Downregulation of placental S100P is associated with cadmium exposure in Guiyu, an e-waste recycling town in China

Chinese Herbal Medicine as an Adjunctive Therapy Improves the Survival Rate of Patients with Ischemic Heart Disease: A Nationwide Population-Based Cohort Study

Background

Ischemic heart disease (IHD) related to cardiovascular or cerebrovascular disease is the leading cause of mortality and an important issue of public health worldwide. The cost of long-term healthcare for IHD patients may result in a huge financial burden.

Objectives

To analyze the medical expenditure incurred for and survival of IHD patients treated with Chinese herbal medicine (CHM) and Western medicine.

Methods

Subjects were randomly selected from the National Health Insurance Research Database in Taiwan. The Cox proportional hazards regression model, Kaplan–Meier estimator, logrank test, chi-square test, and analysis of variance were applied. Landmark analysis was used to assess the cumulative incidence of death in IHD patients.

Results

We identified 11,527 users of CHM combined with Western medicine and 11,527 non-CHM users. CHM users incurred a higher medical expenditure for outpatient care within 1 (24,529 NTD versus 18,464 NTD, P value <0.0001) and 5 years (95,345 NTD versus 60,367 NTD, P value <0.0001). However, CHM users had shorter hospitalizations and lower inpatient medical expenditure (7 days/43,394 NTD in 1 year; 11 days/83,141 NTD in 5 years) than non-CHM users (11 days/72,939 NTD in 1 year; 14 days/107,436 NTD in 5 years). The CHM group's adjusted hazard ratio for mortality was 0.41 lower than that of the non-CHM group by Cox proportional hazard models with time-dependent exposure covariates. Danshen, Huang qi, Niu xi, Da huang, and Fu zi were the most commonly prescribed Chinese single herbs; Zhi-Gan-Cao-Tang, Xue-Fu-Zhu-Yu-Tang, Tian-Wang-Bu-Xin-Dan, Sheng-Mai-San, and Yang-Xin-Tang were the five most frequently prescribed herbal formulas in Taiwan.

Conclusions

Combining Chinese and Western medicine can reduce hospital expenditure and improve survival for IHD patients.

Human Body Burden of Heavy Metals and Health Consequences of Pb Exposure in Guiyu, an E-Waste Recycling Town in China

Guiyu accommodates millions of tons of e-waste from overseas and domestic sources each year and is notorious for its e-waste dismantling industry. As a consequence, Guiyu has been described as "the world's most toxic place" and "junk town". Informal e-waste recycling activities have caused severe pollution to the local environment and are associated with extensive health problems to the residents. This review provides updated insights on the body burden of heavy metals derived from e-waste and health outcomes resulted from lead (Pb) exposure. The review identified that Guiyu has been highly contaminated by heavy metals, especially Pb. Excessive exposure to Pb has been associated with multi-system and long-term effects in neonates and children, covering nervous, cardiovascular, adaptive immune, and hematologic systems as well as chromosome and DNA damage. Our review indicates strong associations that emphasize the need to develop strong regulations for prevention of exposure and health consequences in Guiyu and similar sites around the world.

Environmental contamination and public health effects of electronic waste: an overview

Purpose

In recent years, electronic waste has become the fastest growing waste stream globally with potential deleterious environmental and public health effects from its hazardous constituents. This review aims at providing an up-to-date information on the environmental and public health effects of e- wastes, and also identify research gaps that could form basis of further innovative studies on this important subject.

Methods

We carried out literature survey using several search engines. All available literature which reported directly on environmental contamination of air, soil, and water by e-wastes, and their effects on exposed plants, animals, and humans were used in other to generate an updated information.

Results

High production volume coupled with indiscriminate disposal and informal recycling has made electronic waste (e-waste) to become a global public and environmental health issue. E-waste is made up of different hazardous substances such as heavy metals and persistent organic pollutants with the capacity to contaminate the environment if processed or recycled inappropriately. Humans and animals become exposed to e-waste constituents via ingestion, inhalation, and dermal contact. Several health effects have been linked to e-wastes. The most susceptible were children, pregnant women, and workers in primitive recycling sites. Generation of e-waste is predicted to increase drastically in the next decade with the potential complex interactive effects of its constituents.

Conclusion

This review is an up-to-date assessment of studies and reports on e-waste environmental contamination and public health effects. The review has shown that e-waste contains constituents that caused adverse environmental effects and toxicity to the biota. However, there is an enormous data gap between exposure quantification and possible health effects. More studies are needed to elucidate and provide holistic information on environmental and public health dangers posed by e-waste constituents.

Environmental and health impacts due to e-waste disposal in China - A review

E-waste is discarded and shipped mostly to developing countries located in Asian continent for disposal from other developed countries. Especially 70% of the world's e-waste ends up in Guiyu, a small town located in Guangdong Province of China. As little as 25% is recycled in formal recycling centers with adequate protection for workers and the other e-waste arrived in those areas is not handled in organized manner. As per reports only roughly 12.5% of e-waste is actually recycled, and the recycling efforts in those regions are primitive and result in toxic substances being leached into the surrounding ecosystems. In addition to persistent organic pollutants, there are many heavy metals found in the ground and river sediments in Guiyu, exceeding the threshold set to protect human health. Those areas are no longer suitable for growing food, and water is unsafe for drinking, due to the amount of toxins leached into the groundwater and land. Hazardous threats to environment and human health due to hazardous substances of e-waste all around China, as well as the current e-waste management were documented in this review. The article concludes with controlled contamination sources, and eco-friendly and efficient remediation technologies to solve e-waste problem in China.

Blood lead and cadmium levels associated with hematological and hepatic functions in patients from an e-waste-polluted area

Chronic exposures to toxic trace metals have hazardous effects on human health, especially exposure to lead (Pb) and cadmium (Cd). Blood Pb and Cd reflect toxicity on human health. A total of 267 hospitalized patients, of which 158 were from Guiyu (exposed group) in China, and 109 from Jinping (reference group), were recruited in this study. Blood Pb and Cd were measured by graphite furnace atomic absorption spectrometry. Blood Pb and Cd levels from the exposed group were both higher than in the reference group. Blood Pb levels are positively associated with blood Cd levels from the two groups. Blood Pb and Cd levels are associated with elevated hematological and hepatic parameters in patients from the exposed and reference groups. The results suggest toxic trace metals may increase liver metabolic burden, inducing abnormal liver function.

Concentrations of selected heavy metals in placental tissues and risk for neonatal orofacial clefts

Orofacial clefts (OFCs) have multifactorial etiologies. Prenatal exposure to heavy metals can induce OFCs in animal models, but evidence from studies of human subjects is scarce. We examined whether concentrations of mercury (Hg), cadmium (Cd), lead (Pb), and arsenic (As) in placental tissues are associated with risk for OFCs in offspring. This population-based case-control study included 103 newborns affected by OFCs with available placental tissues and 206 controls randomly selected from 509 non-malformed newborns with available placenta samples, recruited in five rural counties in northern China. Sociodemographic information was collected using a structured questionnaire in face-to-face interviews. The concentrations of Hg, Cd, Pb, and As in placental tissues were analyzed using an inductively coupled plasma-mass spectrometry in helium mode. The median concentrations of Hg (7.4 ng/g), Cd (57.1 ng/g), and Pb (96.1 ng/g) were all statistically significantly higher in OFC cases than in controls (Hg 5.5 ng/g, Cd 38.6 ng/g, and Pb 67.9 ng/g, respectively); no differences were observed between the two groups in median concentrations of As. Concentrations above the median for all subjects were associated with a 2.33-fold (95% confidence interval [CI] 1.33-2.09) increased OFC risk for Cd and a 3.08-fold (95% CI 1.74-5.47) increased risk for Pb. The risk for OFCs increased with concentration tertiles, with an adjusted odds ratio of 3.06 (95% CI 1.36-6.88) for the second tertile and 8.18 (95% CI 6.64-18.37) for the highest tertile of Cd, and 3.88 (95% CI 1.78-8.42) for the second tertile and 5.17 (95% CI 2.37-11.29) for the highest tertile of Pb. The association between Hg concentration and OFC risk was borderline nonsignificant after adjusting for confounding factors. Prenatal exposure to Cd and Pb, as reflected by their concentrations in placental tissues, is associated with an increased risk for neonatal OFCs.

An Assessment of Dietary Exposure to Cadmium in Residents of Guangzhou, China

Cadmium and its compounds are human carcinogens with severe organ toxicity, and their contamination of agricultural soil in China has been frequently reported; however, the dietary exposure to cadmium in residents and the relevant health risk have seldom been reported. In this study, the concentration of cadmium in various types of food collected from 2013 to 2015 were analyzed using graphite furnace atomic absorption spectrometry, and the dietary exposure to cadmium assessed based on a dietary survey in 2976 Guangzhou residents. In total, 3074 out of 4039 food samples had cadmium levels above the limit of detection. The mean ± standard deviation (50th, 95th percentile) cadmium content in all samples was 159.0 ± 112.7 (8.6, 392.4) μg/kg, with levels ranging from 1.0 to 7830 μg/kg. Using the mean cadmium concentrations, the average monthly dietary exposure of Guangzhou residents to cadmium was 14.4 (μg/kg body weight (BW), accounting for 57.6% of the provisional tolerable monthly intake (PTMI). Rice, laver, vegetables, and live aquatic products were the main sources of cadmium intake, on average accounting for 89% of the total value. The dietary cadmium exposure in high consumers (95th percentile food consumption) was 41.0 μg/kg·BW/month, accounting for 163% of the PTMI. Additionally, dietary cadmium exposure at mean consumption but high cadmium food concentration (95th percentile) was 32.3 μg/kg·BW/month, corresponding to 129% of the PTMI. The level of dietary exposure to cadmium in most Guangzhou residents was within the safety limit, thus increased health risk from dietary cadmium exposure is low at present. However, continued efforts by local governments to monitor the levels of cadmium in the four main food categories contributing to exposure are necessary.

Increased memory T cell populations in Pb-exposed children from an e-waste-recycling area

Chronic exposure to heavy metals could affect cell-mediated immunity. The aim of this study was to explore the status of memory T cell development in preschool children from an e-waste recycling area. Blood lead (Pb) levels, peripheral T cell subpopulations, and serum levels of cytokines (IL-2/IL-7/IL-15), relevant to generation and homeostasis of memory T cells were evaluated in preschool children from Guiyu (e-waste-exposed group) and Haojiang (reference group). The correlations between blood Pb levels and percentages of memory T cell subpopulations were also evaluated. Guiyu children had higher blood Pb levels and increased percentages of CD4⁺ central memory T cells and CD8⁺ central memory T cells than in the Haojiang group. Moreover, blood Pb levels were positively associated with the percentages of CD4⁺ central memory T cells. In contrast, Pb exposure contributed marginally in the change of percentages of CD8⁺ central memory T cells in children. There was no significant difference in the serum cytokine levels between the e-waste-exposed and reference children. Taken together, preschool children from an e-waste recycling area suffer from relatively higher levels of Pb exposure, which might facilitate the development of CD4⁺ central memory T cells in these children.

S100P is a potential molecular target of cadmium-induced inhibition of human placental trophoblast cell proliferation

Cadmium, a common and highly toxic pollutant, has been known to accumulate high concentrations in placenta with deleterious effects on placental structure and function. Cadmium inhibits cell proliferation in placenta via targeting metal binding proteins. S100P, a Ca²⁺-binding protein, plays an important role in promoting cell proliferation and our previous study found its downregulation was linked to cadmium exposure in Guiyu, a famous e-waste recycling town in China. So, the present study was aimed to define whether cadmium inhibited cell proliferation through interfering with S100P. Using human trophoblast-derived HTR-8/SVneo cells as a model in vitro, we showed that cadmium exposure led to decreases in both cell proliferation and S100P expression. Knockdown of S100P in HTR-8/SVneo cells led to an obvious decrease of cell proliferation, and upregulation of S100P resulted in a significant increase of cell proliferation. Furthermore, after 24h of exposure to cadmium (20μM), cells transfected with pcDNA3.1-S100P showed a 1.3-fold higher S100P protein level, 38% higher proliferation evaluated with MTT assay than cells with no transfection, indicating that S100P expression attenuated cadmium-induced inhibition of cell proliferation. Taken together, we demonstrate that cadmium inhibits S100P expression and cell proliferation in placenta, meanwhile, S100P expression affects cell proliferation. Thus, our study is the first to indicate that cadmium may induce inhibition of placental trophoblast cell proliferation through targeting S100P.

Environmental Exposure to Cadmium: Health Risk Assessment and its Associations with Hypertension and Impaired Kidney Function

Cadmium (Cd) is a toxic metal. This study was aimed to estimate the potential health risks in a Cd-polluted district in China, and examine the relationship between urinary cadmium(UCd) and hypertension and impaired kidney function at low exposure levels (UCd: GM 1.3 μg/g creatinine). Blood pressure measurement, questionnaires, and collection of urinary samples were conducted from 217 residents. Environmental samples, food, and cigarette samples were collected and detected to estimate the risks posed by Cd and the contribution of inhalation, ingestion, and dermal contact pathways to these risks. A logistic regression model was used in examining associations between exposure and hypertension and impaired kidney function. Results show that this population is at high risk. For non-smokers, incremental lifetime cancer risk (ILCR) and hazard quotient (HQ) are 1.74E-04 and 2.96, and for smokers, they are 1.07E-03 and 52.5, respectively. Among all exposure pathways, smoking and foods cause the major increases in ILCR and HQ. UCd is significantly associated with hypertension (odds ratio (OR) = 1.468; 95% confidence interval (CI): 1.104, 1.953; P = 0.008) and impaired kidney function (OR = 1.902, 95% CI: 1.054, 3.432; P = 0.033). The results demonstrate that Cd can potentially lead to adverse health effects.

The role of the PM2.5-associated metals in pathogenesis of child Mycoplasma Pneumoniae infections: a systematic review

The peak occurrence of Mycoplasma pneumoniae (M. pneumoniae) infections in childhood and haze episodes is concurrent. Together, the prevalence of macrolide-resistant M. pneumoniae varies among countries might also be related to the concentration of ambient fine particulate mass (aerodynamic diameter ≤2.5 μm, PM2.5). Numerous cohort studies have identified consistent associations between ambient PM2.5 and cardiorespiratory morbidity and mortality. PM2.5 is a carrier of the heavy metals. The relationship between PM2.5-associated metals and M. pneumoniae infections in childhood has been increasingly drawing public attention. First, we reviewed original articles and review papers in Pubmed and Web of Science regarding M. pneumoniae and PM2.5-associated metal and analyzed the structural basis of PM2.5-associated metal interaction with M. pneumoniae. Then, the possible mechanisms of action between them were conjectured. Mechanisms of oxidative stress induction and modulation of the host immune system and inflammatory responses via Toll-like receptors (TLRs) and/or the nuclear factor-kappa B (NF-κB) pathway are postulated to be the result of PM2.5-associated metal complex interaction with M. pneumoniae. In addition, a heavy metal effect on M. pneumoniae-expressed community-acquired respiratory distress syndrome (CARDS) toxin, and activation of the aryl hydrocarbon receptor (AhR) and TLRs to induce the differentiation of T helper (Th) cells are also regarded as important reasons for the influence of the heavy metals on the severity of M. pneumoniae pneumonia and the initial onset and exacerbation of M. pneumoniae associated asthma. PM2.5-associated metals via complex mechanisms can exert a great impact on the host through interaction with M. pneumoniae.

Differential proteomic expression of human placenta and fetal development following e-waste lead and cadmium exposure in utero

Prenatal exposure to lead (Pb) and cadmium (Cd) has been associated with a series of physiological problems resulting in fetal growth restriction. We aimed to investigate the effects of Pb and Cd exposure on placental function and the potential mechanisms involved in fetal development. Placental specimens and questionnaires were collected from an e-waste area and a reference area in China. Two-dimensional electrophoresis combined with MALDI-TOF-MS/MS and molecular network relationship were performed to analyze differentially expressed proteins using a compositing sample pool. Compared with the reference group, the exposed group exhibited significantly higher levels of placental Pb and Cd (p<0.01), shorter body length and higher gestational age (p<0.01). After bivariate adjustment in a linear regression model, decreases of 205.05g in weight and 0.44cm in body length were associated with a 10ng/g wt increase in placental Cd. Pb showed a negative trend but lacked statistical significance. Proteomic analysis showed 32 differentially-expressed proteins and were predominantly involved in protein translocation, cytoskeletal structure, and energy metabolism. Fumarate hydratase was down-regulated in the exposed placenta tissues and validated by ELISA. Alterations in placental proteome suggest that imbalances in placental mitochondria respiration might be a vital pathway targeting fetal growth restriction induced by exposure to Cd.

Children with health impairments by heavy metals in an e-waste recycling area

E-waste recycling has become a global environmental health issue. Pernicious chemicals escape into the environment due to informal and nonstandard e-waste recycling activities involving manual dismantling, open burning to recover heavy metals and open dumping of residual fractions. Heavy metals derived from electronic waste (e-waste), such as, lead (Pb), cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), mercury (Hg), arsenic (As), copper (Cu), zinc (Zn), aluminum (Al) and cobalt (Co), differ in their chemical composition, reaction properties, distribution, metabolism, excretion and biological transmission. Our previous studies showed that heavy metal exposure have adverse effects on children's health including lower birth weight, lower anogenital distance, lower Apgar scores, lower current weight, lower lung function, lower hepatitis B surface antibody levels, higher prevalence of attention-deficit/hyperactivity disorder, and higher DNA and chromosome damage. Heavy metals influence a number of diverse systems and organs, resulting in both acute and chronic effects on children's health, ranging from minor upper respiratory irritation to chronic respiratory, cardiovascular, nervous, urinary and reproductive disease, as well as aggravation of pre-existing symptoms and disease. These effects of heavy metals on children's health are briefly discussed.

E-waste environmental contamination and harm to public health in China

The adverse effects of electronic waste (e-waste) on the human body have stirred up concern in recent years. China is one of the countries that confront serious pollution and human exposure of e-waste, and the majority of the population is exposed to potentially hazardous substances that are derived from informal e-waste recycling processes. This study reviews recent reports on human exposure to e-waste in China, with particular focus on exposure routes (e.g., inhalation and ingestion) and several toxicities of human (e.g., endocrine system, respiratory system, reproductive system, developmental toxicity, neurotoxicity, and genetic toxicity). Pieces of evidence that associate e-waste exposure with human health effects in China are assessed. The role of toxic heavy metals (e.g., lead, cadmium, chromium, mercury, and nickel) and organic pollutants (e.g., polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyl (PCBs), polycyclic aromatic hydrocarbons (PAHs), polybrominated biphenyls (PBBs), polyhalogenated aromatic hydrocarbons (PHAHs), bisphenol A (BPA)) on human health is also briefly discussed.

Associations of cadmium, bisphenol A and polychlorinated biphenyl co-exposure in utero with placental gene expression and neonatal outcomes

In utero co-exposure to endocrine disrupting compounds can perturb fetal development. However, the effect of co-exposure on pivotal regulatory genes has seldom been investigated. We explored the effects of in utero co-exposure to cadmium (Cd), bisphenol A (BPA) and polychlorinated biphenyls (PCBs) on master regulator genes. We recruited 284 healthy pregnant women, of whom 262 provided both cord blood and placenta samples, and 200 had all measurements taken. Placental Cd, cord blood BPA and total PCBs in the exposed group were higher than a reference group. KISS1 expression level in placental tissue was threefold higher in the exposed group than in the reference, and was positively associated with all toxicants. Leptin and leptin receptor expression were also significantly higher, but were only associated with BPA. From our findings, we conclude that lower birth weight is correlated with Cd and PCBs, and may result from the increased KISS1 mRNA expression.

Effects of decabromodiphenyl ether on lead mobility and microbial toxicity in soil

Lead (Pb) and decabromodiphenyl ether (BDE209) are the main pollutants at e-waste recycling sites (EWRSs). Focus on joint toxicological effects of the two chemicals has increasingly gained a great amount of interest. Therefore, the lab study was performed to determine the Pb mobility and microbial toxicity in a Pb-polluted soil in the presence of BDE209 for the first time. The results showed that BDE209 was barely degraded and could elicit the combined effects with Pb exposure during the entire incubation period. The exchangeable (EXCH) and carbonates fractions of Pb were transformed to organic, Fe/Mn oxides and residual fractions, and the addition of an appropriate amount (100mgkg(-1)) of BDE209 facilitated the transformation compared with Pb alone. In addition, soil microbial biomass C (Cmic), soil basal respiration (SBR) and metabolic quotient (qCO2) increased in the beginning of the experiment and then declined with the incubation period extension, and BDE209 addition might cause notable different response relative to the control. Significant correlations between EXCH or mobility factor (MF) of Pb and SBR, Cmic, or qCO2 in soil treated with BDE209 can be clearly observed. Results of the observations provide a better understanding of ecotoxicological effects of Pb and BDE209 joint exposure on indigenous microorganisms in soil at EWRSs.

A review on human health consequences of metals exposure to e-waste in China

As the world's the largest dumping ground for e-waste, much of the population in China is exposed to heavy metals due to informal e-waste recycling processes. We reviewed recent studies on body burdens and human health effects of heavy metals from the major e-waste recycling sites in China. The results showed that the residents in the e-waste recycling sites are facing a potential higher daily intake of heavy metals. Moreover, heavy metals had entered subjects' bodies (the collected 5 tissue samples). Additionally,individual exposure to heavy metals in e-waste has also caused negative health outcomes,especially in neonates and children. We also recorded plausible outcomes associated with exposure to e wast (to heavy metals). A precautionary approach toward exposure, especially in neonates and children, therefore seems warranted.

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.

Environmental effects of heavy metals derived from the e-waste recycling activities in China: a systematic review

As the world's leading manufacturing country, China has become the largest dumping ground for e-waste, resulting in serious pollution of heavy metals in China. This study reviews recent studies on environmental effects of heavy metals from the e-waste recycling sites in China, especially Taizhou, Guiyu, and Longtang. The intensive uncontrolled processing of e-waste in China has resulted in the release of large amounts of heavy metals in the local environment, and caused high concentrations of metals to be present in the surrounding air, dust, soils, sediments and plants. Though the pollution of many heavy metals was investigated in the relevant researches, the four kinds of heavy metals (Cu, Pb, Cd and Cr) from e-waste recycling processes attracted more attention. The exceedance of various national and international standards imposed negative effects to the environment, which made the local residents face with the serious heavy metal exposure. In order to protect the environment and human health, there is an urgent need to control and monitor the informal e-waste recycling operations.

A systematic review of the human body burden of e-waste exposure in China

As China is one of the countries facing the most serious pollution and human exposure effects of e-waste in the world, much of the population there is exposed to potentially hazardous substances due to informal e-waste recycling processes. This report reviews recent studies on human exposure to e-waste in China, with particular focus on exposure routes (e.g. dietary intake, inhalation, and soil/dust ingestion) and human body burden markers (e.g. placenta, umbilical cord blood, breast milk, blood, hair, and urine) and assesses the evidence for the association between such e-waste exposure and the human body burden in China. The results suggest that residents in the e-waste exposure areas, located mainly in the three traditional e-waste recycling sites (Taizhou, Guiyu, and Qingyuan), are faced with a potential higher daily intake of these pollutants than residents in the control areas, especially via food ingestion. Moreover, pollutants (PBBs, PBDEs, PCBs, PCDD/Fs, and heavy metals) from the e-waste recycling processes were all detectable in the tissue samples at high levels, showing that they had entered residents' bodies through the environment and dietary exposure. Children and neonates are the groups most sensitive to the human body effects of e-waste exposure. We also recorded plausible outcomes associated with exposure to e-waste, including 7 types of human body burden. Although the data suggest that exposure to e-waste is harmful to health, better designed epidemiological investigations in vulnerable populations, especially neonates and children, are needed to confirm these associations.

Potential health risks of heavy metals in cultivated topsoil and grain, including correlations with human primary liver, lung and gastric cancer, in Anhui province, Eastern China

Environmental exposure to heavy metals is a well-known risk factor for cancers. To evaluate potential health risks of heavy metals (Cr, Cd, Pb, As and Hg) and Se in cultivated topsoil and grains, we investigated the concentrations of Hg, As and Se using atomic fluorescence spectrometry and Cr, Cd and Pb using inductive coupled plasma emission spectrometry (ICP-MS). We also analyzed human cancer tissues for heavy metals. Potential health risks for local residents were evaluated by calculating the hazard index (HI) and the total carcinogenic risk (TCR) for soil heavy metals and the target hazard quotient (THQ) and the carcinogenic risk (CR) for grain heavy metals. A bioconcentration factor (BCF) was applied to quantify the bioaccumulation of heavy metals. Our results demonstrated that the mean concentrations of heavy metals in soil were all within the safety limits set by FAO/WHO and Chinese regulations; however, the mean concentrations of Cr and Hg in grain exceeded the safety limits. HI and TCR for soil heavy metals were all within acceptable levels, but the THQ for four grain heavy metals exceeded the target value of 1 (Cr, 2.64; Pb, 1.41; As, 1.24; Hg, 1.07; Cd, 0.39). The grain CR for Cr, Pb and As exceeded the accepted risk level of 10(-6). BCF values indicated that the bioaccumulation capacity decreased in the following sequence: Hg>Se>Cd>Cr>Pb>As. We also observed statistically significant correlations of topsoil Pb concentration with human gastric cancer and grain Hg with human liver cancer. Therefore, long-term low dose exposure of heavy metals may play a key role in tumorigenesis, and it may not be necessary to accumulate a high concentration of heavy metals in the human body for those metals to induce tumorigenesis.

Elevated serum polybrominated diphenyl ethers and alteration of thyroid hormones in children from Guiyu, China

Informal electronic waste (e-waste) recycling results in serious environmental pollution of polybrominated diphenyl ethers (PBDEs) and heavy metals. This study explored whether there is an association between PBDEs, heavy metal and key growth- and development-related hormones in children from Guiyu, an e-waste area in southern China. We quantified eight PBDE congeners using gas chromatographic mass spectrometry, lead and cadmium utilizing graphite furnace atomic absorption spectrometry, three thyroids with radioimmunoassay and two types of growth hormones by an enzyme-linked immune-sorbent assay (ELISA) in 162 children, 4 to 6 years old, from Guiyu. In blood, median total PBDE was 189.99 ng/g lipid. Lead and cadmium concentrations in blood averaged 14.53±4.85 µg dL-1 and 0.77±0.35 µg L-1, respectively. Spearman partial correlation analysis illustrated that lead was positively correlated with BDE153 and BDE183. Thyroid-stimulating hormone (TSH) was positively correlated with almost all PBDE congeners and negatively correlated with insulin-like growth factor binding protein-3 (IGFBP-3), whereas free triiodothyronine (FT3) and free thyroxine (FT4) were negatively correlated with BDE154. However, no correlation between the hormones and blood lead or cadmium levels was found in this study. Adjusted multiple linear regression analysis showed that total PBDEs was negatively associated with FT3 and positively associated with TSH. Notably, FT4 was positively correlated with FT3, house functions as a workshop, and father's work involved in e-waste recycling and negatively correlated with vitamin consumptions. TSH was negatively related with FT4, paternal residence time in Guiyu, working hours of mother, and child bean products intake. IGFBP-3 was positively correlated with IGF-1 and house close to an e-waste dump. These results suggest that elevated PBDEs and heavy metals related to e-waste in Guiyu may be important risk factors for hormone alterations in children.

Comparative evaluation of environmental contamination and DNA damage induced by electronic-waste in Nigeria and China

In the last decade, China and Nigeria have been prime destinations for the world's e-waste disposal leading to serious environmental contamination. We carried out a comparative study of the level of contamination using soils and plants from e-waste dumping and processing sites in both countries. Levels of polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were analyzed using gas chromatography/spectrophotometry and heavy metals using atomic absorption spectrophotometry. DNA damage was assayed in human peripheral blood lymphocytes using an alkaline comet assay. Soils and plants were highly contaminated with toxic PAHs, PCBs, PBDEs, and heavy metals in both countries. Soil samples from China and plant samples from Nigeria were more contaminated. There was a positive correlation between the concentrations of organics and heavy metals in plant samples and the surrounding soils. In human lymphocytes, all tested samples induced significant (p<0.05) concentration-dependent increases in DNA damage compared with the negative control. These findings suggest that e-waste components/constituents can accumulate, in soil and surrounding vegetation, to toxic and genotoxic levels that could induce adverse health effects in exposed individuals.