Incremental Lifetime Cancer Risk Research Articles

Personal exposure to aldehydes and potential health risks among schoolchildren in the city.

Schoolchildren are sensitive to airborne aldehyde exposures. The knowledge regarding inhalation exposure to aldehydes and the factors influencing exposure in schoolchildren is limited. This study aimed to assess the variability and potential health risks of exposure to aldehydes (including formaldehyde) in schoolchildren. The important factors affecting personal exposure to aldehydes were also explored. Forty schoolchildren were recruited from the urban and suburban areas of Taiwan for aldehyde samplings and questionnaire surveys. Personal and indoor home samples of aldehydes were collected simultaneously during warm and cold seasons. We also identified the potential variables associated with aldehyde exposure based on the participant's responses to the questionnaires using mixed-effects models. The dominant three abundant aldehydes identified in personal exposure samples were formaldehyde (geometric mean, GM = 12.2µg/m3), acetaldehyde (GM = 5.53µg/m3), and hexaldehyde (GM = 8.79µg/m3), accounting for approximately 80% of the total selected aldehydes. Higher personal exposure to aldehydes was observed during the warm season. Moreover, the within-subject variance was predominant, accounting for 66.6 to > 99.9% of the total variance in exposure. Schoolchildren had a high probability of overexposure to formaldehyde and acrolein, which resulted in an incremental lifetime cancer risk of 1.59 × 10-4 (95th percentile = 4.64 × 10-4). Season, location, household refurbishment, and indoor ventilation variables were significantly associated with personal exposure to aldehydes. The results can improve our understanding of aldehyde exposure among schoolchildren to propose mitigation strategies. These findings may be applied to further epidemiological studies.

The Sources of Polycyclic Aromatic Hydrocarbons in Road Dust and Their Potential Hazard

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants (POPs) found in the environment, posing significant health concerns for the population. This research aimed to assess the PAH levels in road dust near bus stops, identify their sources, and evaluate potential health risks. The analysis involved the use of a gas chromatography–flame ionization detector (GC-FID) to measure PAHs and absolute principal component score-multiple linear regression (APCS-MLR) for source apportionment of PAHs. The results indicated that the measured PAHs concentrations in road dust ranged from 137.8 to 5813 ng g−1, with Indeno[1,2,3-c,d]pyrene having the highest PAHs concentrations. The study identified three main sources of PAHs such as oil spills, fuel combustion, and coal burning, determined through APCS-MLR modeling. Further analysis revealed that the aggregate incremental lifetime cancer risk (ILCR) for children and adults were 2.16 × 10−6 and 2.08 × 10−6, respectively. Additionally, the hazard index (HI) for children exceeded that of adults, suggesting greater vulnerability to the potential health effects of PAH exposure. The findings indicate that long-term exposure to PAHs may negatively impact lung function and increase the risk of cancer and skin diseases. As a result, it is crucial for the local government to implement effective measures aimed at improving fuel quality and promoting green public transportation within the city. These initiatives may help mitigate PAH emissions and safeguard public health.

Integrative assessment of urban dust polycyclic aromatic hydrocarbons using ground and satellite data in Iran.

Recently, for quick urbanization and industrialization, pollutants, especially urban dust, have posed many threats to the human environment. Polycyclic aromatic hydrocarbons (PAHs) are regarded as the main dangerous pollutants that are widespread, persistent, and carcinogenic. The present work aimed to investigate the contamination and sources of PAHs, as well as to assess the risk of cancer for 16 priority PAHs, in urban dust samples in Ahvaz, Isfahan, and Shiraz cities in Iran. We measured PAH concentrations by gas chromatography-mass spectrometry (GC-MS). The average concentrations of the 16 PAHs in Ahvaz, Isfahan, and Shiraz were 6215.11, 7611.03, and 7810.37 μg kg-1, respectively. The domination of low-molecular-weight (LMW) PAHs was observed in Ahvaz, while maximum contribution was observed for high-molecular-weight (HMW) PAHs in Esfahan and Shiraz. For PAHs' source identification, diagnostic ratio, correlation analysis, clustering, and positive matrix factorization (PMF) model were used. PAHs had a combustion (coal and wood, oil, fossil fuels) and gasoline/diesel engine emissions in all cities. Comparative studies suggest that the PAH compounds' level is higher in the research area than in other countries, except for China and India. Also, the pollution of urban dust PAHs has increased over time compared to previous studies in the same cities. The cancer risk from exposure to dust contaminated with PAHs was assessed using the Incremental Lifetime Cancer Risk (ILCR) model. According to the findings, a high risk of exposure to cancer was observed in Ahvaz, Isfahan, and Shiraz. However, compared to adults, children are at higher risk of cancer in their daily lives via dermal contact and unconscious ingestion. Based on the ILCR values, the risk of cancer is in the order of Shiraz > Isfahan > Ahvaz. To assess air pollutants and their effects on urban dust, TROPOMI onboard the Sentinel-5P data were used in the studied cities during 2018-2021. The results show that Ahvaz has different high levels of CO compared to the other 2 cities. Also, Isfahan has different high levels of NO2 compared to the other 2 cities, but Shiraz has different low levels of O3. According to satellite time series data, the trend of the Aerosol Absorbing Index (AAI) has been increasing, while there was a decreasing trend in AAI from the beginning of the COVID-19 pandemic until 12 months later. Therefore, the natural and anthropogenic sources of urban dust PAHs have been increasing in all studied cities. Our findings show that PAH compounds in urban dust pose a significant threat to human health. Therefore, strategic management and planning are vital in reducing urban dust pollution.

Inhalation bioaccessibility and risk assessment for PM-bound organic components: Co-effects of component physicochemical properties, PM properties, and sources

Inhalation bioaccessibility and deposition in respiratory tracts of organic components in atmospheric particulate matter (PM) are key factors for accurately estimating health risks and understanding human exposures. This study evaluated the in-vitro inhalation bioaccessibility of polycyclic aromatic hydrocarbons (PAHs) and PAH derivatives, phthalic acid esters (PAEs), polychlorinated biphenyls (PCBs), and organophosphate flame retardants (OPFRs) in size-resolved PM from a Chinese megacity. The bioaccessibility ranged from 0.2% to 77.8% in the heating period (HP), and from 0.7% to 94.2% in the non-heating period (NHP). Result suggests that less hydrophobic organics might be more bioaccessible. Bioaccessibility of medium logKow organics in sizes > 0.65 µm was significantly inhibited by high carbon fractions, indicating the co-effects. Then, this is the first study to explore effects of sources on inhalation bioaccessibility of organics. Coal and biomass combustion in HP and traffic emission in NHP negatively correlated with bioaccessibility. Secondary particles also negatively correlated with bioaccessibility of medium logKow organics. Incremental lifetime cancer risk (ILCR) and non-cancer risk (HQ) for all measured components in PM10 were estimated after considering the bioaccessibility and deposition efficiencies and the HQ and ILCR were within the acceptable range. BaP and DEHP were strong contributors to HQ and ILCR, respectively.

Occurrence, Sources, and Health Risks of Polycyclic Aromatic Hydrocarbons in Road Environments from Harbin, a Megacity of China.

To obtain a comprehensive understanding about that occurrence, sources, and effects on human health of polycyclic aromatic hydrocarbons (PAHs) in road environmental samples from Harbin, concentrations of 32 PAHs in road dust, green belt soil, and parking lot dust samples were quantified. The total PAH concentrations ranged from 0.95 to 40.7 μg/g and 0.39 to 43.9 μg/g in road dust and green belt soil, respectively, and were dominated by high molecular weight PAHs (HMW-PAHs). Despite the content of PAHs in arterial roads being higher, the composition profile of PAHs was hardly influenced by road types. For parking lot dust, the range of total PAH concentrations was 0.81-190 μg/g, and three-ring to five-ring PAHs produced the maximum contribution. Compared with surface parking lots (mean: 6.12 μg/g), higher total PAH concentrations were detected in underground parking lots (mean: 33.1 μg/g). The diagnostic ratios of PAHs showed that petroleum, petroleum combustion, and biomass/coal combustion were major sources of PAHs in the samples. Furthermore, according to the Incremental Lifetime Cancer Risk model, the cancer risks of three kinds of samples for adults and children were above the threshold (10-6). Overall, this study demonstrated that PAHs in the road environment of Harbin have a certain health impact on local citizens.

Occurrence and exposure evaluation of polycyclic aromatic hydrocarbons in tea samples consumed in Beijing-Tianjin-Hebei regions of China

In this study, the concentrations of polycyclic aromatic hydrocarbons (PAHs) were investigated in a total of 129 tea samples marketed in Beijing-Tianjin-Hebei (BTH) regions of China. The total concentrations of 16 PAHs (Σ16 PAHs) varied from 16.6 to 781.6 μg/kg with a mean value of 211.7 μg/kg. Tea samples were contaminated mainly with low molecular weight PAH compounds. During tea infusion, 4.9–9.3% of the Σ16 PAHs contained in different types of tea samples were released into the liquor. The dietary exposure of PAHs and risk assessments of adults in BTH region were then performed by calculating estimated daily intake (EDI), margin of exposure approach (MOE) and incremental lifetime cancer risk (ILCR). Compared to semi-fermented or unfermented tea samples, EDIs of PAHs in fullyfermented tea displayed the highest exposure risk. The MOEs results in all six types tea for local population are at safe range (MOE ≥ 10,000). These ILCR values indicated there is significant potential of carcinogenic risk related to tea consumption, but no significant cancer risk.

Comprehensive evaluation on safe utilization potential of ten oilseed rape cultivars in a cadmium contaminated soil

Oilseed rape (Brassica napus L.) planting could be a promising approach for the safe utilization of cadmium (Cd) contaminated soil. However, comprehensive evaluation on safe utilization potential of oilseed rape was lacked, including phytoextraction efficiency, health risk, and economic benefits. In this study, ten oilseed rape cultivars were planted in Cd-contaminated soils immobilized with limestone and a comprehensive evaluation was performed on the safe utilization potential. Results showed that the highest biomass of rapeseed (1363-1569 kg ha−1) was found in Zhongshuang 11, Xiangzayou 787, and Luoyouza 101. Zhongyouza 19, Zhongshuang 11 and Dadi 199 had the highest Cd phytoextraction efficiency (3.31-3.76 g ha−1). The Cd concentrations in all the rapeseeds ranged from 0.18–0.45 mg kg−1 and were lower than the limit of food security standards, but oil Cd concentrations of three cultivars (Fengyou 730, Dadi 199, and Yangguang 50) were 0.90-1.56 times higher than those in the reference oils (0.04-0.05 mg kg−1). Target hazard quotient (THQ) suggested that the Cd in all the oils were under the acceptable level for adults and children, whereas only of three cultivars (Huihaoyou 26, Luoyouza 101, and Zhongshuang 11) were at acceptable level at incremental lifetime cancer risk (ILCR) value. Based on the yields and market price of rapeseed, Luoyouza 101, Xiangzayou 787, and Zhongshuang 11 had the highest economic benefits (9812-11300 CNY ha−1). Overall, the comprehensive evaluation indicates that Zhongshuang 11 is the most suitable for the safe utilization of Cd contaminated soil.

Content, Distribution, Source Analysis, and Risk Assessment of PAHs in Arable Soils of Taiyuan

PAHs (polycyclic aromatic hydrocarbons) accumulated in arable soils have significant impacts on farmland quality and human health, which has attracted wide attention from scientists and the public. A total of 22 arable soil samples were collected from Taiyuan, an old industrial city, including three districts (industrial zones, hilly areas, and sewage irrigation area), and the contents of 21 PAHs were detected using the GC-MS method. The sources of PAHs in soils were analyzed using the diagnostic ratios (DRs) method and positive matrix factorization (PMF) model, and the soil health risks were analyzed using the incremental lifetime cancer risk (ILCR) model. The results indicated that the average concentrations of Σ21PAHs and Σ16PAHs in arable soils of Taiyuan were 934.6 ng·g-1 and 787.7 ng·g-1, respectively, which were lower than the soil pollution risk screening value of agricultural land stipulated in GB 15168-2018. 3-5 rings PAHs were the dominant components, accounting for~90% of the Σ21PAHs. Approximately 60% of sites in industrial zones, 13% in hilly areas, and 33% in the sewage irrigation area had high PAHs contents larger than 1000 ng·g-1. The spatial distribution of PAHs showed that more severe PAHs pollution in the soil occurred in industrial areas than that in the other two districts. The DRs suggested that the combustion of coals, bio-masses, and traffic emissions were the dominant sources for PAHs pollution in arable soils in Taiyuan. The simulation results of the PMF model indicated that the sources and contribution rates of PAHs in cultivated soils were coal and biomass burning sources (59%), traffic sources (22%), and coking sources (19%). The risk assessment confirmed that the arable soils in Taiyuan had high potential carcinogenic risks; thus, more attention should be paid to the PAHs pollutions in arable soils.

Trace elements exposure through the dietary intake of fruits and vegetables collected from a divisional city of Bangladesh: Human health implications

BackgroundDietary exposure is the main source of bioaccumulation of trace elements through contaminated fruits and vegetables, which are rich sources of vitamins and minerals, but also toxic elements, which harm our health and well-being. ObjectivesThis study focused on human health nutrition and risks associated with the cancer-causing and non-cancerous trace elements in commonly available winter fruits and vegetables collected from Mymensingh divisional city markets. MethodsSix locally available fruits (viz. pineapple, guava, hog plum, water chestnut, banana, Indian olive) and six seasonal vegetables (viz. red amaranth, radish leaves, brinjal, bottle gourd, radish, and carrot) were collected. The atomic absorption spectrophotometer was used to determine the contents of Zn, Fe, Mn, Cu, Pb, Cr, and Cd. Target Hazard Quotient (THQ), Hazard Index (HI), and Cumulative Incremental Lifetime Cancer Risk (∑ILCR) were calculated to estimate non-cancer and cancer health risks. ResultsAll trace element contents were higher in vegetables than in fruits except Cu. Chromium contents were below the detectable limit for all fruits and vegetables. The highest amounts of Zn (10.54 µg g−1 fresh wt.), Fe (68.75 µg g−1 fresh wt.) and Mn (55.65 µg g−1 fresh wt.) were found in radish leaves. On the other hand, the maximum amounts of Pb (0.388 µg g−1 fresh wt.) and Cd (0.180 µg g−1 fresh wt.) were found in red amaranth, while the highest content of Cu (5.67 µg g−1 fresh wt.) was determined from banana. The calculated HI was <1 in every case except red amaranth suggesting none of the fruit and other vegetable samples poses individual non-cancerous risk after consumption. On the other hand, the measured ILCR values for Cd for both males and females ranged from 1.51E-04 to 6.45E-03 and 2.12E-04 to 9.03E-03, respectively, indicating cancer risk in all fruit and vegetable samples, either individually or cumulatively. ConclusionThe locally available fruits and vegetables of the Mymensingh divisional city area posed significant human health risks. However, regular monitoring of toxic metal contents is necessary to ensure the food safety of locally grown indigenous fruits and vegetables for the city dwellers.

Characterization and Risk Assessment of PM2.5-Bound Polycyclic Aromatic Hydrocarbons and their Derivatives Emitted from a Typical Pesticide Factory in China.

Polycyclic aromatic hydrocarbons (PAHs) and their derivatives have received extensive attention due to their negative effects on the environment and on human health. However, few studies have performed comprehensive assessments of PAHs emitted from pesticide factories. This study assessed the concentration, composition, and health risk of 52 PM2.5-bound PAHs during the daytime and nighttime in the vicinity of a typical pesticide factory. The total concentration of 52 PAHs (Σ52PAHs) ranged from 53.04 to 663.55 ng/m3. No significant differences were observed between daytime and nighttime PAH concentrations. The average concentrations of twenty-two parent PAHs, seven alkylated PAHs, ten oxygenated PAHs, and twelve nitrated PAHs were 112.55 ± 89.69, 18.05 ± 13.76, 66.13 ± 54.79, and 3.90 ± 2.24 ng/m3, respectively. A higher proportion of high-molecular-weight (4-5 rings) PAHs than low-molecular-weight (2-3 rings) PAHs was observed. This was likely due to the high-temperature combustion of fuels. Analysis of diagnostic ratios indicated that the PAHs were likely derived from coal combustion and mixed sources. The total carcinogenic equivalent toxicity ranged from 15.93 to 181.27 ng/m3. The incremental lifetime cancer risk from inhalation, ingestion, and dermal contact with the PAHs was 2.33 × 10-3 for men and 2.53 × 10-3 for women, and the loss of life expectancy due to the PAHs was 11,915 min (about 0.023 year) for men and 12,952 min (about 0.025 year) for women. These results suggest that long-term exposure to PM2.5 emissions from a pesticide factory has significant adverse effects on health. The study results support implementing the characterization of PAH emissions from pesticide factories and provides a scientific basis for optimizing the living environment around pesticide factories.

Polycyclic Aromatic Hydrocarbons from Domestic Solid Waste Incinerators in Nam Dinh Province, Northern Area of Vietnam: A Comprehensive Assessment of Emission, Source Markers and Human Health Risk.

A comprehensive research of the polycyclic aromatic hydrocarbons (PAHs) emission from domestic waste incinerators in northern areas of Vietnam, were investigated. Sixty-four samples from two domestic waste incinerators were collected and analyzed for PAHs. The PAHs concentrations in the samples were determined using gas chromatography coupled with mass spectrometry. In April, June, September, and November 2021, Σ16PAHs mean concentrations in chimney air samples were 970.9 ± 57.4, 1061.9 ± 49.8, 1070.7 ± 41.3 and 1136.1 ± 136.5µg m-3, respectively. The mean emission factors of Σ16PAHs were 7.5mg/kg. The mean percentages of low molecular weight PAHs were predominant in the analyzed air samples. The toxic equivalent quotient of samples ranged from 30.7 to 41.7mg/kg, whereas the incremental lifetime cancer risk exceeded 10- 3. This results implied a high level of concern with potentially negative health consequences. The four diagnostic ratios of PAHs were found and can be used for identification of sources markers from domestic waste incinerators.

An evaluation of arsenic contamination status and its potential health risk assessment in villages of Nadia and North 24 Parganas, West Bengal, India.

The present study was conducted to evaluate the arsenic (As) contamination and possible associated health hazards to exposed population in four villages of two districts (Nadia and North 24 Parganas) of West Bengal, India. The study included two villages each from Nadia (Jaguli and Kugacchi) and North 24 Parganas (Chamta and Byaspur) districts. Groundwater, surface water, soil, rice grains and rice-based food samples were collected from these villages. The results revealed the presence of As in high concentrations in groundwater (35.00 to 186.00µg L-1), surface water (30.00 to 61.00µg L-1), soil (46.17 to 66.00mgkg-1), rice grains (0.017 to 1.27µgg-1) and rice-based food products (0.012 to 0.40µgg-1). The maximum As levels were recorded in all types of samples collected from Kugacchi village. The rice grain samples included high-yielding and local varieties, and the level of As in high-yielding varieties was found to be higher (0.72 to 1.27µgg-1) than in local varieties (0.25 to 1.06µgg-1). The data of As concentrations was used for understanding the hazard quotient (HQ) and incremental lifetime cancer risk (ILCR) to the As-exposed population, and significant non-carcinogenic and carcinogenic risks were revealed considering consumption of rice grains at 400g per day. The study demonstrates the severity of As contamination in the surveyed villages, which may pose a hindrance to attainment of sustainable development goals (SDGs) by 2030 and proposes the implementation of requisite safety measures.

Bioaccumulation and Human Health Risk Assessment of Arsenic and Chromium Species in Water–Soil–Vegetables System in Lephalale, Limpopo Province, South Africa

The accumulation of potentially toxic elements (PTEs) in water, soil and vegetables can pose a severe threat to the respective organisms and lead to human health risks upon exposure. Water, soil and vegetable samples were collected from the Mokolo River and its vicinity. Total concentration quantification and speciation analysis of chromium (Cr) and arsenic (As) were performed using inductively coupled plasma-mass spectrometry (ICP-MS) and high-performance liquid chromatography hyphenated to inductively coupled plasma-mass spectrometry (HPLC-ICP-MS), respectively. The total concentrations of Cr and As were below the maximum permissible levels (MPLs) set by the World Health Organization (WHO) and South Africa’s Department of Water Affairs and Forestry (DWAF) for drinking water. The soil quality guideline value of 64.0 µg/g for Cr was surpassed in most sites and posed a great risk to the vegetables growing in it, whereas the guideline value of 12.0 µg/g for As was surpassed in one sampling site. The observed high concentrations in soil could be linked to the use of fertilizers and atmospheric deposits introduced through coal burning by power stations. In vegetables, the total Cr concentration surpassed the recommended MPL of 0.5 µg/g, rendering the vegetables unsafe for human consumption. Concentrations ranging from 197 to 1180 ng/g and 374 to 17400 ng/g were detected for Cr(VI) and Cr(III), respectively. The consumption of vegetables containing high levels of Cr and As would result in health risks in adults and children as the total hazard quotient (THQ) exceeded 1. The consumption of some vegetables particularly by children could cause serious health risks as the THQ &gt; 10 was observed for some Cr-contaminated vegetables. The incremental lifetime cancer risk (ILCR) threshold of 1 × 10−4 was exceeded, indicating that the overall consumption of vegetables had high cancer risks for adults and children. This study suggests that the consumption of vegetable samples would lead to health risks in the population.

Air pollution prevention in central China: Effects on particulate-bound PAHs from 2010 to 2018

Long-term trends in particulate-bound polycyclic aromatic hydrocarbon (PAH) concentrations in air in Zhengzhou (a severely polluted city in central China) between 2010 and 2018 were studied to assess the effectiveness of an air pollution prevention and control action plan (APPCAP) implemented in 2013. The PM2.5, sum of 16 PAHs (Σ16 PAHs), benzo[a]pyrene (BaP), and BaP toxic equivalent concentrations were high before 2013 but 41%, 77%, 77%, and 78% lower, respectively, after the APPCAP. The maximum daily Σ16 PAHs concentration between 2014 and 2018 was 338 ng/m3, 65% lower than the maximum of 961 ng/m3 between 2010 and 2013. The ratio between the Σ16 PAHs concentrations in winter and summer decreased over time and was 8.0 in 2011 and 1.5 in 2017. The most abundant PAH was benzo[b]fluoranthene, for which the 9-year mean concentration was 14 ± 21 ng/m3 (15% of the Σ16 PAHs concentration). The mean benzo[b]fluoranthene concentration decreased from 28 ± 27 ng/m3 before to 5 ± 4 ng/m3 after the APPCAP (an 83% decrease). The mean daily BaP concentrations were 0.1–62.8 ng/m3, and >56% exceeded the daily standard limit of 2.5 ng/m3 for air. The BaP concentration decreased from 10 ± 8 ng/m3 before to 2 ± 2 ng/m3 after the APPCAP (a 77% decrease). Diagnostic ratios and positive matrix factorization model results indicated that coal combustion and vehicle exhausts were important sources of PAHs throughout the study period, contributing >70% of the Σ16 PAHs concentrations. The APPCAP increased the relative contribution of vehicle exhausts from 29% to 35% but decreased the Σ16 PAHs concentration attributed to vehicle exhausts from 48 to 12 ng/m3. The PAH concentration attributed to vehicle exhausts decreased by 79% even though vehicle numbers strongly increased, indicating that pollution caused by vehicles was controlled well. The relative contribution of coal combustion remained stable but the PAH concentration attributed to coal combustion decreased from 68 ng/m3 before to 13 ng/m3 after the APPCAP. Vehicles made dominant contributions to the incremental lifetime cancer risk (ILCRs) before and after the APPCAP even though the APPCAP decreased the ILCRs by 78%. Coal combustion was the dominant source of PAHs but contributed only 12–15% of the ILCRs. The APPCAP decreased PAH emissions and changed the contributions of different sources of PAHs, and thus strongly affected the overall toxicity of PAHs to humans.

Environmental and Health Impacts: Presence of Radionuclides and Toxic Metals in Mining Areas in Niger State, Nigeria

The distribution of radionuclides and heavy metals (carcinogenic and non-carcinogenic) in soil and plants grown in lead contaminated areas were determined using gamma spectrometry and AAS (Atomic Absorption Spectrometry). The values of Dout (outdoor dose rate) and Din (indoor dose rate) were found to vary from 49.10 to 96.59 nGy h-1 with a mean value of 73.75 nGy h-1 and 97.30 to 191.67 nGy h-1 with a mean value of 143.39 nGy h-1 for Kawo; 51.64 to 105.26 nGy h-1 with a mean value of 75.36 nGy h-1 and 104.43 to 205. 87 nGy h-1 with a mean value of 157.13 nGy h-1 for Magiro. The weighted mean concentrations of Pb, Cu, Fe, Cr, Cd and Ni in mg kg-1 in soil and crop were (2.20,2.29), (3.14, 0.16), (15.10, 19.33), (0.16, 0.25), (0.24, 0.05), (0.43, 0.06) and (3.00, 3.18), (6.09, 0.34), (16.83, 10.10), (0.22,0.36), (0.25, 0.05), (0.43, 0.06) for Kawo and Magiro respectively. The total incremental lifetime cancer risk ΣILCR for both adults (0.73 x 10-2) and children (1.03 x 10-2) were above tolerable acceptable risk (given as 1 x 10-6 to 1 x 10-4). Therefore, the areas need remedial action and proper monitoring.

Molecular compositions and stable carbon isotopes (δ13C) of PAHs in wintertime PM2.5 in urban Xi'an, China: Implications for source distribution and atmospheric oxidation

Atmospheric polycyclic aromatic hydrocarbons (PAHs) are potentially carcinogenic and mutagenic to human beings, and thus have attracted significant attention in recent decades. Compound-specific stable carbon isotopes (δ13C) of PAHs are indicative for source identification, but have not been extensively applied in tracing atmospheric oxidation processes. In this study, we examined the molecular compositions and δ13C values of PAHs in wintertime PM2.5 in a highly polluted urban region in Norwest China. The average concentrations of total parent-PAHs (pPAHs) and oxygenated-PAHs (OPAHs) were measured as 70 ± 29 and 36 ± 17 ng m−3, respectively. The results obtained from the incremental lifetime cancer risk (ILCR) model suggested a high potential cancer risk of PAHs in the urban region. The temperoal variations of PAHs and carbonaceous fractions implied that the contribution of secondary organic compounds was limited during the severe pollution period (PM2.5 > 115 μg m−3). Both molecular diagnostic ratios and δ13C values indicated that the major emission sources of the pPAHs were coal and/or biomass burning. The δ13C value of fluorene became heavier as the OPAHs concentration increased, while the concentrations of fluorene was negatively correlated with OPAHs, indicating the secondary formation of OPAHs from fluorene oxidation in the cold season. Our results also confirmed that δ13C values of pPAHs are indeed indicative of atmospheric oxidation processes.

Concentrations, Source Apportionment and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Household Dust Samples, the Case of City of Khorramabad, Iran

Individuals spend a lot of time indoors; thus, they can generally be exposed to polycyclic aromatic hydrocarbons (PAHs) such as teratogens, mutagens, and carcinogens with the potential of environmental and also human health risks. Therefore, the current study was conducted for the analysis, source identification, and health risk assessment of PAHs in household dust samples of the city of Khorramabad, Lorestan province, Iran in 2020. In so doing, 50 household dust samples were collected from 10 sampling sites. After extraction of the analytes, the gas chromatography/mass spectrometry (GC–MS) method was used to determine the PAHs contents in the samples. Sixteen priority PAHs were detected and quantified in the samples. The median values of ∑16PAHs were found to be 18.4 µg kg−1. Although based on the results of molecular diagnostic ratios (MDRs), PAH compounds could be originated from both petrogenic and pyrogenic sources, the pyrogenic sources including smoking, natural gas combustion, and traffic prevailed. Total incremental lifetime cancer risks (ILCRs) of children and adults with average values of 2.07E-04 and 1.83E-04, were both classified in the 'high critical value’ category. The cancer risk levels via dermal contact (1.15E-04) and direct ingestion (9.19E-05), indicated that both routes greatly contributed to the cancer risk for children. Similarly, the risk value of dermal contact (1.17E-04) and direct ingestion (6.58E-05) were found to be important pathways that adults could be exposed to contaminated dust. Accordingly, the mean values of ILCRs ranked in the following order: dermal contact > direct ingestion > inhalation for both cases (ie, children and adults). In conclusion, to maintain the health of both the man and the environment, it is recommended that regular and periodic analyses of these pollutants in different environmental samples including soil, sediment, dust, particulate matter, air, water, and tissues of living organisms in be performed to help prevent exposure risks of PAHs.

Human health risk model for microplastic exposure in the Arctic region

Microplastics enriched with carcinogens like heavy metals, polycyclic aromatic hydrocarbons (PAHs), and their derivatives are ubiquitous in Arctic waters. They contaminate the local land and sea-based food sources, which is a significant health hazard. It is thus imperative to assess the risk posed by them to the nearby communities, which primarily rely on locally available food sources to meet their energy requirements. This paper proposes a novel ecotoxicity model to assess the human health risk posed by microplastics. The region's geophysical and environmental conditions affecting human microplastic intake, along with the human physiological parameters influencing biotransformation, are incorporated into the developed causation model. It investigates the carcinogenic risk associated with microplastic intake in humans via ingestion in terms of incremental excess lifetime cancer risk (IELCR). The model first evaluates microplastic intake and then uses reactive metabolites produced due to the interaction of microplastics with xenobiotic metabolizing enzymes to assess cellular mutations that result in cancer. All these conditions are mapped in an Object-Oriented Bayesian Network (OOBN) framework to evaluate IELCR. The study will provide a vital tool for formulating better risk management strategies and policies in the Arctic region, especially concerning Arctic Indigenous peoples.

Polycyclic Aromatic Hydrocarbons in Topsoils Along the Taipu River Banks in the Yangtze River Delta, China: Occurrence, Source and Risk Assessment.

Taipu River is an important transboundary river and drinking water source in the Yangtze River Delta, China. This study collected 15 topsoil samples along the Taipu River banks and subsequently determined the polycyclic aromatic hydrocarbons (PAHs) concentrations, sources, and ecological and health risks. The sum of toxic 15 PAHs concentrations ranged from 83.13 to 28342.53 ng/g, with a mean of 2828.69 ng/g. High molecular weight (HMW) PAHs were the dominant components and Indene (1,2,3, -cd) benzopyrene (InP) accounted for the highest proportion in individuals. The average PAH concentration in residential land was the highest, followed by those in industrial and agricultural land. The PAH concentration was positively related to contents of total carbon, total nitrogen, ammonium nitrogen, and aminopeptidase activity in soils. The mixed combustion of biomass, coal, and petroleum and traffic emissions could be the primary PAH contributors. The total PAHs at over half of sampling points had relatively high risk quotients and incremental lifetime cancer risk (ILCR) values, posing potential or great ecological threats and health risks.

Promoting the design of future urban metro systems to improve air pollution: Based on metal element pollution in Chinese metro system

Metro system metal element pollution and its human hazards have gained widespread attention. Using the Chinese metro as representative of a modern urban metro system, we investigated pollution levels, sources, and their health effects, to provide a basis for designing future healthy, sustainable urban metro environments. Through searching and analyzing previous studies on metal elements in the Chinese metro system, we showed that tunnels are the most contaminated areas for metal elements due to mechanical wear, while platforms, carriages, and halls are mainly affected by airflow diffusion. Using the UNEP-SETAC toxicity (USEtox) model to calculate health impacts, we determined that metal elements caused approximately 700 deaths per 1 million people annually. According to the US Environmental Protection Agency (US EPA) health risk model, health risks were evaluated from respiratory exposure for child and adult passengers, drivers, station attendants, and security checkers. Total incremental lifetime cancer risk (TILCR) for all populations was higher than 10−4, indicating a high carcinogenic risk. Finally, based on international studies, we propose corresponding strategies to improve metro system sustainability.