Metal sources and exposures in the homes of young children living near a mining-impacted Superfund site

Ecological and health risk assessment of heavy metals in interior dust from college campus

Contamination of college campus dust with heavy metals and the calculation of their ecological and health risks to the students and staff did not receive much attention except in recent years. This study aims to assess the ecological and human health risks of Cd, Cr, Cu, Pb, and Zn in interior dust of College of Science/University campus. An atomic absorption spectrophotometer was utilized to estimate the samples that were collected from 46 locations of the college campus including: classrooms, offices, and laboratories. The Pb, Cu, Cr and Zn metals in the interior dust of the College of Science pose low potential ecological risk, whereas Cd generates medium potential ecological risk. The gained results showed that the student and staff of the College are exposed to low non-cancerous health risks (HI < 1) caused by Cd, Cr, Cu, Pb, and Zn in interior dust. The total lifetime carcinogenic risks (TLCR) of Cd, Cr, and Pb are within the acceptable safe limit (10-6-10-4). The low non-carcinogenic health risks of Cd, Cr, Cu, Pb, and Zn and that the carcinogenic health risks of Cd, Cr and Pb fall within acceptable safe limits, measured in the interior dust of the campus of the College of Science, does not mean neglecting the continuous assessment of those risks.

An assessment of nanotechnology-based interventions for cleaning up toxic heavy metal/metalloid-contaminated agroecosystems: Potentials and issues

Heavy metals (HMs) are among the most dangerous environmental variables for a variety of life forms, including crops. Accumulation of HMs in consumables and their subsequent transmission to the food web are serious concerns for scientific communities and policy makers. The function of essential plant cellular macromolecules is substantially hampered by HMs, which eventually have a detrimental effect on agricultural yield. Among these HMs, three were considered, i.e., arsenic, cadmium, and chromium, in this review, from agro-ecosystem perspective. Compared with conventional plant growth regulators, the use of nanoparticles (NPs) is a relatively recent, successful, and promising method among the many methods employed to address or alleviate the toxicity of HMs. The ability of NPs to reduce HM mobility in soil, reduce HM availability, enhance the ability of the apoplastic barrier to prevent HM translocation inside the plant, strengthen the plant's antioxidant system by significantly enhancing the activities of many enzymatic and nonenzymatic antioxidants, and increase the generation of specialized metabolites together support the effectiveness of NPs as stress relievers. In this review article, to assess the efficacy of various NP types in ameliorating HM toxicity in plants, we adopted a 'fusion approach', in which a machine learning-based analysis was used to systematically highlight current research trends based on which an extensive literature survey is planned. A holistic assessment of HMs and NMs was subsequently carried out to highlight the future course of action(s).

Methodologies for the collection of parameters to estimate dust/soil ingestion for young children

Background

Heavy metals, pesticides and a host of contaminants found in dust and soil pose a health risk to young children through ingestion. Dust/soil ingestion rates for young children can be estimated using micro-level activity time series (MLATS) as model inputs. MLATS allow for the generation of frequency and duration of children's contact activities, along with sequential contact patterns. Models using MLATS consider contact types, and transfer dynamics to assign mechanisms of contact and appropriate exposure factors for cumulative estimates of ingestion rates.

Objective

The objective of this study is to describe field implementation, data needs, advanced field collection, laboratory methodologies, and challenges for integrating into and updating a previously validated physical-stochastic MLATS-based model framework called the Child-Specific Aggregate Cumulative Human Exposure and Dose (CACHED) model. The manuscript focuses on describing the methods implemented in the current study.

Methods

This current multidisciplinary study (Dust Ingestion childRen sTudy [DIRT]) was implemented across three US regions: Tucson, Arizona; Miami, Florida and Greensboro, North Carolina. Four hundred and fifty participants were recruited between August 2021 to June 2023 to complete a 4-part household survey, of which 100 also participated in a field study.

Discussion

The field study focused on videotaping children's natural play using advanced unattended 360° cameras mounted for participants' tracking and ultimately conversion to MLATS. Additionally, children's hand rinses were collected before and after recording, along with indoor dust and outdoor soil, followed by advanced mass analysis. The gathered data will be used to quantify dust/soil ingestion by region, sociodemographic variables, age groups (from 6 months to 6 years), and other variables for indoor/outdoor settings within an adapted version of the CACHED model framework.

Significance

New innovative approaches for the estimation of dust/soil ingestion rates can potentially improve modeling and quantification of children's risks to contaminants from dust exposure.

Federal Housing Assistance and Blood Lead Levels in a Nationally Representative US Sample Age 6 and Older: NHANES, 1999-2018

BACKGROUND

Federal housing assistance is an important policy tool to ensure housing security for low-income households. Less is known about its impact on residential environmental exposures, particularly lead.

OBJECTIVES

We conducted a quasi-experimental study to investigate the association between federal housing assistance and blood lead levels (BLLs) in a nationally representative US sample age 6 y and older eligible for housing assistance.

METHODS

We used the 1999-2018 National Health and Nutrition Examination Survey (NHANES) linked with US Department of Housing and Urban Development (HUD) administrative records to assess BLLs of NHANES participants with concurrent HUD housing assistance (i.e., current recipients, n = 3 , 0 71 ) and those receiving assistance within 2 y after the survey (i.e., pseudo-waitlist recipients, n = 1,235 ). We estimated BLL least squares geometric means (LSGMs), odds ratio (OR) for BLL ≥ 3.5 μ g / dL , and percent differences in LSGMs by HUD housing assistance status adjusting for age, sex, family income-to-poverty ratio, education, country of birth, race/ethnicity, region, and survey year. We also examined effect modification using interaction terms and stratified analyses by program type [i.e., public housing, multifamily, housing choice vouchers (HCV)], and race/ethnicity.

RESULTS

Current HUD recipients had a significantly lower LSGM [1.07 μ g / dL ; 95% confidence interval (CI): 1.02, 1.12] than pseudo-waitlist recipients (1.21   μ g / dL ; 95% CI: 1.14, 1.28), with an adjusted OR of 0.60 (95% CI: 0.42, 0.87) for BLL ≥ 3.5 μ g / dL . Some effect modification were observed: The protective association of HUD assistance on BLL was strongest among public housing (- 19.5 % LSGM; 95% CI: - 27.5 % , - 1 0 . 7 % ), multifamily (- 12.5 % LSGM; 95% CI: - 2 0 . 7 % , - 3.5 % ), and non-Hispanic White (- 2 0 . 6 % LSGM; 95% CI: - 29.8 % , - 1 0 . 3 % ) recipients. It was weaker to null among HCV (- 5.7 % LSGM; 95% CI: - 12.7 , 1.7%), non-Hispanic Black (- 1.6 % LSGM; 95% CI: - 8.1 % , 5.4%), and Mexican American (-12.5% LSGM; 95% CI: - 31.9 % , 12.5 % ) recipients.

DISCUSSION

Our research underscores the importance of social-structural determinants like federal housing assistance in providing affordable, stable, and healthy housing to very low-income households. More attention is needed to ensure housing quality and racial equity across HUD's three major housing assistance programs. https://doi.org/10.1289/EHP12645.

Multi-Hazard property buyouts: Making a case for the acquisition of flood and contaminant-prone residential properties in Galena Park, TX

The aftermath of extreme flood events can be particularly devastating for residential communities in proximity to flood-prone petrochemical facilities, as they are likely to experience multiple impacts from a single flood event. Hazard impacts could be from flood inundation to their properties, and floodwaters carrying contaminants from nearby facilities into their homes. While property acquisition or buyouts have been effectively used as a flood mitigation strategy, current buyout selection processes only factor in flood exposure, thereby ignoring other hazards such as exposure of properties to potential chemical substance transfer. In this paper, we identify properties that are eligible for flood buyouts but are also at a high risk of contaminant transferal during extreme flood events. We apply a benefit-cost analysis methodology to assess the economic viability of buyouts and proximity metrics to prioritize buyouts of contaminant-prone properties in Galena Park, Texas. Results indicate that, in selected flood-only property acquisition scenarios, cumulative avoided flood losses exceed the cost of property acquisition. However, although with lower cost-benefit values, a selection criterion that factors a combination of flood and contaminant-prone properties as buyouts results in multiple properties being removed from harm's way. Our findings emphasize the potential economic benefits of applying a multi-hazard selection criterion in dealing with flood property buyouts, especially in socially vulnerable communities with high exposure to both flooding and contaminant transfer.

Metal mixtures modeling identifies birth weight-associated gene networks in the placentas of children born extremely preterm

Prenatal exposure to toxic metals is linked to numerous adverse birth and later-in-life outcomes. These outcomes are tied to disrupted biological processes in fetal-derived tissues including the placenta and umbilical cord yet the precise pathways are understudied in these target tissues. We set out to examine the relationship between metal concentrations in umbilical cord and altered gene expression networks in placental tissue. These novel relationships were investigated in a subset of the Extremely Low Gestational Age Newborn (ELGAN) cohort (n = 226). Prenatal exposure to 11 metals/metalloids was measured using inductively coupled plasma tandem-mass spectrometry (ICP-MS/MS) in cord tissue, ensuring passage through the placental barrier. RNA-sequencing was used to quantify >37,000 mRNA transcripts. Differentially expressed genes (DEGs) were identified with respect to each metal. Weighted gene co-expression analysis identified gene networks modulated by metals. Two innovative mixtures modeling techniques, namely principal components analysis and quantile-based g-computation, were employed to identify genes/gene networks associated with multi-metal exposure. Individually, lead was associated with the strongest genomic response of 191 DEGs. Joint lead and cadmium exposure was related to 657 DEGs, including DNA Methyl Transferase 1 (DNMT1). These genes were enriched for the Eukaryotic Initiation Factor 2 (EIF2) pathway. Four gene networks, each containing genes within a Nuclear Factor kappa-light-chain-enhancer of Activated B Cells (NF-kB)-mediated network, were significantly increased in average expression level in relation to increases in all metal concentrations. All four of these metal mixture-associated gene networks were negatively correlated with important predictors of neonatal health including birth weight, placenta weight, and fetal growth. Bringing together novel methodologies from epidemiological mixtures analyses and toxicogenomics, applied to a unique cohort of extremely preterm children, the present study highlighted critical genes and pathways in the placenta dysregulated by prenatal metal mixtures. These represent potential mechanisms underlying the developmental origins of metal-induced disease.

Potentially toxic elements in human scalp hair around China's largest polymetallic rare earth ore mining and smelting area

There is a growing concern about human health of residents living in areas where mining and smelting occur. In order to understand the exposure to the potentially toxic elements (PTEs), we here identify and examine the cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in scalp hair of residents living in the mining area (Bayan Obo, n = 76), smelting area (Baotou, n = 57) and a reference area (Hohhot, n = 61). In total, 194 hair samples were collected from the volunteers (men = 87, women = 107) aged 5-77 years old in the three areas. Comparing median PTEs levels between the young and adults, Ni levels were significantly higher in adults living in the smelting area while Cr was highest in adults from the mining area, no significant difference was found for any of the elements in the reference area. From the linear regression model, no significant relationship between PTEs concentration, log₁₀(PTEs), and age was found. The concentrations of Ni, Cd, and Pb in hair were significantly lower in the reference area when compared to both mining and smelting areas. In addition, Cu was significantly higher in the mining area when compared to the smelting area. Factor analysis (FA) indicated that men and women from the smelting area (Baotou) and mining area (Bayan Obo), respectively, had different underlying communality of log10(PTEs), suggesting different sources of these PTEs. Multiple factor analysis quantilized the importance of gender and location when combined with PTEs levels in human hair. The results of this study indicate that people living in mining and/or smelting areas have significantly higher PTEs (Cu, Ni, Cd, and Pb) hair levels compared to reference areas, which may cause adverse health effects. Remediation should therefore be implemented to improve the health of local residents in the mining and smelting areas.

Elevated soil and blood lead levels with increasing residential proximity to a mine tailings facility in Soweto, South Africa

Mining has long been associated with the release of a range of toxic metals including lead, elevated levels of which have been found in land surrounding mine dumps as far afield as Spain, India, Macedonia and Nigeria. Mining has been a key pillar of economic development in South Africa for around a century and a half, and has left a legacy of major environmental contamination, with the poorest experiencing the highest burden of exposure. The current study was undertaken to ascertain the concentrations of lead in soil and in the blood of adults and children residing at increasing distances from a cluster of large tailings facilities (MTFs) in greater Johannesburg, South Africa. Through a cross-sectional survey data on household characteristics were collected through a questionnaire survey, and supplemented with samples of soil from household gardens, together with blood samples from child-adult pairs from all households included in the study. Soil lead concentrations decreased significantly (median = 35.7 mg/kg closest to the mine tailings facility (MTF) and 8.6 mg/kg at the furthest point in the study site) with increasing distance from the MTF. Blood lead levels were highest in both adults (median = 3.0 μg/dL) and children (median = 4.0 μg/dL) who lived closest (≤500 m) to the MTF, and lowest (1.4 μg/dL in adults and 2.5 μg/dL in children) in those who lived furthest away (4-5 km). The study findings point to a need for greater emphasis on the precautionary principle in environmental health and for health impact assessments to inform decisions on planning, especially with regard to the location of human settlements relative to major, polluting development initiatives.

Metal Exposures in Residents Living Near an Urban Oil Drilling Site in Los Angeles, California

Urban environmental justice communities are potentially exposed to multiple toxic metals, through contaminated air, soil, water, and food. However, information on metals and their sources is lacking. This study uses non-negative matrix factorization (NMF) in a community-based participatory research study to identify potential sources and to understand how these metals cluster in a population near an urban oil drilling site. We recruited 203 Latinx, Black, and Asian residents who lived within 1 km of an oil drilling site in south Los Angeles and collected toenail clippings to assess exposure to arsenic (As), cadmium (Cd), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), and antimony (Sb). Using NMF, we identified three clusters based on concentrations in the participants' toenails. As, Cd, Pb, and Sb grouped together, indicative of an industrial source. A second grouping was composed of Ni and Mn, which may be related to oil drilling. We also identified a third source factor predominantly driven by Hg and As, which may arise from dietary sources. Utilizing NMF, a dimension reduction method, we identified a source factor high in Ni and Mn in residents living in a neighborhood near an active oil drilling site.

Impact of Environmental Risk Factors on Mitochondrial Dysfunction, Neuroinflammation, Protein Misfolding, and Oxidative Stress in the Etiopathogenesis of Parkinson's Disease

As a prevalent progressive neurodegenerative disorder, Parkinson's disease (PD) is characterized by the neuropathological hallmark of the loss of nigrostriatal dopaminergic (DAergic) innervation and the appearance of Lewy bodies with aggregated α-synuclein. Although several familial forms of PD have been reported to be associated with several gene variants, most cases in nature are sporadic, triggered by a complex interplay of genetic and environmental risk factors. Numerous epidemiological studies during the past two decades have shown positive associations between PD and several environmental factors, including exposure to neurotoxic pesticides/herbicides and heavy metals as well as traumatic brain injury. Other environmental factors that have been implicated as potential risk factors for PD include industrial chemicals, wood pulp mills, farming, well-water consumption, and rural residence. In this review, we summarize the environmental toxicology of PD with the focus on the elaboration of chemical toxicity and the underlying pathogenic mechanisms associated with exposure to several neurotoxic chemicals, specifically 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), rotenone, paraquat (PQ), dichloro-diphenyl-trichloroethane (DDT), dieldrin, manganese (Mn), and vanadium (V). Our overview of the current findings from cellular, animal, and human studies of PD provides information for possible intervention strategies aimed at halting the initiation and exacerbation of environmentally linked PD.

Remediation of Pb-contaminated soil using modified bauxite refinery residue

This study examines amendment of Pb-contaminated soil with modified bauxite refinery residue (MBRR) to decrease soil Pb mobility and bioaccessibility. Amendment experiments were conducted using four soils contaminated with Pb from various sources, including smelting, shooting-range activities and Pb-based paint waste. Lead L₃-edge X-ray absorption spectroscopy (XAS) indicated that Pb speciation in these soils was a mixture of Pb sorbed to Fe (hydr)oxide and clay minerals, along with Pb bound to organic matter. Amendment with MBRR decreased water-soluble Pb and/or Toxicity Characteristic Leachate Procedure (TCLP) Pb concentrations. Lead L₃-edge XAS and X-ray diffraction (XRD) indicated that Pb retention by MBRR occurred via sorption to Fe- and Al-(hydr)oxides at low Pb loadings, in addition to formation of hydrocerussite (Pb₃(CO₃)₂(OH)₂) at high loadings. Soil amendment with MBRR had relatively little effect on gastric-phase Pb bioaccessibility; as quantified via the Solubility/Bioavailability Research Consortium, SBRC, in vitro assay. In contrast, amendment with MBRR caused substantial decreases in relative intestinal-phase Pb bioaccessibility (Rel-SBRC-I) due to increased Pb sorption by MBRR's Fe- and Al-hydr(oxide) minerals as simulated GI tract conditions shifted from the gastric- to the intestinal-phase. These decreases in Rel-SBRC-I point to the potential efficacy of using amendment with MBRR to decrease soil Pb bioavailability.

Identification of Legacy and Active Sources of Metal Contamination in Soils in Brooklyn, NY

The purpose of this study was to examine the spatial distribution and potential anthropogenic sources of lead (Pb), zinc (Zn), copper (Cu), manganese (Mn), and iron (Fe) in surface soils throughout Brooklyn, NY. We collected soil samples (n = 1,373) from 176 different New York City parks. Samples were analyzed ex-situ using a portable X-ray fluorescence with a subset of samples laboratory confirmed. The effect of multiple sources on concentrations were determined by multivariable linear regression with generalized estimating equations. Median concentrations of Pb, Zn, Cu, Fe, and Mn were 108 ppm, 145 ppm, 49 ppm, 14,034 ppm, and 279 ppm, respectively. All metals were significantly correlated with one another (p < 0.001), with the strength of the correlation ranging from a low of approximately ρ = 0.3 (Pb-Mn and Zn-Mn) to a high of ρ = 0.7 (Pb-Cu). In final multivariate modeling significant association were observed between scrap yards and Mn concentration (β = 0.075, 0.019), National Priorities List (NPL) sites and Pb, Fe and Mn (β = 0.134, p = 0.004; β = 0.038, p = 0.014; β = 0.057, p = 0.037, respectively), and bridges nearby and Pb and Zn (β = 0.106, p = 0.003; β = 0.076, p = 0.026, respectively). Although manufacturing and industry have mostly left the area, smaller scrap metal recyclers are abundant and associated with increased Cu and Mn soil concentrations. In addition, NPL sites contributed to increased concentrations of all five metals within 800 m. Roadways have long been established to be sources of urban pollution; however, in our study we also found the presence of bridges within 800 m were also strongly predictive of increased Pb, Cu, and Zn concentrations.

Human health risks associated with consumption of fish contaminated with trace elements from intensive mining activities in a peri-urban region

Worldwide, numerous rural communities and low-income groups depend on fish harvested by subsistence fishers from local rivers and its impoundments as a source of protein. The aim of the present study was to determine the trace element bioaccumulation (As, Cd, Cr, Cu, Ni, Pb, Pt, Zn) in three edible fish species (Cyprinus carpio, Clarias gariepinus, Oreochromis mossambicus) from two impoundments in the Hex River system, South Africa, as well as the chronic health risk these trace elements pose to regular fish consumers. Trace element concentrations in the Hex River are naturally high (geogenic source), however, increased anthropogenic activities, such as intensive platinum mining activities, elevate the already high background concentrations. Concentrations of As, Cr, and Pt in C. carpio and C. gariepinus, as well as Ni and Zn in O. mossambicus were significantly higher in the impacted impoundment as compared to the reference impoundment. Concentrations of Cr and Cu were at both sampling sites the highest in O. mossambicus. From the human health risk assessment, As poses non-carcinogenic (HQ = 2-7) and carcinogenic risks (33-93 out of 10,000 people), while Cr (3-10 out of 10,000 people) and Ni (2-6 out of 10,000 people) pose only carcinogenic risks for the regular consumption of all three fish species from both impoundments, indicating a high probability of adverse human health effects. For As, Cr and Ni, also the sediment concentrations exceeded the levels of concern within the consensus based sediment quality guideline (CBSQG), while Cd, Cu, Ni and Zn exceeded the water quality guideline values. Thus, the CBSQG approach could be a promising tool for predicting human health risk associated with fish consumption. Since the present study only focused on the individual trace element risks, mixed toxicity of these trace elements and possible other pollutants within these fish species may pose an even greater risk to people who consume these fish regularly.

Metals dust in workers' homes and potential for take home in the Greater Boston area: Pilot study

Toxic metals such as lead, cadmium, arsenic, are present at construction worksites. From work, metals can easily, unintentionally be transported to homes of workers, contaminating living spaces and affecting others including children, known as "take-home exposure." Focus has been given to minimizing lead take-home exposure but less is known about other metals. This pilot study aims to better understand the sources and predictors of metals in the home primarily of construction workers (n = 21), but also explore other workers potentially exposed [janitorial (n = 4) and auto repair (n = 2) jobs]. Greater Boston workers were recruited in 2018-2019 through collaboration with community-based organizations and worker unions serving low-income/immigrant workers. During a home visit, a dust vacuum sample was collected, a worker questionnaire was administered, and home observations were performed to determine factors that could affect home metals concentration. Thirty elements were analyzed in the dust via inductively coupled plasma coupled to atomic emission and mass spectrometry. We performed univariable and multivariable models, potential predictive factors, and multivariable mixed-effect regression analyses combining metals. Arsenic, chromium, copper, lead, manganese, nickel, and tin, commonly found in construction, were higher in construction workers' home dust compared to other workers, although not statistically significant. Sociodemographic/work/home-related variables affected home metals dust concentrations. Various work-related factors were associated with higher metal dust levels, for example: no work locker vs. locker (nickel ratio of means or ROM = 4.2, p < 0.05); mixing vs. no mixing work/personal items (nickel ROM = 1.6, p < 0.05); dusty vs. no dusty at work (copper ROM = 3.1, p < 0.05); not washing vs. washing hands after work (manganese ROM = 1.4, p < 0.05); not changing vs. changing clothes after work (cadmium ROM = 6.9, p < 0.05; copper ROM = 3.6, p < 0.05). Mixed effect regression confirmed statistical significance, which suggests a likelihood of metal mixtures carrying a "take-home" potential. Lead home interventions should evaluate other metals exposure reduction.

International Analysis of Sources and Human Health Risk Associated with Trace Metal Contaminants in Residential Indoor Dust

People spend increasing amounts of time at home, yet the indoor home environment remains understudied in terms of potential exposure to toxic trace metals. We evaluated trace metal (and metalloid) concentrations (As, Cu, Cr, Mn, Ni, Pb, and Zn) and health risks in indoor dust from homes from 35 countries, along with a suite of potentially contributory residential characteristics. The objective was to determine trace metal source inputs and home environment conditions associated with increasing exposure risk across a range of international communities. For all countries, enrichments compared to global crustal values were Zn > Pb > Cu > As > Cr > Ni; with the greatest health risk from Cr, followed by As > Pb > Mn > Cu > Ni > Zn. Three main indoor dust sources were identified, with a Pb-Zn-As factor related to legacy Pb sources, a Zn-Cu factor reflecting building materials, and a Mn factor indicative of natural soil sources. Increasing home age was associated with greater Pb and As concentrations (5.0 and 0.48 mg/kg per year of home age, respectively), as were peeling paint and garden access. Therefore, these factors form important considerations for the development of evidence-based management strategies to reduce potential risks posed by indoor house dust. Recent findings indicate neurocognitive effects from low concentrations of metal exposures; hence, an understanding of the home exposome is vital.

Spatial distribution and composition of mine dispersed trace metals in residential soil and house dust: Implications for exposure assessment and human health

Trace metal exposure from environmental sources remains a persistent global problem, particularly in communities residing adjacent to metal extraction and processing industries. This study examines front yard soil and house dust from 62 residences throughout the Australian Ag-Pb-Zn mining city of Broken Hill to better understand spatial variability in metal distributions, compositions and exposures across an industrially polluted urban environment. X-ray fluorescence analysis of paired soil/dust samples indicated that geomean concentrations (mg/kg) of Cu (32/113), Zn (996/1852), As (24/34) and Pb (408/587) were higher in house dust while Ti (4239/3660) and Mn (1895/1101) were higher in outdoor soil. Ore associated metals and metalloids (Mn, Zn, As, Pb) in soil and house dust were positively correlated and declined in concentration away from mining areas, the primary source of metalliferous emissions in Broken Hill. The rate of decline was not equivalent between soil and house dust, with the indoor/outdoor concentration ratio increasing with distance from mining areas for Zn/Pb (geomean = 1.25/1.05 (<1 km); 2.14/1.52 (1-2 km); 2.54/2.04 (>2 km)). House dust and Broken Hill ore Pb isotopic compositions (²⁰⁶Pb/²⁰⁷Pb; ²⁰⁸Pb/²⁰⁷Pb) were more similar in homes nearest to mining areas than those further away (geomean apportioned ore Pb = 88% (<1 km); 76% (1-2 km); 66% (>2 km)), reflecting spatial shifts in the balance of sources contributing to indoor contamination. Incorporation of house dust Pb reduced overestimation of IEUBK modelled blood Pb concentrations compared to when only soil Pb was used. These findings demonstrate that even in contexts where the source and environmental burden of metals are relatively apparent, geochemical relationships and exposures between outdoor and indoor environments are not always predictable, nor easily disaggregated.

Sources and composition of metals in indoor house dust in a mid-size Canadian city

House dust is an important medium for exposure to persistent pollutants, such as metals. Detailed characterization of metal composition is needed to identify sources and potential health impacts of exposure. In this study we show that specific metals in dust dominate in different locations within residential homes in a mid-size Canadian city (Fort McMurray, Alberta), up to two years after a major wildfire event in 2016. Dust samples were collected in high-traffic (e.g. bedroom, N = 186), low-traffic (e.g. basement, N = 158), and entranceway areas (N = 171) of residential homes (N = 125), and analyzed for 25 trace metal elements using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The profile of metal concentrations in the entranceway resembled that of outdoor soils, especially for crustal elements. On the other hand, Cu, Zn, and Pb concentrations in dust sampled in indoor living areas were on average three to six times higher than in other indoor locations indicating indoor sources for these elements. In general, Pb concentrations were similar or lower than in an average Canadian residence, but a substantial fraction showed anomalously high concentrations in the low-traffic areas, particularly on concrete surfaces in basements. Notably, the 2016 wildfires showed limited influence on metal concentrations in indoor dust, despite the widespread concerns in the community about long term exposure. Enrichment factor ratio calculations and principal component analysis showed two classes of sources of metals in dust that represent geogenic-outdoor sources and anthropogenic-indoor sources. Overall, we demonstrate that outdoor and indoor sources of dust impact its composition, and these influences are reflected in the different areas of a home.

Assessing Children's Lead Exposure in an Active Mining Community Using the Integrated Exposure Uptake Biokinetic Model

Lead exposure has been shown to be harmful to humans in various settings and there are no safe levels of blood lead in children. At an Alternative Superfund site in Hayden-Winkelman, Arizona, with an active copper smelter and concentrator, lead exceedances in air and soil have been measured in the past 20 years. In this work, the U.S. Environmental Protection Agency's Integrated Exposure Uptake Biokinetic (IEUBK) model was used to estimate Hayden-Winkelman children's (age 6 months-7 years) blood lead levels (BLLs) using site-specific lead concentrations measured in indoor and outdoor air, soil, indoor dust, and drinking water. Values used by a state agency's airborne lead risk forecast program were also evaluated to determine whether their forecasting program is useful in protecting children's public health. Using site-specific values in the model, the results demonstrated that lead ingested via indoor dust was the major contributor to children's BLLs. In addition, the output of the IEUBK model overestimated actual BLLs of children sampled in the community. The IEUBK model was particularly sensitive to high indoor dust levels, and these site-specific measures increased modeled BLL values. This finding is of significance as the IEUBK model is used worldwide in communities with industrial contamination. This study confirmed that the chief contributor to lead exposure in children is household dust. Thus, for lead exposure risk reduction, agencies working at Superfund sites should focus efforts on decontaminating outdoor soil and dust and indoor lead decontamination.

Physicochemical Properties of Indoor and Outdoor Particulate Matter 2.5 in Selected Residential Areas near a Ferromanganese Smelter

Particulate matter (PM) of different sizes and elemental composition is a leading contributor to indoor and outdoor air pollution in residential areas. We sought to investigate similarities between indoor and outdoor PM_2.5 in three residential areas near a ferromanganese smelter in Meyerton to apportion the emission source(s). Indoor and outdoor PM_2.5 samples were collected concurrently, using GilAir300 plus samplers, at a flow rate of 2.75 L/min. PM_2.5 was collected on polycarbonate membrane filters housed in 37 mm cassettes coupled with PM_2.5 cyclones. Scanning electron microscopy coupled with energy-dispersive spectroscopy was used to study the morphology, and inductively coupled plasma-mass spectroscopy was used to analyse the elemental composition of the PM_2.5. Mean indoor and outdoor PM_2.5 mass concentrations were 10.99 and 24.95 µg/m³, respectively. Mean outdoor mass concentration was 2.27-fold higher than the indoor concentration. Indoor samples consisted of irregular and agglomerated particles, ranging from 0.09 to 1.06 µm, whereas outdoor samples consisted of irregular and spherical particles, ranging from 0.10 to 0.70 µm. Indoor and outdoor PM_2.5 were dominated by manganese, silicon, and iron, however, outdoor PM_2.5 had the highest concentration of all elements. The ferromanganese smelter was identified as the potential main contributing source of PM_2.5 of different physicochemical properties.

Understanding Potential Heavy Metal Contamination, Absorption, Translocation and Accumulation in Rice and Human Health Risks

Rice is a worldwide staple food and heavy metal contamination is often reported in rice production. Heavy metal can originate from natural sources or be present through anthropogenic contamination. Therefore, this review summarizes the current status of heavy metal contamination in paddy soil and plants, highlighting the mechanism of uptake, bioaccumulation, and health risk assessment. A scoping search employing Google Scholar, Science Direct, Research Gate, Scopus, and Wiley Online was carried out to build up the review using the following keywords: heavy metals, absorption, translocation, accumulation, uptake, biotransformation, rice, and human risk with no restrictions being placed on the year of study. Cadmium (Cd), arsenic (As), and lead (Pb) have been identified as the most prevalent metals in rice cultivation. Mining and irrigation activities are primary sources, but chemical fertilizer and pesticide usage also contribute to heavy metal contamination of paddy soil worldwide. Further to their adverse effect on the paddy ecosystem by reducing the soil fertility and grain yield, heavy metal contamination represents a risk to human health. An in-depth discussion is further offered on health risk assessments by quantitative measurement to identify potential risk towards heavy metal exposure via rice consumption, which consisted of in vitro digestion models through a vital ingestion portion of rice.

Health risk assessment of heavy metals exposure via consumption of crops grown in phosphogypsum-contaminated soils

The management of phosphogypsum (PG) heap, located south of the Sfax city in Tunisia, has been going on for decades. But dumping this solid waste still poses environmental problems. Even though valorized as amendment to agriculture soils, the sanitary impact of this practice is not seriously considered. To assess the risk of the transference of contaminants from PG to agricultural soil-plants food chain, a wild plant species Salicornia arabica grown in PG-contaminated field and tomato (Lycopersicon esculentum) and oat (Avena sativa) grown in laboratory using different rates (10, 20 and 30%) of PG amendment, were tested. The cadmium, lead, chromium, nickel, copper and zinc concentrations in soils and plants were determined by atomic absorption spectrometry and by inductively coupled plasma-mass spectrometry, respectively. Measurements showed that Ni, Cu and Pb levels in the amended soils were below international standards except for Cd and Cr which exceeded Chinese, FAO/WHO and European allowable standard limits. Gathered results showed that the more the PG rate increases, the more the bioconcentration factors of heavy metals increased in plants, particularly in the roots. This is a prospective study assuming direct or indirect exposure scenario of different human cohorts by consuming varied common food stuffs. The Human Exposure to Soil Pollutants evaluation and United State Environment Protection Agency models were adopted for the hazard quotient calculation to assess the acceptability of sanitary risk related to each metal. The direct and indirect health risk assessments varied in the decreasing order: children, adolescents and then adults. Therefore, the PG amendment must not exceed the rate of 10%.

The presence of Superfund sites as a determinant of life expectancy in the United States

Superfund sites could affect life expectancy (LE) via increasing the likelihood of exposure to toxic chemicals. Here, we assess to what extent such presence could alter the LE independently and in the context of sociodemographic determinants. A nationwide geocoded statistical modeling at the census tract level was undertaken to estimate the magnitude of impact. Results showed a significant difference in LE among census tracts with at least one Superfund site and their neighboring tracts with no sites. The presence of a Superfund site could cause a decrease of -0.186 ± 0.027 years in LE. This adverse effect could be as high as -1.22 years in tracts with Superfund sites and high sociodemographic disadvantage. Specific characteristics of Superfund sites such as being prone to flooding and the absence of a cleanup strategy could amplify the adverse effect. Furthermore, the presence of Superfund sites amplifies the negative influence of sociodemographic factors at lower LEs.

Factors affecting lead dust in construction workers' homes in the Greater Boston Area

Lead is a known reproductive, developmental, and neurological toxicant. Workers with a high likelihood of being exposed to lead at work may inadvertently transport lead home from work, known as "take-home exposure." This is concerning for many workers for whom a workplace intervention is not feasible because their worksites and employers often change, rendering centralized strategies insufficient. This study aimed to better understand the connection between lead in the home of workers living with children and work in construction (n = 23), while other occupations were used as a comparison group (janitorial n = 5, autobody n = 2). Thirty workers living in disadvantaged communities in the Greater Boston area were recruited in 2018-2019 through collaboration with non-profits and worker unions with expertise working with low-income or immigrant workers. Construction workers that performed renovations, bridge constructions, welding, metal work, and demolitions were prioritized during recruitment. During a visit to their residences, a worker questionnaire was administered, and observations and a dust vacuumed sample of the home were collected. Factors predicting lead in home dust were explored by a bivariate analysis and a multivariable regression model. We found lead in homes' dust in the range of 20-8,310 ppm. Homes of construction workers generally had higher and more variable lead dust concentrations (mean 775, max 8,300 ppm) than autobody and janitor worker homes combined (mean 296, max 579 ppm). Five of the construction workers' home lead dust concentrations exceeded US guidelines for yard soil in children's play areas of 400 ppm, and were similar to other studies of homes near lead smelters, superfund sites, or in the Boston area in the early 1990s, pointing to disparities relating to work. Results from the multivariable regression model suggest that lead dust in homes of workers was associated with sociodemographic-, home-, and work-related factors, and pointed to overlapping vulnerabilities; however, a larger sample size is needed to verify findings. Results provide evidence that work-related factors are important to consider when assessing home exposures, and that take-home exposures for workers in lead high-risk jobs such as construction may be an important source of exposure in the home prime for public health intervention at work, home, and community levels.

Bioavailable soil Pb minimized by in situ transformation to plumbojarosite

Exposure to lead (Pb) during early life has persistent adverse health effects. During childhood, ingestion of bioavailable Pb in contaminated soils can be a major route of Pb absorption. Remediation to alter physiochemical properties of soil-borne Pb can reduce Pb bioavailability. Our laboratory-based approach for soil Pb remediation uses addition of iron (Fe) sulfate and application of heat to promote formation of plumbojarosite (PLJ), a sparingly soluble Pb-Fe hydroxysulfate mineral. We treated two soils with anthropogenic Pb contamination and samples of clean topsoil spiked with various Pb compounds (i.e., carbonate, chloride, phosphate [P], or sulfate) to convert native Pb species to PLJ and used a mouse assay to assess relative bioavailability (RBA) of Pb in untreated (U) and remediated soils. Bone and blood Pb levels were significantly lower (P < 0.001, Student's t test) in mice that consumed diets amended with remediated soils than with U soils. Estimated RBA for Pb in both remediated natural soils and Pb-mineral spiked soils were reduced by >90% relative to Pb RBA for U soils, which is substantially more effective than other soil amendments, including P. X-ray absorption spectroscopy showed that >90% of all Pb species in remediated soils were converted to PLJ, and ingested PLJ was not chemically transformed during gastrointestinal tract transit. Post treatment neutralization of soil pH did not affect PLJ stability, indicating the feasibility in field conditions. These results suggest that formation of PLJ in contaminated soils can reduce the RBA of Pb and minimize this medium's role as a source of Pb exposure for young children.

Effects of Toxic Metal Contamination in the Tri-State Mining District on the Ecological Community and Human Health: A Systematic Review

Although extensive research exists on toxic environments in the Tri-State Mining District (TSMD), there has been a lack of research on how harmful effects in TSMD could affect residents living in those areas. However, quite recently, such research regarding relationships between the health conditions of residents and toxic elements in the TSMD began to grow. The increase of empirical studies means greater complexity of the findings that require a more intricate understanding. To meet the goals of this study, an extensive, systematic review of the literature using PRISMA was conducted. This method resulted in 19 articles that define the harmful effects of the TSMD on the ecology and the physical health of residents. This research found that toxic metals not only negatively impact natural processes in the TSMD environments (fish species reduction, kidney and liver problems, and toxic diet) but also continuously affect the health of residents (high blood Pb and mortality).This study makes a vital contribution building upon the existing outcomes of the correlations between toxic elements in the TSMD areas and the health of residents. Furthermore, conclusions of this study provide updated information to policymakers and health-related professionals by providing adequate and innovative remediations and health-related services in the TSMD.

Opportunities for evaluating chemical exposures and child health in the United States: the Environmental influences on Child Health Outcomes (ECHO) Program

The Environmental Influences on Child Health Outcomes (ECHO) Program will evaluate environmental factors affecting children's health (perinatal, neurodevelopmental, obesity, respiratory, and positive health outcomes) by pooling cohorts composed of >50,000 children in the largest US study of its kind. Our objective was to identify opportunities for studying chemicals and child health using existing or future ECHO chemical exposure data. We described chemical-related information collected by ECHO cohorts and reviewed ECHO-relevant literature on exposure routes, sources, and environmental and human monitoring. Fifty-six ECHO cohorts have existing or planned chemical biomonitoring data for mothers or children. Environmental phenols/parabens, phthalates, metals/metalloids, and tobacco biomarkers are each being measured by ≥15 cohorts, predominantly during pregnancy and childhood, indicating ample opportunities to study child health outcomes. Cohorts are collecting questionnaire data on multiple exposure sources and conducting environmental monitoring including air, dust, and water sample collection that could be used for exposure assessment studies. To supplement existing chemical data, we recommend biomonitoring of emerging chemicals, nontargeted analysis to identify novel chemicals, and expanded measurement of chemicals in alternative biological matrices and dust samples. ECHO's rich data and samples represent an unprecedented opportunity to accelerate environmental chemical research to improve the health of US children.

Human exposure and risk associated with trace element concentrations in indoor dust from Australian homes

This study examines residential indoor dust from 224 homes in Sydney, Australia for trace element concentrations measured using portable X-ray Fluorescence (pXRF) and their potential risk of harm. Samples were collected as part of a citizen science program involving public participation via collection and submission of vacuum dust samples for analysis of their As, Cr, Cu, Mn, Ni, Pb and Zn concentrations. The upper 95% confidence level of the mean values for 224 samples (sieved to <250 μm) were 20.2 mg/kg As, 99.8 mg/kg Cr, 298 mg/kg Cu, 247 mg/kg Mn, 56.7 mg/kg Ni, 364 mg/kg Pb and 2437 mg/kg Zn. The spatial patterns and variations of the metals indicate high homogeneity across Sydney, but with noticeably higher Pb values in the older areas of the city. Potential hazard levels were assessed using United States Environmental Protection Agency's (US EPA) carcinogenic, non-carcinogenic and Integrated Exposure Uptake Biokinetic (IEUBK) model human health risk assessment tools for children and adults. US EPA hazard indexes (HI) for Cr and Pb were higher than the safe level of 1.0 for children. HI > 1 suggests potential non-carcinogenic health effects. Carcinogenic risks were estimated for As, Cr and Pb whose carcinogenic slope factors (CSF) were available. Only the risk factor for Cr exceeded the US EPA's carcinogenic threshold (1 × 10^-4) for children. Children aged 1-2 years had the highest predicted mean child blood lead (PbB) of 4.6 μg/dL, with 19.2% potentially having PbB exceeding 5 μg/dL and 5.80% exceeding 10 μg/dL. The Cr and Pb levels measured in indoor dust therefore pose potentially significant adverse health risks to children.

Heavy metal phytoavailability in a contaminated soil of northeastern Oklahoma as affected by biochar amendment

High concentrations of heavy metals (HM) in soils have negative impacts on plants, human health, and the environmental quality. The purpose of this study was to evaluate the effects of biochars on the bioaccessibility of Zn, Pb, and Cd in a contaminated soil in the Tar Creek area of NE Oklahoma, as well as on the growth and uptake of these elements by perennial ryegrass (Lolium perenne). Biochars were produced from switchgrass (SGB) and poultry litter (PLB) feedstocks at 700 °C and applied to the soil at 0.0, 0.5, 1.0, 2.0, and 4.0% (w/w), with three replications. Regardless of the feedstock, both soil organic carbon (SOC or OC) and pH increased as the rates of biochars increased, which significantly decreased the HM bioaccessibility (p < 0.01). The Zn and Cd extracted by DTPA were highly correlated (p < 0.0001) with their concentration in ryegrass shoots and roots. Except for some significant positive correlations (p < 0.05), HM concentrations in ryegrass shoots and roots were not correlated with their biomass (p > 0.05). Both bioconcentration factor (BCF) and transfer factor decreased as the rates of biochars applied increased, especially for Pb and Cd (p < 0.01). Our results suggest it is beneficial to use biochars at Tar Creek as a soil amendment to reduce HM bioaccessibility and metal uptake by ryegrass.

Heavy Metals Can either Aid or Oppose the Protective Function of the Placental Barrier

BACKGROUND:

In developing countries, toxic heavy metals are a threatening catastrophe to human health, particularly in the vulnerable group of pregnant mothers and their fetuses. Fortunately, the placenta can be a protective barrier to the fetuses.

AIM:

To explore the relationship between serum lead, cadmium and arsenic levels in pregnant mothers and their newborns, to address the placental barrier in this situation.

METHODS:

A cross-sectional study was conducted on 100 pregnant mothers at the time of labour and their newborns. Serum cadmium, lead, and arsenic levels were measured using the Inductively Coupled Plasma Mass Spectrometry.

RESULTS:

All the studied heavy metals concentrations showed a significant elevation in the maternal blood relative to the cord blood. There was a significant association between the maternal lead and both fetal lead and arsenic. Meanwhile, a negative but insignificant correlation was recorded between the maternal cadmium and each of the fetal cadmium, lead, and arsenic.

CONCLUSION:

The study findings indicated a weak relation between maternal and fetal blood heavy metals, except for the influence of maternal lead, so it can be assumed that the placental barriers are partially protective against those toxic pollutants, putting into consideration the influence of their different natures.

Contamination assessment, source apportionment and health risk assessment of heavy metals in paddy soils of Jiulong River Basin, Southeast China

To trace the sources and evaluate the health risks of heavy metals in paddy soils of Jiulong River Basin, seventy-one samples of paddy soils were collected in July 2017. The heavy metals contents were determined using inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrophotometry (AFS). The geo-accumulation index (I_geo) and potential ecological risk index (RI) methods were applied to evaluate the contamination of heavy metals, principal component analysis (PCA) and absolute principal component scores-multiple linear regression (APCS-MLR) were applied to trace the sources, and dose–response model was applied to assess the health risks to the human body. The results indicated that the paddy soils were moderately to heavily polluted by Cd and slightly polluted by Hg, Pb, As and Zn. Heavy metals in paddy soils presented considerable to high potential ecological risk, mostly contributed by Cd and Hg with contribution rates of 59.4% and 26.2%, respectively. The heavy metals contaminating paddy soils were derived from natural sources, agricultural activities, industrial discharge, coal combustion and unidentified sources, with source contribution rates of 31.37%, 24.87%, 19.65%, 18.05% and 6.06%, respectively. The heavy metals in paddy soils presented carcinogenic risks which humans can tolerate and no non-carcinogenic risks. The total non-carcinogenic risks mainly derived from agricultural activities and coal combustion, with contribution rates of 62.16% and 20.21%, respectively, while the total carcinogenic risks mainly derived from natural sources and industrial discharge, with contribution rates of 51.17% and 18.98%, respectively.

APCS-MLR and dose–response model were combined to identify the sources and human health risks of heavy metals in paddy soils.

Contamination levels and health risk assessments of heavy metals in an oasis-desert zone: a case study in northwest China

Rapid and extensive social and economic development has caused severe soil contamination by heavy metals in China. The spatial distribution, pollution levels, and health risks of metals were identified in an oasis-desert zone of northwest China. The mean concentrations of six heavy metals exceeded their corresponding background contents, and each metal concentration in farmland samples was higher than that in Gobi samples. Moreover, these heavy metals followed a similar spatial pattern and showed significant positive correlations with each other, indicating that they have the same sources. The contamination features of heavy metals and ecological risks were calculated using several quality indicators, and their health risks for population groups were quantified. The results showed that the Gobi and farmland soils were uncontaminated to moderately contaminated by heavy metals, and that farmland pollution was more serious than that of Gobi. The Gobi and farmland soils posed low ecological risks. As a whole, the non-carcinogenic risk which was caused by heavy metals was low for local residents, and the carcinogenic risk was within an acceptable level. Comparatively speaking, children were the more vulnerable population to health risks. The Zn and Cu pollution was relatively serious, and Cr and V were major contributors to health risks. Graphical abstract ᅟ.

Maternal and Cord Blood Manganese Concentrations and Early Childhood Neurodevelopment among Residents near a Mining-Impacted Superfund Site

BACKGROUND

Environmental manganese exposure has been associated with adverse neurodevelopmental outcomes among school-aged children; yet, few studies have evaluated prenatal exposure.

OBJECTIVES

Our study examines associations between prenatal manganese concentrations and placental transfer of manganese with neurodevelopment in 224 2-y-old children residing near the Tar Creek Superfund Site.

METHODS

We collected maternal and cord blood at delivery, measured manganese using inductively coupled plasma mass spectrometry, and assessed neurodevelopment using the Bayley Scales of Infant Development-II. Associations between manganese and mental (MDI) and psychomotor (PDI) development indices were estimated in multivariable models. Placental transfer, approximated by cord/maternal manganese ratio, cord/total manganese ratio (total=maternal+cord), and by joint classification according to high or low (above or below median) maternal and cord manganese, was evaluated as a predictor of neurodevelopment.

RESULTS

Median levels [interquartile ranges (IQR)] of manganese in maternal and cord blood, respectively, were 24.0 (19.5-29.7) and 43.1 (33.5-52.1) μg/L. Adjusting for lead, arsenic, and other potential confounders, an IQR increase in maternal manganese was associated with -3.0 (95% CI: -5.3, -0.7) points on MDI and -2.3 (95% CI: -4.1, -0.4) points on PDI. Cord manganese concentrations were not associated with neurodevelopment scores. Cord/maternal and cord/total manganese ratios were positively associated with MDI [cord/maternal: β=2.6 (95% Cl: −0.04, 5.3); cord/total: β=22.0 (95% Cl: 3.2, 40.7)] and PDI (cord/maternal: β=1.7 (95% Cl: −0.5, 3.9); cord/total: β=15.6 (95% Cl: 0.3, 20.9)). Compared to mother-child pairs with low maternal and cord manganese, associations with neurodevelopment scores were negative for pairs with either high maternal, high cord, or high maternal and cord manganese.

CONCLUSIONS

Maternal blood manganese concentrations were negatively associated with early childhood neurodevelopment scores in our study. Findings highlight the importance of understanding maternal exposures during pregnancy and factors influencing placental transfer. https://doi.org/10.1289/EHP925.

Geochemical investigation of potentially harmful elements in household dust from a mercury-contaminated site, the town of Idrija (Slovenia)

A comprehensive geochemical investigation of potentially harmful elements (PHEs) in household dust from the town of Idrija (Slovenia), once a world-famous Hg mining town that is now seriously polluted, was performed for the first time. After aqua regia digestion, the content of mercury (Hg), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), molybdenum (Mo), nickel (Ni), lead (Pb) and zinc (Zn) was measured. PHE-bearing particles were recognised and observed by scanning electron microscopy and energy-dispersive spectrometry before and after exposure to simulated stomach acid (SSA). Mercury binding forms were identified by Hg thermal desorption technique and gastric bioaccessible Hg was estimated after SSA extraction by ICP-MS. With regard to rural and urban background values for Slovenia, high Hg content (6-120 mg/kg) and slightly elevated As content (1-13 mg/kg) were found. Mercury pollution is a result of past mining and ore processing activities. Arsenic content is potentially associated with As enrichment in local soils. Four Hg binding forms were identified: all samples contained Hg bound to the dust matrix, 14 samples contained cinnabar, two samples contained metallic Hg (Hg⁰), and one sample assumingly contained mercury oxide. After exposure to SSA, Hg-bearing phases showed no signs of dissolution, while other PHE-bearing phases were significantly morphologically and/or chemically altered. Estimated gastric Hg bioaccessibility was low (<0.006-0.09 %), which is in accordance with identified Hg binding forms and high organic carbon content (15.9-31.5 %) in the dust samples.

Physiochemical characteristics of aerosol particles in the typical microenvironment of hospital in Shanghai, China

Health risk of populations dwelling in the hospital has been a global concern, but has not been adequately examined. PM_2.5 and PM₁ samples were collected in two indoor locations (outpatient department and inpatient department) and one outdoor location (courtyard) of the hospital in Shanghai. The concentrations of size-fractionated trace metals and the morphology of single particles were determined to accurately assess the health risk for populations in the hospital. The results indicated that the mean concentrations of PM_2.5 and PM₁ were in the order of outpatient department>courtyard>inpatient department. The mean concentrations of PM₁ decreased with floors (first floor: 78.0μg/m³, second floor: 64.1μg/m³, fourth floor: 48.4μg/m³). However, the mean PM_2.5 concentrations were in the order of first floor (124.0μg/m³)>fourth floor (91.4μg/m³)>second floor (90.6μg/m³), which was likely associated with the number of patients. The PM_2.5 and PM₁ concentrations have begun to increase rapidly from 9:00am and decreased after 15:00pm in the first floor, whereas they remain relatively stable in the second and fourth floor. The abundance of Mg, Ca, Al and K in the fine particles and coarse particles were both higher than other elements for all floors. The concentrations of trace metals (e.g., Zn, Ba, Fe, Mn, Cr, Ca, Ti, Na, and K) except Mg and Al in the coarse particles (>2.5μm) decreased with floors, whereas Zn, Ba, Fe, and Cr in the fine particles (<2.5μm) displayed opposite variation. Trace metals in the first floor were mainly concentrated in the >2.5μm and 1-2.5μm, whereas they chiefly peaked at 0.25-0.5μm and below 0.25μm in the second and fourth floor. Single particles analysis showed that mineral particles, soot, and Fe-rich particles were mainly concentrated in the first floor, indicating the impacts of walking of patients, traffic emissions, and food cooking, respectively. Sulfate particles were internally mixed with soot, fly ash and Fe-rich particles in the second floor, which suggested that these sulfate particles probably underwent aging processes during the atmospheric long-range transport. In the fourth floor, fly ash, sulfate particles, Zn-rich particles, and biogenic particles were identified under the transmission electron microscopy (TEM). Higher abundance of sulfates and absence of chlorate hinted existence of heterogeneous reactions during long-range transport with the Cl^- replaced by SO₄^2-. The index of average daily intake (ADI), hazard quotient (HQ), and carcinogenic risks (CR) indicated that Cr pose carcinogenic risks to the surrounding populations, while non-carcinogenic risks of Mn, Zn, and Cr were not remarkable.

Pathways of inhalation exposure to manganese in children living near a ferromanganese refinery: A structural equation modeling approach

Manganese (Mn) is both essential element and neurotoxicant. Exposure to Mn can occur from various sources and routes. Structural equation modeling was used to examine routes of exposure to Mn among children residing near a ferromanganese refinery in Marietta, Ohio. An inhalation pathway model to ambient air Mn was hypothesized. Data for model evaluation were obtained from participants in the Communities Actively Researching Exposure Study (CARES). These data were collected in 2009 and included levels of Mn in residential soil and dust, levels of Mn in children's hair, information on the amount of time the child spent outside, heat and air conditioning in the home and level of parent education. Hair Mn concentration was the primary endogenous variable used to assess the theoretical inhalation exposure pathways. The model indicated that household dust Mn was a significant contributor to child hair Mn (0.37). Annual ambient air Mn concentration (0.26), time children spent outside (0.24) and soil Mn (0.24) significantly contributed to the amount of Mn in household dust. These results provide a potential framework for understanding the inhalation exposure pathway for children exposed to ambient air Mn who live in proximity to an industrial emission source.

Manganese and Developmental Neurotoxicity

Manganese (Mn) is an essential metal that plays a fundamental role for brain development and functioning. Environmental exposure to Mn may lead to accumulation in the basal ganglia and development of Parkinson-like disorders. The most recent research is focusing on early-life overexposure to Mn and the potential vulnerability of younger individuals to Mn toxicity also in regard to cognitive and executive functions through the involvement of the frontal cortex.Neurodevelopmental disturbances are increasing in the society, and understanding the potential role of environmental determinants is a key for prevention. Therefore, assessing the environmental sources of Mn exposure and the mechanisms of developmental neurotoxicity and defining appropriate biomarkers of exposure and early functional alterations represent key issues to improve and address preventive strategies. These themes will be reviewed in this chapter.

Consumer Product Chemicals in Indoor Dust: A Quantitative Meta-analysis of U.S. Studies

Indoor dust is a reservoir for commercial consumer product chemicals, including many compounds with known or suspected health effects. However, most dust exposure studies measure few chemicals in small samples. We systematically searched the U.S. indoor dust literature on phthalates, replacement flame retardants (RFRs), perfluoroalkyl substances (PFASs), synthetic fragrances, and environmental phenols and estimated pooled geometric means (GMs) and 95% confidence intervals for 45 chemicals measured in ≥3 data sets. In order to rank and contextualize these results, we used the pooled GMs to calculate residential intake from dust ingestion, inhalation, and dermal uptake from air, and then identified hazard traits from the Safer Consumer Products Candidate Chemical List. Our results indicate that U.S. indoor dust consistently contains chemicals from multiple classes. Phthalates occurred in the highest concentrations, followed by phenols, RFRs, fragrance, and PFASs. Several phthalates and RFRs had the highest residential intakes. We also found that many chemicals in dust share hazard traits such as reproductive and endocrine toxicity. We offer recommendations to maximize comparability of studies and advance indoor exposure science. This information is critical in shaping future exposure and health studies, especially related to cumulative exposures, and in providing evidence for intervention development and public policy.

Associations between metals in residential environmental media and exposure biomarkers over time in infants living near a mining-impacted site

Infant exposures to metals are a concern for mining-impacted communities, although limited information is available to assess residential exposures over the first year of life. We measured lead (Pb), manganese, arsenic, and cadmium in indoor air, house dust, yard soil, and tap water from 53 infants' homes near the Tar Creek Superfund Site (Oklahoma, USA) at two time points representing developmental stages before and during initial ambulation (age 0-6 and 6-12 months). We measured infant metal biomarkers in: umbilical cord blood (n=53); 12- (n=43) and 24- (n=22) month blood; and hair at age 12 months (n=39). We evaluated cross-sectional and longitudinal associations between infant residential and biomarker concentrations. A doubling of mean dust Pb concentration was consistently associated with 36-49% higher 12-month blood Pb adjusting for cord blood Pb (P⩽0.05). Adjusted dust concentration explained 29-35% of blood Pb variance, and consistent associations with other media were not observed. Although concentrations in dust and blood were generally low, strong and consistent associations between dust and body burden suggest that house dust in mining-impacted communities may impact children's health. These relationships were observed at a young age, typically before blood Pb levels peak and when children's development may be particularly vulnerable to toxic insult.

Associations between metals in residential environmental media and exposure biomarkers over time in infants living near a mining-impacted site

Infant exposures to metals are a concern for mining-impacted communities, although limited information is available to assess residential exposures over the first year of life. We measured lead (Pb), manganese, arsenic, and cadmium in indoor air, house dust, yard soil, and tap water from 53 infants' homes near the Tar Creek Superfund Site (Oklahoma, USA) at two time points representing developmental stages before and during initial ambulation (age 0-6 and 6-12 months). We measured infant metal biomarkers in: umbilical cord blood (n=53); 12- (n=43) and 24- (n=22) month blood; and hair at age 12 months (n=39). We evaluated cross-sectional and longitudinal associations between infant residential and biomarker concentrations. A doubling of mean dust Pb concentration was consistently associated with 36-49% higher 12-month blood Pb adjusting for cord blood Pb (P⩽0.05). Adjusted dust concentration explained 29-35% of blood Pb variance, and consistent associations with other media were not observed. Although concentrations in dust and blood were generally low, strong and consistent associations between dust and body burden suggest that house dust in mining-impacted communities may impact children's health. These relationships were observed at a young age, typically before blood Pb levels peak and when children's development may be particularly vulnerable to toxic insult.

Comparison of stationary and personal air sampling with an air dispersion model for children's ambient exposure to manganese

Manganese (Mn) is ubiquitous in the environment and essential for normal growth and development, yet excessive exposure can lead to impairments in neurological function. This study modeled ambient Mn concentrations as an alternative to stationary and personal air sampling to assess exposure for children enrolled in the Communities Actively Researching Exposure Study in Marietta, OH. Ambient air Mn concentration values were modeled using US Environmental Protection Agency's Air Dispersion Model AERMOD based on emissions from the ferromanganese refinery located in Marietta. Modeled Mn concentrations were compared with Mn concentrations from a nearby stationary air monitor. The Index of Agreement for modeled versus monitored data was 0.34 (48 h levels) and 0.79 (monthly levels). Fractional bias was 0.026 for 48 h levels and -0.019 for monthly levels. The ratio of modeled ambient air Mn to measured ambient air Mn at the annual time scale was 0.94. Modeled values were also time matched to personal air samples for 19 children. The modeled values explained a greater degree of variability in personal exposures compared with time-weighted distance from the emission source. Based on these results modeled Mn concentrations provided a suitable approach for assessing airborne Mn exposure in this cohort.

Prenatal Arsenic Exposure and Birth Outcomes among a Population Residing near a Mining-Related Superfund Site

BACKGROUND

Limited epidemiologic data exist on prenatal arsenic exposure and fetal growth, particularly in the context of co-exposure to other toxic metals.

OBJECTIVE

We examined whether prenatal arsenic exposure predicts birth outcomes among a rural U.S. population, while adjusting for exposure to lead and manganese.

METHODS

We collected maternal and umbilical cord blood samples at delivery from 622 mother-infant pairs residing near a mining-related Superfund site in Northeast Oklahoma. Whole blood arsenic, lead, and manganese were measured using inductively coupled plasma mass spectrometry. We modeled associations between arsenic concentrations and birth weight, gestational age, head circumference, and birth weight for gestational age.

RESULTS

Median (25th-75th percentile) maternal and umbilical cord blood metal concentrations, respectively, were as follows: arsenic, 1.4 (1.0-2.3) and 2.4 (1.8-3.3) μg/L; lead, 0.6 (0.4-0.9) and 0.4 (0.3-0.6) μg/dL; manganese, 22.7 (18.8-29.3) and 41.7 (32.2-50.4) μg/L. We estimated negative associations between maternal blood arsenic concentrations and birth outcomes. In multivariable regression models adjusted for lead and manganese, an interquartile range increase in maternal blood arsenic was associated with -77.5 g (95% CI: -127.8, -27.3) birth weight, -0.13 weeks (95% CI: -0.27, 0.01) gestation, -0.22 cm (95% CI: -0.42, -0.03) head circumference, and -0.14 (95% CI: -0.24, -0.04) birth weight for gestational age z-score units. Interactions between arsenic concentrations and lead or manganese were not statistically significant.

CONCLUSIONS

In a population with environmental exposure levels similar to the U.S. general population, maternal blood arsenic was negatively associated with fetal growth. Given the potential for relatively common fetal and early childhood arsenic exposures, our finding that prenatal arsenic can adversely affect birth outcomes is of considerable public health importance.

CITATION

Claus Henn B, Ettinger AS, Hopkins MR, Jim R, Amarasiriwardena C, Christiani DC, Coull BA, Bellinger DC, Wright RO. 2016. Prenatal arsenic exposure and birth outcomes among a population residing near a mining-related Superfund site. Environ Health Perspect 124:1308-1315; http://dx.doi.org/10.1289/ehp.1510070.

Risk of neuroblastoma and residential proximity to industrial and urban sites: A case-control study

BACKGROUND

Neuroblastoma is the most common extracranial solid tumor in children but its etiology is not clearly understood. While a small fraction of cases might be attributable to genetic factors, the role of environmental pollution factors needs to be assessed.

OBJECTIVES

To ascertain the effect of residential proximity to both industrial and urban areas on neuroblastoma risk, taking into account industrial groups and toxic substances released.

METHODS

We conducted a population-based case-control study of neuroblastoma in Spain, including 398 incident cases gathered from the Spanish Registry of Childhood Tumors (period 1996-2011), and 2388 controls individually matched by year of birth, sex, and region of residence. Distances were computed from the respective subject's residences to the 1271 industries and the 30 urban areas with ≥75,000 inhabitants located in the study area. Using logistic regression, odds ratios (ORs) and 95% confidence intervals (95%CIs) for categories of distance (from 1km to 5km) to industrial and urban pollution sources were calculated, with adjustment for matching variables and socioeconomic confounders.

RESULTS

Excess risk (OR; 95%CI) of neuroblastoma was detected for the intersection between industrial and urban areas: (2.52; 1.20-5.30) for industrial distance of 1km, and (1.99; 1.17-3.37) for industrial distance of 2km. By industrial groups, excess risks were observed near 'Production of metals' (OR=2.05; 95%CI=1.16-3.64 at 1.5km), 'Surface treatment of metals' (OR=1.89; 95%CI=1.10-3.28 at 1km), 'Mines' (OR=5.82; 95%CI=1.04-32.43 at 1.5km), 'Explosives/pyrotechnics' (OR=4.04; 95%CI=1.31-12.42 at 4km), and 'Urban waste-water treatment plants' (OR=2.14; 95%CI=1.08-4.27 at 1.5km).

CONCLUSIONS

These findings support the need for more detailed exposure assessment of certain substances released by these industries.

Reporting back environmental exposure data and free choice learning

Reporting data back to study participants is increasingly being integrated into exposure and biomonitoring studies. Informal science learning opportunities are valuable in environmental health literacy efforts and report back efforts are filling an important gap in these efforts. Using the University of Arizona's Metals Exposure Study in Homes, this commentary reflects on how community-engaged exposure assessment studies, partnered with data report back efforts are providing a new informal education setting and stimulating free-choice learning. Participants are capitalizing on participating in research and leveraging their research experience to meet personal and community environmental health literacy goals. Observations from report back activities conducted in a mining community support the idea that reporting back biomonitoring data reinforces free-choice learning and this activity can lead to improvements in environmental health literacy. By linking the field of informal science education to the environmental health literacy concepts, this commentary demonstrates how reporting data back to participants is tapping into what an individual is intrinsically motivated to learn and how these efforts are successfully responding to community-identified education and research needs.

The uptake and bioaccumulation of heavy metals by food plants, their effects on plants nutrients, and associated health risk: a review

Heavy metal contamination is a globally recognized environmental issue, threatening human life very seriously. Increasing population and high demand for food resulted in release of various contaminants into environment that finally contaminate the food chain. Edible plants are the major source of diet, and their contamination with toxic metals may result in catastrophic health hazards. Heavy metals affect the human health directly and/or indirectly; one of the indirect effects is the change in plant nutritional values. Previously, a number of review papers have been published on different aspects of heavy metal contamination. However, no related information is available about the effects of heavy metals on the nutritional status of food plants. This review paper is focused upon heavy metal sources, accumulation, transfer, health risk, and effects on protein, amino acids, carbohydrates, fats, and vitamins in plants. The literature about heavy metals in food plants shows that both leafy and nonleafy vegetables are good accumulators of heavy metals. In nonleafy vegetables, the bioaccumulation pattern was leaf > root ≈ stem > tuber. Heavy metals have strong influence on nutritional values; therefore, plants grown on metal-contaminated soil were nutrient deficient and consumption of such vegetables may lead to nutritional deficiency in the population particularly living in developing countries which are already facing the malnutrition problems.

P, Muckelbauer R, Casiot C, Freydier R, Duprey JL, Chen CM, Müller-Nordhorn J, Keil T. Toxic trace elements in maternal and cord blood and social determinants in a Bolivian mining city

This study assessed lead, arsenic, and antimony in maternal and cord blood, and associations between maternal concentrations and social determinants in the Bolivian mining city of Oruro using the baseline assessment of the ToxBol/Mine-Niño birth cohort. We recruited 467 pregnant women, collecting venous blood and sociodemographic information as well as placental cord blood at birth. Metallic/semimetallic trace elements were measured using inductively coupled plasma mass spectrometry. Lead medians in maternal and cord blood were significantly correlated (Spearman coefficient = 0.59; p < 0.001; 19.35 and 13.50 μg/L, respectively). Arsenic concentrations were above detection limit (3.30 μg/L) in 17.9% of maternal and 34.6% of cord blood samples. They were not associated (Fischer's p = 0.72). Antimony medians in maternal and cord blood were weakly correlated (Spearman coefficient = 0.15; p < 0.03; 9.00 and 8.62 μg/L, respectively). Higher concentrations of toxic elements in maternal blood were associated with maternal smoking, low educational level, and partner involved in mining.

Risk assessment of particle dispersion and trace element contamination from mine-waste dumps

In this study, a model to delimit risk zones influenced by atmospheric particle dispersion from mine-waste dumps is developed to assess their influence on the soil and the population according to the concentration of trace elements in the waste. The model is applied to the Riotinto Mine (in SW Spain), which has a long history of mining and heavy land contamination. The waste materials are separated into three clusters according to the mapping, mineralogy, and geochemical classification using cluster analysis. Two of the clusters are composed of slag, fresh pyrite, and roasted pyrite ashes, which may contain high concentrations of trace elements (e.g., >1 % As or >4 % Pb). The average pollution load index (PLI) calculated for As, Cd, Co, Cu, Pb, Tl, and Zn versus the baseline of the regional soil is 19. The other cluster is primarily composed of sterile rocks and ochreous tailings, and the average PLI is 3. The combination of particle dispersion calculated by a Gaussian model, the PLI, the surface area of each waste and the wind direction is used to develop a risk-assessment model with Geographic Information System GIS software. The zone of high risk can affect the agricultural soil and the population in the study area, particularly if mining activity is restarted in the near future. This model can be applied to spatial planning and environmental protection if the information is complemented with atmospheric particulate matter studies.

Impact of ferromanganese alloy plants on household dust manganese levels: implications for childhood exposure

Adolescents living in communities with ferromanganese alloy plant activity have been shown to exhibit deficits in olfactory and fine motor function. Household dust may serve as an important manganese (Mn) exposure pathway to children, though dust Mn concentrations have not previously been measured to assess household contamination from ferromanganese alloy plant emissions. Here we determined the association between dust concentrations and surface loadings of Mn and other metals (Al, Cd, Cr, Cu, Fe, Pb, and Zn) in indoor and outdoor household dust from three Italian communities that differ by history of ferromanganese alloy plant activity: Bagnolo Mella, with an active ferromanganese alloy plant (n=178 households); Valcamonica, with historically active plants (n=166); and Garda Lake, with no history of ferromanganese plant activity (n=99). We also evaluated Mn levels in other environmental (soil, airborne particulates) and candidate biomarker (blood, hair, saliva, fingernails) samples from children within the households. Household dust Mn concentrations and surface loadings were significantly different between the three sites, with levels highest in Bagnolo Mella (outdoor median Mn concentration=4620, range 487-183,000µg/g), intermediate in Valcamonica (median=876, range 407-8240µg/g), and lowest in Garda Lake (median=407, range 258-7240µg/g). Outdoor dust Mn concentrations in Bagnolo Mella, but not the other communities, were significantly inversely related with distance from the plant (R(2)=0.6630, P<0.0001). Moreover, outdoor dust Mn concentrations and loadings were highly predictive of but significantly higher than indoor dust Mn concentrations and loadings by ~2 to ~7-fold (Mn concentrations) and ~7 to ~20-fold (Mn loadings). Finally, both indoor and outdoor dust Mn concentrations and outdoor dust Mn loading values were highly significantly correlated with both soil and air Mn concentrations, and with children's hair and fingernail Mn concentrations, but weakly or not associated with saliva or blood Mn levels. Given the evidence associating elevated Mn exposure with neurological impairments in children, these data support that dust Mn levels should be reduced in contaminated environments to protect the health of resident children.

Source identification and health risk assessment of metals in indoor dust in the vicinity of phosphorus mining, Guizhou Province, China

An investigation was performed to identify the sources of arsenic (As) and heavy metals in house dust and to assess the associated human health risks in the vicinity of phosphorus (P) mining in Guizhou, China. The concentrations and spatial distributions of mercury (Hg), As, cadmium (Cd), lead (Pb), iron (Fe), copper (Cu), manganese (Mn), and P in 23 house dust samples from the study area were determined. Greater concentrations of As and Pb were found compared with values in other investigations in various countries. Pollution sources were identified using multivariate statistical analysis. As, Pb, Mn, and Hg pollution was mainly attributed to mining activities, and Mn and Cd levels were largely associated with automobile emissions. The dominant wind direction and the distance of the residence from the mining region were found to play an important role in element distributions. A health risk assessment showed that As and Pb should be paid more attention, although the noncancer risks of the studied elements were within the safe range and the cancer risks of As and Cd are within the acceptable range under present conditions.