Main Exposure Pathway Research Articles

Evaluation of acute and chronic exposure to aflatoxin B1 in indigenous women of the Huasteca Potosina, Mexico.

Aflatoxin B1 (AFB1) is one of the most studied mycotoxins due to its high occurrence in food and its hepatotoxic, immunosuppressive, carcinogenic, childhood growth, genotoxic, mutagenic, and teratogenic effects in humans and animals. Exposure to AFB1 is reported to be both, acute and chronic; the main exposure pathway to AFB1 is through the intake of contaminated food. In Mexico, although the reports of several studies addressing the problem of aflatoxins in maize and other foods, the evidence has been centered on exposure to AFB1 and to the quantification of the Aflatoxins themselves, but there is null evidence about genotoxic effects of aflatoxins in vulnerable populations. Therefore, this study focused on assessing chronic AFB1 exposure through the AFB1-lys biomarker adduct and acute exposure through total AFB1-DNA adducts in women from a rural indigenous community in the Huasteca Potosina (Mexico). A hundred percent of the studied population presented total AFB1-DNA and AFB1-lys adducts in concentrations of 1.08 (0.48-1.34) μmol of adduct/mol of DNA and 2.33 (1.08-102.6) pg/mg of albumin respectively (median (min-max)). Thus, continuous monitoring and important changes in regulations are desired and recommended. The results in this study provide enough evidence to support the toxic effects that the exposure to AFB1 represents, as well as the population risk that it poses, and in the same sense, the current need to create an intervention program that directly influences the control of the sources of exposure in order to reduce it.

Human and ecological risk assessment of heavy metals in different particle sizes of road dust in Muscat, Oman.

Heavy metal contamination of Hg, As, Cu, Cr, Zn, and Pb was investigated in three different fractions 45, 125, and 200μm of road dust in Muscat, Oman. Dust samples were collected from three different traffic roads, viz. high, medium, and low based on traffic volume and then sieved individually before they analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES). Cu has the highest level among the analyzed metals while the lowest amount was for Hg. Most of the metals in all traffic sites have higher concentration in finer fraction and the concentrations of Cu, Pb, and Zn in HT road dust decreased significantly from finer fraction (45μm) to bigger fraction size (200μm). The risks of analyzed heavy metals to the urban ecosystem and human health were calculated by the potential ecological risk index and human exposure model, respectively. Risk index levels of studied metals in the three fractions and roads vary from strong to very strong potential. Hg found to have the greatest contribution in risk index in the three different fractions and roads. The values of risk levels for individual metal contamination in the dust street samples from different roads and fractions were ranked in the following order: Hg > Cu > Pb > Cr > Zn. Ingestion is the main pathway of exposure to road dust particles for both children and adults, followed by dermal contact absorption. The HI for children and adults exposed to 45- and 125-μm particles were higher than exposed to 200-μm particles, which indicated that finer particles tend to have higher non-carcinogenic risk. The non-carcinogenic risks of the studied heavy metals to children and adults are within safe threshold value; however, health risks of Cr, Pb, and Cu were relatively high for children.

Groundwater NO3 concentration and its potential health effects in Beni Moussa perimeter (Tadla plain, Morocco)

In this research, the concentrations of nitrates were investigated in well water sampled from the irrigated perimeter of Beni Moussa (Tadla plain, Morocco), and human health risks via ingestion and dermal pathways for individuals in different age brackets were assessed using the chronic daily intake, the dermal absorbed dose and hazard index (HI).The results showed that the groundwater NO3 contents were between 4.20 to 80.46 mg L− 1, with an average of 32.11 mg L− 1, indicating anthropogenic inputs caused by the infiltration of nitrates not consumed by plants or surface industrial and domestic wastewater into the shallow aquifer. Compared to the Moroccan standard, 17.78%, 40.00%, 37.78% and 4.44% of sampled wells showed poor, fair, good or excellent quality, respectively. For non-carcinogenic risk, the oral ingestion of nitrate appeared to be the main exposure pathway for local human receptors causing the high non-carcinogenic risk, and the dermal exposure met within the accepted precautionary criterion. Infants in the study area are more likely to experience adverse effects to higher nitrate level in groundwater (3.04E-01 < HI < 1.80E+ 00), followed by female (2.39E-01 < HI < 1.41E+ 00), then male (2.22E-01 < HI < 1.31E+ 00) and finally children (2.08E-01 < HI < 1.23E+ 00). The resulting spatial variation in HI values was greatly influenced by human activities and population density.The results of this study could help to shape effective environmental management measures for enhancing the groundwater quality and ensuring safe drinking water.

Status of arsenic accumulation in agricultural soils across China (1985–2016)

Based on 1677 published studies, 1648 sites across China collected from 1985 to 2016 were used to research the concentrations of arsenic in agricultural soils. In order to understand the status of arsenic pollution in agricultural soils in China over the past three decades, and to learn about the arsenic stocks in agricultural soils in various regions, and compared the relationship with annual arsenic emissions in China, and finally evaluated the potential ecological risks and human health risks. The median arsenic concentration in the surface agricultural soils of China was 10.40 mg Kg−1, and it ranged from 0.4 mg Kg−1 to 175.8 mg Kg−1. The inventory of arsenic in Chinese agricultural surface soils was estimated to be 3.71 × 106 t. In this study, the arsenic concentrations were found to be higher in Central, South, and Southwest China than those in other regions. The trend of arsenic pollution in agricultural soils has gradually increased over the past three decades. However, the growth rate of arsenic concentrations pollution in farmlands agricultural in China slowed during 2012–2016. The ecological risk index and geoaccumulation index revealed that arsenic in Chinese agricultural soil poses a low risk to the ecosystem. For human health assessment, the dietary pathway was the main pathway of exposure to arsenic in farmland soil of China. However, children's soil intake also contributed 34.48% to the exposure to arsenic, owing to their behavior. This study can provide a reference for the management of arsenic agricultural pollution in farmland soils in China.

Surface topography, mineralogy, and Pb isotope survey of wheel weights and solder: Source of metal contaminants of roadways and water systems

Wheel weights and solders are among the most important anthropogenic lead sources in modern society. Characterization of size, shape, and stages of degradation of wheel weights and solders by scanning electron microscopy provides fundamental knowledge toward better understanding of processes related to abrasion, dissolution, and transfer of metallic lead to the surface environment. Our studies of wheel weights identified partially abraded and chemically corroded textures, with coatings of reconstituted Pb particles, including litharge (PbO) and/or plattnerite (PbO2), in a matrix of soil components, mainly clays, feldspars, silica, and iron-oxides. Pb oxide particles abraded from wheel weights have a major component of <1 μm-size particles and consist of acicular needles and hair-like crystals are of concern because the size and particle shapes are known to have significant adverse health impacts if ingested, inhaled, or imbedded in the human body.Pb isotope analysis (by TIMS and HR-ICPMS) provides a way to identify the main lead exposure pathways if wide differences in isotopic ratios exist among possible local sources. Lead isotopic ratios for wheel weights from the U.S. plot along narrow arrays in plots of 206Pb/207Pb (~1.130–1.230) vs. 208Pb/207Pb (~2.410–2.470). The apparent trend in the 208Pb/207Pb and 206Pb/207Pb plot implicates a lead source from central U.S. from Mississippi Valley-type deposits, and a less radiogenic endmember which may link to an international lead source, such as from deposits of China. Wheel weights and corresponding leachates are analytically indistinguishable. Degradation of wheel weight particles will influence the Pb isotopic composition of local surface and groundwater regardless of whether the contribution is from solid particles, derived from grain erosion, or from dissolved Pb. The legacy of past and current uses of lead metal in manufactured products will continue to be of global concern for the foreseeable future because Pb-rich products, such as wheel weights and solders, remain commercially available through both primary and secondary global markets.

Direct and indirect effects of microplastics on bivalves, with a focus on edible species: A mini-review

Bivalves play important roles in the ecosystem. However, bivalve populations have suffered a global decline in recent decades. This decline has caused public concern, because bivalves provide ecosystem services and are important sources of protein and ornaments (such as pearls) that support the fishing industry in coastal zones worldwide. Microplastics are an emerging global threat for bivalves and have been commonly detected in commercial edible bivalves, including mussels, oysters and clams. To comprehensively understand impacts of microplastics on bivalves, the potential exposure pathways by which microplastics affect bivalves are reviewed. The existing scientific evidence indicates that microplastics not only directly affect the physiology of bivalves, but also indirectly affect them by changing the structure of their sedimentary habitats, impairing their food resources and delivering persistent organic pollutants. In addition, the consumption of contaminated bivalves is a main pathway of exposure to microplastics by humans, which raises potential human health concerns. An evaluation of the hazards associated with the consumption of bivalves that contain microplastics and associated toxic chemicals is urgently needed. More studies related to the effects of microplastic fibers on bivalves should be conducted, because microplastic fibers comprise the largest proportion of microplastics in the environment and bivalves.

Characteristics and Health Risk Assessment of Potentially Toxic Metals in Urban Topsoil in Shenyang City, Northeast China

AbstractSoil samples are collected from 74 sites in Shenyang city, northeast China, and the concentrations, spatial distribution, enrichment factors (EF), and potential ecological and human health risk (Er) of potentially toxic metals (Sr, Zn, Cr, Pb, Cu, Ni, and As) are investigated. The mean concentrations of potentially toxic metals in topsoil follow the order Sr &gt; Zn &gt; Cr &gt; Pb &gt; Cu &gt; Ni &gt; As. Compared with 2011, the contamination magnitude has improved in 2017, but the pollution status still exists, especially for As and Cr. EF and the mean Er of potentially toxic metals decrease following the order As &gt; Pb &gt; Cu &gt; Ni &gt; Zn &gt; Cr &gt; Sr and As &gt; Cu &gt; Zn &gt; Pb &gt; Sr &gt; Ni &gt; Cr, suggesting that the potentially toxic metals in the topsoil of Shenyang city mainly come from natural sources, and the potential ecological risk for potentially toxic metals is low. There are potentially non‐carcinogenic and carcinogenic health risks, but they are not considered significant. For non‐carcinogenic health risks, oral ingestion is the main exposure pathway, and Cr and Pb are the major pollutants. Finally, As is found to be the main carcinogenic contamination metal.

Assessment of the Ecotoxicity of Nanoplastics

The presence of micro- and nanoplastics in aquatic environments (including freshwater and marine ecosystems as well as their sediments) is becoming an increasingly serious problem worldwide. A wide range of studies have addressed the ecological effects these particles pose on biota. The main exposure pathway are food chains, e.g. under laboratory conditions these particles accumulate in the brain tissues of fish that feed on zooplankton causing brain damage. These studies, however, report mainly on the physical effects. In order to establish actual ecotoxicological effects, nanoplastics (50 nm in diameter) were assessed using the Vibrio fischeri bioluminescence inhibition bioassay (VFBIA). Our results showed that even environmentally relevant concentrations might trigger ecotoxicological effects. This study can be con- sidered to be a first screening, however, results indicate the need for more complex testing on a battery of aquatic test organisms.

Characteristics and risk assessment of organophosphorus flame retardants in urban road dust of Dalian, Northeast China

We investigated the occurrence, distribution, and potential sources of 10 organophosphorus flame retardants (OPFRs) in road dust from the urban area of Dalian, China, as well as their associated human exposures and health risks. The total concentration of Σ10OPFRs ranged from 300 to 7480 ng/g with a median of 1600 ng/g. Relatively high concentrations were observed mainly near prosperous business districts or dense residential areas. Tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCIPP), and triphenylphosphine oxide (TPPO) were detected in all dust samples. TCIPP was the dominant congener, followed by TPPO. It was found that traffic flow can obviously influence the concentration of OPFRs in road dust, suggesting vehicles may be the major sources of OPFRs in road dust, presumably from materials used in their interiors. Correlations between certain OPFRs and population density indicate a significant influence by anthropogenic activities on OPFR levels. The average daily doses (ADD) of Σ10OPFRs via ingestion, inhalation and dermal absorption from road dust were evaluated as 0.26 and 0.087 ng/(kg-bw·d) for children and adults respectively, with dust ingestion as the main exposure pathway of OPFRs. Although the exposure risk of OPFRs via road dust was relatively low in Dalian, further studies on the exposure of OPFRs are still necessary due to combined effects with other exposure pathways.

Pollution characteristics and health risk assessment of heavy metals in dry atmospheric deposits from Sfax solar saltern area in southeast of Tunisia

Concentrations of six heavy metals such as Fe, Pb, Cu, Cd, Ni and Zn in dry atmospheric deposits weekly collected through 20 sample sites from Sfax solar saltern during two successive sampling campaigns, selected from a long time monitoring, have been examined in order to evaluate their contamination levels as well as their human health risk; such concentrations (expressed in mg/kg) have shown that Fe varied from 7006.24 to 7856.45, Pb from 8.64 to 344.45, Cu from 9.33 to 298.67, Cd from 0.16 to 85.24, Ni from 6.02 to 150.02, and Zn from 12.23 to 624.57. During the study period, average concentrations (mg/kg) have been 7315.99, 103.08, 82.34, 15.93, 46.21 and 142.39, for Fe, Pb, Cu, Cd, Ni and Zn, respectively. Except for Fe, the other concentrations in dry atmospheric deposits have recorded the highest level during the first campaign especially in the sites which are close and more exposed to emissions of local pollutant industries, as well as nearby main road, resulting from high exposure frequencies. Statistical approaches, such as principal component analysis and hierarchical cluster analysis have been applied to all data, revealing an affinity between analyzed metals resulting from their origins, and confirming the influence of exposure frequencies on the spatial variability of heavy metal concentrations. Human health risk assessment has revealed that ingestion of heavy metals is the main exposure pathway for the local population. Computed Hazardous Quotient and Hazardous Index have been higher for children than for adults, thus indicating that the former may be subjected to potentially higher health risk than the latter especially during the first campaign. Calculated carcinogenic risks through ingestion and dermal contact, as well as the total carcinogenic risk for the selected heavy metals, have shown that cancer could occur more probably through ingestion than dermal contact, for children than adult, and during the first campaign (during C1: average values CRing = 8.72 × 10-4 and CRder = 1.40 × 10-6 for child; average values CRing = 5.61 × 10-5 and CRder = 2.84 × 10-6 for adult) than the second one (during C2: average values CRing = 1.59 × 10-4 and CRder = 2.54 × 10-7 for child; average values CRing = 1.02 × 10-5 and CRder = 5.19 × 10-7 for adult). The total calculated carcinogenic risk through all the sites have infrequently signaled high to very high carcinogenic risk in the first campaign (average CRA = 8.73 × 10-4 for child and CRA = 5.89 × 10-5 for adult) and occasionally exceeded the safe range for the local population in the second one (average CRA = 1.59 × 10-4 for child and CRA = 1.07 × 10-5 for adult).

Effects of soil particle size on metal bioaccessibility and health risk assessment

Oral ingestion is the main exposure pathway through which humans ingest trace metals in the soil, particularly for children. Metals in different soil particle size fractions may vary in terms of concentration and properties. Urban school/kindergarten soil samples were collected from three cities: Lanzhou in northwest China, Wuhan in central China, and Shenzhen in southeast China. Soil samples were classified according to particle size (<63 μm, 63–150 μm, 150–250 μm, and 250–2000 μm) to estimate the effects of soil particle size on the total content and bioaccessibility of metals (Cd, Cr, Cu, Ni, Pb, and Zn). Based on the results, we assessed whether the standard size <150 μm (containing < 63 μm and 63–150 μm), recommended by the Technical Review Workgroup (TRW) of the Environmental Protection Agency (EPA), and <250 μm (containing < 63 μm, 63–150 μm, and 150–250) recommended by the Bioaccessibility Research Group of Europe (BARGE), are suitable where the largest proportion adhering to hands is the finest soil (<63 μm). The results showed that different metals exhibited different relationships between soil particle size and content and between soil particle size and bioaccessibility. Pb and Zn generally exhibited the greatest bioaccessibility in the coarsest particle sizes (250–2000 μm); whereas the highest Ni bioaccessibility occurred in the finest sizes (<63 μm); the bioaccessibility of other metals did not exhibit any obvious relationships with particle size. When assessing health risks using bioaccessible metal content in the recommended soil particle size ranges (<150 μm and <250 μm) and in finer particles (<63 μm), the results for noncarcinogenic risks to children exhibited no obvious difference, while the actual carcinogenic risks may be underestimated with the use of soil particle size ranges < 150 μm and <250 μm. Therefore, when choosing an optimal particle size fraction to evaluate the health risk of oral soil ingestion, we recommend the use of the bioaccessible metal content in <63 μm soil fraction.

Concentration, fluxes, risks, and sources of heavy metals in atmospheric deposition in the Lihe River watershed, Taihu region, eastern China

This study investigated ecological and human-health risks associated with heavy-metal pollution arising from deposition in the Lihe River region of eastern China. Ecological risk assessment was based on the geoaccumulation index and health risk using a US Environmental Protection Agency health risk assessment model. Pollution source contributions were assessed through enrichment factors, positive matrix factor analysis, and Pb isotopic analyses. Mean concentrations of Cd, Cr, Cu, Ni, Pb, and Zn measured in deposited particulates were 8.842, 79.92, 150.3, 46.86, 231.7 and 1920 mg kg−1, respectively. Deposition fluxes of these six heavy metals were 0.6, 6.0, 10.9, 3.3, 16.4, and 157 mg m−2 a−1, respectively. The order of ecological risk was Cd > Zn ≈ Pb > Cu > Ni > Cr. Ingestion is the main pathway of human exposure, however hazard quotient and hazard index values of the heavy metals studied were <1, indicating little or minimal risk to human health. The contributions to atmospheric deposition of coal-fired industries were Cd 82.4%, Cu 51.9%, Ni 51.2%, and Pb 68.3%. Zn was derived mainly from vehicular emissions (75.7%), and Cr concentrations (66.3%) were controlled mainly by natural sources. The qualitative and quantitative methods employed here resulted in improved accuracy of source apportionment. The results provide insights into the management of heavy-metal pollution in atmospheric deposition and serve as a reference for other regions of China.

Non-dietary exposure to phthalates for pre-school children in kindergarten in Beijing, China

This study measured concentrations of seven phthalates in gas-phase, particle-phase and dust/soil in kindergarten indoors and outdoors in Beijing, China, during May to July 2012. We analysed phthalate pollution characteristics, examined phthalate co-occurrence and estimated intake of phthalates via dust ingestion, inhalation, and dermal absorption through direct air-through-skin using Monte Carlo simulation. Phthalate pollution level indoors were higher than outdoors. Di (2-Ethylhexyl) phthalate (DEHP), Diisobutyl phthalate (DiBP) and Di-n-butyl phthalate (DnBP) was the most abundant phthalate in dust, gas-phase and particle-phase indoors, respectively, with an average contribution of 48.4%, 41.0% and 41.1%. DEHP was the most predominant phthalate in outdoor sampled medias, and the average contribution was in the range of 45.5%–48.6%. Indoor phthalate concentration in dust is not related to the sampled surface and grade, and is related to the sampled kindergartens. The co-occurrence of phthalates is related to the type of phthalates and sampling medias. The pollution level of DiBP and DnBP in dust and airborne is more serious in kindergarten in China, which should be paid more attention. Total intake of DiBP is the most in kindergarten. Outdoor phthalate exposure is much lower than indoor, only contributing from 2.68% to 7.07% to total intake. Dermal absorption is the main exposure pathway for indoor exposure of DiBP and DnBP, contributing 57.8% and 60.3%, while dust ingestion is the main exposure pathway for indoor exposure of DEHP, contributing 74.4%. We should take some control approaches to decrease the phthalate exposure for pre-children.

Occurrence and distribution of clinical and veterinary antibiotics in the faeces of a Chinese population

Antibiotics ingested in the human gut may create selective pressure to change the composition of the gut microbiota, which could adversely effect the immune system of the host. However, the occurrence and distribution of antibiotics in the human gut remains unclear. A total population of 180 individuals, across three Chinses regions with different economic development levels, including children, adults, and elders, were sampled in 2017. A total of 19 representative antibiotics, including both clinical and veterinary antibiotics, were investigated in human faeces. While clinical use and prescriptions were the main exposure pathways for children, environmental media were the exposure pathway to adults. In addition, significant differences (P < 0.05) in antibiotic residues in human faeces were observed amongst various economic development levels, where human faeces from underdeveloped areas were mostly associated with higher levels of antibiotics. This study first to investigate the occurrence and distribution of typical antibiotics in the faeces of a Chinese population and thereby provide a reference for the intensive study of the effects and mechanisms of antibiotics on human gut microbiota.

Occurrence and distribution of perfluorooctane sulfonate and perfluorooctanoic acid in three major rivers of Xinjiang, China.

Drinking water is a main pathway of human exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). These two compounds have been identified in environmental waters worldwide, but little is known about their occurrence in Xinjiang. In this study, 155 water samples were obtained from 37 locations across Ulungur River, Manasi River, and Tarim River in Xinjiang, and were assessed by using liquid chromatography tandem-mass spectrometry. PFOS and PFOA were detected in over 50% of the samples with mean concentrations of 3.194 ng/L for PFOS and 3.460 ng/L for PFOA. Spatial and regional distribution differences do exist among the three analyzed rivers. PFOS and PFOA in Manasi River were observed at the highest levels (especially in M10 and M11), but no aggravation occurred from 2014 to 2017. Seasonal variations of PFOS and PFOA concentrations showed that water samples collected during summer were higher than those in other three seasons. The occurrence, levels, and distribution patterns of PFOS and PFOA were investigated in the present study, which provides useful theory and data support for human health risk assessment. The findings of the present study can be considered for controlling these water pollutants in environmental waters.

Activation of NF-κB pathways mediating the inflammation and pulmonary diseases associated with atmospheric methylamine exposure

The effects of methylamine on human health have been debated for several years, but the exact adverse outcomes and definite signaling cascades have not been elucidated yet. Herein, a NF-κB signal pathway, a positive regulator of inflammation was identified as the main pathway of methylamine exposure induced adverse effects in bronchial airway cells (16HBE) for the first time. The results indicated that methylamine could stimulate the overproduction of reactive oxygen species (ROS) in cytoplasm and mitochondria of 16HBE cells. Moreover, ROS accelerate the translocation and phosphorylation of NF-κB in nucleic and promote the expression of inflammatory, such as IL-8 and IL-6. As a result, methylamine was found to be increased ROS-mediated NF-κB activation in cells, leading to the production of inflammatory cytokine. Furthermore, the results also showed that methylamine could affect the expression of cytokines related genes, p53, STAT3, Bcl2, c-myc, Cyclin D, Hes1, Mcl-1, TGF-β2. The breakdown of those cell proliferation and apoptosis related genes were leading to a common toxic mechanism of cell death. In summary, our work uncovers a mechanism by which methylamine can induce the formation of inflammation response and demonstrates potential inflammation and carcinogenesis in human airway cell upon the methylamine inhaled.

Nuclear medicine: workplace monitoring and internal occupational exposure during a ventilation/perfusion single-photon emission tomography.

The administration of 99mTc-HDP to diagnose pulmonary thromboembolisms leads to the presence of 99mTc in the environment of a nuclear medicine department, which could pose a potential risk of internal contamination to medical staff. Therefore, air samples from the administration room, gamma camera room and corridor of such a department were taken for the purpose of performing a workplace monitoring program of the medical centre under study, with maximum activity values of 640 ± 30kBq/m3, 1.5 ± 0.1kBq/m3 and 54 ± 3kBq/m3, respectively, being obtained. These results correspond to committed effective doses received by exposed employees, via inhalation, when one ventilation/perfusion single-photon emission tomography study was performed, of 0.7μSv, 0.004μSv and 0.2μSv, respectively. As inhalation is the employees' main exposure pathway to radio-aerosols, the internal dose of the nuclear medicine department's medical staff was also evaluated via urine bioassay measurements. Nuclear medicine nurses showed the highest 99mTc activity in 24-h urine samples (2100 ± 130Bq/day), resulting in a committed effective dose of 21μSv for each diagnostic study performed. Even so, the performance of ventilation/perfusion diagnostic studies did not constitute a substantial radiological risk since the annual dose limit for exposed employees was not exceeded.

Potential health risks associated to heavy metal contamination of soils in the Yellow River Delta, China

The level of inhalable particulate matter (PM10) in the Yellow River Delta (YERD), an oil production area in north China, are generally high, resulting in an increase exposure to heavy metals (HMs) from soil. This exposure increases during winter and spring periods. In order to determine potential health risks posed by 9 HMs (i.e. Cr, Cd, As, Cu, Hg, Ni, Mn, Zn and Pb) in this area, high density sampling of surface soils across the YERD was undertaken. Results indicate that even through PM10 is generally high, no significant carcinogenic and non-carcinogenic health risks in YERD were identified. Ingestion rather than inhalation or dermal contact is the main exposure pathway. Hazard Index (HI) and total probability of carcinogenic risk (TCR) values indicated that children experienced higher carcinogenic and non-carcinogenic risks. Arsenic contributed the most to carcinogenic and non-carcinogenic health risks, while the effects of other HMs were minor. Our results also demonstrate that, based on the spatial trending of HI and TCR of high-risk areas, oil production will cause an unacceptable level of health risk. Due to the close proximity of this area to the coast, the wash effect of sea water will remove HMs from the soil and lower the health risks. Therefore, investigations related to coastal oilfields should investigate the transfer of HMs to seawater or local sediments. Our results provide a basis for environmental management in the YERD and other rapidly developing industrial regions around the world.

Aerosols from a wastewater treatment plant using oxidation ditch process: Characteristics, source apportionment, and exposure risks

The study of aerosol dispersion characteristics in wastewater treatment plants (WWTPs) has attracted extensive attention. Oxidation ditch (OD) is a commonly implemented process during biological wastewater treatment. This study assessed the component characteristics, source apportionment, and exposure risks of aerosols generated from a WWTP using the OD process (AWO). The results indicated that the aeration part of oxidation ditch (ODA) exhibited the highest concentrations and proportions of the respiratory fractions (RF) of bacteria, Enterobacteriaceae, Staphylococcus aureus, and Pseudomonas aeruginosa. Some pathogenic or opportunistic-pathogenic bacteria and carcinogenic metal(loid)s were detected in the AWO. The source apportionment results indicated that the outdoor wastewater treatment processes and ambient air contributed to the constitution of the AWO. The indoor aerosols were mainly constituted by composition of the wastewater treatment process such as the sludge dewatering room (SDR). The pathogenic or opportunistic-pathogenic bacteria with eight genera (Colinsella, Dermatophilus, Enterobactor, Erycherichia-Shigella, Ledionella, Selenomonas, Xanthobacter, and Veillonella) were largely attributed to wastewater or sludge. The risk assessment suggested that inhalation was the main exposure pathway for aerosols (including bacteria and metal(loid)s). Additionally, As indicated the highest non-carcinogenic risks. Furthermore, As, Cd, and Co were associated with high carcinogenic risks. The ODA and sludge dewatering room (SDR) indicated the highest carcinogenic and non-carcinogenic risks of metal(loid)s, respectively. Thus, the AWO should be sufficiently researched and monitored to mitigate their harmful effects on human health, particularly with regard to the health of the site workers.

Bordetella pertussis Infection in Infants and Young Children in Shanghai, China, 2016-2017: Clinical Features, Genotype Variations of Antigenic Genes and Macrolides Resistance.

The global resurgence of pertussis in countries with high vaccination coverage has been a concern of public health. Nasopharyngeal swabs were collected for Bordetella pertussis culture from children with suspected pertussis. Clinical and vaccination information were reviewed through electronic medical chart and immunization record. Antibiotics susceptibility was evaluated using E-test for erythromycin, azithromycin, clarithromycin and sulfamethoxazole/trimethoprim. The MLST genotypes and 7 antigenic genes (ptxP, ptxA, ptxC, Prn, fim3, fim2 and tcfA) of Bordetella pertussis were identified by polymerase chain reaction amplification and sequencing. During January 2016 to September 2017, a total of 141 children 1-48 months of age were culture-confirmed with pertussis, of whom 98 (69.5%) were younger than 6 months, 25 (17.7%) had completed at least 3 doses of DTaP and 75 (53.2%) had a clear exposure to household members with persistent cough. Fully vaccinated cases manifested milder disease than unvaccinated and not-fully vaccinated cases. All strains were MLST2. High-virulent strains characteristic of ptxP3/prn2/ptxC2 constituted 41.1% (58/141) and were all susceptible to macrolides while low-virulent strains characteristic of ptxP1/prn1/ptxC1 constituted 58.9% (83/141) and 97.6% (81/83), respectively, were highly resistant to macrolides. Pertussis is resurging among infants and young children in Shanghai, and household transmission is the main exposure pathway. The high-virulent strains harboring ptxP3/prn2/ptxC2 and the macrolide-resistant Bordetella pertussis strains are quite prevalent. These issues impose a public health concern in Shanghai. Our findings are important to modify the DTaP vaccination strategy and the management guideline of pertussis in China.