Total Incremental Lifetime Cancer Risk Research Articles

Assessing drinking water quality based on water quality indices, human health risk, and burden of disease attributable to heavy metals in rural communities of Yazd County, Iran, 2015–2021

The water quality indices, health risk, and burden of disease attributable to heavy metals in rural communities of Yazd County, Iran during 2015–2021 were studied. The drinking water quality index (DWQI) based on 27 parameters (including heavy metals) and heavy metal pollution index (HPI) were used for assessing drinking water quality. The health risk and burden of disease from heavy metals in drinking water were estimated in terms of hazard quotient (HQ), hazard index (HI), incremental lifetime cancer risk (ILCR), and disability-adjusted life year (DALY). Based on the DWQI scores by community, the drinking water quality in rural communities of Yazd County was characterized as good for 61 %, fair for 25 %, marginal for 2 %, and poor for 12 %. The distribution of the rural communities into the HPI categories was as follows: 43 % for excellent, 36 % for good, 14 % for poor, and 7 % for unsuitable. In about 20 % of the rural communities, the average HI level of heavy metals was higher than the boundary limit of one. The highest average HQ level at the county level was related to arsenic (As) to be 0.44. In all the communities, the total ILCR values of the heavy metals were in the category of significant increased cancer risk (10−6 to 10−4). At the county level, As and cadmium (Cd) exhibited the two highest cancer risk levels to be 1.96 × 10−4 and 1.87 × 10−4 for ILCR, respectively. The DALY rate (per 100,000 people) induced by exposure to the heavy metals via drinking water was 13.9, which was considered relatively high as compared to that of other drinking water pollutants obtained in the previous studies. The drinking water quality improvement through decreasing Cd and As levels below the standard values can drastically reduce the attributable burden of disease and promote the public health in the rural communities.

Seasonal variation and concentration of PAHs in Lake Balaton sediment: A study on molecular weight distribution and sources of pollution

The temporal and spatial variations of 16 Polycyclic Aromatic Hydrocarbons (PAHs) were examined at multiple sites around Lake Balaton from February 2023 to January 2024. The results indicated that the concentrations of PAHs in sediment were high during the winter months, 448.35 to 619.77 ng/g dry weight, and low during the summer months, 257.21 to 465.49 ng/g dry weight. The concentration of high molecular weight PAHs (HMWPAHs), consisting of 5–6 rings, was greater than that of low molecular weight PAHs (LMWPAHs), which had 2–3 rings. The total incremental lifetime cancer risk (ILCR) for both dermal and ingestion pathways was high for both adults and children during the four seasons, with the highest records as the following: winter > spring > summer > autumn. The ecological effects of the 16 PAHs were negligible except for acenaphthylene (Acy) and fluorene (Fl), which displayed slightly higher concentrations during the autumn and spring, respectively.

Health risk assessment of heavy metals from grains and grain products in Gansu Province, China, 2012-2020.

In this study, heavy metals including lead (Pb), chromium (Cr), cadmium (Cd), arsenic (As), and mercury (Hg) in 3520 samples (6 varieties) were measured using ICP-MS and assessed through multiple exposure pathways. We estimated the health risks from various grains and grain products, classified according to gender. The estimated daily intake (EDI) of each heavy metal in men was lower than the reference dose (RfD), and the wheat of Cr in women was above RfD at the P95 exposure level. The health risks of dietary exposure in adults were assessed using deterministic evaluation and Monte Carlo Simulation (MCS). The deterministic evaluation showed that the total hazard index of each heavy metal was below 1, and the total incremental lifetime cancer risks of Cd, As, and Cr were above 1.0E-04. Dietary intake was the primary route of exposure. MCS indicated that only 10% of men and 15% of women for Cr ranged over hazard quotient (1), and the ILCRs of most adults were above 1.0E-04 through dietary exposure. Consequently, we conclude that adults are more likely to be exposed to carcinogenic risks in Gansu province.

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.

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.

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.

Characterization and risk assessment of polycyclic aromatic hydrocarbons (PAHs) pollution in particulate matter in rural residential environments in China-A review

In recent years, air pollution in rural residential environments in China has received significant attention, with polycyclic aromatic hydrocarbons (PAHs) pollution being particularly important which is associated with various health problems. Although some studies have investigated indoor air pollution in rural China, a comprehensive exploration of PAHs pollution has not been completed. Therefore, this study screened peer-reviewed Chinese and English articles on PAHs in indoor particulate matter in rural China published between January 1, 2010, and September 30, 2022, and retrieved a total of 2010 papers. After selection criteria, 24 papers were ultimately chosen for data extraction and comprehensive analysis. The results showed that the level of PAHs pollution in rural residential environments in China was 1408.27±1888.85 ng/m3 (62.17∼6606.53 ng/m3). The kitchen was the most severely polluted area in households, with pollution levels highest in the spring and winter. The use of clean energy to replace traditional solid fuels can significantly reduce PAH emissions, but most households still use a mixture of fuels, and the level of PAH pollution remains high. It is worth emphasizing that the cancer risk assessment indicated that rural Chinese residents' total incremental lifetime cancer risk (TILCR) was greater than 10−4, indicating a high risk of cancer. This study provides accurate information on the current status of PAHs pollution in indoor particulate matter in rural China, which will serve as a solid foundation for future prevention and control efforts.

Concentrations, Source Identification and Potential Ecological and Human Health Risks Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Agricultural Soils of Hamedan County, West of Iran

ABSTRACT This study was performed to examine the possible ecological impact of sixteen PAHs listed as priorities by the US EPA in the agricultural soils of Hamedan County (ASHC), west of Iran, in 2021. In so doing, 36 surface soil samples were collected from 12 agriculturally-related sampling locations. The soxhlet method was employed to extract analytes, and the gas chromatography/mass spectrometry (GC-MS) method was utilized to identify the chemicals PAHs in the samples. Based on the data, there were 16PAHs (∑16PAHs) in total concentrations (µg kg−1), ranging from 435 to 3292, with an average of 1806. The PAH profiles were dominated by PAHs with larger molecular weights (≥4 rings), accounting for 78% of the total mass of 16PAH. Based to Molecular Diagnostic Ratios (MDRs) the majority of PAH molecules were found to have pyrogenic origins. As the results indicated, Indeno(1,2,3-cd)pyrene and benz(ghi)perylene posed very little ecological harm to soil organisms, based on the data, while other PAHs reflected significant environmental risks in these soils. All of the stations were identified as being in the low-risk group by the overall ecological risk of 16PAH in surface soil samples. The total incremental lifetime cancer risks (Total ILCRs) of PAH compounds for children with an average of 7.51 × 10−7 (ranging from 1.66 × 10−7 to 1.50 × 10−6) indicated negligible potential cancer and human health risks; whereas, the total ILCRs for adults with an average of 1.59 × 10−6 (ranging from 3.65 × 10−7 to 3.30 × 10−6) showing a low potential carcinogenic risk of PAH compounds in the study location. These findings imply that eating food cultivated in contaminated soils and directly digesting soil may be harmful to human health. Therefore, regular and periodic monitoring of agricultural soils is recommended to maintain consumer’s health of agricultural products.

Impacts of COVID-19's restriction measures on personal exposure to VOCs and aldehydes in Taipei City

The Coronavirus Disease 2019 (COVID-19) pandemic provided an unprecedented natural experiment, that allowed us to investigate the impacts of different restrictive measures on personal exposure to specific volatile organic compounds (VOCs) and aldehydes and resulting health risks in the city. Ambient concentrations of the criteria air pollutants were also evaluated. Passive sampling for VOCs and aldehydes was conducted for graduate students and ambient air in Taipei, Taiwan, during the Level 3 warning (strict control measures) and Level 2 alert (loosened control measures) of the COVID-19 pandemic in 2021–2022. Information on the daily activities of participants and on-road vehicle counts nearby the stationary sampling site during the sampling campaigns were recorded. Generalized estimating equations (GEE) with adjusted meteorological and seasonal variables were used to estimate the effects of control measures on average personal exposures to the selected air pollutants. Our results showed that ambient CO and NO2 concentrations in relation to on-road transportation emissions were significantly reduced, which led to an increase in ambient O3 concentrations. Exposure to specific VOCs (benzene, methyl tert-butyl ether (MTBE), xylene, ethylbenzene, and 1,3-butadiene) associated with automobile emissions were remarkably decreased by ~40–80 % during the Level 3 warning, resulting in 42 % and 50 % reductions of total incremental lifetime cancer risk (ILCR) and hazard index (HI), respectively, compared with the Level 2 alert. In contrast, the exposure concentration and calculated health risks in the selected population for formaldehyde increased by ~25 % on average during the Level 3 warning. Our study improves knowledge of the influence of a series of anti-COVID-19 measures on personal exposure to specific VOCs and aldehydes and its mitigations.

Pollution Characteristics, Source Apportionment, and Health Risk of Polycyclic Aromatic Hydrocarbons (PAHs) of Fine Street Dust during and after COVID-19 Lockdown in Bangladesh

The COVID-19 period has had a significant impact on both the global environment and daily living. The COVID-19 lockdown may provide an opportunity to enhance environmental quality. This study has evaluated the effect of the COVID-19 lockdown on the distribution of polycyclic aromatic hydrocarbons (PAHs) in the street dust (diameter < 20 µm) of different land use areas in Dhaka city, Bangladesh, using gas chromatography–mass spectrometry (GC–MS). The maximum (2114 ng g−1) concentration of ∑16 PAHs was found in the industrial area during without lockdown conditions and the minimum (932 ng g−1) concentration was found in the public facilities area during the complete lockdown. Meanwhile, due to the partial lockdown, a maximum of 30% of the ∑16 PAH concentration decreased from the situation of without lockdown in the industrial area. The highest result of 53% of the ∑16 PAH concentration decreased from the situation without lockdown to the complete lockdown in the commercial area. The 4-ring PAHs had the highest contribution, both during and after the lockdown conditions. PAH ratios, correlation, principal component analysis (PCA), and hierarchical clustering analysis (HCA) were applied in order to evaluate the possible sources. Two major origins of PAHs in the street dust were identified as petroleum and petrogenic sources, as well as biomass and coal combustion. Ingestion and dermal pathways were identified as the major exposure routes to PAHs in the dust. The total incremental lifetime cancer risk (ILCR) due to exposure for adults and children ranged from 8.38 × 10−8 to 1.16 × 10−7 and from 5.11 × 10−8 to 1.70 × 10−7, respectively. These values were lower than the baseline value of acceptable risk (10–6), indicating no potential carcinogenic risk. This study found that the COVID-19 lockdown reduced the distribution of PAHs in the different sites of Dhaka city, thus providing a unique opportunity for the remarkable improvement of degraded environmental resources.

Abundance, Source Apportionment and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons and Nitro-Polycyclic Aromatic Hydrocarbons in PM2.5 in the Urban Atmosphere of Singapore

In this study, the levels of fine particulate matter (PM2.5), polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs (NPAHs) in PM2.5 samples were determined from 2020 to 2021 in Singapore. For analysis convenience, the sampling period was classified according to two monsoon periods and the inter-monsoon period. Considering Singapore’s typically tropical monsoon climate, the four seasons were divided into the northeast monsoon season (NE), southwest monsoon season (SW), presouthwest monsoon season (PSW) and prenortheast monsoon season (PNE)). The PM2.5 concentration reached 17.1 ± 8.38 μg/m3, which was slightly higher than that in 2015, and the average PAH concentration continuously declined during the sampling period compared to that reported in previous studies in 2006 and 2015. This is the first report of NPAHs in Singapore indicating a concentration of 13.1 ± 10.7 pg/m3. The seasonal variation in the PAH and NPAH concentrations in PM2.5 did not obviously differ owing to the unique geographical location and almost uniform climate changes in Singapore. Diagnostic ratios revealed that PAHs and NPAHs mainly originated from local vehicle emissions during all seasons. 2-Nitropyrene (2-NP) and 2-nitrofluoranthene (2-NFR) in Singapore were mainly formed under the daytime OH-initiated reaction pathway. Combined with airmass backward trajectory analysis, the Indonesia air mass could have influenced Singapore’s air pollution levels in PSW. However, these survey results showed that no effect was found on the concentrations of PAHs and NPAHs in PM2.5 in Indonesia during SW because of Indonesia’s efforts in the environment. It is worth noting that air masses from southern China could impact the PAH and NPAH concentrations according to long-range transportation during the NE. The results of the total incremental lifetime cancer risk (ILCR) via three exposure routes (ingestion, inhalation and dermal absorption) for males and females during the four seasons indicated a low long-term potential carcinogenic risk, with values ranging from 10−10 to 10−7. This study systematically explains the latest pollution conditions, sources, and potential health risks in Singapore, and comprehensively analyses the impact of the tropical monsoon system on air pollution in Singapore, providing a new perspective on the transmission mechanism of global air pollution.

Seasonal variation of dissolved bioaccessibility for potentially toxic elements in size-resolved PM: Impacts of bioaccessibility on inhalable risk and uncertainty

The health effects of potentially toxic elements (PTEs) in airborne particulate matter (PM) are strongly dependent on their size distribution and dissolution. This study examined PTEs within nine distinct sizes of PM in a Chinese megacity, with a focus on their deposited and dissolved bioaccessibility in the human pulmonary region. A Multiple Path Particle Dosimetry (MPPD) model was used to estimate the deposited bioaccessibility, and an in-vitro experiment with simulated lung fluid was conducted for dissolved bioaccessibility. During the non-heating season, the dissolved bioaccessible fraction (DBF) of As, Cd, Co, Cr, Mn, Pb and V were greater in fine PM (aerodynamics less than 2.1 μm) than in coarse PM (aerodynamics between 2.1 and 10 μm), and vice versa for Ni. With the increased demand of heating, the DBF of Pb and As decreased in fine particle sizes, probably due to the presence of oxide/silicate compounds from coal combustion. Inhalation health risks based on the bioaccessible concentrations of PTEs displayed the peaks in <0.43 μm and 2.1–3.3 μm particulate sizes. The non-cancer risk was at an acceptable level (95th percentiles of hazard index (HI) was 0.49), but the cancer risk exceeded the threshold value (95th percentiles of total incremental lifetime cancer risk (TCR) was 8.91 × 10−5). Based on the results of uncertainty analysis, except for the exposure frequency, the total concentrations and DBF of As and Cr in <0.43 μm particle size segment have a greater influence on the uncertainty of probabilistic risk.

Source identification and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in air and dust samples of Lahore City

During two consecutive summer and winter seasons in Lahore, the health risk of air and dust-borne polycyclic aromatic hydrocarbons (PAHs) was evaluated. Gas chromatography/mass spectrometry (GS/MS) was used to determine air and dust samples from various functional areas across the city. The mean ∑16PAHs were higher in air 1035.8 ± 310.7 (pg m−3) and dust 963.4 ± 289.0 (ng g−1 d.w.) during winter seasons as compared to summer seasons in air 1010.9 ± 303.3 (pg m−3) and dust matrices 945.2 ± 283.6 (ng g−1 d.w.), respectively. PAHs ring profile recognized 3 and 4 rings PAHs as most dominant in air and dust samples. Estimated results of incremental lifetime cancer risk (ILCR) highlighted high carcinogenic risk among the residents of Lahore via ingestion and dermal contact on exposure to atmospheric PAHs. The total ILCR values in air among children (summer: 9.61E − 02, winter: 2.09E − 02) and adults (summer: 1.45E − 01, winter: 3.14E − 02) and in dust, children (summer: 9.16E − 03, winter: 8.80E − 03) and adults (summer: 1.38E − 02, winter: 1.33E − 02) during the study period. The isomeric ratios in the study area revealed mixed PAH sources, including vehicular emission, petroleum, diesel and biomass combustion. As a result, it is advised that atmospheric PAHs should be monitored throughout the year and the ecologically friendly fuels be used to prevent PAHs pollution and health concerns in the city. The findings of this study are beneficial to the local regulating bodies in terms of controlling the exposure and promoting steps to reduce PAHs pollution and manage health in Lahore.

A case study on the occurrence of polycyclic aromatic hydrocarbons in indoor dust of Serbian households: Distribution, source apportionment and health risk assessment

This study was conducted in order to obtain the first insight into the occurrence, potential sources, and health risks of polycyclic aromatic hydrocarbons (PAHs) in indoor dust. Samples (n = 47) were collected from households in four settlements in the northern Serbian province of Vojvodina. Total concentrations of 16 EPA priority PAHs in the dust samples varied from 140 to 8265 μg kg−1. Mean and median values for all samples were 1825 and 1404 μg kg−1, respectively. According to the international guidelines for indoor environment, PAH content can be regarded as normal (<500 μg kg−1) for ∼6% of the samples, high (500–5000 μg kg−1) for ∼87% of the samples, and very high (5000–50000 μg kg1) for ∼6% of the samples. In all settlements, PAHs with 4 rings were the most prevalent (accounting for 40–53% of the total PAHs). They were followed by 3-ringed PAHs (29–40%), which indicates rather uniform PAH profiles in the analyzed dust. Based on diagnostic ratios, principal component analysis (PCA), and positive matrix factorization (PMF), pyrogenic sources, such as vehicle emissions and wood combustion were the dominant sources of PAHs in analyzed samples. Health risk assessment, which included incidental ingesting, inhaling and skin contact with PAHs in the analyzed dust, was evaluated by using the incremental lifetime cancer risk (ILCR) model. Median total ILCR was 3.88E-04 for children, and 3.73E-04 for adults. Results revealed that major contribution to quite high total ILCRs was brought by dermal contact and ingestion. Total cancer risk for indoor dust indicated that 85% of the studied locations exceeded 10–4. This implies risk of high concern, with potential adverse health effects. The results are valuable for future observation of PAHs in indoor environment. They are also useful for regional authorities who can use them to create policies which control sources of pollution.

Comparison of indoor and outdoor polycyclic aromatic hydrocarbons from multiple urban residences in Northern China: Coastal versus inland area

Passive air and dust samples were simultaneously collected from urban residences in three functional areas at a coastal site (Weihai) and an inland site (Heze) in Northern China. Samples were concurrently collected in bedrooms, kitchens, and an adjacent outdoor area for each home during the non-heating and heating seasons. Nineteen polycyclic aromatic hydrocarbons (PAHs) were studied by gas chromatography-mass spectrometry (GC-MS). The higher concentrations of PAHs occurred in inland than coastal and industrial area than other districts. The PAHs were more concentrated in outdoor air samples in both cities, but the opposite trend was observed in the dust samples. Compared with bedrooms, higher concentrations of gas-phase PAHs occurred in kitchen. PHE (36.4%) and FLU (18.0%) were the dominant PAHs measured in air samples, whereas middle molecular weight PAHs (34.0%) and high molecular weight PAHs (44.3%) were greater in dust bound PAHs. The I/O ratios of 2–3 rings PAHs in the air were greater than 4–7 rings in both cites indicating that indoor sources had a greater impact on low molecular weight PAHs. The positive matrix factorization (PMF) model identified vehicle exhaust and biomass/coal combustion as the main PAH sources in both outdoor air and dust samples while cooking and solvent use contributed more to indoor samples. Dermal contact with dust accounted for 79.1–85.1% of the total incremental lifetime cancer risk (ILCR) in the study area. Children's ingestion risk was 1.34 and 1.37 times that of adults for both indoor and outdoor sampling areas, respectively.

Assessing Levels and Health Risks of Fluoride and Heavy Metal Contamination in Drinking Water

A systematic study was carried out to assess the level of contamination with fluorides and heavy metals in the drinking water of the city of Daloa as well as the risks to the health of consumers. The waters of 11.11% of the sites sampled exceeded the fluoride limit for drinking water with a contamination index (CI) greater than 0. All the waters recorded concentrations of cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn) and lead (Pb) above the recommended values with CI > 0. However, 22.22% of the sites recorded concentrations below the standard for zinc (Zn) with IC 1 for children in 22.22% of drinking water studied. HQs have an average of less than 1 for fluorine and greater than 1 for all metals. Moreover, the danger indices have values greater than 1. The incremental lifetime cancer risk (ILCR) and the total ILCR are above the recommended values. These results showed that the drinking water sampled is of poor quality due to higher levels of heavy metals, which can constitute a danger to human health. Long-term use of one of these poor quality waters can lead to cancer in consumers. It is therefore necessary to treat this water in order to eliminate the metals before using it for drinking. This study can help decision-makers and competent authorities in charge of water management.

Source identification and health risk assessment of PAHs in surface soils from the vicinity of Arad-Kouh processing and disposal complex, Tehran, Iran

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) as ubiquitous pollutants can pose potential environmental and also human health risks. Therefore, this study was conducted for detecting, identifying the sources and evaluating the health risks of PAHs in topsoils in vicinity of Arad-Kouh processing and disposal complex, Tehran, Iran in 2020. In so doing, a total of 30 surface soil samples were collected from 10 sampling sites adjacent to Arad-kouh complex. After extraction of analytes, the gas chromatography/mass spectrometry (GC–MS) method was used to determine the rates of PAH compounds in surface soil samples. Based on the results obtained, the total concentrations (µg kg−1) of 16 PAHs ranged from 863 to 1384 with a mean of 1123. PAHs with 4–6 rings in their molecules with 65.3% of ∑16PAH mass dominated the PAH profiles. Molecular diagnostic ratios (MDRs) indicated that most of PAH compounds could originate from pyrogenic sources. The total incremental lifetime cancer risks (ILCRs) of PAH compounds with an average value of 4.20E-05 (ranging from 3.02E-05 to 5.23E-05), indicating a low potential carcinogenic risk of PAH compounds in the study area, especially through dermal contact. Although, the ILCRs values showed negligible adverse health effects from direct ingestion and inhalation of PAH compounds in the study area, regular and periodic monitoring of content and sources identification of PAHs in different environments and efforts to mitigate of their pollution for human health maintenance are recommended.

Seasonal occurrence, source apportionment, and cancer risk assessment of PAHs in the second largest international holy metropolitan: Mashhad, Iran.

Street dust resuspension is one of the main sources of particulate matter with impacts on air quality, health, and climate. This research was aimed to determine the concentration, source, and health risk of polycyclic aromatic hydrocarbons (PAHs) in street dust of Mashhad city. To this end, USEPA-regulated 16 PAHs were measured in 84 dust samples using gas chromatography coupled to mass spectrometry (GC-MS). The source of Σ16PAHs was identified using diagnostic ratios (DRs), positive matrix factorization (PMF), and principal component analysis (PCA). The measured Σ16PAHs demonstrated different spatial concentrations (from 1,005 to 9,138.96 μg kg-1) and showed higher levels in summer (1,206.21-9,138.96 μg kg-1), although 4-ring PAHs exhibited maximum levels in both summer and winter. The findings revealed that the dust-deposited PAHs are predominantly emitted through combustion of fossil fuels (such as diesel and gasoline) and natural gas. The total incremental lifetime cancer risk (ILCR) was assessed by considering three possible exposure routes separately for children and adults and calculated carcinogenic risk values of 2.24E-06 and 2.14E-06, respectively. ILCR is above the baseline value (1.0E-06) for children and adults in both seasons.

Characterization, sources and risk assessment of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) in Huanggang city, central China

Huanggang City in central China, is a regional site connect with the north air mass from Xiangyang and Suizhou in Hubei Province and the eastern air mass from Dabie-shan which located at the junction of Hubei and Anhui Province. To enrich the aerosol database in central China and provide reference for the control of air pollution in Huanggang City and surrounding cities in central China, totally 62 PM2.5 samples were collected during the year 2018 for season variation (January 2018–January 2019, once a week) and 16 priority PAHs were analyzed. The annual average concentrations of PM2.5 and PM2.5-bound PAHs were 60.4 ± 38.6 μg m−3 and 7.35 ± 6.79 ng m−3, respectively. Positive matrix factorization (PMF) model showed that the main sources of PM2.5-bound PAHs were vehicle emissions (56.8%), coal and biomass burning (29.5%) and petroleum sources (13.7%). PM2.5 and PM2.5-bound PAHs in Huanggang were mainly came from local emissions and relatively short-range transport and the high probability areas were concentrated in Hubei and Henan Province. The total incremental lifetime cancer risks (TILCR) values were ranged from 10−4 to 10−6, indicating the potential cancer risk for adults and children in Huanggang. However, ILCRing and ILCRdem were four orders of magnitude higher than ILCRinh, indicating that ingestion and dermal contact were the main exposure routes for cancer. Vehicle emission contributed the most to TILCR (70.9%), followed by coal and biomass combustion (21.8%) and petroleum sources (7.39%).

Health risks of exposure to soil-borne dichlorodiphenyltrichloroethanes (DDTs): A preliminary probabilistic assessment and spatial visualization

Residues of dichlorodiphenyltrichloroethane and its metabolites (DDTs) in soils continue to severely threaten and endanger human health. This present study comprehensively interprets the health risks associated with exposure to soil-borne DDTs and also identifies the spatial visualization of risks at a large regional scale in Fujian, China. There was significant spatial variability of human risk across the region, while levels of health risk displayed a significant positive correlation with population density (p < 0.05). High risk levels occurred mostly in the coastal areas in northeastern Fujian, with additional hotspots in inland areas. The highest total incremental lifetime cancer risks (ILCRs) occurred in Sanming, reaching up to 9.52 × 10−5, 3.27 × 10−5, and 1.76 × 10−4 for children, teens, and adults, respectively. Further, the highest hazard index (HI) value was observed in Fuzhou, reaching up to 6.09, 3.84, and 2.37, respectively. The 95% confidence interval of data regarding ILCRs exceeded the recognized safe threshold, whereas the HI has been deemed accepted. Adults were identified as the most susceptible population in terms of cancer risks, with o,p′-DDT being the primary contributor of ILCRs. Moreover, children were showed to be the most vulnerable in terms of non-cancer risks, with p,p′-DDD being the main contributor of HI. Food ingestion appeared to be the dominant exposure pathway, for both cancer and non-cancer risks. The concentration of DDTs (Csoil) and exposure duration (ED) also greatly influenced the risk, together contributing to over 99% of the ILCRs and HI.