Sweat lead levels in persons with high blood lead levels: experimental elevation of blood lead by ingestion of lead chloride.

Blood lead levels were experimentally elevated in two subjects by ingestion of single oral doses of lead as lead chloride. Serial samples of blood, urine and sweat were collected subsequently. Sweat samples were collected in polythene armbags while subjects cycled on a bicycle ergometer in a hot chamber. In spite of increases in blood and urinary lead levels, no increases in sweat lead levels were recorded. Possible reasons for this observation are discussed.     

Environmental exposure to lead and arsenic among children living near a glassworks

Concentrations of lead (Pb) in blood (B-Pb, geometric mean 34.6 micrograms l-1, n = 127) and inorganic arsenic (As) and its metabolites in urine (U-As, mean 5.1 micrograms/g creatinine, n = 35) did not differ between children living in a village close to a glassworks emitting both Pb and As and children living in a reference area. There was no significant effect on B-Pb and U-As related to parents working at the glassworks or consumption of domestically grown vegetables. Neither was there any significant effect upon B-Pb of sex, age, potentially lead-exposing hobbies, or consumption of canned foods. Boys had higher U-As than girls (5.8 vs 4.2 micrograms/g creatinine, p = 0.005), and there was a decrease with age (range 8.4-10.4 years, 27% per year, p = 0.01). Further, parental smoking habits had a significant effect on both B-Pb and U-As. In children of non-smoking parents the B-Pb was 30 micrograms l-1, in children with one parent who smoked 39 micrograms l-1 (smoking father 37, smoking mother 41 micrograms l-1) and in children with two parents who smoked 47 micrograms l-1 (p less than 0.001). The corresponding values for U-As were 4.2, 5.5, and 13 micrograms/g creatinine, respectively (p = 0.01).     

Environmental exposure to lead in a population of adults living in northern France: lead burden levels and their determinants

As part of the assessment of a site in northern France polluted by metals from two smelters (in particular, lead, cadmium and mercury), a cross-sectional study was carried out which intended to estimate the levels of the lead burden of the adult population living on the site and the factors associated with these levels. The exposed zone included 10 municipalities in the Nord-Pas de Calais region, located in the vicinity of two non-ferrous metal smelters. The soils in these municipalities contained between 100 and 1700 ppm of lead. The non-polluted zone contained 20 municipalities from the same region, drawn randomly from those in the region of comparable size but free from any industrial lead exposure. The adult study population (301 men and 300 women) was stratified according to age, sex, employment status and exposure level. The inclusion criteria required subjects who were aged between 20 and 50 years and had been living in the exposed zone for at least 8 years; the exclusion criteria were pregnancy, cancer, kidney disease and diabetes. No more than 10% of the subjects participating could work at one of the two smelters. Data collection took place at home; visiting nurses interviewed subjects to complete a questionnaire and also took blood samples. The lead assay was performed by atomic absorption spectrometry. The geometric mean of the blood-lead levels was 74 microg/l, 95% CI = 69-80 among men and 49 microg/l, 95% CI = 46-53 among women. Blood-lead levels exceeding 100 microg/l were found among 30% of men and 12% of women. Several factors were associated with variation of the mean blood-lead level: the blood-lead level was significantly higher among the men for subjects living less than 1 km from the smelters (geometric mean x 1.3, 95% CI = 1.1-1.6), for those who drink alcoholic beverages (x 1.1, 95% CI = 1.0-1.2 for consumption of 30 g/day), those who smoke (x 1.2, 95% CI = 1.0-1.3 for 20 cigarettes/day), and for subjects with occupational exposure; among the women, for subjects living less than 1 km from the smelters (geometric mean x 1.5, 95% CI = 1.2-1.7), for those who drink alcohol (x 1.1, 95% CI = 1.1-1.2 for a daily consumption of 10 g), and for women living in a building constructed before 1948 (x 1.2, 95% CI = 1.0-1.4).     

Blood lead levels in Papua New Guinea children living in a remote area

Improved contamination-free micro blood sampling and chemical analysis techniques were used to study the lead in blood (PbB) levels in 100 Papua New Guinea children living in a remote area. Six soil samples from different locations in the area were also chemically analysed as a check on environmental conditions. The mean value for PbB was 5.2 μg/100 ml with a range of 1.0–13.0 μg/100 ml. The standard deviation was 2.5 μg/100 ml. The results indicate much lower PbB levels for children living in a remote area than the earlier commonly reported levels for similar areas. These results indicate a need to reappraise the comparisons often made with PbB levels for urban children.     

Multiple causes of anaemia amongst children living near a lead smelter in Brazil

A prevalence study of anaemia was carried out amongst children, aged one to nine years, living near a lead smelter in Santo Amaro City, Northeast Brazil. It was found that the variation in haemoglobin levels was significantly associated with malnutrition and with the interaction between malnutrition and iron deficiency, but not with lead poisoning, iron deficiency, or hookworm infection, having allowed for the effects of age, area of residence, family per capita income and race. The effect of the interaction between malnutrition and iron deficiency on haemoglobin levels was most prominent amongst children aged one year and amongst those living in the most deprived area. The lack of demonstrable interaction between lead poisoning and iron deficiency in the causation of anaemia amongst these children is discussed.     

Reducing the risks of children living near the site of a former lead smeltery

The sources of lead exposure, soil, household dust, diet and ambient air near a former lead smeltery were studied. The blood lead level of small children was also determined. The aim of the study was to define, based primarily on blood lead measurements, whether children living in the contaminated area may be at risk. Within 500 m from the site of the smeltery, there were several areas where the Finnish limit value for soil Pb, i.e. 300 mg/kg, was exceeded. In the recently built areas, the surface soil has been replaced and soil remediation has taken place in schoolyards and the playgrounds of children's day-care centres. Lead content in household dust was clearly elevated in the contaminated areas. In approximately 20 years, after the smeltery was closed in 1984, the lead concentrations of the fruits and berries in local gardens have decreased to one-tenth. In some samples, the limit values are still exceeded. The lead concentration in ambient air is now 50 times lower than in the 1970s. The blood lead level of the children living in the area is slightly but statistically significantly higher than that of the children in the control areas. The critical blood lead level, i.e. 10 microg/100 ml, was not exceeded in any of the children examined. The average and maximum lead concentrations of 63 analysed blood samples were 2.2 and 5 microg/100 ml, respectively. In contrast, the average and maximum blood lead levels of school children in 1981 were 6.7 and 13.0 microg/100 ml, respectively. The risk reduction measures undertaken during the past 20 years are described.     

Lead associated caries development in children living in a lead contaminated area, Thailand

In an observational cross-sectional design, a sample of 292 children aged 6-11 years from two primary schools around a shipyard area, known to be an area contaminated with lead (from the industry), were examined to verify the cariogenicity of lead. The number of decayed and filled surfaces on deciduous teeth (dfs), and the number of decayed, missing, and filled surfaces on permanent teeth (DMFS), the salivary flow rate, pH, buffer capacity, oral hygiene, Lactobacillus spp. and mutans streptococci counts were recorded. The mean (range) of DMFS and dfs were respectively 1.3 (range 0-17) and 13.2 (range 0-45); and the geometric mean blood lead level (PbB) and SD were 7.2 and 1.5 microg/dl. The level of dfs, but not DMFS correlated with the blood lead level (R(s)=0.25, p=0.00 / R(s)=0.09, p=0.14). The odds ratio for DMFS>or=1 and dfs>5 for a doubling of PbB after adjusting for other factors were 1.28 (95%CI, 0.81-2.04; p value=0.35) and 2.39 (95%CI, 1.36-4.20; p value=0.004), respectively. The cariogenicity of lead is evident in deciduous teeth but not in permanent teeth for this age group.     

Blood lead levels during pregnancy in women living in Rio de Janeiro, Brazil

The present study was designed to determine variations in blood lead levels during pregnancy and the influence of physiological anemia during this period on these findings. An exploratory study was made of a cohort of 38 pregnant women whose blood was tested for lead level and erythrocyte counts at different stages of pregnancy. The values obtained for lead were adjusted to take account of the erythrocyte count values, in order to control the influence of pregnancy-related physiological anemia on blood lead levels. A statistically significant increase in blood lead levels at a 5% level was observed between the first and third trimester. The median blood lead levels for the first, second and third trimester were 5.1 microg/dl, 5.9 microg/dl, and 8.25 microg/dl, respectively (Kruskal-Wallis=11.9, P<0.002). Statistical significance was also shown for raw data, when blood lead levels were not adjusted to erythrocyte count values. The median blood lead levels observed in this latter situation were 5.55 microg/dl, 5.65 microg/dl and 7.3 microg/dl, respectively (Kruskal-Wallis=8.3, P<0.02). It is concluded that there was a significant increase in blood lead concentration during pregnancy in this group of women.     

Blood lead levels in children aged 5-9 years living in Cartagena, Colombia

During June-August 2004, blood lead (BPb) levels and various hematological parameters were evaluated in children aged 5-9 years old at ten primary schools located in eight neighborhoods in Cartagena, Colombia. The schools selected for this study are attended mainly by children from families of low income. A total of 189 subjects participated in the survey. The arithmetic mean+/-standard error BPb level was 5.49+/-0.23 microg/dL (range<1.0-21.0 microg/dL). The geometric mean was 4.74 microg/dL (95% CI: 4.29-5.18). A proportion of the children (7.4%) had BPb levels above the US Centers for Disease Control and Prevention's threshold of concern (10 microg Pb/dL). BPb levels were correlated weakly, but significantly and positively, with red blood cell count (RBC), and negatively with child body size, age, mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH). BPb levels did not differ significantly between boys and girls but significant differences were observed between neighborhoods (P<0.001). Activities such as metal melting-related processes and fishing net sinker production are the main sources of Pb exposure in Cartagena.     

如何处理住宅卫生间施工中的渗漏问题

就如何处理住宅卫生间施工中的渗漏问题做了探讨，阐述了卫生间渗漏的现象，从设计、施工、装修及房产商四方面分析了卫生间渗漏的原因，并提出了解决渗漏的处理措施，以最大程度地处理好卫生间的渗漏问题，保证施工质量。     

Some further studies on factors affecting the leaching of lead from unplasticized poly (vinyl chloride) pipes

Several extractants were used to further study the leaching rate of lead from unplasticized poly (vinyl chloride) pipes under different temperatures. The effects of the concentration of extractant and extraction time on the leaching of lead were also investigated. The results show that the complexing agent (EDTA) extracts much more lead from the pipes than other extractants. The study also shows that the extrusion temperature of the pipe affects the leaching rate of lead by tap water, nitrate, sulphate, carbonate, phosphate and EDTA. The lower rate of lead extraction is obtained from the pipe when extruded at 190°C as compared to those extruded at 170 to 180°C.     

Secondary effects of anion exchange on chloride, sulfate, and lead release: systems approach to corrosion control

Water treatment processes can cause secondary changes in water chemistry that alter finished water quality including chloride, sulfate, natural organic matter (NOM), and metal release. Hence, the goal of this research was to provide an improved understanding of the chloride-to-sulfate mass ratio (CSMR) with regards to chloride and sulfate variations at full-scale water treatment plants and corrosion potential under simulated premise plumbing conditions. Laboratory corrosion studies were conducted using Pb-Sn solder/Cu tubing galvanic cells exposed to model waters with low (approx. 5 mg/L Cl⁻ and 10 mg/L SO₄^2-) and high (approx. 50 mg/L Cl⁻ and 100 mg/L SO₄^2-) concentrations of chloride and sulfate at a constant CSMR of ∼0.5. The role of NOM during corrosion was also evaluated by changing the type of organic material. In addition, full-scale sampling was conducted to quantify the raw water variability of chloride, sulfate, and NOM concentrations and the changes to these parameters from magnetic ion exchange treatment. Test conditions with higher concentrations of chloride and sulfate released significantly more lead than the lower chloride and sulfate test waters. In addition, the source of NOM was a key factor in the amount of lead released with the model organic compounds yielding significantly less lead release than aquatic NOM.     

Peripheral blood cells among community residents living near nuclear power plants.

Information about hematopoieses as a result of exposure to very low levels of radiation is scarce. To investigate the human hematopoietic effect of very low level radiation exposure, measurements of peripheral blood components were performed among 3602 men and women, aged 35 and above, living in a community near two nuclear power installations in Chinshan, Taiwan. The radiation level that each individual was exposed to was represented by a surrogate level, '1/D2(1i) + 1/D2(2i)', a transformed distance from each individual's residence to the two power plants D1 and D2. In addition to comparing average hematology measurements, multiple regression analyses were done to include age, gender, smoking, drinking status and the surrogate radiation exposure level as independent variables. Univariate and bivariate analyses showed that the hematology measurements had significant associations with age, gender, smoking or drinking. The multiple regression analyses revealed that significant positive associations with '1/D2(1i) + 1/D2(2i)' were found for hemoglobin, hematocrit, platelet, white blood cell and red blood cell. The platelet count might increase for 208.7 x 10(3)/microl if the exposure from the nuclear plants increased by one exposure unit. This type of association implies that those who lived closer to the nuclear power installation had a higher blood cell count; we suspect that this could be a type of radiation hormesis.     

Concentrations of lead in blood,hair and saliva of German children living in three different areas of traffic density

Lead contents in hair, whole blood and saliva were determined for 245 healthy children (121 male, 124 female, age: 8-10 years) from three residential areas of Düsseldorf (North-Rhine-Westphalia, Germany) with different traffic densities. The geometric mean for the lead content in hair was found to be 0.87 microg/g (range: 0.2-9.9 microg/g) for the entire test group. While the levels of lead in hair in the suburban population were significantly lower than in the two city centre populations, no significant difference concerning the lead content in hair could be detected in the latter. The geometric mean for lead concentration in whole blood amounted to 25.0 microg/l (range: 8.0-154 microg/l). There was no significant difference between the sub-groups. The lead concentrations found in saliva were rather low (range: < 1.5-47.0 microg/l). Of the values, 89% were below the detection limit of 1.5 microg/l. Due to reduced levels of lead in fuel, the present study exposes that the amount of lead in the children examined has further decreased compared to preceding surveys. The correlation between the lead content in hair and the road traffic density was not corroborated by the findings with regard to amounts of lead found in blood, indicating that residual lead from fuel does not result in a substantial burden of lead found in the whole body. In contrast to levels of lead found in blood, levels of lead found in hair may be influenced more by environmental conditions. Saliva is not a suitable material for biological monitoring with respect to lead exposure in children.     

优化视野的人文居室

城市里的高层公寓楼房，大都采用墙面这种传统而有效的方式来阻隔各个功能区域的空间划分。而今天我们看到的这个居室，将墙面的比例“删减”到最小，用动态的设计取代一切固态的定格材料，让居住空间从各个方向看，都是如此开敞、通透。     

和谐人居视野下的住宅小区户外空间设计

以济南市花园洲住宅小区为例,探讨了和谐人居视野下住宅小区户外空间的设计原则,详细地介绍了花园街住宅小区的设计,分析了和谐理念在花园洲小区环境中的特色体现,以使住宅小区的环境设计更合理。     

Studies on vinyl chloride migrating into drinking water from polyvinyl chloride pipe and reaction between vinyl chloride and chlorine

To determine the conditions for the migration of vinyl chloride monomer (VCM) into water from polyvinyl chloride (PVC) pipes and to examine the reaction between VCM and the chlorine present in drinking water, we studied the migration of VCM into water. It was found that migration of VCM into water from PVC pipes (containing 29.5 ppm VCM) could only be detected by using an apparatus that prevented volatilization of VCM and increasing the surface area of the pipe wall in contact with the water. The amount of VCM which could undergo action of the chlorine in the water decreased markedly with the age of the pipes and when the pH was lowered. VCM occurred in the water was converted to chloroacetaldehyde, chloroacetic acid, etc., by its reaction with chlorine, while the amounts of these reactants varied with pH of the solution was changed.     

居住空间的适应性

介绍了居住空间的适应性．从适应可持续发畏、适应市场的变化等方面进行了论述，指出居住空间要适应家庭的居住情况，只有以人为本，才能设计出好怍品。     

氯盐环境条件下预应力混凝土氯离子侵蚀模型研究

文章总结了国内外有关混凝土中氯离子侵蚀模型的研究现状,并对国内外几种典型的扩散方程进行了分析评价;针对氯盐侵蚀的预应力混凝土结构,讨论了氯离子扩散系数的计算。氯离子扩散系数对于预应力混凝土来说是一个重要的因素,因此合理确定氯离子扩散系数,对预测氯离子环境条件下预应力结构的耐久性具有重要意义。对于预应力混凝土,计算氯离子扩散系数除了要考虑混凝土与氯离子之间的结合能力、环境温度、湿度影响外,还要考虑混凝土的应力水平,氯离子有效扩散系数是变化的,且氯离子扩散系数对PC结构耐久性的影响很大。本文对预应力混凝土氯离子侵蚀模型进行了改进,并根据试验结果对改进后模型进行了评价。