Cadmium in blood and hypertension

OBJECTIVES: This study is to examine the effect of cadmium exposure on blood pressure in Korean general population. METHODS: The study population consisted of 958 men and 944 women who participated in the 2005 Korean National Health and Nutrition Examination Survey (KNHANES), in which blood pressure and blood cadmium were measured from each participant. RESULTS: The mean blood cadmium level was 1.67 microg/L (median level 1.55). The prevalence of hypertension was 26.2%. The blood cadmium level was significantly higher among those subjects with hypertension than those without (mean level 1.77 versus 1.64 microg/dL). After adjusting for covariates, the odds ratio of hypertension comparing the highest to the lowest tertile of cadmium in blood was 1.51 (95% confidence interval 1.13 to 2.05), and a dose-response relationship was observed. Systolic, diastolic, and mean arterial blood pressure were all positively associated with blood cadmium level, and this effect of cadmium on blood pressure was markedly stronger when the kidney function was reduced. CONCLUSIONS: Cadmium exposures at the current level may have increased the blood pressure of Korean general population.     

The relationship between self-reported tobacco exposure and cotinines in urine and blood for pregnant women

To explore the relationship of self-reported exposure to tobacco smoke and the cotinine levels in the urine and blood over the follow-up period for pregnant women. Three hundred ninety-eight pregnant women undergoing prenatal care were interviewed in different trimesters at three hospitals in central Taiwan using a structured questionnaire. Based on their self-reported smoking experience, the participants were classified into three groups (25 smokers, 191 passive smokers, and 182 non-smokers) and were tracked in this study up to the time of delivery. Cotinine levels were tested for the maternal blood and urine at the end of each trimester and for the umbilical cord-blood of the newborns. All specimens were measured using a sensitive high-performance liquid chromatographic (HPLC) technique. In general, urinary cotinine levels were higher in subjects who smoked (including current- and ex-smokers) than those who never smoked. The pattern of distribution of cotinine levels among smoking/ETS exposure group in the urine sample was similar to that in the blood sample. The umbilical cord-blood cotinine levels was found to be highest in the active smoking group, followed by the ETS group exposed to ETS both at home and in the workplace. Over the course of the pregnancies, there was an increase in cotinine levels in urine and maternal blood for each of 3 exposure groups. Exposure to smoking by self-reported information in pregnant women has been found to be directly related to the levels of cotinine in the umbilical cord-blood of the fetus. Cotinine is a sensitive measure of ETS exposure, but if biochemical analysis is not available or convenient for a pregnant woman, then self-reported exposure to ETS can provide a good estimate if the information is gathered by a well-trained interviewer in a structured way.     

Cadmium monitoring in saliva and urine as indicator of smoking addiction

Cadmium is one of the many substances that may be acquired through active and passive smoking of tobacco. Saliva and urine are proposed for cadmium monitoring of non-smokers, second hand smokers, smokers and tobacco chewing appertaining to San Luis citizens without occupational exposition. Biological samples were collected by the same subjects, under strict proceeding instructions of sampling. Physical characteristics of samples were observed and checked with commercial test. Samples were analyzed using an adapted molecular fluorescence methodology with a previous extraction step. Stability of biological samples was daily studied for a period of one month. The method was successfully validated for accuracy, precision, linearity, specificity, and sensitivity. The simplicity and low coefficient of variance confirm the suitability of the method for urinary and salivary cadmium analyses. On the other side, the obtained results are in concordance with previous national epidemiological dates.     

Cadmium exposure pathways in a population living near a battery plant

OBJECTIVES: The objectives of the present study were to assess the relative impact of different pathways of environmental cadmium (Cd) exposure and to evaluate the contribution from locally produced vegetables and root crops to the total dietary intake of Cd. METHODS: Cadmium in urine was determined for 492 individuals living near a closed down battery factory in Sweden. For each individual we created an environmental exposure-index based on Cd emissions to ambient air and number of years living at various distances from the plant. This information as well as dietary data were collected via questionnaires. Samples of soil, carrots and/or potatoes were collected from 37 gardens and analysed for Cd concentration. RESULTS: Eating home grown vegetables/potatoes, environmental Cd-exposure-index, female gender, age above 30 years and smoking more than one pack of cigarettes daily for at least 10 years were found to be significantly associated with increased urine concentrations of Cd (UCd>1.0 nmol/mmol creatinine). We found a statistically significant relation between Cd in urine and environmental Cd-exposure-index in persons eating home grown vegetables/potatoes regularly. Cd concentrations in home grown carrots, potatoes and in garden soil were highest in the area closest to the factory. Daily consumption of potatoes and vegetables cultivated in the vicinity of the closed battery factory was estimated to increase Cd intake by 18-38%. CONCLUSION: The present study shows that consumption of locally grown vegetables and root crops was an important exposure pathway, in subjects living near a nickel-cadmium battery plant, whereas direct exposure via ambient air was less important.     

Benzene in blood as a biomarker of low level occupational exposure.

The occupational airborne exposure to benzene of 150 workers employed in petrol stations and a refinery plant was assessed using personal sampling pumps. All workers provided blood samples after the end of work and on the following morning before resuming work. Benzene concentrations in the blood of 243 non-occupationally-exposed subjects were also measured. The median occupational benzene exposure for all 150 workers studied was 80 micrograms/m3. Overall median blood benzene of all workers was 251 ng/l at the end of the shift, and 174 ng/l the following morning. The benzene concentrations measured in blood collected the following morning proved to be significantly lower than those measured at the end of the shift. Median blood benzene for the 243 'normal' subjects was 128 ng/l, which was significantly lower than that measured in the workers before a new work shift. The median blood benzene concentration was significantly higher in smokers than in non-smokers, both in the general population (210 ng/l vs. 110 ng/l) and in the exposed workers at the end of the shift (476 ng/l vs. 132 ng/l) and the following morning (360 ng/l vs. 99 ng/l). End-of-shift blood benzene correlated significantly with environmental exposure; this correlation was better in the 83 non-smokers than in the 67 smokers. In non-smokers with the median benzene occupational exposure of 50 micrograms/m3, no difference was found in blood benzene concentration in exposed and non-exposed subjects.     

An interlaboratory comparison programme for several toxic substances in blood and urine

Since 1979, the Centre de Toxicologie du Québec has operated an interlaboratory comparison programme for several toxic substances in blood and urine. We initiated this program due to the unavailability of reliable and representative reference materials for toxic elements in blood and urine. The main objective is to enable participants to improve or maintain the accuracy of their analytical work by periodically comparing their results. There are presently 76 laboratories registered in the programme for one or more substances. The majority are located in North America with several others in Europe and South America. Available substances include lead and cadmium in blood, aluminum in serum, and mercury, arsenic, cadmium, fluoride and chromium in urine. Samples are prepared by pooling specimens obtained from exposed workers. We have examined the performance of participants over the course of the years using as criteria the deviation from the target value, the scatter of results and the proficiency within preset limits of toxicological significance. Whenever possible the influence of analytical methods was evaluated. The feedback provided by participation in the programme appears to be a significant factor in the maintenance or improvement of analytical proficiency. The vast majority of participants obtain results of adequate reliability for use in the monitoring of exposed workers.     

饮用水源突发镉污染的应急处理技术研究

为应对可能出现的突发性镉污染事件,采用连续流试验考察了常规混凝沉淀工艺、KMnO4预氧化/混凝沉淀工艺、粉末炭(PAC)吸附/混凝沉淀工艺、KMnO4和PAC联用/混凝沉淀工艺以及高锰酸盐复合药剂(PPC)预氧化/混凝沉淀工艺对镉的去除效果。结果表明,常规混凝沉淀工艺的除镉效果有限,聚合氯化铝投量为4 mg/L时,对Cd2+的去除率仅为10.5%;KMnO4预氧化/混凝沉淀工艺、PAC吸附/混凝沉淀工艺、KMnO4和PAC联用/混凝沉淀工艺对Cd2+的去除率均有提高,但出水水质仍不能满足国家饮用水水质标准。PPC预氧化/混凝沉淀工艺的除镉效果明显,当PPC投量为3.5 mg/L时,沉后水中剩余Cd2+浓度降低至3.3μg/L,达到了国家饮用水水质标准,去除率为95.2%。因此,PPC预氧化可以作为东江沿岸水厂应对镉污染的一种有效的应急处理措施。     

Cadmium content of indicator and target organs in rats after graded doses of cadmium

Eleven groups of inbred Wistar rats, five males and five females in each group, received graded doses of CdCl₂, from 0–25 ppm, in the drinking water from conception until sacrifice at ten weeks of age. Litter‐size, weight and water consumption were recorded at different ages of the animals. The Cd levels of indicators as blood, hair, incisors and molars, and target organs as femur, kidney cortex, liver, spleen, heart, gastrocnemius muscle and adrenal glands were recorded by atomic absorption spectrophotometry. Cd in the drinking water had no influence on number of animals in each litter, water consumption and growth of the animals. The results further confirmed that the primary target organs of Cd were the soft tissues, but that Cd can to some degree accumulate in teeth and bone, especially molars. The Cd content of all tissues, both indicators and targets, was positively and significantly correlated with dose. The positive significant correlation between the Cd levels of hair or molars, and every target organ suggests that hair and molars of rats are very useful indicators of a Cd exposure in progress. It is supposed that rodent molars are comparable to human deciduous teeth. It is thus suggested that human deciduous teeth and human hair can be used as an indicator of a Cd exposure in progress.     

Metabolites of chlorinated solvents in blood and urine of subjects exposed at environmental level

After a two-level selection, 141 blood donors living in Milan, Italy, were analyzed for their content of plasma and urinary trichloroacetic acid (TCA) and trichloroethanol (TCE). Environmental levels of exposure to trichloroethylene (TRI) and tetrachloroethylene (PER) through drinking water and air were also measured. The plasma TCA levels were in the range of previously found concentrations. Relationships among plasma and urinary metabolites were found and discussed.     

Correlation between concentration in urine and in blood of cadmium and lead among women in Asia

The objectives of the present study are to examine if there exists a quantitative relationship between lead in urine (Pb-U) and that in blood (Pb-B), and also between cadmium in urine (Cd-U) and that in blood (Cd-B) among the general populations who are environmentally (and not occupationally) exposed to these elements at various levels. For this purpose, peripheral blood and morning spot urine samples were collected in 1991-1998 from approximately 50 non-smoking adult women each in four cities in south-east Asia and five cities in mainland China, and two cities each in Japan and Korea. The samples were wet-ashed and then analyzed by inductively-coupled plasma mass spectrometry for Pb-B, Cd-B, Pb-U and Cd-U. Measured values were subjected to analysis to detect possible correlation between the pairs of parameters. A significant correlation between Pb-B and Pb-U was observed when the intensity of Pb exposure (as expressed by Pb-B) was relatively high so that the correlation was significant in all cases studied when Pb-B level was, e.g. 50 microg/l or above. It was also observed that the correlation between Cd-B and Cd-U was significant when Cd-B was, e.g. > 1 microg/l. Thus, it is possible to deduce that, in environmental health, Pb-B and Cd-U levels can be estimated on a group basis from Pb-U and Cd-B, respectively, when Pb and Cd exposure levels are relatively high, e.g. with Pb-B and Cd-B of > 50 microg/l and > 1 microg/l.     

Cadmium and lead in infant cereals--electrothermal-atomic absorption spectroscopic determination.

Because infant cereals are an important component of the infant diet from the fourth month of life onwards and therefore contribute to the dietetic intake of metals by infants, cadmium and lead were measured in samples of cereals commercially available in Spain. For this purpose an electrothermal atomic absorption (ET-AAS) method for determining cadmium and lead in these products was studied. The ET-AAS instrumental conditions and temperature/time furnace program were selected. The analytical parameters of the method (linearity, detection and quantification limits and precision) show its usefulness in measuring cadmium and lead in infant cereal products. The method was applied to eight different types of infant cereals from four different manufacturers, in all 29 different infant cereal products commercially available in Spain. The cadmium and lead contents of milk-free infant cereals range from 6.6 to 35.8 ng/g and from 36.1 to 305.6 ng/g, respectively, while the ranges corresponding to milk-added infant cereals are 2.9-40.0 ng/g for cadmium and 53.5-598.3 ng/g for lead. The cadmium and lead contents of cereal products of the same type from different manufacturers is responsible for the large confidence intervals and made it impossible to detect significant differences among the different products. Given the values found for lead and the correlation between chronic exposure to low lead doses and neuropsychological damage in early childhood, efforts should be made to reduce lead contamination.     

Predicted risk of childhood allergy, asthma, and reported symptoms using measured phthalate exposure in dust and urine

The associated risk of phthalate exposure, both parent compounds in the home and their metabolites in urine, to childhood allergic and respiratory morbidity, after adjusting for exposures of indoor pollutants, especially bioaerosols, was comprehensively assessed. Levels of five phthalates in settled dust from the homes of 101 children (3-9 years old) were measured, along with their corresponding urinary metabolites. Other environmental risk factors, including indoor CO2, PM2.5, formaldehyde, 1,3-β-D-glucan, endotoxin, allergen and fungal levels, were concomitantly examined. Subject's health status was verified by pediatricians, and parents recorded observed daily symptoms of their children for the week that the home investigation visit took place. Significantly increased level of benzylbutyl phthalate, in settled dust, was associated with test case subjects (allergic or asthmatic children). Higher levels of dibutyl phthalate and its metabolites, mono-n-butyl phthalate, and mono-2-ethylhexyl phthalate were found to be the potential risk factors for the health outcomes of interest. Similarly, indoor fungal exposure remained a significant risk factor, especially for reported respiratory symptoms. The relative contribution from exposure to phthalates and indoor biocontaminants in childhood allergic and respiratory morbidity is, for the first time, quantitatively assessed and characterized. PRACTICAL IMPLICATIONS: For asthmatic and allergic children living in subtropical and highly developed environments like homes in Taiwan, controlling environmental exposure of phthalates may be viewed as equally important as avoiding indoor microbial burdens, for the management of allergy-related diseases. It is also recognized that multidisciplinary efforts will be critical in realizing the true underlying mechanisms associated with these observations.     

Suppression of IL-6 level in human peripheral blood mononuclear cells stimulated with PHA/LPS after occupational exposure to chromium

The toxic metals alter the immune response of animals as well as humans. In addition to the well documented and numerous toxic effect of chromium on various target organs, number of studies shown that acute and chronic exposure to inorganic chromium may result in impairment of immune functions in the experimental systems. Immunosuppression appears to be more subtle effect of exposure to heavy metals. Therefore, we have taken two different groups of chromium exposed individuals. These were leather tanning workers and chromeplaters. These groups of individuals were regularly exposed to chromium. All the leather tanning workers were highly exposed to chromium having a mean of 96.60+/-113.95 mg/dl (range 12.4-417.21 mg/dl). A suspension of exposed and unexposed human PBMC (0.5x10(6) cells/ml) prepared and cultured in RPMI-1640 supplemented with 10% FCS for 18 h in the presence or absence of PHA (5 microg/ml) and LPS (10 ng/ml) which used for stimulation of IL-2, IL-4, TNF-alpha, IL-10 and IL-6, respectively. The levels of Th1/Th2 cytokine: IL-2, IL-4, TNF-alpha, IL-10 and IL-6 were evaluated in the sera and PHA/LPS stimulated culture supernatant of human PBMCs of chromium exposed workers. In these workers the level of IL-6 was 543.95+/-123.75 pg/ml and 388.40+/-61.24 pg/ml in PHA/LPS stimulated culture supernatant of normal individuals and highly chromium exposed workers, which was significant (P<0.05). This observation suggests that IL-6 levels were suppressed in chromium exposed groups as compared to unexposed healthy volunteers. Although the level of IL-2 in PHA stimulated culture supernatant of PBMCs was suppressed in chromium exposed individuals but it was not significant, IL-4 and IL-10 could not be detected. However, there was no difference in TNF-alpha levels in sera samples as well as unstimulated culture supernatant of h-PBMCs of chromium exposed individuals as compared to control.     

Prenatal exposure to lead in Spain: cord blood levels and associated factors

Introduction and Objective

Lead is a known neurotoxic. Fetuses and infants are very vulnerable to lead exposure, since their blood-brain barrier is not completely formed. Hence, there is an importance for monitoring of blood lead levels prenatally and during early infancy. The aim of this study is to evaluate the prenatal exposure to lead and its association with maternal factors in four population based mother-child cohorts in Spain. The present research was carried out within the framework of the INMA project INfancia y Medio Ambiente (Environment and Childhood).

Methods

A total of 1462 pregnant women were recruited between 2004 and 2008. Lead was analyzed in a sample of cord blood by thermal decomposition, amalgation, and Atomic Absorption Spectrometry. Maternal sociodemographic, lifestyle and dietary factors were obtained by questionnaires during pregnancy. A multivariate logistic regression model was constructed. The dependent variable was a dichotomous lead level variable (detected vs no detected, i.e. ≥ vs < 2 μg/dL).

Results

A low percentage of cord blood samples with lead levels ≥ 2 μg/dL were found (5.9%). Geometric mean and maximum were 1.06 μg/dL and 19 μg/dL, respectively. Smoking at the beginning of pregnancy, age, social class, weight gain during pregnancy, gravidity, and place of residence were the maternal factors associated with detectable cord blood lead levels. Mother's diet does not appear to be a determining factor of lead exposure. Nevertheless, daily intake of iron and zinc may act as a protective factor against having cord blood lead levels ≥ 2 μg/dL.

Conclusion

In the different regions of Spain taking part in this study, lead levels to which newborns are exposed are low. Mobilization of lead from bones may be the main contributor to the cord blood levels.     

Cadmium adsorption by sediment in a turbulence tank.

The mechanism sediment motion that affects cadmium (Cd) adsorption on sediment particles was studied in a turbulence tank in the presence (and absence) of bed mud. The experimental results were verified by a mathematical model for heavy metal transport-transformation developed for the turbulence tank. The mathematical model includes the equations of water flow, sediment motion, heavy metal transport-transformation, heavy-metal reaction kinematics and equations for prescribing the initial conditions and boundary conditions for the experiment. The model conforms the transport-transformation of heavy-metal pollutants in surface waters to following the law of convective-diffusive of common tracers and the characteristics of fate and transport of sediment motion. Variations of dissolved Cd concentrations and suspended particulate Cd concentrations with time and in the water column were measured and computed. The experimental measurements correspond with the computed results. Both the experimental measurements and computed results show that it takes about 6 h to reach equilibrium condition for cadmium adsorption by sediment particles. This is different from the result obtained from experiments conducted in continuously stirred tank reactors (or batch reactors) in which adsorption equilibrium can be achieved in about 20 min. Determination of the model parameters for sediment adsorption-desorption of metals in the tank is discussed. The experimental and computed results obtained in this study are useful to solve practical engineering problems in surface waters.     

Behavior of FRP-confined concrete after high temperature exposure

This paper presents the results of an experimental program to investigate the effect of high temperature on the performance of concrete externally confined with FRP sheets. For this purpose, a two-phase experimental program was conducted. In the first phase, 42 standard 100 × 200 mm concrete cylinders were prepared. Out of these specimens, 14 cylinders were left unwrapped; 14 specimens were wrapped with one layer of CFRP sheet; and the remaining 14 specimens were wrapped with one layer of GFRP sheet. Some of the unconfined and FRP-confined specimens were exposed to room temperature; whereas, other cylinders were exposed to heating regime of 100 °C and 200 °C for a period of 1, 2 or 3 h. After high temperature exposure, specimens were tested under uniaxial compression till failure. The test results demonstrated that at a temperature of 100 °C (a little more than the glass transition temperature (T_g) of the epoxy resin), both CFRP- and GFRP-wrapped specimens experienced small loss in strength resulting from melting of epoxy. This loss of strength was more pronounced when the temperature reached 200 °C. In the second phase of the experimental program, three 100 × 100 × 650 mm concrete prisms were prepared and then overlaid by one layer of CFRP and GFRP laminates for conducting pull-off strength tests as per ASTM D4541 – 09. The objective of this testing was to evaluate the degradation in bond strength between FRP and concrete substrate when exposed to elevated temperature environments. One prism was exposed to room temperature whereas the other two specimens were exposed to heating regime of 100 °C and 200 °C for a period of 3 h. It was concluded that a significant degradation in the bond strength occurred at a temperature of 200 °C especially for CFRP-overlaid specimens.     

Retrospective analysis of an archived soil collection. II. Cadmium

Soil samples collected and stored since the mid-1800s to the present day have been analysed recently for Cd. The samples from long-term experiments under permanent grassland or arable crops at Rothamsted Experimental Station (U.K.) were selected to investigate time trends in elemental composition, due either solely to atmospheric deposition or to a combination of atmospheric deposition and various soil treatments. Increases in soil Cd of 27-55% since the 1850s due to atmospheric deposition were observed. This corresponds to an increase in the soil plough layer Cd concentration of between 0.7 and 1.9 micrograms kg-1 year-1 and is equivalent to an increase of 1.9-5.4 g Cd ha-1 year-1. The changes in soil Cd concentrations since 1846 at one control site corresponded well to predicted increases in the plough layer Cd burden based on assumptions about the temporal trends in atmospheric Cd emissions. In addition, sub-samples of a selection of rock phosphates of known origin and superphosphates, mainly from one supplier, collected and stored in the archive from 1925 onwards were also analysed for Cd. The concentrations ranged from 3.6 to 92 (mean 36) mg Cd kg-1 for rock phosphates and from 3.3 to 40 (9.7) mg kg-1 for superphosphates. On the basis of these data and known application rates the estimated input of Cd to P-treated plots at Rothamsted was 2 g ha-1 year-1, but there was little further increase in soil Cd due to this addition in three long-term arable experiments where soil pH was greater than 6.5. On P-treated plots the mean increase in soil Cd was 1.2 micrograms kg-1 year-1, which is equivalent to an increase in the plough layer burden of 3.1 g Cd ha-1 year-1. By contrast, P-treated soils under permanent grassland with a higher organic matter content and lower pH have increased their Cd content by 7.2 g ha-1 year-1. When permanent grassland soils ranging in pH from 5 to 7 were examined it was found that organic matter had a larger effect on Cd concentration than pH and the effects of pH were not consistent. Farmyard manure applied to some experimental plots at Rothamsted appears to have been a more significant source of Cd than combined atmospheric and phosphate fertiliser inputs.     

Cadmium and lead pollution from secondary metal refinery operations.

A study was made of cadmium and lead levels around a small secondary metal recovery factory as part of an environmental monitoring programme in a London borough. Lead levels were essentially typical for an urban environment whereas the levels of cadmium-in-air and in household dust gave rise to very considerable concern. Some of the problems associated with assessing the potential hazard and the steps taken to control the emission are considered. It is suggested that clearly-defined standards and procedures are necessary in order to deal efficiently with similar cases as they are discovered.     

Experiments on the effects of several factors on the 1-hydroxypyrene level in human urine as an indicator of exposure to polycyclic aromatic hydrocarbons.

The concentration of 1-hydroxypyrene in human urine was determined in six volunteers who lived under the same conditions. Samples were collected four times per day for three consecutive days; the maximum concentration of 1-hydroxypyrene was found in the samples collected late in the evening (21:00-23:00 h) which is the time recommended as suitable for determination of urinary 1-hydroxypyrene for the purpose of evaluating human exposure to polycyclic aromatic hydrocarbons (PAHs). Statistical tests show that the influence of sex, age, and smoking on urinary 1-hydroxypyrene is statistically insignificant.     

Secondary exposure to dioxins through exposure to PCP and its derivatives.

This study discusses the potential exposure of occupational workers and general consumers in the European Union (EU) to polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) caused by exposure to pentachlorophenol (PCP) and its derivatives. A synthesis of reported exposure data relating exposure to PCP and its derivatives in an occupational setting has indicated that the PCDD/F intake for exposure in the 1990s averaged over a lifetime is likely to be in the order of 0.02-1 pg I-TEQ kg-1 bw day-1 with actual exposures more likely to occur at the lower end of the range, around the median of 0.16 pg I-TEQ kg-1 bw day-1. Workers who have experienced past exposure to PCP and its derivatives especially in the early to mid 1980s, will have been subjected to higher exposures to PCDD/Fs due to the generally higher concentrations of PCDD/Fs in PCP products at that time. Exposure to PCP and its derivatives via the food chain is judged to be the most significant intake route of PCDD/Fs into consumers. The ingestion of milk and dairy products obtained from cows grazed on pasture dressed with sewage sludge has the potential to raise the average daily intake of PCDD/Fs via the diet by about 40% if all foods consumed derived from sludge amended soil. To the extent quantifiable, exposure to PCP in an occupational setting contributed approximately 16% as a median to the overall background exposure to PCDD/Fs, while for consumers this contribution ranged from 2 to 60% depending on the exposure to sludge amended foods.