic acids. Enrichment factors > 100 were obtained for Pb, Cd, Zn, Cu, Sn, B, Se, Bi, Sb and Mo, showing the contribution of industrial emissions and nearby major roads. Principal component analysis revealed that vehicle, industrial and biomass burning emissions accounted for 66%, 11% and 9%, respectively, of the total PM_2.5-bound PAHs. Some of the detected organic constituents are likely associated with plasticiser ingredients and thermal stabilisers used in the manufacture of PVC and other plastics in the industrial complex. Photooxidation products of both anthropogenic (e.g., toluene) and biogenic (e.g., isoprene and pinenes) precursors were also observed. It was estimated that biomass burning accounted for 13.8% of the PM_2.5 concentrations and that secondary OC represented 37.6% of the total OC. The lifetime cancer risk from inhalation exposure to PM_2.5-bound PAHs was found to be negligible, but it exceeded the threshold of 10⁻⁶ for metal(loi)s, mainly due to Cr and As.     

癌症及其发生的水土环境

本文从环境学角度分析了癌症高发区的水土环境。表明癌症高发区除水土严重污染,许多常量成份出现异常外,一些微量元素还明显缺少或严重超量。     

某污水灌区居民胃癌高发的病因研究

某污水灌区居民恶性肿瘤死亡回顾调查发现,胃癌标化死亡率重污染地区明显高于一般污染区及对照区,是全国农村胃癌标化死亡率的3倍.通过污灌区居民临床体检和肠型胃癌的肠上皮抗原——α_2GP 对血清免疫学检测,发现胃癌高发与本地人群慢性萎缩性胃炎的粘膜肠上皮化生有密切联系,环境卫生与环境流行病学调查进一步证明污灌地区居民的胃粘膜肠上皮化生又和灌区污染的井水及稻米中某些矿物油、苯并(a)芘等污染物长期刺激有关,经试验均具有效突变活性.据此,作者初步提示了某污灌区居民胃癌的发生模型.