Trace metals in resuspended fraction of settled bus dust and assessment of non-occupational exposure

Estimate of the maximum amount of dust adhering to skin and the upper limit of dust-skin adherence factor for young adults: An example from Changchun, China

Contaminants present in dust adhering to the skin can pose a significant risk to human health through dermal absorption and hand-to-mouth contact. The adhesion capacity of dust differs significantly from that of soil due to its physicochemical properties. Therefore, applying the raw soil exposure parameters to estimate the health risks associated with dermal exposure to dust may lead to erroneous conclusions. In this study, we quantified the maximum amount of dust that adhered to the skin (MADmax) and the upper limit of dust-skin adherence factor (DSAFmax) in 26 adults using element markers as a proxy for dust. The volunteers were exposed to dust and rinse water samples were collected from their hands, forearms, lower legs, and feet. We analyzed both the raw dust samples and the rinse water samples for 11 element markers, including Be, V, Cr, Mn, Co, Ni, Cu, Zn, Se, Ba, and Pb. The results showed that the MADmax of indoor dust and outdoor dust increased by 0.08-0.62 mg and 0.33-0.56 mg following a 1 cm2 increase in skin surface area, respectively. Based on best dust element markers, the body part-weighted dust-skin adherences (WDSAFmaxs) of indoor dust and outdoor dust were 0.35 and 0.64 mg/cm2, respectively. A smaller particle size and higher moisture content resulted in a larger DSAFmax. Only when indoor dust concentrations exceed 24.2 mg/m3 or outdoor dust concentrations exceed 44.3 mg/m3, can the WDSAFmax be applied directly in the health risk assessment of dermal exposure to dust. The method from this study can be re-applied in different regions, and the adherence data can help to improve future studies on the health effects of dermal exposure to dust.

Assessment of sources, environmental, ecological, and health risks of potentially toxic elements in urban dust of Moscow megacity, Russia

Potentially toxic elements (PTEs) in urban dust of Moscow megacity and related risks have been studied. 78 samples were collected in the Moscow downtown in sites with different anthropogenic load, namely, major highways, residential area, and recreation zones. The concentrations of PTEs in urban dust were determined by ICP-MS and ICP-AES. Then, environmental, ecological and health risks of PTEs in urban dust were assessed. In addition, potential sources of PTEs in dust were identified. It is shown that Moscow dust is mainly contaminated by Sb, Zn, Pb, Cd, Cu, Sn, and Mo, which according to the data of principal component and correlation analyses can be attributed to anthropogenic sources (non-exhaust vehicle emissions). Potential ecological risk factor demonstrates that Cu, Mo, and Cd have moderate potential ecological risks in 13% of studied area, while Sb has this risk in 62% of area. Potential ecological risk indices indicate that 41% of studied territory is of moderate ecological risk. Concerning the human risks through ingestion, dermal contact, and inhalation pathways, PTEs in Moscow dust have no significant non-carcinogenic risks for adults. However, the value of total hazard index for children is 1.8 showing that non-carcinogenic risks may occur. Moreover, possible carcinogenic risks caused by Cr are evaluated. The finding of the present study can be used for ecological management in the megacity to reduce both ecological and human risks. A special attention should be given to periods of hot and dry weather and to traffic-related emissions.

Trace elements in indoor dust-Children's health risk considering overall daily exposure

Indoor dust presents an important source of daily exposure to toxic elements. The present study reports for the first time the levels of Al, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Sn, Se, Sr, Tl, V, and Zn measured in dust samples collected from 10 kindergartens and 21 cars from Zagreb, Croatia. Based on the obtained data, we assessed the health risks from overall daily exposure to trace elements for children aged 2-6 years taking into account three pathways of dust intake-ingestion, dermal absorption, and inhalation. The median concentration of most elements was significantly higher in dust obtained from cars compared to kindergartens, especially in the cases of Co (11.62 vs. 3.60 mg kg^-1 ), Cr (73.55 vs. 39.89 mg kg^-1 ), Cu (186.33 vs. 26.01 mg kg^-1 ), Mo (8.599 vs. 0.559 mg kg^-1 ), Ni (37.05 vs. 17.38 mg kg^-1 ), and Sn (9.238 vs. 1.159 mg kg^-1 ). Oral intake was identified as the most important exposure pathway, except for Cr, Ni, and Sb where dermal contact was the main route of exposure. Health risk assessment indicated that no adverse effects are expected from overall exposure to trace elements. Although the cases of high exposure to toxic elements are not common in areas with no significant environmental pollutants, due to the health threat they may present even at low levels, their status should be carefully monitored.

Heavy metals in indoor dust: Spatial distribution, influencing factors, and potential health risks

Given the large proportion of time that people spend indoors, the potential health risks posed by heavy metals in the indoor environment deserve greater attention. A global-scale assessment of heavy metal contamination in indoor dust was conducted in this study based on >127 articles published between 1985 and 2019. The pollution levels, spatio-temporal variations, sources, bioaccessibilities, influencing factors, and health risks of heavy metals associated with indoor dust were analyzed. Children's blood lead levels (BLLs) were also estimated using the integrated exposure uptake biokinetic model. The results indicated that the median concentrations of Cu and Zn in 71.9% and 71.0% of the study sites surpassed the corresponding permissible limits, 100 and 300 mg/kg, respectively; thus, their control should be given priority. Heavy metal concentrations in indoor dust from different areas of the world varied greatly, which was closely associated with the type of local human activities, such as mining, melting, e-waste recycling and Pb-related industries. The bioaccessibilities of some key elements, e.g., Pb, Cd, Cu, and Zn, in household dust were high. The levels of heavy metals in indoor dust were mainly affected by a combination of outdoor and indoor sources and related critical factors, and future studies should focus on quantifying the contributions of different sources. Based on the health risk assessment, dust Pb exposure is a major health concern in e-waste recycling areas, which warrants greater attention. 49.8%, 36.8% and 14.4% of study sites showed BLLs exceeding 35 μg/L (threshold limit in Germany), 50 μg/L (threshold limit in the USA), or 100 μg/L (threshold limit in China), respectively. Finally, Pb exposure from indoor dust represents a major contributor to children's blood Pb poisoning in many developing countries. This study details the overall heavy metal contamination status of indoor dust and provides insights for policymakers with respect to pollution prevention measures.

Individual heavy metal exposure and birth outcomes in Shenqiu county along the Huai River Basin in China

Background: Exposure to heavy metals during pregnancy is an important risk factor for adverse birth outcomes. We aimed to investigate the current heavy metal exposure levels in cord blood from healthy pregnant women residing in the Huaihe River Basin, China, and examined the association between heavy metal levels and dietary habits and lifestyle factors. In this study, we measured the exposure levels of five heavy metals in the umbilical cord blood from 350 healthy pregnant women and administered 350 self-reported questionnaires regarding the general characteristics and dietary habits of those women. Methods: This study was undertaken in Shenqiu county, Henan province, which is in the area of the Huai River Basin, in a cohort of pregnant women and newborn babies in 2013-2014. We recruited a sample of 1000 pregnant women among those receiving prenatal examination, measured the real individual newborn exposure to heavy metals in serum by ICP-MS, collected information regarding the pregnant women with a questionnaire survey and obtained data on environmental quality from environmental protection agencies and the available literature. We estimated the daily individual exposure to heavy metals of all the 1000 participants throughout the pregnancy and recorded their birth outcomes after delivery. Then we analyzed the association between birth outcome and individual exposure to heavy metals. Results: 54 newborn children had birth defects. The geometric means of cord blood levels of As, Cd, Cr, Pb and Hg were measured at 0.92 ± 1.01 ng mL-1, 0.11 ± 0.17 ng mL-1, 4.57 ± 5.02 ng mL-1, 3.37 ± 3.81 ng mL-1 and 0.89 ± 1.69 ng mL-1 for subjects (n = 54) who gave birth to infants with birth defects and 0.43 ± 0.88 ng mL-1, 0.52 ± 3.86 ng mL-1, 1.94 ± 2.92 ng mL-1, 4.38 ± 4.96 ng mL-1 and 0.43 ± 0.91 ng mL-1 for subjects (n = 296) with healthy infants, respectively. The contents of all five heavy metals in the whole blood of both of these two groups were higher than the reference values of the Chinese general population (P < 0.001). Conclusions: The occurrence of birth defects was 15.4% in this cohort, and was correlated to exposure of parents to environments containing heavy metal contaminants in Shenqiu county in the Huai River Basin. The heavy metal exposure situation of the investigated population had serious effects in terms of reproductive defects in children. The specific link between newborn defects and environmental heavy metal contaminants suggested that contamination in pregnant women persisted over time, and that the exposure may have a long term effect.

Use of simulated epithelial lung fluid in assessing the human health risk of Pb in urban street dust

In many urban contexts, non-dietary Pb exposure from street dusts may add to the overall exposure burden, and the presence of high total Pb content is well documented in urban street dust from across the globe. Given the increasing recognition of the potential adverse health effects from both the quantity and the chemical and physical composition of the inhaled fraction, and the recognition that it is the soluble fraction rather than the total element content that has more direct links to health effects, attention has focused in this study on the human health risks via this exposure pathway. In order to investigate the environmental exposure to Pb from the inhalation of urban street dusts, a newly developed in vitro simulated epithelium lung fluid (SELF) has been applied to the <10μm fraction of urban street dusts. In this context, 21 urban street dust samples, across five UK cities, were selected based on their high pseudo-total Pb content. The work revealed that inhalation bioaccessibility, and hence inhalation dose, varied across the cities but was generally found to be low (<10%). Indeed, the lung bioaccessibility was far lower (% lung bioaccessibility ranged from 1.2 to 8.8) than is currently applied in two of the most commonly employed risk assessment models i.e. the Integrated Exposure Uptake Biokinetic model (IEUBK, USA) and the Contaminated Land Exposure Assessment model (CLEA, UK). The estimated inhalation dose (for adults) calculated from the PM10 bioaccessibility ranged from 7ngkg^-1_BWday^-1 (Edinburgh) to 1.3ngkg^-1_BWday^-1 (Liverpool). The results indicate a low potential inhalation bioaccessibility for Pb in these urban street dust samples when modelled using the neutral pH conditions of the SELF.