Pb In Dust Research Articles

Toxic metal accumulation, health risk, and distribution in road dust from the urban traffic-intensive environment.

Owing to increasing levels of potentially toxic metals in road dust, air pollutants suspended in the air, pose significant health risks due to rapid, unplanned urbanization and industrialization. This study investigated the pollution status and health risks of trace metals (i.e., Cr, Cd, Ni, Cu, and Pb) in road dust collected from 16 locations across six land-use categories in Eskişehir, Türkiye, including residential, roadside, traffic, tram stations, and car industrial areas. The analysis of trace metals revealed distinct types of urban pollution based on these functional areas. In areas with heavy traffic, high concentrations of the elements, especially Zn, Cr, and Ni, would indicate significant toxic metal pollution. The overall contamination was evaluated using three indices: enrichment factor (EF 0.45-65.75), geo-accumulation index (Igeo - 2.50-4.18), and pollution index (PI 0.27-27.22). Human health risks of potentially toxic trace metals in urban road dust were evaluated for children and adult groups based on hazardous index (HI) and total cancer risk (TCR). The health risk assessments revealed that children (mean HIchildren 8.62E - 01; TCRchildren 6.99E + 04) are more vulnerable to toxic metal exposure than adults (mean HIadults 1.01E - 01; TCRadults 3.01E + 04), with ingestion being the primary exposure route over dermal contact and inhalation. In conclusion, we have captured the interaction between road dust and health risks, especially for children.

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.

A correlation study of road dust pollutants, tire wear particles, air quality, and traffic conditions in the Seoul (South Korea)

The interdependence of traffic dynamics and air quality on the concentrations of tire wear particles (TWP), heavy metals, and carbon black (CB) in road dust collected from 15 locations in Seoul, South Korea, was assessed. Pearson correlation, principal component analysis, and network analysis were employed to evaluate the correlations among traffic volume, vehicle speed, air quality parameters (PM10, PM2.5, NOx, and CO), and the concentrations of TWP (5934 to 16,253 mg/kg, average 9581 ± 4086 mg/kg), CB (371–22,287 mg/kg, average 4291 ± 6096 mg/kg), and heavy metals (Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, and Pb) in road dust. The enrichment factors for heavy metals and the pollution index of TWP and CB were also calculated to evaluate the contribution of vehicle-derived particulate substances to road dust contamination. It was found that Cluster B, characterized by traffic-related variables such as traffic volume, vehicle speed, and heavy metals (Zn, Cd, and Pb), was significantly correlated with these pollutants, with correlation coefficients reaching up to 0.933. TWP was identified as a significant mediator in the increase of Zn, Pb, and Cd concentrations linked to traffic activities, contributing to pollution levels that were 2–16 times higher than the geochemical background. The presence of TWP and CB in road dust was identified as an indicator of contamination from traffic-related activities, highlighting the importance of Zn, Pb, and Cd as emerging pollutants that require targeted management strategies.

Oral bioaccessibility of potentially toxic elements in various urban environmental media

An important aspect of geochemical studies is determining health hazard of potentially toxic elements (PTEs). Key information on PTEs behaviour in the human body in case of their ingestion is provided with the use of in vitro bioaccessibility tests. We analysed and compared oral bioaccessibility of a wide range of PTEs (As, Cd, Ce, Cr, Cu, Hg, La, Li, Ni, Pb, Sb, Sn, Zn), including some that are not often studied but might pose a human health hazard, in soil, attic dust, street dust, and household dust, using Unified BARGE Method (UBM). Additionally, feasibility of usage of scanning electron microscope techniques in analyses of solid residuals of UBM phases was tested. Results show that bioaccessible fractions (BAFs) of PTEs vary significantly between individual samples of the same medium, between different media and between the gastric and gastro-intestinal phases. In soil, attic dust and street dust, bioaccessibility of individual PTE is mostly higher in gastric than in gastro-intestinal phase. The opposite is true for PTEs in household dust. In all four media, with the exception of Pb in household dust, among the most bioaccessible PTEs in gastric phase are Cd, Cu, Pb, and Zn. During the transition from the stomach to small intestine, the mean BAFs of most elements in soil, attic dust, and street dust decreases. The most bioaccessible PTEs in gastro-intestinal phase are Cu, Cd, Ni, and As. Micromorphological and chemical characterisation at individual particle level before and after bioaccessibility test contribute significantly to the understanding of oral bioaccessibility.

Lead Speciation, Bioaccessibility, and Sources for a Contaminated Subset of House Dust and Soils Collected from Similar United States Residences.

Residential lead (Pb) exposure is of critical concern to families globally as Pb promotes severe neurological effects in children, especially those less than 5 years old, and no blood lead level is deemed safe by the US Center for Disease Control. House dust and soils are commonly thought to be important sources of Pb exposure. Probing the relationship between house dust and soil Pb is critical to understanding residential exposure, as Pb bioavailability is highly influenced by Pb sources and/or species. We investigated paired house dust and soil collected from homes built before 1978 to determine Pb speciation, source, and bioaccessibility with the primary goal of assessing chemical factors driving Pb exposure in residential media. House dust was predominately found to contain (hydro)cerussite (i.e., Pb (hydroxy)carbonate) phases commonly used in Pb-based paint that, in-turn, promoted elevated bioaccessibility (>60%). Pb X-ray absorption spectroscopy, μ-XRF mapping, and Pb isotope ratio analysis for house dust and soils support house dust Pb as chemically unique compared to exterior soils, although paint Pb is expected to be a major source for both. Soil pedogenesis and increased protection from environmental conditions (e.g., weathering) in households is expected to greatly impact Pb phase differences between house dust and soils, subsequently dictating differences in Pb exposure.

United States house dust Pb concentrations are influenced by soil, paint, and house age: insights from a national survey

BackgroundLead (Pb) in house dust contributes significantly to blood lead levels (BLLs) in children which may result in dire health consequences. Assessment of house dust Pb in the United States, relationships with Pb in soil and paint, and residential factors influencing Pb concentrations are essential to probing drivers of house dust Pb exposure.ObjectivePb concentrations in vacuum-collected house dust are characterized across 346 homes participating in the American Health Homes Survey II (AHHS II), a US survey (2018–2019) evaluating residential Pb hazards. Connections between house dust Pb and soil Pb, paint Pb, and other residential factors are evaluated, and dust Pb concentration data are compared to paired loading data to understand Pb hazard standard implications.ResultsMean and median vacuum dust Pb concentrations were 124 µg Pb g−1 and 34 µg Pb g−1, respectively. Vacuum-collected dust concentrations and dust wipe Pb loading rates were significantly correlated within homes (α < 0.001; r ≥ 0.4). At least one wipe sample exceeded current house dust Pb loading hazard standards (10 µg ft−2 or 100 µg Pb ft−2 for floors and windowsills, respectively) in 75 of 346 homes (22%). House dust Pb concentrations were correlated with soil Pb (r = 0.64) and Pb paint (r = 0.57). Soil Pb and paint Pb were also correlated (r = 0.6).ImpactThe AHHS II provides a window into the current state of Pb in and around residences. We evaluated the relationship between house dust Pb concentrations and two common residential Pb sources: soil and Pb-based paint. Here, we identify relationships between Pb concentrations from vacuum-collected dust and paired Pb wipe loading data, enabling dust Pb concentrations to be evaluated in the context of hazard standards. This relationship, along with direct ties to Pb in soil and interior/exterior paint, provides a comprehensive assessment of dust Pb for US homes, crucial for formulating effective strategies to mitigate Pb exposure risks in households.

Geochemical base for As, Co, Cu, Ni, P, Pb, S, V and Zn in road dust collected in areas of oil industry activity in the Metropolitan Region of Salvador, Bahia, Brazil

Road dust collection was carried out in Salvador and some municipalities in the Metropolitan Region of Salvador (MRS), such as Simões Filho, Candeias, Madre de Deus and São Francisco do Conde, situated within an area of oil activity. In the chemical-physical characterisation of the road dust collected, the average fractions of coarse sand (17.44 %), medium (27.15 %), fine (32.63 %) and very fine (15.54 %) were found in the 17 samples collected. The samples underwent an acid extraction procedure in a closed digester block, with the mixture HCl + HNO3 + H2O2. The extract was analysed and concentrations of Al, As, Co, Cu, Fe, Ni, Pb, P, Sb, V and Zn were determined. Linear regression analysis was applied to the concentrations of As, Co, Cu, Ni, Pb, P, V and Zn, generating the equations of the straight lines, which served as a geochemical baseline for the region of road dust samples. For the enrichment factor (EF), most chemical elements showed values lower than < 1 at the collection points, except for Cu, Mn, and P (10 < EF < 25) and for Co, Cu, P and Ni (5 < EF < 10), in the regions of Candeias and Simões Filho. On the other hand, the geoaccumulation index (Igeo) of most points were evaluated as uncontaminated (class 0) and moderate or uncontaminated (class 1) for Igeo, except for P (class 4) and Mn (class 5). Principal component analysis (PCA) showed accumulated total variance corresponding to 76.45 %. For the hierarchical cluster analysis (HCA), the results agree with those found in the PCA. Points P3 (Candeias) and P16 (Simões Filho) were the points that showed less dissimilarity with the other points analysed, indicating possible enrichment of the chemical elements found at these points, confirmed by the EF values.

Spatial distribution characteristics and source apportionment of heavy metal(loid)s in park dust in the Mianyang urban area, China.

Park dust is a carrier of heavy metal pollutants and could potentially harm the health of urban residents. The concentrations of 10 heavy metal(loid)s (HMs) in park dust from the Mianyang urban area were analysed via X-ray fluorescence spectrometry. Based on ArcGIS spatial analysis, Spearman correlation analysis, spatial autocorrelation analysis, and the positive matrix factorization (PMF) model, the spatial distribution and sources of HMs in park dust were studied. The average contents of Zn, Co, Cu, Cr, Pb, and Ba in park dust were 185.0, 33.7, 38.7, 178.7, 51.0, and 662.1mg/kg, respectively, which are higher than the reference values. The 10 HMs exhibited obvious spatial distribution and local spatial agglomeration patterns. High concentrations of As and Pb were primarily concentrated in the eastern part of the Mianyang urban area. High concentrations of Zn, Cr, and Cu were largely distributed in parks near the Changjiang River and Fujiang River. A high concentration of Co was concentrated in the northern region. The high-value areas of Mn, Ba, V, and Ni occurred far from the city centre and were located in the southwestern region. We found that Pb and As primarily originated from mixed traffic and natural sources; Zn, Cr, and Cu mainly originated from industrial activities; Co largely originated from building sources; and Ba, Ni, Mn, and V were mostly derived from natural sources. Mixed, industrial, building, and natural sources accounted for 24.5%, 24.8%, 24.7%, and 26.0%, respectively, of the HM sources. Co, Cu, Cr, and Zn in the Mianyang urban area were obviously influenced by human activities and should receive close attention.

Variability of Metal(loid) Contamination in Road Dust from an Urban Park and a Traffic Intersection Between Two Rainfall Events and Its Implications

ABSTRACT Metal(loid) pollutants in road dust (road-deposited sediment) show obvious seasonal characteristics under the influence of sources. However, the short-term (days to weeks) variations of metal contamination in road dust in different functional areas with antecedent dry days (ADDs) and their relationships with the source factors were poorly understood, which reduced the comparability of researches and effectiveness of pollution remediation. Herein, temporal characteristics of As, Ba, Ca, Cd, Cr, Cu, Pb and Zn contamination in road dust were studied in two distinct functional areas in Nanjing, i.e. an urban park (Xuanwu, XW) and a stop light-controlled traffic intersection (Baima, BM), following a continuous 23-day sampling between two rainfall events. Mean concentrations of each metal at BM and XW were 1.6–29.5 and 1.3–10.8 times higher than those in the background soil, respectively. The enrichment factor (EF) was used to compensate for grain-size effect. EFs of metals were between 1.3 and 50.3, showing minor to extremely high contamination and different temporal trends. Combined with the EFs and positive matrix factorization (PMF) results, dry atmospheric deposition of industrial and construction sources was the main cause for comparable contamination levels of As, Ca, Cd and Zn between BM and XW and those stable temporal trends. Due to the traffic contribution, contamination levels of Cu, Ba, Pb and Cr at BM were higher (p < .05) than at XW. Different from the stable contamination levels at XW, contamination levels of Cu, Ba, Pb and Cr decreased at BM with the ADDs due to the dilution of traffic particles by less metal enriched atmospheric deposition. These results shed light on the quite different variations of metal contamination in road dust from different functional areas with ADDs under the influence sources, and have instructive significance on road dust sampling, metal contamination remediation and comparison between studies.

Seasonal quantification of Zn2+, Pb2+ and Cu2+ in urban dusts in a semiarid city in northwest Mexico

Arid and semi-arid cities are of especial interest due to the high amount of dusts that are deposited daily. Dust particles contain heavy metals that are considered potentially toxic elements (PTEs). High concentrations of PTEs in dust particles can result in risks to human health. Few studies have documented accumulation rates of atmospheric deposition and the influence of the North American Monsoon (NAM) in the movement of PTEs. Precipitation and urban runoff derived from the NAM play an important role in the deposition and resuspension of PTEs on urban surfaces. In this work, we quantified spatial and temporal patterns of Zn2+, Pb2+ and Cu2+ in an urban-rural gradient using ion-exchange resin (IER) collectors. Three monitoring periods were chosen and the samplings were carried out during the dry and rainy season in a city influenced by the NAM. Results from the IER collectors during the first monitoring period estimated 4.6 gZn2+ha−1 15 wk−1, 3.3 gPb2+ha-115 wk−1 and 3.7 gCu2+ha-115 wk−1. During the second period, the deposition rates were 5.6 gZn2+ha−1 37 wk−1, 1.1 gPb2+ha−1 37 wk−1 and 1.5 gCu2+ha−1 37 wk−1. Finally, in the third period 7.0 gZn2+ ha-117 wk−1, 0.6 gPb2+ha−1 17 wk−1 and 0.9 gCu2+ha−1 17 wk−1 were found. The central area of the city exhibited the highest deposition rates of PTEs influenced by precipitation and flood areas. Results of this work demonstrate the importance of the NAM in the movement of PTEs caused by precipitation and winds that promote the movement of particles in an urban area.

Pine needles as bioindicator and biomagnetic indicator of selected metals in the street dust, a case study from southeastern Iran

Among the different approaches currently being used to evaluate the contamination level of street dust, the magnetic susceptibility of dust and urban tree leaves has received little attention. The key objectives of this study were: (i) to investigate the feasibility of using pine needles as a bioindicator and biomagnetic indicator for estimating the concentration of selected metals in street dust, and (ii) to predict the contamination level of street dust by selected metals using magnetic susceptibility. Street dust and pine tree needle samples were taken from 60 locations in three adjacent cities in Kerman province (Kerman, Rafsanjan, and Sirjan), southeastern Iran. The total concentrations of selected metals, including Cu, Zn, Fe, Mn, Ni, and Pb, and the magnetic susceptibility (χlf and χhf) values of both pine tree needles and street dust samples were determined. Among the three cities studied, samples from Kerman showed the highest magnetic susceptibility and metal concentration values. This could be attributed to the larger size and much higher population density of this city, with more industrial activities and urban traffic than the other two cities investigated. The results also showed that the concentrations of metals in pine needles were strongly correlated (p < 0.01) with those in street dust. The magnetic susceptibility of pine needles and the concentrations of Fe, Pb, Zn, Cu, Ni, and Mn in street dust showed a statistically significant correlation (p < 0.01). A strong and statistically significant correlation (p < 0.01) was also found between magnetic susceptibility and the concentration of metals in pine needles. In conclusion, strong relationships between magnetic properties and metal concentrations of pine needles with those of street dust samples seem to make pine needles a good bioindicator and biomagnetic estimator of the contamination level of metals in street dust.

Contaminations evaluation and ecological risk assessment of selected potentially harmful elements in dusts, sediments and soils of Akure, Nigeria

Indiscriminate discharge of waste and high traffic density as well as incessant flooding are major challenges that characterised Akure metropolis. Potentially harmful elements such as Pb, Cd, Ni, Zn are toxins that after exposure may pose a potential lifetime health risk especially to children. This study investigated and traced the contamination levels and the ecological risk of some Potentially-Harmful-Elements (PHEs) (Cu, Zn, Cd, Pb and Ni) in soils, drainage sediments and dusts of the city of Akure, southwestern Nigeria. Composite samples consisting of 40-soils, 30-stream-sediments, 20-road-dust samples and ten representative rock samples were collected for the study. The samples were air dried, pulverized, sieved and digested using aqua regia while the elemental compositions were determined using the ICP-MS. The level of contamination and the ecological risk assessment were determined by comparing with statutory guidelines and calculation of contamination indices, and ecological risk factors. The results (mg/kg) showed that Zn ranged from 13.50 to 384.60; Cu, 3.77 to 99.43; Pb, 13.60 to 69.10; Ni, 2.40 to 27.60 and Cd, 0.02 to 0.31 in sediments. For the soils, Zn ranged from 25.00 to 552.00; Cu, 10.00 to 71.00; Pb, 12.00 to 158.00; Ni, 5.00 to 32.00 and Cd, 0.50 to 1.50 while in dusts, Zn ranged from 118.00 to 876.00; Cu, 35.00 to 148.00; Pb, 52.00 to 487.00; Ni, 9.00 to 23.00; and Cd, 0.50 to 1.40. The concentrations of the analysed PHEs were observed to be elevated in samples from city center characterized by high population and traffic density. The soils, sediments and dusts of Akure metropolis were found to have been moderately contaminated with Cu, Pb, and Zn. The ecological-risk-indices of the three media showed that Ni and Zn were of low to considerable risk, while Cu, Pb and Cd were low to very high risk. The potential ecological risk factor in sediments, soils and dusts was of low to considerable risk, low to high risk and considerable risk to high risk, respectively. The status of the quality of the environmental media requires urgent remediation attention in order to ensure clean and sustainable environment for the city dwellers.

Total contents, fractionation and bioaccessibility of nine heavy metals in household dust from 14 cities in China

The potential health risk caused by long-term exposure to heavy metals in household dust is not only depended on their total content, but also bioaccessibility. In this study, twenty-one dust samples were collected from residential buildings, schools, and laboratories in 14 provincial-capital/industrial cities of China, aiming to evaluate the total contents, fractionation, bioaccessibility and health risks of nine heavy metals (As, Cd, Cr, Ni, Pb, Mn, Zn, Fe, and Cu). Results showed that the highest levels of Cd, Cr, Ni and Zn were found in laboratory dust, As, Pb and Mn in school dust, and Fe and Cu in residential dust, indicating different source profiles of the heavy metals. The mean bioaccessibility of the heavy metals across all samples as evaluated using SBRC (Solubility Bioavailability Research Consortium), IVG (In Vitro Gastrointestinal), and PBET (Physiologically Based Extraction Test) assays was 58.4%, 32.4% and 17.2% in gastric phase (GP), and 24.9%, 21.9% and 9.39% in intestinal phase (IP), respectively. Cadmium had the highest content in the fractions of E1+C2 (43.7%), as determined by sequential extraction, and Pb, Mn, and Zn had a higher content in E1+C2+F3 (64.2%, 67.2%, 78.8%), resulting in a higher bioaccessibility of these heavy metals than others. Moreover, the bioaccessibility of most heavy metals was inversely related to dust pH (R = −0.18 in GP; −0.18 in IP; P < 0.01) and particle size, while a positive correlation was observed with total organic carbon (R = 0.40 in GP; 0.38 in IP; P < 0.01). The exposure risk calculated by the highest bioaccessibility was generally lower than that calculated by the total content. However, Pb in one school dust sample had an unacceptable carcinogenic risk (adult risk = 1.19 × 10−4; child risk = 1.08 × 10−4). This study suggests that bioaccessibility of heavy metals in household dust is likely related to geochemical fractions and physical/chemical properties. Further research is needed to explore the sources of bioaccessible heavy metals in household dust.

Health Hazard Related to Fine Road Dust in Poland

Abstract Air pollution emissions from road vehicles majorly contribute to particulate pollution. This poses significant threats to the environment and human health. Road dust contains various potentially toxic elements, which, when exposed to humans, can lead to severe illnesses such as asthma, cardiovascular diseases, and cancer. This study assessed adult health risks through accidental ingestion, inhalation, and dermal contact associated with heavy metals (Cr, Cu, Ni, Pb, and Zn) in road dust (with a fraction size &lt; 0.1 mm). The analysis covers areas between sound-absorbing screens (S), in open spaces without screens (F), and at highway/express exits (E) with different surfaces: asphalt (A) and concrete (C). Results indicate the highest health risk levels are associated with Zn in road dust in S and E areas, indicating its potential negative impact on human health. When comparing results for all metals, road dust collected from A surfaces might pose a greater health risk than C surfaces. The carcinogenic risk for Cr and Ni found in road dust collected from A and C surfaces at points S, F, and E is medium. The most significant carcinogenic risk (medium-high) is associated with Cr in road dust from A surfaces in the F area, whereas the lowest risk (low-medium) for both A and C surfaces is linked to Ni exposure in the S point. The contributions of Cr and Ni highlight the need to reduce emissions of these elements in areas surrounding heavily trafficked roads.

Children's lead exposure in the U.S.: Application of a national-scale, probabilistic aggregate model with a focus on residential soil and dust lead (Pb) scenarios

Lead (Pb) exposures from soil and dust ingestion contribute to children's blood lead levels (BLLs) in the United States. The U.S. Environmental Protection Agency (EPA)'s Strategy to Reduce Lead Exposures and Disparities in U.S. Communities and the Federal Action Plan to Reduce Childhood Lead Exposure describe multi-pronged collaborative approaches. These include reducing multi-media lead exposures nationally using analytical tools such as EPA's Stochastic Human Exposure and Dose Simulation model for lead [SHEDS-Pb; formerly known as SHEDS-IEUBK (Integrated Exposure Uptake Biokinetic model)], which was initially developed and applied with a focus on children's drinking water exposures. In this study we applied SHEDS-Pb to determine what residential soil Pb and dust Pb concentrations (individually and their sum) can keep BLLs of potentially exposed young children in the general U.S. population below specified values, considering aggregate exposures from water, soil, dust, food, and air. We considered two age groups (1 to <2 years and 2 to <6 years), two BLL values (5 μg/dL and 3.5 μg/dL), and two population percentiles (95th and 97.5th). Sensitivity analyses were conducted using several alternative model inputs and data sets, yielding 15 scenarios summarized in the paper. Of those scenarios, we focused on ones with the most recent science and available data. Modeled soil Pb concentrations by age group, population percentile and reference BLL scenarios for the focus scenarios ranged from 70 ppm to 220 ppm; and modeled dust Pb concentrations ranged from 110 ppm to 240 ppm. These results are consistent with current soil and dust Pb concentrations in the U.S. general population and are lower than most of the current U.S. Federal standards. Estimated BLLs compared well with measured BLLs from CDC's NHANES 2009–2016 (0–27 % relative error for focus scenarios). This analysis can be used to inform EPA and other federal Pb efforts.

Pesticide, allergen, PCB, and lead measurements in childcare centers located on tribal lands in the Pacific Northwest, United States

BackgroundChildren’s potential exposures to chemical and biological agents in tribal childcare centers are not well characterized.Objectives(1) The environmental health of childcare centers in Portland Area Indian Country was characterized by measuring selected pesticides, polychlorinated biphenyls (PCBs), allergens, and lead (Pb) in outdoor soil and indoor dust. (2) We compared our results to other studies of childcare centers in both the United States and globally.MethodsAt 31 tribal childcare centers in Washington, Oregon, and Idaho, we collected indoor dust and outdoor soil samples from at least one classroom, multipurpose room, and outdoor play area. Number of rooms sampled depended on facility size. Surface wipes were collected from the floor, play/work surface, and windowsill and analyzed for selected pesticides and PCBs. Vacuum samples were collected from the floor and analyzed for selected allergens. Lead was measured in surface wipes and outdoor soil collected at 11 centers. A questionnaire collected information on demographics, cleaning habits, and pesticide usage.ResultsAt least one pesticide was measured at all childcare centers. cis-Permethrin (surface wipes: 0.003–180 ng/cm2), trans-permethrin (surface wipes: 0.002–200 ng/cm2) and piperonyl butoxide (surface wipes: 0.001–120 ng/cm2) were measured in all centers. Lead was measured in most surface wipes (<0.25–14 ng/cm2) and all outdoor soil samples (8.4–50 mg/kg). Aroclors 1242 and 1254 were detected on indoor surfaces in three centers at very low loadings. Allergen residues were measured at very low concentrations in vacuum dust samples (Der p 1: <0.012–0.12 µg/g; Der f 1: <0.012–0.09 µg/g; Mus m 1: <0.002–10.055 µg/g). In general, we observed lower levels of chemical and biological agents than what has been reported previously.SignificanceBy understanding the environmental health of childcare centers, we can better understand the role of child-specific environments in promoting children’s health and well-being.Impact statementTo our knowledge, this is the first study to characterize the environmental health of tribal childcare centers in the Pacific Northwest. Combined with the information we have on childcare centers from around the world, this study expands our knowledge on young children’s potential exposures to chemical and biological agents in locations where they spend significant amounts of time.

Heavy metals contamination, receptor model-based sources identification, sources-specific ecological and health risks in road dust of a highly developed city.

The present study quantified Ni, Cu, Cr, Pb, Cd, As, Zn, and Fe levels in road dust collected from a variety of sites in Tangail, Bangladesh. The goal of this study was to use a matrix factorization model to identify the specific origin of these components and to evaluate the ecological and health hazards associated with each potential origin. The inductively coupled plasma mass spectrometry was used to determine the concentrations of Cu, Ni, Cr, Pb, As, Zn, Cd, and Fe. The average concentrations of these elements were found to be 30.77 ± 8.80, 25.17 ± 6.78, 39.49 ± 12.53, 28.74 ± 7.84, 1.90 ± 0.79, 158.30 ± 28.25, 2.42 ± 0.69, and 18,185.53 ± 4215.61 mg/kg, respectively. Compared to the top continental crust, the mean values of Cu, Pb, Zn, and Cd were 1.09, 1.69, 2.36, and 26.88 times higher, respectively. According to the Nemerow integrated pollution index (NIPI), pollution load index (PLI), Nemerow integrated risk index (NIRI), and potential ecological risk (PER), 84%, 42%, 30%, and 16% of sampling areas, respectively, which possessed severe contamination. PMF model revealed that Cu (43%), Fe (69.3%), and Cd (69.2%) were mainly released from mixed sources, natural sources, and traffic emission, respectively. Traffic emission posed high and moderate risks for modified NIRI and potential ecological risks. The calculated PMF model-based health hazards indicated that the cancer risk value for traffic emission, natural, and mixed sources had been greater than (1.0E-04), indicating probable cancer risks and that traffic emission posed 38% risk to adult males where 37% for both adult females and children.

Risk assessment and source apportionment of heavy metals pollution from atmospheric deposition in Nanjing, China

Heavy metals (HMs) are the toxic pollutants in urban environment, and their sources are complex. Dust might be a good carrier of HMs into ecosystem and human. In this study, 48 dust samples were collected in Nanjing, an industrial city and transportation hub in the Yangtze River Delta, China. The concentrations, spatial distribution, sources and risks of heavy metals (Cr, Ni, Cu, Zn, Cd and Pb) in dust were determined and analyzed. The results showed that although the health risks of some HMs had decreased, Cr, Zn, and Cd had high concentrations and high risks on ecosystem/human. And thus, the total risks of the target HMs were higher than the threshold of non-risks. Especially, children may face the highest possible risks due to the frequent hand-oral ingestion when children play. The hot spot regions of the HMs were mainly in the industrial district in the north, urban, and rural region in south, relating with the industrial, traffic, and agricultural sources, respectively. The analysis for the risks of individual sources further confirmed these sources should be further controlled. The results in this study will provide information on the priority of HMs’ monitoring and source management.

Extending Regulatory Biokinetic Lead Models towards Food Safety: Evaluation of Consumer Baby Food Contribution to Infant Blood Lead Levels and Variability.

The U.S. Food and Drug Administration released proposed lead (Pb) action levels for foods intended for babies and young children in January 2023 based on the agency's interim reference value of 2.2 µg/day for dietary Pb. Since the 1980s, biokinetic models have estimated blood lead levels (BLLs) associated with environmental contamination, but their use in food safety assessment has been limited. We compared three recent biokinetic models (IEUBK Model, ICRP Model Version 5, and AALM) to develop insights on contributors to variability in potential exposures to Pb in consumer baby food products. While modest variation was observed for babies, the predictions trended to convergence for children aged 3 and older, approaching the U.S. FDA dietary conversion factor of 0.16 µg Pb/dL blood per µg Pb intake/day. We applied the IEUBK model in a probabilistic exposure assessment framework characterizing the distribution of Pb in soil, dust, water, and food intake in the United States. Soil and dust were the primary contributors to variance in infant BLLs, while food and water contributed <15% combined. Thus, reductions in upper-bound soil and dust concentrations will be necessary before achieving appreciable reductions in the frequency of BLLs greater than the BLRV of 3.5 µg/dL.

Lead and mercury in historical books and their contribution to dust contamination

Historical products are often a source of toxic substances, like heavy metals, that have since been restricted. In this study, the lead (Pb) and mercury (Hg) content of 133 books housed in two collections in southwest England (a university library and council repository), and published between 1704 and 2018, have been determined on-site by X-ray fluorescence spectrometry. Lead was detected in the front panels, text blocks and interior colour illustrations of most books, with maximum concentration of 15,100 mg kg-1, 8680 mg kg-1 and 12,800 mg kg-1, respectively. However, concentrations above 1000 mg kg-1 were generally restricted to books published between about 1850 and 1960. Mercury was detected in fewer cases, but concentrations above 5000 mg kg-1 were found in the red panels, coloured illustrations and red fore-edging of books published in the Victorian era. Mean concentrations of Pb in dusts from council repository shelves (112 mg kg-1) and library shelves (159–224 mg kg-1) and light casings (71.7 mg kg-1) were significantly higher than mean concentrations in household dusts from buildings constructed over the same period (24.8 mg kg-1). The findings suggest that historical books could be a source of Pb exposure where collections are housed or sold and could also be used to improve evaluations of historical indoor pollution.