Lead and cadmium levels in daily foods, blood and urine in children and their mothers in Korea

Spatio-temporal distribution of cadmium levels in Chinese population and its potential risk factors

Cadmium (Cd), a ubiquitous heavy metal, exists in numerous environmental matrices and has severe adverse effects on various human organs and tissues. This research evaluates blood and urine Cd levels in the Chinese population through data mining using Monte Carlo simulation (MCS). A total of 168 scientific studies (120 on urine and 48 on blood) published between January 1980 and December 2020, reflecting a population of 109,743 individuals in China, were included in the study. The results indicate that the blood and urine Cd levels in the Chinese population exhibited a peak from 1990 to 1995 and remained stable after 1995, averaging 1.21 μg/L of blood Cd (BCd) and 0.61 μg/L of urine Cd (UCd). The spatial trend of Cd levels varied significantly. Shandong, Zhejiang, Heilongjiang, and Guangdong provinces were identified as the top provinces with high Cd levels, which were related to factors such as tobacco sales, E-waste amounts, and contaminated rice. Additionally, the study highlights that BCd concentrations are highest among preschool-aged individuals, whereas school-age and adolescent groups exhibit the lowest levels. However, no significant difference existed among the different age groups. Males showed significantly higher Cd levels than females in the general population. Moreover, exposure to smoking, drinking, and staple food preferences had an impact on Cd levels. Furthermore, this comprehensive study, using biological monitoring and data mining, provides valuable information on Cd pollution levels in the Chinese population. It presents a statistical analysis that can aid decision-makers in implementing effective measures to control potential Cd pollution and improve the health of vulnerable populations.

Narrative review of lead poisoning in humans caused by industrial activities and measures compatible with sustainable industrial activities in Republic of Zambia

Lead (Pb) pollution and human exposure to Pb, is an important issue for the international community to address being associated with 0.90 million deaths from long-term effects. The Republic of Zambia is a typical mineral resource-rich country, with long-standing mining and smelting activities of metals including Pb in several parts of the country. This narrative review provides a comprehensive overview of previous papers that have assessed human exposure to Pb and related health effects in Zambia. Environmental remediation methods that should be applied locally, ways to reduce Pb exposure of the population, and issues that need to be addressed by various sectors are discussed. Environmental remediation methods using locally available and affordable materials are needed to ensure both sustainable industrial activities and pollution prevention. In the Zambian mining towns, including Kabwe, various research activities have been conducted, including environmental monitoring, human biomonitoring and health impact assessments. The town of Kabwe, which was one of Zambia's largest Pb mining area in the 20th century, continues to have formal and informal Pb-related industries and is known as one of the most polluted areas in the world. For example, despite the World Health Organization asserting that "For an individual with a blood Pb concentration ≥ 5 μg/dL, appropriate action should be taken to terminate exposure", there are reports of blood Pb levels in Kabwe children exceeding 100 μg/dL. While Pb pollution is a global issue, not many places have such continuous and comprehensive research has been conducted, and there is much to be learned from the knowledge accumulated in these areas. Because the high levels of Pb accumulation in humans and the adverse health effects were clarified, we consider that it is important to combine mining activities, which are a key industry, with measures to prevent environmental pollution.

Blood Concentrations and Dietary Intake of Cd among the General Population in South Korea

This study aimed to identify the time trends of blood Cd concentrations and their correlation with the Cd-B and the intakes of food groups as an influencing factor for Cd exposure among the general population in South Korea. During seven Korea National Health and Nutrition Examination Surveys from 2005 to 2017, a total of 9578 individuals (4317 men and 5261 women) participated in a 24 h recall test for a dietary survey and a blood-metal survey using physical examinations performed in the same survey year. The blood Cd concentration was observed to decrease significantly (p < 0.05) from 1.51 µg/L in 2005 to 0.76 µg/L in 2017. In terms of the food groups, grains and cereals, potatoes and starch, and fruits were significantly correlated with the corresponding Cd concentrations and also showed decreased intakes. For Koreans, the observed decrease in blood Cd concentrations was probably caused by a decrease in the intake of food groups of plant origin.

The Road to Practical Application of Cadmium Phytoremediation Using Rice

Cadmium (Cd) is a toxic heavy metal that causes severe health issues in humans. Cd accumulates in the human body when foods produced in Cd-contaminated fields are eaten. Therefore, soil remediation of contaminated fields is necessary to provide safe foods. Rice is one of the primary candidates for phytoremediation. There is a genotypic variation of Cd concentration in the shoots and grains of rice. Using the world rice core collection, ‘Jarjan’, ‘Anjana Dhan’, and ‘Cho-ko-koku’ were observed with a significantly higher level of Cd accumulation in the shoots and grains. Moreover, OsHMA3, a heavy metal transporter, was identified as a responsive gene of quantitative trait locus (QTL) for high Cd concentration in the shoots of these three varieties likewise. However, it is difficult to apply practical phytoremediation to these varieties because of their unfavorable agricultural traits, such as shatter and easily lodged. New rice varieties and lines were bred for Cd phytoremediation using OsHMA3 as a DNA marker selection. All of them accumulated Cd in the shoots equal to or higher than ‘Cho-ko-koku’ with improved cultivation traits. Therefore, they can be used for practical Cd phytoremediation.

Indoor particulate matter and blood heavy metals in housewives: A repeated measured study

BACKGROUND

Particulate matter (PM) less than 2.5 μm in diameter and 10 μm (PM₁₀) contains heavy metals, but whether exposure to PM is significantly associated with the burden of heavy metal exposure in the population is unknown. We investigated the association between exposure to PM and blood concentrations of lead (Pb), cadmium (Cd), and mercury (Hg) in Korean housewives.

MATERIALS & METHODS

From July 2017 to January 2020, we recruited 115 housewives in Ulsan, Republic of Korea. After excluding participants with missing information, we finally included 88 Korean housewives in our study. We measured the concentrations of indoor PM using a gravimetric method 24 h before blood sampling and the concentrations of Cd, Pb, and Hg in blood, twice at a 1-year interval. We used a linear mixed effect model to estimate the associations between indoor PM and blood heavy metals.

RESULTS

Exposure to PM₁₀ was significantly associated with blood concentrations of Cd among Korean housewives. A 10 μg/m³ increase of PM₁₀ the previous day was associated with a 2.8% (95% confidence interval (CI) = 1.1%, 4.6%) and a 1.5% (95% CI = -0.1%, 3.1%) increase in blood concentrations of Cd and Pb in the linear mixed effect model, respectively.

CONCLUSION

There was a significant association between indoor PM exposure and blood Cd concentrations among Korean housewives. This result suggests that the body burden of heavy metals is significantly associated with air pollution.

Association Among Sources Exposure of Cadmium in the Adult Non-smoking General Population of Tehran

Acute and chronic exposure to cadmium can cause numerous health effects including poisoning, as well as, bone, liver, and kidney diseases. Cadmium competes with iron absorption in blood and can induce anemia. Cadmium body burden can be measured through urine and blood samples. Urine reflects chronic and blood indicates recent and cumulative exposures to cadmium. Dietary is considered as the main source of exposure to cadmium in non-smoking general population. The study was conducted to determine cadmium level in blood, urine, and in diet of 120 non-smoking adults in Tehran. Dietary components and consumption pattern of participants estimated by a food frequency questionnaire. Next, the correlation investigated between them. Moreover, serum ferritin measured as a marker of iron storage in blood to determine its association with cadmium. The prediction of cadmium fate in the body is determined by toxicokinetic models. This study tried to evaluate one of these models' validity which is developed to predict urinary cadmium from dietary. Afterwards, the predicted urinary compared with the measured urinary cadmium. The correlation coefficient between dietary and blood cadmium equaled 0.66 which was statically significant, but the correlation between dietary and urinary cadmium was minimal and not statically significant (p > 0.05). An inverse and negative correlation was found between serum ferritin and blood cadmium. The mean predicted urinary cadmium calculated by the model was 2.5-fold higher than the measured value in the total population. Results of the present study revealed that blood cadmium reflected mainly acute exposure. There was no correlation between chronic and acute exposures to cadmium. The low serum ferritin level increased cadmium amount in blood. Moreover, the mean predicted urinary cadmium by the model was greater than the measured value. It can because of characteristics of populations and type of dietary exposure. Thus, it is suggested that the model coefficients are determined in each society based on their characteristics.

A new criterion for the health risk assessment of Se and Pb exposure to residents near a smelter

There is an increasing evidence linking protective effect of selenium (Se) against Pb toxicology; however, Pb exposure risk assessments usually consider only the environmental Pb contamination and dietary intake. Based on the current understanding of mechanisms of SePb interactions, the physiological function/toxicology of Se and the toxicology of Pb, a new criterion for Se and Pb exposure assessment is developed. Additionally, seven existing criteria were also used to assess the resident health risks around a smelter in China. The Pb concentrations in locally-produced foods exceeded the national tolerance limits of China and the Se in the foods were similar to those in areas with adequate Se levels. In accordance with the illustrated assessments of the new criterion and seven existing criteria, we found a large knowledge gap between the new and traditional assessments of exposure to Pb and/or Se. The new assessment criteria suggested that almost all the residents were facing the Se deficiency and 58% of the residents not only had the adverse health of Se deficiency, but also had the health risks of Pb toxicity. The Pb and Se in the hair and urine may partly support the new criterion. This study suggested that the process of Se counteracting the Pb toxicity may result in Se deficiency. Pb exposure combined Se intake should be considered in future assessments of Pb exposure (or Se intake).

Analysis of lead and cadmium in cereal products and duplicate diets of a small group of selected Brisbane children for estimation of daily metal exposure

Exposure to toxic metals such as lead (Pb) and cadmium (Cd) from foods is a concern for young children. The aims of the study were to analyse the levels of Pb and Cd in breakfast cereals, rice products and diets of selected children, and to estimate the daily intakes of Pb and Cd in these children. The samples (n = 82) of ready-to-eat breakfast cereals and rice products (n = 36) were collected and obtained from various markets in Brisbane, Australia. The samples for a duplicate diet study were collected for 3 consecutive days from normal healthy children (n = 15). The analysis was performed using ICP-MS after microwave digestion. The levels of Pb and Cd found in breakfast cereals and rice products ranged from <0.01 to 0.25 mg/kg for Pb and <0.01 to 0.11 mg/kg for Cd. The estimated daily intakes of Pb and Cd in children varied widely and ranged from 0.90 to 11.7 (5.6 ± 3.5 μg/day) for Pb and 0.98 to 9.5 (4.0 ± 2.2 μg/day) for Cd. The study shows low intakes of Pb and Cd in children.

Impact of prenatal heavy metal exposure on newborn leucocyte telomere length: A birth-cohort study

Arsenic, cadmium and lead are toxic environmental contaminants. They were shown to be associated with telomere length (TL) in adults. Although they can cross the placental barrier, the effect of prenatal exposure of these metals on newborn TL is unknown. The aim of this study was to examine whether prenatal exposure to heavy metals has an impact on newborn leucocyte TL. A birth-cohort study was conducted with 409 pregnant women and their newborns in Myanmar. During the first visit, face-to-face interviews were conducted, and maternal spot urine sampling was performed. Cord blood samples were collected during follow-up. Urinary heavy metal concentration was measured by ICP-MS and adjusted for creatinine. Relative TL was measured by quantitative real-time polymerase chain reaction. The extent of prenatal arsenic, cadmium and lead exposure and their associations with newborn leucocyte TL were assessed using multivariate linear regression. The median values of maternal urinary arsenic, cadmium, and lead concentrations were 73.9, 0.9, and 1.8 μg/g creatinine, respectively. Prenatal arsenic and cadmium exposure was significantly associated with newborn TL shortening (lowest vs highest quartile, coefficient = - 0.13, 95% CI: - 0.22, - 0.03, p = 0.002, and coefficient = - 0.17, 95% CI: - 0.27, - 0.07, p = 0.001, respectively), and the associations remained robust after adjusting for confounders. There was no significant association between prenatal lead exposure and newborn TL. The present study identified the effect of arsenic and cadmium exposure on TL shortening, even in utero exposure at a lower concentration.

Lead and cadmium excretion in feces and urine of children from polluted townships near a lead-zinc mine in Kabwe, Zambia

Lead (Pb) and cadmium (Cd) are toxic metals that exist ubiquitously in the environment. Children in polluted areas are particularly vulnerable to metal exposure, where clinical signs and symptoms could be nonspecific. Absorbed metals are excreted primarily in urine and reflect exposure from all sources. We analyzed Pb and Cd concentrations in blood, feces and urine of children from polluted townships near a lead-zinc mine in Kabwe, Zambia, to determine concurrent childhood exposure to the metals. Moreover, the study determined the Pb and Cd relationships among urine, feces and blood as well as accessed the potential of urine and fecal analysis for biomonitoring of Pb and Cd exposure in children. Fecal Pb (up to 2252 mg/kg, dry weight) and urine Pb (up to 2914 μg/L) were extremely high. Concentrations of Cd in blood (Cd-B) of up to 7.7 μg/L, fecal (up to 4.49 mg/kg, dry weight) and urine (up to 18.1 μg/L) samples were elevated. metal levels were higher in younger children (0-3 years old) than older children (4-7). Positive correlations were recorded for Pb and Cd among blood, urine and fecal samples whereas negative correlations were recorded with age. These findings indicate children are exposed to both metals at their current home environment. Moreover, urine and feces could be useful for biomonitoring of metals due to their strong relationships with blood levels. There is need to conduct a clinical evaluation of the affected children to fully appreciate the health impact of these metal exposure.

Environmental cadmium exposure is associated with elevated risk of chronic otitis media in adults

Objectives

Chronic otitis media (COM) is caused by an infection of the middle ear, although it may also be associated with environmental pollutants. Recent reports found that cadmium exposure could be toxic to middle ear cell lines, but the role of cadmium in the development of COM in humans has not been examined to date. We hypothesised that environmental cadmium exposure was associated with an increased risk of COM in the general population.

Methods

We analysed cross-sectional data for 5331 adults of 20 years of age or above, obtained from the Korea National Health and Nutrition Examination Survey 2010–2012. We examined the association between blood cadmium levels and COM diagnosed by an otolaryngologist.

Results

The highest quartile group of cadmium blood concentration was associated with an OR of 3.33 (95% CI 1.78 to 7.53) for COM, after adjusting for potential confounding factors. Doubling blood cadmium concentration resulted in an OR of 1.58 (95% CI 1.19 to 2.08) for COM. These associations were robust on sensitivity analyses after excluding current smokers and former smokers and after excluding subjects with a potential history of occupational exposure to cadmium.

Conclusions

The results of our study suggest that environmental cadmium exposure is associated with increased risk of COM, and further studies are warranted to understand the pathogenetic mechanism by which COM is caused by cadmium exposure.

Prenatal Heavy Metal Exposure and Adverse Birth Outcomes in Myanmar: A Birth-Cohort Study

Arsenic, cadmium and lead are well-known environmental contaminants, and their toxicity at low concentration is the target of scientific concern. In this study, we aimed to identify the potential effects of prenatal heavy metal exposure on the birth outcomes among the Myanmar population. This study is part of a birth-cohort study conducted with 419 pregnant women in the Ayeyarwady Division, Myanmar. Face-to-face interviews were performed using a questionnaire, and maternal spot urine samples were collected at the third trimester. Birth outcomes were evaluated at delivery during the follow up. The median values of adjusted urinary arsenic, cadmium, selenium and lead concentration were 74.2, 0.9, 22.6 and 1.8 μg/g creatinine, respectively. Multivariable logistic regression revealed that prenatal cadmium exposure (adjusted odds ratio (OR) = 1.10; 95% confidence interval (CI): 1.01–1.21; p = 0.043), gestational age (adjusted OR = 0.83; 95% CI: 0.72–0.95; p = 0.009) and primigravida mothers (adjusted OR = 4.23; 95% CI: 1.31–13.65; p = 0.016) were the predictors of low birth weight. The present study identified that Myanmar mothers were highly exposed to cadmium. Prenatal maternal cadmium exposure was associated with an occurrence of low birth weight.

Blood cadmium concentrations in Korean adolescents: From the Korea National Health and Nutrition Examination Survey 2010-2013

OBJECTIVE

To assess blood cadmium levels in Korean adolescents with respect to demographic and lifestyle factors.

METHODS

We analyzed data from the Korea National Health and Nutrition Examination Survey from 2010 to 2013, totaling 1472 adolescents aged 10-18 years. Geometric means of blood cadmium were calculated using a complex samples general linear model to compare blood levels in different demographic and lifestyle groups. Multivariate logistic regression analyses were also used to find predictors for high blood cadmium (>90th percentile).

RESULTS

The geometric mean of the blood cadmium concentrations was 0.30μg/L in Korean adolescents. Older age, type of housing (multifamily house and commercial building), smoking and alcohol consumption, and iron deficiency/iron deficiency anemia (IDA) were significantly associated with higher blood cadmium concentrations (P<0.05). Blood cadmium concentrations were not significantly affected by gender, region, body mass index status, or household income. In multivariate logistic regression analysis, independent predictors for higher blood cadmium levels included current smoker (OR=7.77), alcohol consumption (OR=4.31), living in a multifamily house or commercial building (OR=3.11-3.46), and IDA (OR=2.64).

CONCLUSIONS

Possible associations between blood cadmium levels and type of housing or alcohol consumption in adolescents are suggested for the first time in this study. Further studies are needed to elucidate the mechanism of these findings.

Cadmium exposure and age-related macular degeneration

Cadmium (Cd) has been proposed as a risk factor for age-related macular degeneration (AMD), but the association between Cd exposure and AMD risk in large population studies is unknown. This study evaluated the association of Cd exposure with AMD in a large representative sample of Korean men and women. This was a cross-sectional study of 3865 Korean adults ≥ 40 years of age who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) during 2008-2011. Cd concentrations in whole blood were measured by graphite-furnace atomic absorption spectrometry. The presence of AMD was determined in digital non-mydriatic fundus photographs. Cd levels were higher in participants with AMD compared with those without AMD (1.3 vs 1.1 μg/l, respectively, P<0.001). In fully adjusted models, the odds ratio for AMD comparing the highest with the lowest Cd quartiles was 1.92 (95% CI=1.08-3.39; P for trend 0.029). In restricted cubic spline models, the association between Cd and AMD was approximately linear, with no evidence of threshold effects. Blood Cd concentrations were independently associated with the prevalence of AMD. If the association is proven causal, population-based preventive strategies to decrease Cd exposure could reduce the population burden of AMD.

Time trend of cadmium intake in Korea

OBJECTIVES

The aim of this study was to elucidate past and current levels of cadmium (Cd) intake among the general populations in Korea.

METHODS

For this purpose, publications reporting dietary intake of cadmium (Cd-D), cadmium concentration in blood (Cd-B) and that in urine (Cd-U) in Korea were retrieved through literature survey for a period from 1975 to 2015.

RESULTS

In practice, 9, 21 and 14 articles were available on Cd-D, Cd-B and Cd-Ucr (Cd-U as corrected for creatinine concentration), respectively. Linear regression analyses of the reported values as a function of years (i.e., the year when each survey was conducted) showed steady decreases in all of the three exposure markers of Cd-D, Cd-B and Cd-U(cr). Factors possibly contributing for the reduction were discussed including the government-set guideline of 0.2 mg/kg for rice and changes in food habits among general populations.

CONCLUSIONS

There have been steady decreases in Cd-D, Cd-B and Cd-U(cr). The current estimates for Cd-D, Cd-B and Cd-Ucr were 6.0-7.4 μg/day, 0.73-0.83 μg/L and 0.60-0.95 μg/g cr, respectively.

The association between blood lead level and clinical mental disorders in fifty thousand lead-exposed male workers

BACKGROUND

While there has been research into the relationship between blood lead (BPb) level and mental disorders, there have been few investigations that use clinically diagnosed mental disorders in the adult population with a retrospective cohort study design. Hence, our study investigated the association between BPb level and risk of clinically diagnosed mental disorders.

METHODS

The data of male workers exposed to lead (Pb; n=54,788) were collected from annual Pb associated medical check-ups from 2000 to 2004 in Korea. The workers' hospital admission histories due to mental disorders (International Classification of Diseases, 10th revision, F00-F99) were used to identify clinically diagnosed mental disorders. After merging the data, the hazard ratio (HR) with a 95% confidence interval (95% CI) was calculated by survival analysis using the Cox proportional hazards model according to the quartile level of BPb (1st quartile<4.10 μg/dl, 2nd quartile<6.04 μg/dl, 3rd quartile<10.00 μg/dl, and 4th quartile≥10 μg/dl).

RESULTS

In a total of 54,788 workers, there were 223 admission cases of mental disorders (F00-F99) during the follow-up period. The HR (95% CI) of total mental and behavioral disorders (F00-F99) was 1.63 (1.12-2.39) in the 4th quartile group compared to the HR of the 1st quartile group after adjusting for age. The HR (95% CI) of the 4th quartile group was 2.59 (1.15-5.82) for mood (affective) disorders (F30-F39).

LIMITATION

The hospital admission data, not outpatient data, were used for current study while almost affective disorder treated at outpatient clinic level.

CONCLUSION

Our study highlighted that Pb exposure can cause clinical mental disorders that require hospital admission in adult male workers. Our relatively large sample size strengthens the evidence of the association between BPb level and risk of clinically diagnosed mental disorders.

Assessment of the Cadmium Exposure in the Blood, Diet, and Water of the Pumi People in Yunnan, China

Cadmium (Cd) is considered as one of the most toxic and carcinogenic heavy metals. Accumulation of Cd in the human body can cause multiorgan dysfunction. Long-term irrational mining activities have led to serious Cd pollution in soil, water, and even agricultural products. Therefore, evaluating the Cd exposure levels of people living in mining areas is of great importance. In the current study, we chose the Pumi people who lived in Jinding and Tongdian towns of Lanping county in Yunnan province, China, to do the on-site nutritional epidemiology investigation and laboratory detection. We analyzed the content of the Cd in peripheral blood and mixed dietary, as well as water samples in the Pumi residents of the two towns. Results showed that the blood Cd levels of people in Jinding town, which is nearer the mining district, were statistically significantly higher than those in Tongdian town. The P 50 of blood Cd level of the two towns was 0.64 ng/mL. In addition, the P 50 of the mixed diet of the two towns was 8.32 μg/kg. There was a weak correlation between blood Cd levels and Cd exposure in the mixed diet, PTDI, and PTWI of the Pumi people. In addition, higher concentrations of Cd were observed in the water of Jinding town, indicating people in Jinding town risking more Cd exposure. These results indicated that diet and water are critical factors of Cd exposure for the residents and the nearer people living to mining district risking the more Cd exposure.

Pilot study testing a European human biomonitoring framework for biomarkers of chemical exposure in children and their mothers: experiences in the UK

Exposure to a number of environmental chemicals in UK mothers and children has been assessed as part of the European biomonitoring pilot study, Demonstration of a Study to Coordinate and Perform Human Biomonitoring on a European Scale (DEMOCOPHES). For the European-funded project, 17 countries tested the biomonitoring guidelines and protocols developed by COPHES. The results from the pilot study in the UK are presented; 21 school children aged 6-11 years old and their mothers provided hair samples to measure mercury and urine samples, to measure cadmium, cotinine and several phthalate metabolites: mono(2-ethyl-5-hydroxyhexyl)phthalate (5OH-MEHP), mono(2-ethyl-5-oxo-hexyl)phthalate (5oxo-MEHP) and mono(2-ethylhexyl)phthalate (MEHP), mono-ethyl phthalate (MEP), mono-iso-butyl phthalate (MiBP), mono-benzyl phthalate (MBzP) and mono-n-butyl phthalate (MnBP). Questionnaire data was collected on environment, health and lifestyle. Mercury in hair was higher in children who reported frequent consumption of fish (geometric mean 0.35 μg/g) compared to those that ate fish less frequently (0.13 μg/g, p = 0.002). Cadmium accumulates with age as demonstrated by higher levels of urinary cadmium in the mothers (geometric mean 0.24 μg/L) than in the children(0.14 μg/L). None of the mothers reported being regular smokers, and this was evident with extremely low levels of cotinine measured (maximum value 3.6 μg/L in mothers, 2.4 μg/L in children). Very low levels of the phthalate metabolites were also measured in both mothers and children (geometric means in mothers: 5OH-MEHP 8.6 μg/L, 5oxo-MEHP 5.1 μg/L, MEHP 1.2 μg/L, MEP 26.8 μg/L, MiBP 17.0 μg/L, MBzP 1.6 μg/L and MnBP 13.5 μg/L; and in children: 5OH-MEHP 18.4 μg/L, 5oxo-MEHP 11.4 μg/L, MEHP 1.4 μg/L, MEP 14.3 μg/L, MiBP 25.8 μg/L, MBzP 3.5 μg/L and MnBP 22.6 μg/L). All measured biomarker levels were similar to or below population-based reference values published by the US National Health and Nutrition Examination Survey (NHANES) and Germany's GerES surveys. No results were above available health guidance values and were of no concern with regards to health. The framework and techniques learnt here will assist with future work on biomonitoring in the UK.

Relationship between blood levels of heavy metals and lung function based on the Korean National Health and Nutrition Examination Survey IV-V

BACKGROUND

Heavy metal exposure may contribute to inflammation in the lungs via increased oxidative stress, resulting in tissue destruction and obstructive lung function (OLF). In this study, we evaluated the relationship between lead and cadmium levels in blood, and lung function in the Korean population.

METHODS

Pooled cross-sectional data from 5,972 subjects who participated in the Korean National Health and Nutrition Examination Survey 2008-2012 were used for this study. OLF was defined as forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) <0.7. Graphite-furnace atomic absorption spectrometry was used to measure levels of lead and cadmium in blood.

RESULTS

Adjusted means for age, sex, body mass index, and smoking status in blood lead and cadmium levels were increased with age and were higher in men and current smokers. The FEV1/FVC ratio was lower in the highest quartile group of lead (78.4% vs 79.0%; P=0.025) and cadmium (78.3% vs 79.2%; P<0.001) concentrations, compared with those in the lowest quartile groups. Multiple linear regression demonstrated an inverse relationship between the FEV1/FVC ratio and concentrations of lead (estimated -0.002; P=0.007) and cadmium (estimated -0.005; P=0.001). Of the 5,972 subjects, 674 (11.3%) were classified into the OLF group. Among current smokers, the risk of OLF was higher in subjects in the highest quartile group of cadmium concentration than in those in the lowest quartile group (odds ratio 1.94; 95% confidence interval 1.06-3.57).

CONCLUSION

We demonstrated a significant association between the FEV1/FVC ratio and blood concentrations of lead and cadmium in the Korean population. The risk for OLF was elevated with increasing concentrations of cadmium among current smokers.

Simultaneous Exposure to Heavy Metals among Residents in the Industrial Complex: Korean National Cohort Study

A survey was conducted to evaluate the multi-exposure level and correlation among toxic metal biomarkers (Cd, Pb, and Hg). A total of 592 individuals who participated in the survey were residents near an industrial complex in Gwangyang and Yeosu (exposed group) and of Hadong and Namhae (control group) in southern Korea from May 2007 to November 2010. The Gwangyang and Yeosu area exposed groups had slightly higher blood Pb (2.21 and 1.90 µg/dL), urinary Cd observed values (2.20 and 1.46 µg/L), urinary Cd with a urinary creatinine correction (1.43 and 1.25 µg/g Cr), and urinary Hg observed values (2.26 and 0.98 µg/L) in women participants than those in the Hadong and Namhae area (control group). Blood Pb (3.18 and 2.55 µg/dL), urinary Hg observed values (1.14 and 0.92 µg/L), and urinary Hg with a urinary creatinine correction (1.06 and 0.96 µg/L) for male participants were also slightly higher than those in the Hadong and Namhae area (control group). The correlation among urinary Cd, Hg and Pb concentrations in the blood was significant. We suggest that the exposed group of residents were simultaneously exposed to Pb, Cd, and Hg from contaminated ambient air originating from the iron manufacturing industrial complex.

Food intake survey of kindergarten children in Korea: Part 3 cadmium and lead burden

OBJECTIVES

This study was initiated to elucidate the extent of dietary exposure of children in Korea to two pollutant metals of cadmium (Cd) and lead (Pb). Possible urban-rural difference was also examined.

METHODS

Food duplicate and morning spot urine samples were collected from 108 children in 4 kindergartens (KG) (1 KG in Seoul and 3 KGs in Jeju Island), as reported in a previous publication. The samples were analyzed for Cd and Pb by ICP-MS.

RESULTS

Cd and Pb in food duplicate and urine samples were distributed approximately log-normally. Geometric means for Cd and Pb in food duplicate samples were 12.4 and 5.8 μg/day, or 0.58 and 0.27 μg/kg body weight/day, respectively, and the values for Cd and Pb in urine (as observed, i.e., with no correction for urine density) were 0.91 and 1.64 μg/L, respectively. 2.41 and 0.30 μg/day of Cd and Pb (accounting for 19.5 and 5.1%) came from boiled rice, the staple food. The levels of Cd and Pb burden among the children in the present survey were essentially the same with the levels reported for children in Pusan. The reasons for difference in the rank in Cd-D and Cd-U among the 4 KGs need further study.

CONCLUSIONS

The observed levels of Cd and Pb exposure were more or less similar to what were reported for children in Pusan. No apparent urban-rural difference could be detected.

S100β in heavy metal-related child attention-deficit hyperactivity disorder in an informal e-waste recycling area

Exposure to lead even at low levels correlates with attention-deficit/hyperactivity disorder (ADHD). However, lead-contaminated environments are often contaminated with other heavy metals that could exacerbate lead-induced ADHD. We conducted this study to evaluate the relationship between multiple heavy metals and child behaviors, and the involvement of S100 calcium-binding protein β (S100β) expression in child ADHD in Guiyu, an internationally-known e-waste contaminated recycling town. Two hundred and forty kindergarten children, 3- to 7-years of age, who lived in Guiyu, were recruited for this study. Child behavioral assessment was derived from parent and teacher ratings. Serum S100β was assayed by an enzyme-linked immunosorbent assay (ELISA). Lead (Pb), cadmium (Cd) and manganese (Mn) levels in whole blood were measured using graphite furnace atomic absorption spectrometry (GFAAS). The prevalence of children with ADHD symptoms in Guiyu was 18.6%, with the percentage of children suspected to have behavior problems being 46.2% or 46.5%, based on the Rutter parents' or teachers' scale scores, respectively. Child blood levels of Pb, Cd, and Mn correlated with certain behavioral abnormalities, such as conduct problems and antisocial behavior. Serum S100β levels were associated with heavy metal levels in blood, and certain behavioral abnormalities. These findings suggest that exposure to various environmental heavy metals in Guiyu might result in child behavior disorders. Results also indicate that S100β may provide information for laboratory evaluation of neurotoxicity.

Blood levels of cadmium and lead in residents near abandoned metal mine areas in Korea

We analyzed national data on blood lead levels (BLL) and blood cadmium levels (BCL) in residents living near 38 abandoned metal mining areas (n = 5,682, 18-96 years old) in Korea that were collected by the first Health Effect Surveillance for Residents in Abandoned Metal mines (HESRAM) from 2008 to 2011. The geometric mean BCL and BLL were 1.60 μg/L (95 % CI = 1.57-1.62 μg/L) and 2.87 μg/dL (95 % CI = 2.84-2.90 μg/dL), respectively, notably higher than levels in the general population in Korea and other countries. We found significantly higher BLL and BCL levels in people living within 2 km of an abandoned metal mine (n = 3,165, BCL = 1.87 μg/L, BLL = 2.91 μg/dL) compared to people living more than 2 km away (n = 2,517, BCL = 1.31 μg/L, BLL = 2.82 μg/dL; P < 0.0001) and to the general population values reported in the literature.

From laboratory to field: OsNRAMP5-knockdown rice is a promising candidate for Cd phytoremediation in paddy fields

Previously, we reported that OsNRAMP5 functions as a manganese, iron, and cadmium (Cd) transporter. The shoot Cd content in OsNRAMP5 RNAi plants was higher than that in wild-type (WT) plants, whereas the total Cd content (roots plus shoots) was lower. For efficient Cd phytoremediation, we produced OsNRAMP5 RNAi plants using the natural high Cd-accumulating cultivar Anjana Dhan (A5i). Using a positron-emitting tracer imaging system, we assessed the time-course of Cd absorption and accumulation in A5i plants. Enhanced 107Cd translocation from the roots to the shoots was observed in A5i plants. To evaluate the phytoremediation capability of A5i plants, we performed a field experiment in a Cd-contaminated paddy field. The biomass of the A5i plants was unchanged by the suppression of OsNRAMP5 expression; the A5i plants accumulated twice as much Cd in their shoots as WT plants. Thus, A5i plants could be used for rapid Cd extraction and the efficient phytoremediation of Cd from paddy fields, leading to safer food production.

Cadmium blood and urine concentrations as measures of exposure: NHANES 1999-2010

Exposure to cadmium, a heavy metal present in cigarettes, can be assessed in both urine and blood. Few studies have compared the properties of concurrent measurements of urine cadmium (uCd) and blood cadmium (bCd) in relation to the duration and timing of a known exposure. In this study, bCd and uCd were modeled with data from the National Health and Nutrition Examination Survey (1999-2010). Adjusted geometric mean bCd and uCd were estimated from regression results. Each 1% higher geometric mean uCd was associated with 0.50% (95% confidence interval: 0.47%-0.54%; R(2)=0.30) higher bCd. In male never-smokers, bCd was 69% (59%-81%) and uCd was 200% (166%-234%) higher at age ≥70 years versus 20-29 years. Ten pack-years (py) of smoking were associated with 13.7% (10.0%-17.4%) higher bCd and 16.8% (12.6%-21.1%) higher uCd in male smokers. The first year after smoking cessation was associated with 53% (48%-58%) lower bCd and 23% (14%-33%) lower uCd in representative males aged 55 years with 20 py smoking. Smoking in the previous 5 days was associated with 55% (40%-71%) higher bCd and 7% (-3%-18%) higher uCd. Results were similar for women. uCd mainly measures long-term exposure and bCd recent exposure, but with noticeable overlap. Epidemiological studies should base the choice of uCd or bCd on the timing of cadmium exposure relevant to the disease under study.

Metal exposure in schoolchildren and working children. A urinary biomonitoring study from Lahore, Pakistan

In order to document the exposure to trace metals among urban schoolchildren and rural working children, we measured the urinary concentrations of metals in schoolchildren from two areas of differing traffic intensity in Lahore, and in children working in carpet weaving or the brick industry outside Lahore. In a cross-sectional design, we recruited a convenience sample of 339 children aged 8-12 years (mean age 9.9 y, SD 1.4; 47% girls) from two elementary schools in Lahore - one situated in a high air pollution area (n=100) and one situated in an area with lower air pollution (n=79) - and from the carpet weaving industry (n=80) and brick industry (n=80). A spot urine sample was collected and concentrations of 20 metals and metalloids were measured by inductively coupled plasma-mass spectrometry (ICP-MS). Samples of drinking water were similarly analyzed. In general, the urinary concentrations of several toxic metals (including Cr, Mn, As, Mo, Cd, Pb, U) were higher than international reference values. Concentrations of As were especially elevated in children working in the brick making industry [geometric mean (GM) 118 μg/L], but they were also high among urban schoolchildren (GM 68 μg/L and 56 μg/L). Lead (Pb) was higher in urine from schoolchildren in the high air pollution area (GM 11 μg/L) than in those from the lower pollution area (GM 5.3 μg/L). Uranium (U) was high in both carpet weavers (GM 0.28 μg/L) and brick kiln workers (GM 0.45 μg/L). Concentrations of As, Pb, and U in drinking water corresponded well with urinary concentrations of metals. This descriptive study provides evidence for a high exposure to several toxic metals in this area of Pakistan. The concentrations of urinary As are in the order of those found in other regions of the world with high environmental exposure to As. The sources and pathways of exposure and the health significance of these findings need to be further investigated.

Assessment of exposure to trace metals in a cohort of pregnant women from an urban center by urine analysis in the first and third trimesters of pregnancy

Prenatal exposure to trace metals, whether they are essential, non-essential, or toxic, must be assessed for their potential health effects in the offspring. Herein is reported an approach to this end which involved collection of urine samples during the first and third trimesters of pregnancy from 489 mothers from Sabadell (Catalonia, Spain), a highly industrialized town. These samples were analyzed for cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), selenium (Se), arsenic (As), molybdenum (Mo), cadmium (Cd), antimonium (Sb), cesium (Cs), thallium (Tl), and lead (Pb). An acid digestion method was developed and validated for inductively coupled plasma quadruple mass spectrometry (Q-ICP-MS) analysis of these 12 metals. The median concentrations of metals ranged from 0.13 to 290 μg/g creatinine, the highest levels were found for Zn and the lowest for Th. The mean concentrations of most metals except As, Ni, Th, and Pb showed statistically significant differences between both trimesters. The concentrations of Mo, Se, Cd, Cs, and Sb were higher in the first than in the third trimester, whereas the opposite was found for Co, Cu, and Zn. The concentrations of all metals in both sampling periods showed statistically significant correlations (p<0.01 for Mo and Cu, p<0.001 for the others). The significant correlations of metal urine concentrations in the first and third trimesters of pregnancy suggest that the observed differences between both periods are related to physiological changes. Accordingly, the measured urine concentrations during either the first or third trimesters can be used as estimates of exposure during pregnancy and can serve as markers for prenatal intake of these metals in the studied cohort.

Blood lead and cadmium levels and renal function in Korean adults

BACKGROUND

The objective of this study was to evaluate the associations of blood lead and cadmium levels with estimated glomerular filtration rate (eGFR) and proteinuria in Korean adults.

METHODS

This was a cross-sectional study based on the Korea Nation Health and Nutrition Examination Survey (KNHANES) to analyze the association of blood lead and cadmium levels with renal dysfunction and urine protein excretion. We defined renal dysfunction as eGFR < 60 ml/min/1.73 m(2), as measured by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and proteinuria as positive urine dip-stick result.

RESULTS

Blood lead and cadmium levels were significantly increased in the renal dysfunction group compared with the normal renal function group. Lead levels were significantly higher in the proteinuria group than in the group with no proteinuria. There were no differences in cadmium levels according to the amount of proteinuria. Multivariate logistic regression analysis adjusted for age and sex demonstrated higher lead and cadmium levels in the renal dysfunction group than in the group with normal renal function [odds ratio (OR) 1.344, 95 % confidence interval (CI) 1.157-1.162, P < 0.05; OR 1.467, 95 % CI 1.077-1.999, P < 0.05, respectively]. For proteinuria, the fully adjusted ORs comparing the highest versus the lowest lead and cadmium quartiles were 1.22 (95 % CI 1.00-1.50) and 0.51 (95 % CI 0.24-1.08), respectively, showing no significance. For reduced eGFR, the fully adjusted ORs comparing the highest versus the lowest lead and cadmium quartiles were 1.23 (95 % CI 0.98-1.53) and 1.93 (95 % CI 1.39-2.67), respectively, showing the significant association between lead and cadmium levels and renal function. The risk of having reduced eGFR for individuals in the highest quartiles of both lead and cadmium levels in blood was greater than for those in the highest quartile of blood level of lead or cadmium only.

CONCLUSION

The CKD-EPI equation showed that blood lead and cadmium levels were associated with renal dysfunction in the Korean adult population. This finding has significant implications for environmental institutional strategies regarding heavy metal exposure.

What do we know of childhood exposures to metals (arsenic, cadmium, lead, and mercury) in emerging market countries?

Arsenic, cadmium, lead, and mercury present potential health risks to children who are exposed through inhalation or ingestion. Emerging Market countries experience rapid industrial development that may coincide with the increased release of these metals into the environment. A literature review was conducted for English language articles from the 21st century on pediatric exposures to arsenic, cadmium, lead, and mercury in the International Monetary Fund's (IMF) top 10 Emerging Market countries: Brazil, China, India, Indonesia, Mexico, Poland, Russia, South Korea, Taiwan, and Turkey. Seventy-six peer-reviewed, published studies on pediatric exposure to metals met the inclusion criteria. The reported concentrations of metals in blood and urine from these studies were generally higher than US reference values, and many studies identified adverse health effects associated with metals exposure. Evidence of exposure to metals in the pediatric population of these Emerging Market countries demonstrates a need for interventions to reduce exposure and efforts to establish country-specific reference values through surveillance or biomonitoring. The findings from review of these 10 countries also suggest the need for country-specific public health policies and clinician education in Emerging Markets.

The role of heavy-metal ATPases, HMAs, in zinc and cadmium transport in rice

The P(1B)-type heavy metal ATPases (HMAs) are diverse in terms of tissue distribution, subcellular localization, and metal specificity. Functional studies of HMAs have shown that these transporters can be divided into two subgroups based on their metal-substrate specificity: a copper (Cu)/silver (Ag) group and a zinc (Zn)/cobalt (Co)/cadmium (Cd)/lead (Pb) group. Studies on Arabidopsis thaliana and metal hyperaccumulator plants indicate that HMAs play an important role in the translocation or detoxification of Zn and Cd in plants. Rice possesses nine HMA genes, of which OsHMA1-OsHMA3 belong to the Zn/Co/Cd/Pb subgroup. OsHMA2 plays an important role in root-to-shoot translocation of Zn and Cd, and participates in Zn and Cd transport to developing seeds in rice. OsHMA3 transports Cd and plays a role in the sequestration of Cd into vacuoles in root cells. Modification of the expression of these genes might be an effective approach for reducing the Cd concentration in rice grains.

Correlations of trace element levels in the diet, blood, urine, and feces in the Chinese male

In order to explore the associations between trace elements in dietary intake and the other three biological media (blood, urine, or feces) and inter-element interactions among the latter, we simultaneously collected 72-h diet duplicates, whole blood, and 72-h urine and feces from 120 free-living healthy males in China. Correlations among the toxic (cadmium [Cd], lead [Pb]), and nutritionally essential (zinc [Zn], copper [Cu], iron [Fe], manganese [Mn], selenium [Se], iodine [I]) elements were evaluated using Spearman rank correlation analysis based on analytical data determined by inductively coupled plasma-mass spectrometry. Dietary Cd intakes were highly correlated with the fecal Cd and blood Cd levels. Inverse correlations were found for Fe-Cd and Fe-Pb in both diet versus blood and diet versus feces. Cd-Zn and Cd-Se were significantly directly correlated in the urine and feces. Cd-Se and Pb-Se were negatively correlated in blood. In addition, there existed an extremely significant association between urinary Se and urinary I. Moreover, the other two highly direct correlations were found for Se-Fe and for I-Fe in urine. Improved knowledge regarding their mutual associations is considered to be of fundamental importance to understand more the complex interrelationships in trace element metabolism.

Magnesium, calcium, and trace elements excretion in 24-h urine

Urine is a clinical specimen often used in medical diagnostics for monitoring of elements concentrations and kidneys function. We determined the contents of magnesium (Mg), calcium (Ca), zinc (Zn), copper (Cu), iron (Fe), lead (Pb), and cadmium (Cd) in 74 samples of 24-h urine (from 46 women and 28 men). The measurements were realized by the atomic absorption spectrometry (AAS) with atomization in the flame (FAAS) and in the graphite furnace (GFAAS). The received results were the subject of statistical analysis including the sex and age of volunteers. Moreover, correlations between the elements and the relationships between age and amounts of excreted elements with urine were tested. We found the statistically significant higher content of Zn in men's urine than in women(')s one. Moreover, both adult women and men (>18 years) excreted much more Ca in urine in comparison to young subjects. Only in case of Pb the significant positive correlation between its amount in 24-h urine of all donors and age was stated. The correlation analysis has shown the significant positive relationships between Ca-Mg, Ca-Fe, Mg-Fe, Cu-Fe, Cu-Cd, Fe-Cd, and Pb-Cd in total samples of urine. Basing on our results, we concluded that the gender and age of donors may impact on the elemental status of 24-h urine.

Assessment of cadmium exposure for neonates in Guiyu, an electronic waste pollution site of China

This study aimed to determine the levels of placental cadmium (PCd) and cord blood cadmium (CBCd) and the resulting expression of placental metallothionein (MT) in neonates and to investigate cadmium (Cd) exposure levels in neonates and mothers who live in Guiyu, China, an electronic waste (e-waste) pollution site. Among the 423 mothers included in the study from 2004/2005 to 2007, 289 lived in Guiyu (exposed group) and 134 lived in Chaonan, located 10 km away from Guiyu (controls) and had never been exposed to e-waste pollution. CBCd and PCd levels were measured by atomic absorption spectrometry. Placental MT was examined by immunohistochemistry. Information on maternal and neonatal characteristics and exposure conditions was obtained from hospital records and by personal interviews. For the 3 years, the median CBCd was higher for Guiyu neonates than for controls (3.61 vs. 1.25 μg/L), with 25.61% of Guiyu subjects exhibiting a median CBCd that exceeded the safety limit defined by the World Health Organization (5 μg/L), as compared with 14.18% of control neonates (p < 0.01). In Guiyu, the mean PCd was higher than that for controls (0.17 ± 0.48 vs. 0.10 ± 0.11 μg/g, p ≤ 0.01). The high levels of CBCd and PCd were significantly associated with parents' occupational and environmental exposure to e-waste recycling pollutants. Staining for MT was positive and dense for 67.00% (67/100) of Guiyu neonates as compared with 32.69% (17/52) of controls (p < 0.01). Exposure to e-waste recycling pollutants increased Cd exposure in neonates, which was accompanied by increased placental MT expression.

Environmental ecological modeling of human blood lead levels in East Asia

Environmental ecological modeling (EEM), which unifies models simulating transport of chemicals and exposure of humans to chemicals, was used to simulate long-term trends of female adult human blood lead levels (BLLs) and historical exposure to the atmospheric lead in four East Asian countries: Japan, Korea, China, and Vietnam. Anthropogenic lead emissions to the atmosphere in Vietnam were estimated from energy statistics to be 1931 t yr(-1). Calculated BLLs generally agreed with those observed in samples collected in these countries as the error factors were less than 2. The model results revealed that BLLs decreased significantly in Tokyo (by 58%) and Seoul (by 45%) in recent decades and confirmed the effects of efforts to reduce environmental lead in Japan and Korea. The model results also revealed that BLLs in Beijing did not decrease in this decade as much as in Tokyo and Seoul, despite the phasing out of leaded gasoline, and that the contribution from the atmospheric component was increasing (43% in 2009). Finally, we applied EEM to simulate BLLs of children in Hanoi. The probability of children having BLLs greater than 50 μg L(-1) was 7.5%, which was greater than those observed in developed countries.

Estimation of dietary Pb and Cd intake from Pb and Cd in blood or urine

Successful trials were made to estimate the dietary daily intake of lead (Pb) and cadmium (Cd) via foods from the levels of the metals in blood or urine. In practice, 14 and 15 reports were available for Pb and Cd in blood (Pb-B and Cd-B), urine (Pb-U and Cd-U) and 24-h diet duplicates (Pb-D and Cd-D), respectively, from which 68 pairs each of Pb or Cd in blood and food duplicates [each being geometric mean (GM) values for the survey sites] were obtained. Regression analysis revealed that there was a significant correlation between Pb-B and Pb-D, and also between Cd-B and Cd-D, suggesting that it should be possible to estimate both Pb-D and Cd-D from Pb-B and Cd-B, respectively. For Cd-U, the number of available cases was limited (20 pairs), but a significant correlation was detected between Cd-U (as Cd-U(cr), or Cd levels in urine as corrected for creatinine concentration) and Cd-D. Care should be taken in estimating Pb-D from Pb-B, as the ratio of Pb-D over Pb-B may decrease as a function of increasing Pb-B levels. The Pb-D (μg/day) for typical Japanese women with Pb-B of 15 μg/l was best estimated to be 13.5 μg/day. No Cd-B- or Cd-U(cr)-dependent change was detected in case of Cd. The best estimate of Cd-D for Cd-B at 1.5 μg/l should be about 19.4 μg/day.

Determination of toxic and essential elements in children's blood with inductively coupled plasma-mass spectrometry

Recent studies have suggested that low blood lead level, less than 50 microg L(-1), can influence the neurobehavioral performance of children. In addition, nutritional deficiencies in some essential elements may increase the toxicity of lead, and some essential elements may influence the blood concentrations of lead and other toxic metals. These findings, coupled with the scarcity of available data on some elements in children's blood and the introduction of methylcyclopentadienyl manganese tricarbonyl (MMT) to gasoline, accentuate the need to monitor the concentrations of lead, manganese, and other heavy metals and essential elements in children's blood. This study reports on the multi-element analysis of blood of South African school children using inductively coupled plasma-mass spectrometry (ICP-MS). The sample preparation consisted of a nitric acid/hydrogen peroxide open digestion and subsequent dilution with MilliQ water. The accuracy and precision were evaluated from quintuplet analyses of Seronorm trace elements whole blood reference material and human blood samples. Concentrations of lead, arsenic, manganese, copper, zinc, selenium, cobalt, and chromium in the blood of South African school children were determined. The average values were: lead 56.4 microg L(-1), arsenic 1.53 microg L(-1), manganese 8.48 microg L(-1), copper 1195 microg L(-1), zinc 3431 microg L(-1), selenium 176 microg L(-1), cobalt 0.80 microg L(-1), and chromium 1.25 microg L(-1). The level of lead was in line with some reported lower concentrations. The concentrations of arsenic and manganese were generally lower than those found in the literature. The concentrations of cobalt, copper, selenium, and chromium were higher than those found in other studies, whereas that of zinc was lower.

Baden-Wuerttemberg Environmental Health Survey (BW-EHS) from 1996 to 2003: toxic metals in blood and urine of children

The environmental health surveillance system in the Federal State of Baden-Wuerttemberg (South Germany), among others, was implemented to monitor pollutant exposures and their temporal and regional trends in children at the age of about 10 years. The investigations were performed in two larger cities, one small city and one rural area. Between 1996 and 2003, in total 5470 children were investigated in consideration of environmental health parameters in four cross-sectional studies. The data presented here cover the results of the determination of the internal load with toxic metals. The median values observed in the investigation in 2002/03 were: 4.6 microg/l urine for arsenic, less than 0.2 microg/l urine for mercury, 20.7 microg/l blood for lead, and 0.25 microg/l blood for cadmium. From 1996 to 2003, mercury concentrations showed a substantial decrease (-0.027 microg/l/year) and lead levels also decreased (-0.25 microg/l/year), whereas arsenic and cadmium levels did not change significantly over time. There was no consistent difference in the mean internal load of the metals between the four investigation areas. Important factors influencing the measured concentrations were consumption of fish in the last 48 h, which had an impact on arsenic (factor 2), and amalgam fillings, which accounted for an increase in mercury (factor 4.6). In the 2002/03 study period, levels above the limit of health concern for children (German HBM values) were found in about 0.5% of the lead measurements (maximum value 180 microg/l blood) and in about 0.2% of the mercury measurements (maximum value 8.2 microg/l urine). In conclusion, this environmental health survey generates objective data on secular trends and regional differences and provides insight into probable sources of toxic metal exposure in children.

Anthropometric, environmental, and dietary predictors of elevated blood cadmium levels in Ukrainian children: Ukraine ELSPAC group

No comprehensive data on sources or risk factors of cadmium exposure in Ukrainian children are available. In this we measured the blood levels of cadmium among 80 Ukrainian children and evaluated sources of exposure. A nested case-control study from a prospective cohort of Ukrainian 3-year-old children was conducted. We evaluated predictors of elevated blood cadmium using a multivariable logistic regression model. The model included socioeconomic data, parent occupation, environmental tobacco smoke, hygiene, body-mass index, and diet. Dietary habits were evaluated using the 1992 Block-NCI-HHHQ Dietary Food Frequency survey. Elevated cadmium was defined as blood levels in the upper quartile (0.25 microg/L). The mean age for all 80 children was 36.6 months. Geometric mean cadmium level was 0.21 microg/L (range = 0.11-0.42 microg/L; SD = 0.05). Blood cadmium levels were higher among children taking zinc supplements (0.25 vs 0.21 microg/L; P = 0.032), children who ate sausage more than once per week (0.23 vs 0.20; P = 0.007) and children whose fathers worked in a by-product coking industry (0.25 vs 0.21; P = 0.056). In the multivariable model, predictors of elevated blood cadmium levels included zinc supplementation (adjusted OR = 14.16; P < 0.01), father working in a by-product coking industry (adjusted OR = 8.50; P = 0.03), and low body mass index (<14.5; adjusted OR = 5.67; P = 0.03). This is the first study to indicate a strong association between elevated blood cadmium levels and zinc supplementation in young children. Whole-blood cadmium levels observed in this group of Ukrainian children appear to be similar to those reported in other Eastern European countries.

Dietary intake of toxic and essential trace elements by the children and parents living in Tokyo Metropolitan Area, Japan

This study estimated the dietary intakes of 25 pairs of Japanese children and their parents to 12 toxic and essential trace elements using 7-day duplicate diet composites. The estimated intakes of lead (children = 5.34 microg day-1, adults = 6.74 microg day-1) and tin (162 and 152 microg day-1) were below tolerable limits, but large difference in aluminium intakes (7.32 and 12.1 mg day-1) among the subjects warranted further investigations. Intakes of cadmium in both children and adults (13.2 and 15.9 microg day-1) were high, but a low uranium (U) intake was observed (0.593 and 0.587 microg day-1). Intakes of copper (567 and 784 microg day-1), manganese (1.56 and 2.72 mg day-1), zinc (4.93 and 6.75 mg day-1), and molybdenum (103 and 131 microg day-1) were close to the recommended values. Concentrations of chromium, nickel and selenium were lower than the detection limits in most cases.

Cross-sectional analysis of blood lead level of entire Korean lead workers

We analyzed blood lead (PbB) level from the 2003 health surveillance results of 13,043 lead workers from 1,217 total lead industries to evaluate lead intoxication at low level in Korea. Geometric mean of PbB was 6.08 microg/dl and 56.6% and 7.9% of total lead workers had PbB level over than 5 microg/dl and 25 microg/dl, respectively. Male showed relatively higher PbB level compared to women, but "Manufacture of Other Electronic Valves, Tubes and Electronic Components n.e.c." had more women than male in risk of low level lead exposure. While conventional high-risk industry such as "Manufacture of Accumulators" and "Other Basic Non-ferrous Metal Industries" were remained in high-risk group in lead exposure, there were high risks in other industries such as plastic, chemical and part manufacturing. Non-production tasks such as fork lift truck driving, maintenance, lab testing, and supporting function showed high blood lead level in addition to routine manufacturing processes such as smelting and soldering.

Gender-related difference, geographical variation and time trend in dietary cadmium intake in Japan

OBJECTIVES

The present analysis was initiated to examine possible gender-dependency, geographic variation, and time-dependent changes in dietary intake of cadmium (Cd-F) among general populations in Cd-non-polluted areas in Japan. The role of rice as Cd-F source was also within the scope.

METHODS

Two databases on Cd and nutritional analyses were re-visited. Both databases were established through collection of 24-h food duplicate portion samples from residents in areas with no known Cd pollution, and contained information on Cd and energy contents in the duplicate portion, together with daily rice consumption, the gender, the age and the location of the residence of each sample donor. The first and the second databases were established through surveys in the years around 1980 on 564 cases and around 1995 on 702 cases, respectively. The two databases were combined for evaluation by multiple regression (MRA) and other analyses.

RESULTS

The analyses showed that men tended to take more Cd than women, more clearly so in the 1980 survey than in the 1995 survey. When Cd-F in the 1995 survey was compared with that in the 1980 survey, a substantial decrease was observed, e.g. by 30% (from 37.5 to 26.2 microg/day) in case of women. Cd-F values varied subject to the survey sites in a wide range (e.g. from 20 to 86 microg/day among women in the 1980 survey). In MRA with Cd-F as a dependent variable and survey sites and food intake factors (e.g. rice and energy intakes) as independent variables, the survey sites could explain more than 53% and 35% of total variation in Cd-F in the 1980 and 1995 surveys, respectively. Rice consumption was also influential to Cd-F in both surveys with partial correlation coefficients of 0.36 and 0.21, respectively, the influence being stronger in the 1980 survey than in the 1995 survey. A significant correlation was detected between the 1980 and 1995 survey results both in Cd-F and in rice consumption.

CONCLUSION

Geographic and gender-related differences, and time-dependent decrease in dietary Cd intake in Japan were detected through analyses of food duplicate-based databases. The leading role of rice as dietary Cd source was also observed.

Endocrine disruption by cadmium, a common environmental toxicant with paradoxical effects on reproduction

Cadmium (Cd(2+)) is a common environmental pollutant and a major constituent of tobacco smoke. Exposure to this heavy metal, which has no known beneficial physiological role, has been linked to a wide range of detrimental effects on mammalian reproduction. Intriguingly, depending on the identity of the steroidogenic tissue involved and the dosage used, it has been reported to either enhance or inhibit the biosynthesis of progesterone, a hormone that is inexorably linked to both normal ovarian cyclicity and the maintenance of pregnancy. Thus, Cd(2+) has been shown to exert significant effects on ovarian and reproductive tract morphology, with extremely low dosages reported to stimulate ovarian luteal progesterone biosynthesis and high dosages inhibiting it. In addition, Cd(2+) exposure during human pregnancy has been linked to decreased birth weights and premature birth, with the enhanced levels of placental Cd(2+) resulting from maternal exposure to industrial wastes or tobacco smoke being associated with decreased progesterone biosynthesis by the placental trophoblast. The stimulatory effects of Cd(2+) on ovarian progesterone synthesis, as revealed by the results of studies using stable porcine granulosa cells, appear centered on the enhanced conversion of cholesterol to pregnenolone by the cytochrome P450 side chain cleavage (P450scc). However, in the placenta, the Cd(2+)-induced decline in progesterone synthesis is commensurate with a decrease in P450scc. Additionally, placental low-density lipoprotein receptor (LDL-R) mRNA declines in response to Cd(2+) exposure, suggesting an inhibition in the pathway that provides cholesterol precursor from the maternal peripheral circulation. Potential mechanisms by which Cd(2+) may affect steroidogenesis include interference with the DNA binding zinc (Zn(2+))-finger motif through the substitution of Cd(2+) for Zn(2+) or by taking on the role of an endocrine disrupting chemical (EDC) that could mimic or inhibit the actions of endogenous estrogens. Divergent, tissue-specific (ovary vs. placenta) effects of Cd(2+) also cannot be ruled out. Therefore, in consideration of the data currently available and in light of the potentially serious consequences of environmental Cd(2+) exposure to human reproduction, we propose that priority should be given to studies dedicated to further elucidating the mechanisms involved.

A piglet model for studies of gastrointestinal uptake of cadmium in neonates

Newborns are believed to have a higher gastrointestinal uptake of inorganic cadmium (Cd) than adults. However, relevant models for investigations of absorption of dietary Cd in neonates are lacking. In the present study, piglets were exposed to 2 or 20 microg Cd/kg body weight (b wt) per day by repeated oral administrations of CdCl2 dissolved in deionized water or infant follow-up formula from days 0 to 10. Elevated and dose-dependent Cd retention in blood and tissues resulted from this low-dose Cd exposure, as determined at day 11. Follow-up formula reduced Cd uptake in comparison to deionized water. However, Cd distribution to the kidneys was higher when Cd was given in formula than in water. Metallothionein (MT) levels in liver, kidney and duodenum were six, three and two times higher, respectively compared to an un-exposed control. Differences in bioavailability and distribution of low-dose Cd given in various diets to newborns could be detected by the proposed piglet model.