Health and environmental risk assessment of mercury in outdoor and indoor dust in artisanal and small-scale gold mining area in Amansie-west district in the Ashanti Region of Ghana.

Mercury (Hg) pollution around artisanal and small-scale gold mining (ASGM) areas has been of much concern. Many studies have reported elevated Hg concentrations in environmental media, but studies on dust relating to inhalation exposure of Hg around ASGM area are limited. In this study, we investigated Hg in indoor and outdoor dust to reveal environmental and human health risk around ASGM in Amansie West district, Ghana. Indoor and outdoor dust samples were collected from Manso Abore and Manso Nkwanta in Ashanti Region. Concentration of Hg in the samples were analyzed using a direct Hg analyzer. The mean and median value of Hg concentration in the indoor dust (n = 31) were 2.2 ± 3.6 mg/kg and 0.72 mg/kg respectively while that of the outdoor dust (n = 60) were 0.19 ± 0.48 mg/kg and 0.042 mg/kg, respectively. The mean and median Hg concentration in indoor dust were about 11 and 17 times higher respectively than that in the outdoor dust. The Hg concentration in the indoor dust was statistically significantly higher than that of the non-miner in Manso Abore (p < 0.05) but was not significant in Manso Nkwanta, probably due to higher mining activity. The geo-accumulation index of the outdoor dust ranged from unpolluted to extremely polluted while that of the indoor dust ranged from moderately polluted to extremely polluted. Health risk assessments suggested that there was no potential non-carcinogenic health effect for Hg exposure relating to the dust to residents living in rooms of miners and non-miners.

Human Health Risk Assessment from Mercury-Contaminated Soil and Water in Abu Hamad Mining Market, Sudan.

Artisanal and small-scale gold mining (ASGM) poses a significant global threat due to mercury emissions and resulting health hazards. This study focuses on assessing these risks in the Abu Hamad ASGM community in Sudan. Utilizing the Mercury Analyzer 3000 (NIC), analyses of twelve soil samples (including one tailings sample) and seven water samples revealed the highest concentrations near amalgam burning locations: 34.8 mg/kg in soil (S06) and 3.26 µg/L in water (W03). Concentrations decrease with distance, with soil near burning exceeding tailings (S05 = 19.0 mg/kg). Hazard quotients indicate mercury vapor inhalation as the primary exposure route from soil, with the Hazard Index reaching 5.34 for adults and 33.4 for children close to amalgam burning sites. Water samples generally pose little risk except for W03, where children face potential danger via ingestion (HI = 1.74). These findings emphasize the urgent need for adopting retorts and eco-friendly practices to reduce mercury emissions and protect ASGM communities.

Mercury Pollution from Artisanal and Small-Scale Gold Mining in Myanmar and Other Southeast Asian Countries.

Mercury (Hg) is one of the most harmful metals and has been a public health concern according to the World Health Organization (WHO). Artisanal and small-scale gold mining (ASGM) is the world's fastest-growing source of Hg and can release Hg into the atmosphere, hydrosphere, and geosphere. Hg has been widely used in ASGM industries throughout Southeast Asia countries, including Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, and Thailand. Here, 16 relevant studies were systematically searched by performing the PRISMA flow, combining the keywords of "Hg", "ASGM", and relevant study areas. Mercury concentrations exceeding the WHO and United States Environmental Protection Agency guideline values were reported in environmental (i.e., air, water, and soil) and biomonitoring samples (i.e., plants, fish, and human hair). ASGM-related health risks to miners and nonminers, specifically in Indonesia, the Philippines, and Myanmar, were also assessed. The findings indicated severe Hg contamination around the ASGM process, specifically the gold-amalgamation stage, was significantly high. To one point, Hg atmospheric concentrations from all observed studies was shown to be extremely high in the vicinity of gold operating areas. Attentions should be given regarding the public health concern, specifically for the vulnerable groups such as adults, pregnant women, and children who live near the ASGM activity. This review summarizes the effects of Hg in Myanmar and other Southeast Asian countries. In the future, more research and assessment will be required to investigate the current and evolving situation in ASGM communities.

Effects of gestational exposure to bisphenol A on the hepatic transcriptome and lipidome of rat dams: Intergenerational comparison of effects in the offspring.

Our previous studies demonstrated that prenatal bisphenol A (BPA) exposure affected the hepatic transcriptome and lipidome in rat offspring in a sex- and age-dependent manner. In this study, we investigated the effects of gestational exposure to BPA on the rat dams, after weaning period, and compared them with those of their offspring. Our results showed alterations in hepatic transcriptome related to insulin signaling, circadian rhythm, and infectious disease pathways in BPA-treated dams even 4 weeks after the exposure, whereas slight modifications on the lipid profile were found. Alterations in lipid and transcriptome profiles were more prominent in the prenatally BPA-exposed offspring at postnatal day (PND) 1 and 21 than those in the dams, suggesting that in utero exposure to BPA is more serious than exposure in the adulthood. Cryptochrome-1 (Cry1) and peroxisome proliferator-activated receptor delta (Ppard) were commonly altered in both dams and offspring. Nevertheless, the results of DIABLO (Data Integration Analysis for Biomarker discovery using Latent cOmponents), showed that multi-omics data successfully distinguished the exposed dams from the corresponding controls and their offspring with a high level of accuracy. The accuracy rates in BPA50 models (including control and 50 µg BPA/kg bw/day exposed groups) were smaller than those in BPA5000 models (control and 5000 µg BPA/kg bw/day exposed groups), suggesting dose-dependent severity in BPA effects. Palmitic acid and genes related to circadian rhythm, insulin responses, and lipid metabolism (e.g., 1-acylglycerol-3-phosphate O-acyltransferase 2 (Agpat2), B-cell CLL/lymphoma 10 (Bcl10), Cry1, Harvey rat sarcoma virus oncogene (Hras), and NLR family member X1 (Nlrx1)) were identified through DIABLO models as novel biomarkers of effects of BPA across two generations.

Acesulfame as a suitable sewer tracer on groundwater pollution: A case study before and after the 2016 Mw 7.0 Kumamoto earthquakes.

On April 14th and 16th, 2016, two large-scale earthquakes (Mw 6.2 and 7.0) occurred in Kumamoto, Japan. The sewer system was seriously damaged and there were concerns about groundwater pollution by sewer exfiltration. In this study, artificial sweeteners including acesulfame (ACE) in groundwater were analyzed before and after the earthquakes to evaluate sewage pollution and its temporal variation. Before the earthquakes, ACE was detected in 31 of 49 groundwater samples analyzed, indicating that wastewater may have leaked into groundwater. Groundwater was sampled from the same locations 2, 7, 12, and 30 months after the earthquakes. The detection frequency and median concentration of ACE in groundwater increased significantly 7 months after the earthquakes, from several tens to maximumly 189 times greater than the pre-earthquake concentrations. This suggests the earthquakes caused serious damage to sewer pipes and groundwater may be polluted. However, ACE concentrations drastically decreased or remained low 30 months after the earthquakes, probably due to the recovery and restoration work of sewer infrastructure. This study shows that ACE is an excellent tracer for evaluating sewer exfiltration to groundwater. In addition, it is important to obtain data on sewage tracers under normal condition as part of preparations for large-scale earthquakes.

Effects of prenatal bisphenol A exposure on the hepatic transcriptome and proteome in rat offspring.

Developmental exposure to bisphenol A (BPA) is associated with liver dysfunction and diseases in adulthood. The aims of this study were to assess the effects of prenatal BPA exposure on the hepatic transcriptome and proteome in female and male offspring and to understand adverse outcome pathways (AOPs) to observed phenotypic effects. Pregnant Wistar rats were exposed to 50 or 5000 µg BPA/kg bw/day, or 17ß-estradiol (E2, 50 µg/kg bw/day) from embryonic day 3 to 18. The liver transcriptome and proteome profiles were analyzed in the newborn (postnatal day 1; PND1) and weaning (PND21) rat offspring. Based on the differentially expressed genes/proteins derived from transcriptome and proteome profiles, we performed pathway, transcription factor, and disease enrichment analyses. A principal component analysis of transcriptome data demonstrated that prenatal BPA exposure caused masculinization of the hepatic transcriptome in females. Both of transcriptomic and proteomic data showed that prenatal BPA exposure led to the disruption of cell cycle, lipid homeostasis, and hormone balance in offspring. Most of the effects at the transcript level were extended from newborn to weaning in males, but were moderated until weaning in females. The alterations at the transcript and protein levels were accordant with the observation of increases in body weight and anogenital distance and changes in hepatosomatic index in the offspring. Collectively, we constructed AOPs with evidence of sex- and age-specific actions of prenatal BPA exposure in the offspring.

Polycyclic Aromatic Hydrocarbons (PAHs) in Road Dust Collected from Myanmar, Japan, Taiwan, and Vietnam.

In this study, we determined the concentrations of polycyclic aromatic hydrocarbons (PAHs) in road dust from Myanmar, Japan, Taiwan, and Vietnam. PAHs were detected in urban and rural areas of Myanmar at mean concentrations of 630 ng/g dry weight and 200 ng/g dry weight, respectively. PAHs were also detected in road dust from Vietnam (mean 1700 ng/g) and Taiwan (2400 ng/g). PAH diagnostic ratios suggested that fossil fuel vehicular exhaust and biomass combustion are major sources of PAHs in road dust in Myanmar. Road dust samples from Japan, Taiwan, and Vietnam had similar PAH diagnostic ratios, implying that PAH sources are similar. We assessed the human health risks posed by PAHs in road dust using carcinogenic equivalents (CEQs) and incremental lifetime cancer risk (ILCR). Mean CEQs were decreased in the order Taiwan (173 ng/g) > Vietnam (162 ng/g for Hanoi) > Myanmar (42 and 31 ng/g for Yangon and Pathein, respectively) > Japan (30 ng/g for Kumamoto). Benz[a]pyrene, fluoranthene, and benzo[b]fluoranthene, the predominant PAHs, contributed > 70% of total CEQs. High ILCR values were found for Taiwan (5.9 × 10-4 and 9.9 × 10-4 for children and adults, respectively) and Vietnam (6.5 × 10-4 and 9.2 × 10-4 for children and adults, respectively, in Hanoi), indicating that PAHs in road dust pose cancer risks to the inhabitants of Taiwan and Hanoi. To our knowledge, this is the first report to identify PAH pollution in the environment and to evaluate the human health risks of these PAHs in Myanmar.

Effects of 4-Hydroxy-2,3,3',4',5-Pentachlorobiphenyl (4-OH-CB107) on Liver Transcriptome in Rats: Implication in the Disruption of Circadian Rhythm and Fatty Acid Metabolism.

Polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) have been detected in tissues of both wild animals and humans. Several previous studies have suggested adverse effects of OH-PCBs on the endocrine and nervous systems in mammals. However, there have been no studies on transcriptome analysis of the effects of OH-PCBs, and thus, the whole picture and mechanisms underlying the adverse effects induced by OH-PCBs are still poorly understood. We therefore investigated the mRNA expression profile in the liver of adult male Wistar rats treated with 4-hydroxy-2,3,3',4',5-pentachlorobiphenyl (4-OH-CB107) to explore the genes responsive to OH-PCBs and to understand the potential effects of the chemical. Next-generation RNA sequencing analysis revealed changes in the expression of genes involved in the circadian rhythm and fatty acid metabolism, such as nuclear receptor subfamily 1, group D, member 1, aryl hydrocarbon receptor nuclear translocator-like protein 1, cryptochrome circadian clock 1, and enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase, in 4-OH-CB107-treated rats. In addition, biochemical analysis of the plasma revealed a dose-dependent increase in the leucine aminopeptidase, indicating the onset of liver damage. These results suggest that OH-PCB exposure may induce liver injury as well as disrupt the circadian rhythm and peroxisome proliferator-activated receptor-related fatty acid metabolism.

Effect of lead speciation on its oral bioaccessibility in surface dust and soil of electronic-wastes recycling sites.

We measured bioaccessible lead (Pb) in simulated gastrointestinal fluids containing Pb-contaminated soil or dust from electronic waste (e-waste) recycling sites to assess the risk of Pb ingestion. The physiologically based extraction test (PBET) was used as in vitro bioaccessibility assay. Pb speciation was determined using X-ray absorption spectroscopy. The total Pb concentrations in dusts (n=8) and soils (n=4) were in the range of 1630-131,000 and 239-7800mg/kg, respectively. Metallic Pb, a common component of e-waste, was ubiquitous in the samples. We also found Pb adsorbed onto goethite and as oxides and carbonate, implying soil mixing and weathering influences. Pb phosphate and organic species were only found in the soil samples, suggesting that formation was soil-specific. We identified other Pb compounds in several samples, including Pb silicate, Pb chromate, and Pb(II) hydrogen phosphate. A correlation analysis indicated that metallic Pb decreased bioaccessibility in the stomach, while a Pb speciation analysis revealed a low bioaccessibility for Pb phosphates and high bioaccessibility for organic Pb species. The health risk based on bioaccessible Pb was estimated to be much lower than that of total Pb due to the lower concentrations.

Hair mercury levels in relation to fish consumption among Vietnamese in Hanoi.

People are exposed to methylmercury (MeHg) mainly through fish consumption, which is increasing in Vietnam. However, little information is available on estimating the health risk of MeHg exposure through fish consumption in Vietnam. The present study examined the association between mercury (Hg) levels in hair and selenium (Se) levels in toenails of 196 Vietnamese people and their fish consumption, using a dietary questionnaire to obtain information pertinent for assessing health risk owing to MeHg exposure. The geometric mean of Hg levels in the hair of males and females was 617 ng/g and 575 ng/g, respectively. We found that Hg levels in the hair of 98% of the Vietnamese study subjects were lower than the provisional tolerable weekly intake for MeHg (1.6 µg Hg/kg body weight; which is equivalent to a hair Hg concentration of approximately 2,300 ng/g, with an uncertainty factor of 6.4). There were significant differences in the age-adjusted geometric mean of Hg levels found in hair from females related to their frequency of freshwater fish consumption. The levels of Hg in hair and Se in toenails increased with an increased frequency of marine fish consumption, and both showed a significant positive correlation in subjects who consumed marine fish ≥ once/week. This is the first cross-sectional study to investigate the association between hair Hg levels and fish consumption in Vietnam. These findings provide valuable information for future assessments of the health risk of MeHg exposure through fish consumption in Vietnam.

Strain differences in the proteome of dioxin-sensitive and dioxin-resistant mice treated with 2,3,7,8-tetrabromodibenzo-p-dioxin.

Dioxins cause various toxic effects through the aryl hydrocarbon receptor (AHR) in vertebrates, with dramatic species and strain differences in susceptibility. Although inbred mouse strains C3H/HeJ-lpr/lpr (C3H/lpr) and MRL/MpJ-lpr/lpr (MRL/lpr) are known as dioxin-sensitive and dioxin-resistant mice, respectively, the molecular mechanism underlying this difference remains unclear. The difference in the hepatic proteome of the two mouse strains treated with vehicle or 2,3,7,8-tetrabromodibenzo-p-dioxin (TBDD) was investigated by a proteomic approach of two-dimensional electrophoresis (2-DE) coupled with matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF/TOF). To confirm the strain-difference in response to TBDD treatment, cytochrome P450 (CYP) 1A1 and 1A2 protein levels were measured in both strains. A dose of 10 µg/kg body weight of TBDD induced hepatic CYP1A1 and CYP1A2 expression in both strains, but the expression levels of both CYP1A proteins were higher in C3H/lpr mice than in MRL/lpr mice, supporting that C3H/lpr mice are more sensitive to dioxins than MRL/lpr mice. Proteins that were more induced or suppressed by TBDD treatment in C3H/lpr mice were successfully identified by 2-DE and MALDI-TOF/TOF, including proteins responsible for AHR activation through production of endogenous ligands such as aspartate aminotransferase, indolethylamine N-methyltransferase, and aldehyde dehydrogenases, as well as proteins reducing oxidative stress, such as superoxide dismutase and peroxiredoxins. Taken together, our results provide insights into the molecular mechanism underlying the high dioxin susceptibility of the C3H/lpr strain, in which AHR activation by TBDD is more prompted by the production of endogenous ligands, but the adaptation to oxidative stress is also acquired.

Identification of aryl hydrocarbon receptor signaling pathways altered in TCDD-treated red seabream embryos by transcriptome analysis.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces a broad spectrum of toxic effects including craniofacial malformation and neural damage in fish embryos. These effects are mainly mediated by the aryl hydrocarbon receptor (AHR). However, the mode of action between TCDD-induced AHR activation and adverse outcomes is not yet understood. To provide a comprehensive picture of the AHR signaling pathway in fish embryos exposed to TCDD, red seabream (Pagrus major) embryos were treated with graded concentrations of TCDD (0.3-37nM) in seawater, or with a mixture of TCDD and 500nM CH223191, an AHR-specific antagonist. The transcriptome of red seabream embryos was analyzed using a custom-made microarray with 6000 probes specifically prepared for this species. A Jonckheere-Terpstra test was performed to screen for genes that demonstrated altered mRNA expression levels following TCDD exposure. The signals of 1217 genes (as human homologs) were significantly altered in a TCDD concentration-dependent manner (q-value<0.2). Notably, the TCDD-induced alteration in mRNA expression was alleviated by co-exposure to CH223191, suggesting that the mRNA expression level of these genes was regulated by AHR. To identify TCDD-activated pathways, the microarray data were further subjected to gene set enrichment analysis (GSEA) and functional protein-protein interaction (PPI) network analysis. GSEA demonstrated that the effects of TCDD on sets of genes involved calcium, mitogen-activated protein kinase (MAPK), actin cytoskeleton, chemokine, T cell receptor, melanoma, vascular endothelial growth factor (VEGF), axon guidance, and renal cell carcinoma signaling pathways. These results suggest the hypotheses that TCDD induces immunosuppression via the calcium, MAPK, chemokine, and T cell receptor signaling pathways, neurotoxicity via VEGF signaling, and axon guidance alterations and teratogenicity via the dysregulation of the actin cytoskeleton and melanoma and renal cell carcinoma signaling pathways. Furthermore, the PPI network analysis indicated that the adverse outcome pathways of TCDD in the embryos might be propagated through several hub genes such as cell division control protein 42, phosphoinositide-3-kinase regulatory subunit 1, and guanine nucleotide-binding proteins. Understanding these pathways potentially allows for exploring the adverse outcome pathway of the effects of TCDD on the red seabream embryos.

In Vitro and in Silico Analyses for Predicting Hepatic Cytochrome P450-Dependent Metabolic Potencies of Polychlorinated Biphenyls in the Baikal Seal.

The aim of this study was to understand the cytochrome P450 (CYP)-dependent metabolic pathway and potency of polychlorinated biphenyls (PCBs) in the Baikal seal (Pusa sibirica). In vitro metabolism of 62 PCB congener mixtures was investigated by using liver microsomes of this species. A decreased ratio of over 20% was observed for CB3, CB4, CB8, CB15, CB19, CB22, CB37, CB54, CB77, and CB105, suggesting the preferential metabolism of low-chlorinated PCBs by CYPs. The highly activated metabolic pathways in Baikal seals that were predicted from the decreased PCBs and detected hydroxylated PCBs (OH-PCBs) were CB22 to 4'OH-CB20 and CB77 to 4'OH-CB79. The total amount of OH-PCBs detected as identified and unidentified congeners accounted for only a 3.8 ± 1.7 mol % of loaded PCBs, indicating many unknown PCB metabolic pathways. To explore factors involved in CYP-dependent PCB metabolism, we examined the relationships among the structural and physicochemical properties of PCBs, the in silico PCB-CYP docking parameters, and the in vitro PCB decreased ratios by principal component analysis. Statistical analysis showed that the decreased PCB ratio was at least partly accounted for by the substituted chlorine number of PCBs and the distance from the Cl-unsubstituted carbon of docked PCBs to the heme Fe in CYP2A and 2B.

[Relationship between Arsenic (+3 Oxidation State) Methyltransferase Genetic Polymorphisms and Methylation Capacity of Inorganic Arsenic].

Arsenic metabolism affects the susceptibility of humans to arsenic toxicity; therefore, clarification of the factors associated with individual variations in arsenic metabolism is an important task. Genetic polymorphisms such as single nucleotide polymorphisms (SNPs) in arsenic (+3 oxidation state) methyltransferase (AS3MT), which can methylate arsenic compounds using S-adenosyl-l-methionine (AdoMet), have been reported to modify arsenic methylation. In this review, we summarize studies conducted by us in Vietnam and by others on the association of AS3MT genetic polymorphisms with arsenic metabolism as well as human health effects. Most of the SNPs in AS3MT showed inconsistent results in terms of genotype-dependent differences in arsenic metabolism among the studies. However, AS3MT 12390 (rs3740393) and 14458 (rs11191439) were consistently related to arsenic methylation regardless of the study population: AS3MT 12390 (rs3740393) affected the second step of methylation of arsenic, whereas 14458 (rs11191439) affected the first methylation step.

Haptoglobin genotyping of Vietnamese: global distribution of HP del, complete deletion allele of the HP gene.

The haptoglobin (HP) gene deletion allele (HP(del)) is responsible for anhaptoglobinemia and a genetic risk factor for anaphylaxis reaction after transfusion due to production of the anti-HP antibody. The distribution of this allele has been explored by several groups including ours. Here, we studied the frequency of HP(del) in addition to the distribution of common HP genotypes in 293 Vietnamese. The HP(del) was encountered with the frequency of 0.020. The present result suggested that this deletion allele is restricted to East and Southeast Asians. Thus, this allele seems to be a potential ancestry informative marker for these populations.

Human exposure to arsenic from drinking water in Vietnam.

Vietnam is an agricultural country with a population of about 88 million, with some 18 million inhabitants living in the Red River Delta in Northern Vietnam. The present study reports the chemical analyses of 68 water and 213 biological (human hair and urine) samples conducted to investigate arsenic contamination in tube well water and human arsenic exposure in four districts (Tu Liem, Dan Phuong, Ly Nhan, and Hoai Duc) in the Red River Delta. Arsenic concentrations in groundwater in these areas were in the range of <1 to 632 µg/L, with severe contamination found in the communities Ly Nhan, Hoai Duc, and Dan Phuong. Arsenic concentrations were markedly lowered in water treated with sand filters, except for groundwater from Hoai Duc. Human hair samples had arsenic levels in the range of 0.07-7.51 µg/g, and among residents exposed to arsenic levels ≥50 µg/L, 64% of them had hair arsenic concentrations higher than 1 µg/g, which is a level that can cause skin lesions. Urinary arsenic concentrations were 4-435 µg/g creatinine. Concentrations of arsenic in hair and urine increased significantly with increasing arsenic content in drinking water, indicating that drinking water is a significant source of arsenic exposure for these residents. The percentage of inorganic arsenic (IA) in urine decreased with age, whereas the opposite trend was observed for monomethylarsonic acid (MMA) in urine. Significant co-interactions of age and arsenic exposure status were also detected for concentrations of arsenic in hair and the sum of IA, MMA, and dimethylarsinic acid (DMA) in urine and %MMA. In summary, this study demonstrates that a considerable proportion of the Vietnamese population is exposed to arsenic levels of chronic toxicity, even if sand filters reduce exposure in many households. Health problems caused by arsenic ingestion through drinking water are increasingly reported in Vietnam.

Sedimentary records of metal deposition in Japanese alpine lakes for the last 250 years: recent enrichment of airborne Sb and In in East Asia.

Concentrations of 18 elements, including Sb, In, Sn, and Bi, were measured in sediment cores from two pristine alpine lakes on Mount Hachimantai, northern Japan, representing the past 250 years. Vertical variations in concentrations are better explained by atmospheric metal deposition than by diagenetic redistribution of Fe and Mn hydroxide and organic matter. Anthropogenic metal fluxes were estimated from (210)Pb-derived accumulation rates and metal concentrations in excess of the Al-normalized mean background concentration before 1850. Anthropogenic fluxes of Sb and In showed gradual increases starting around 1900 in both lakes, and marked increases after 1980. Comparison of Sb/Pb and Pb stable isotope ratios in sediments with those in aerosols of China or northern Japan and Japanese source materials (recent traffic- and incinerator-derived dust) suggest that the markedly elevated Sb flux after 1980 resulted primarily from enhanced long-range transport in aerosols containing Sb and Pb from coal combustion on the Asian continent. The fluxes of In, Sn, and Bi which are present in Chinese coal showed increasing trends similar to Sb for both study lakes. This suggests that the same source although incinerators in Japan may not be ruled out as sources of In. The sedimentary records for the last 250 years indicate that atmospheric pollution of Sb and In in East Asia have intensified during recent decades.

Vanadium accelerates horizontal transfer of tet(M) gene from marine Photobacterium to Escherichia coli.

Vanadium is a contaminant from steel additive and ship fuel in coastal and port areas, and its effect on marine microbes remains largely unknown. We showed that vanadium accelerates transfer of the tetracycline resistance gene tet(M) from Photobacterium to Escherichia coli, and found a positive correlation between the concentration of vanadium in natural marine sediment and the rate of oxytetracycline resistance. These results suggest the possibility that vanadium may play a role in the preservation and horizontal transfer of antibiotic resistance genes in the marine environment.

Impact of metals in surface matrices from formal and informal electronic-waste recycling around Metro Manila, the Philippines, and intra-Asian comparison.

We report concentrations, enrichment factors, and hazard indicators of 11 metals (Ag, As, Cd, Co, Cu, Fe, In, Mn, Ni, Pb, and Zn) in soil and dust surface matrices from formal and informal electronic waste (e-waste) recycling sites around Metro Manila, the Philippines, referring to soil guidelines and previous data from various e-waste recycling sites in Asia. Surface dust from e-waste recycling sites had higher levels of metal contamination than surface soil. Comparison of formal and informal e-waste recycling sites (hereafter, "formal" and "informal") revealed differences in specific contaminants. Formal dust contained a mixture of serious pollutant metals (Ni, Cu, Pb, and Zn) and Cd (polluted modestly), quite high enrichment metals (Ag and In), and crust-derived metals (As, Co, Fe, and Mn). For informal soil, concentration levels of specific metals (Cd, Co, Cu, Mn, Ni, Pb, and Zn) were similar among Asian recycling sites. Formal dust had significantly higher hazardous risk than the other matrices (p<0.005), excluding informal dust (p=0.059, almost significant difference). Thus, workers exposed to formal dust should protect themselves from hazardous toxic metals (Pb and Cu). There is also a high health risk for children ingesting surface matrices from informal e-waste recycling sites.

Multi-trace element levels and arsenic speciation in urine of e-waste recycling workers from Agbogbloshie, Accra in Ghana.

To understand human contamination by multi-trace elements (TEs) in electrical and electronic waste (e-waste) recycling site at Agbogbloshie, Accra in Ghana, this study analyzed TEs and As speciation in urine of e-waste recycling workers. Concentrations of Fe, Sb, and Pb in urine of e-waste recycling workers were significantly higher than those of reference sites after consideration of interaction by age, indicating that the recycling workers are exposed to these TEs through the recycling activity. Urinary As concentration was relatively high, although the level in drinking water was quite low. Speciation analysis of As in human urine revealed that arsenobetaine and dimethylarsinic acid were the predominant As species and concentrations of both species were positively correlated with total As concentration as well as between each other. These results suggest that such compounds may be derived from the same source, probably fish and shellfish and greatly influence As exposure levels. To our knowledge, this is the first study on human contamination resulting from the primitive recycling of e-waste in Ghana. This study will contribute to the knowledge about human exposure to trace elements from an e-waste site in a less industrialized region so far scantly covered in the literature.