Incremental Lifetime Cancer Risk Research Articles

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.

Exposure and health risk assessment of PM2.5-bound polycyclic aromatic hydrocarbons during winter at residential homes: A case study in four Chinese cities

Residential indoor PM2.5 were concurrently collected in Hong Kong, Guangzhou, Shanghai, and Xi'an during the winter and early spring seasons of 2016–2017, for updating the current knowledge of the spatial variation of indoor air pollution and the potential health risks in China. PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) were characterized, and the associated inhalation cancer risks were assessed by a probabilistic approach. Higher levels of indoor PAHs were identified in Xi'an residences (averaged at 176.27 ng m−3) with those of other cities ranging from 3.07 to 15.85 ng m−3. Traffic-related fuel combustion was identified as a common contributor to indoor PAHs through outdoor infiltration for all investigated cities. Indoor PAHs profiles showed city-specific differences, while distinctions between profiles based on indoor activities or ambient air quality were limited. Similar with the total PAHs concentrations, the estimated toxic equivalencies (TEQ) with reference to benzo[a]pyrene in Xi'an residences (median at 18.05 ng m−3) were above the recommended value of 1 ng m−3 and were magnitudes higher than the other investigated cities with estimated median TEQ ranging from 0.27 to 1.55 ng m−3. Incremental lifetime cancer risk (ILCR) due to PAHs inhalation exposure was identified with a descending order of adult (median at 8.42 × 10−8) > adolescent (2.77 × 10−8) > children (2.20 × 10−8) > senior (1.72 × 10−8) for different age groups. Considering the lifetime exposure-associated cancer risk (LCR), potential risks were identified for residents in Xi'an as an LCR level over 1 × 10−6 was identified for half of the adolescent group (median at 8.96 × 10−7), and exceedances were identified for about 90 % of the groups of adults (10th percentile at 8.29 × 10−7) and seniors (10th percentile at 1.02 × 10−6). The associated LCR estimated for other cities were relatively insignificant.

Risk assessment of polycyclic aromatic hydrocarbons and organochlorine pesticides in olive oil in Jordan

Many organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) pose risks to human health; so, their levels in foods should be constantly monitored. In the present work, the potential health risks of 21 OCPs residues and 16 carcinogenic PAHs in Jordanian olive oil were evaluated. A total of 27 olive oil samples were obtained from nine olive mills in Jordan. The levels of PAHs and OCPs were evaluated by gas chromatography coupled with mass spectrometry detector. Among the studied pesticides, only 4,4-Dichlorodiphenyldichloroethylen (4,4-DDE) was found in the tested samples. The estimated average dietary intake (EADI) and hazard risk index (HRI) were then assessed for the 4,4-DDE. The estimated HRI value of 4,4-DDE was less than 1, thus indicating no health risk to consumers. Regarding PAHs, the average concentration of 16 PAHs in the tested olive oil was 36.5 µg/kg. Health risks due to PAH contamination were estimated by determining the dietary daily intake (DDI) and toxic equivalent quotient (TEQ). The values ranged from 0.139 × 10-2 to 7.70 × 10-2 and 0.01 to 0.57 µg/kg for DDI and TEQ, respectively. Light PAHs were predominant in the samples, while no heavy PAHs were detected. The incremental lifetime cancer risk (ILCR) was estimated, and the values ranged from 0.1 × 10-7 to 5.62 × 10-7, and none of the olive oil samples exceeded the limit value of 10-6, thus indicating insignificant potential risk.

Spatial Distribution, Sources, Air-Soil Exchange, and Health Risks of Parent PAHs and Derivative-Alkylated PAHs in Different Functional Areas of an Oilfield Area in the Yellow River Delta, North China.

The knowledge of the spatial distribution, sources, and air-soil exchange of polycyclic aromatic compounds (PACs) in an oilfield area is essential to the development of effective control practices of PAC pollution. In this study, 48 passive air samples and 24 soil samples were collected during 2018-2019 in seven functional areas (e.g., urban, oil field, suburban, industrial, agricultural, near pump units, and background) in the Yellow River Delta (YRD) where the Shengli Oilfield is located, and 18 parent polycyclic aromatic hydrocarbons (PAHs) and five alkylated-PAHs (APAHs) were analyzed from all the air and soil samples. The ΣPAHs in the air and soil ranged from 2.26 to 135.83 ng/m3 and 33.96 to 408.94 ng/g, while the ΣAPAHs in the atmosphere and soil ranged from 0.04 to 16.31 ng/m3 and 6.39 to 211.86 ng/g, respectively. There was a downward trend of atmospheric ΣPAH concentrations with increasing the distance from the urban area, while both ΣPAH and ΣAPAH concentrations in the soil decreased with distance from the oilfield area. PMF analyses show that for atmospheric PACs, coal/biomass combustion was the main contributor in urban, suburban, and agricultural areas, while crude production and processing source contributes more in the industrial and oilfield area. For PACs in soil, densely populated areas (industrial, urban, and suburban) are more affected by traffic sources, while oilfield and near-pump unit areas are under the impact of oil spills. The fugacity fraction (ff) results indicated that the soil generally emitted low-molecular-weight PAHs and APAHs and act as a sink for high-molecular-weight PAHs. The incremental lifetime cancer risk (ILCR) of Σ(PAH+APAH) in both the air and soil, were below the threshold (≤10-6) set by the US EPA.

The Health Risk and Source Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in the Soil of Industrial Cities in India

Industrial areas play an important role in the urban ecosystem. Industrial site environmental quality is linked to human health. Soil samples from two different cities in India, Jamshedpur and Amravati, were collected and analyzed to assess the sources of polycyclic aromatic hydrocarbons (PAHs) in industrial areas and their potential health risks. The total concentration of 16 PAHs in JSR (Jamshedpur) varied from 1662.90 to 10,879.20 ng/g, whereas the concentration ranged from 1456.22 to 5403.45 ng/g in the soil of AMT (Amravati). The PAHs in the samples were dominated by four-ring PAHs, followed by five-ring PAHs, and a small percentage of two-ring PAHs. The ILCR (incremental lifetime cancer risk) of the soil of Amravati was lower compared to that of Jamshedpur. The risk due to PAH exposure for children and adults was reported to be in the order of ingestion > dermal contact > inhalation while for adolescents it was dermal contact > ingestion > inhalation in Jamshedpur. In contrast, in the soil of Amravati, the PAH exposure path risk for children and adolescents were the same and showed the following order: dermal contact > ingestion > inhalation while for the adulthood age group, the order was ingestion > dermal contact > inhalation. The diagnostic ratio approach was used to assess the sources of PAHs in various environmental media. The PAH sources were mainly dominated by coal and petroleum/oil combustion. As both the study areas belong to industrial sites, the significant sources were industrial emissions, followed by traffic emissions, coal combustion for domestic livelihood, as well as due to the geographical location of the sampling sites. The results of this investigation provide novel information for contamination evaluation and human health risk assessment in PAH-contaminated sites in India.

Calculated cancer risks for polycyclic aromatic hydrocarbon mixtures in mainstream smoke of cigarettes sold in China

China is the world's largest consumer of cigarettes. However, the potential cancer risk posed by polycyclic aromatic hydrocarbons (PAHs) in mainstream cigarette smoke, especially species other than benzo[a]pyrene (BaP) remains unclear. In this study, we collected yield data on multiple PAH species from a variety of cigarettes in the China market and calculated their smoking-related incremental lifetime cancer risk (ILCR) values. The computed ILCRs of the total PAHs (ILCRΣPAHs) for ≥95% of the brands were one order of magnitude higher than the acceptable level. ILCRBaP accounted for only 5.0%–37.7% of ILCRΣPAHs among brands, indicating that using single analyte BaP to represent ΣPAHs would significantly underestimate ILCRΣPAHs. No clear trend of changes in ILCRΣPAHs was found for Chinese cigarettes over multiple years, suggesting that smoking cessation is still the best option to minimize the cancer risk of PAHs. The comparison study showed that rarely reported PAHs from Chinese cigarettes can contribute over half of ILCRΣPAHs for several American cigarettes, highlighting the imperativeness to improve the diversity of analytes for Chinese cigarettes. Adults would need to inhale the air-borne PAHs with a BaP equivalent concentration of at least 53.1 ng/m3 to reach the ILCR value comparable to that obtained from smoking.

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.

Investigation on the Quality of Prolonged Storage of Packaged Water Commonly Produced in North Central, Nigeria

This study investigated the effects of prolonged storage conditions on the physicochemical parameter, toxic metals, microbial loads, and health risks assessment of randomly selected three brands of sachet and bottled water in North Central, Nigeria. One hundred eighty samples of water brands (sachet and bottled) were collected from 10 different factories and were grouped into three. They were analyzed immediately (initial), being exposed to mild sunlight (stored with a container) and exposed to intense sunlight (stored without a container) conditions for six weeks. The results of the physicochemical parameters (sachet and bottle) were within the limits set by the World Health Organization (WHO) and the Standard Organization of Nigeria (SON). While the results of heavy metals analysis for both sachet and bottled water recorded 0.15 - 0.51 mg/L (0.10 mg/L , 0.05 mg/L), 0.13 - 0.38 mg/L (0.015 mg/L, 0.01 mg/L) and 0.55 - 1.11 mg/L (0.03 mg/L, 0.3 mg/L) for Chromium (Cr), Lead (Pb) and Iron (Fe) respectively, as compared to the permissible limits (values in the bracket for each heavy metals) set by WHO and SON. The microbial analysis results ranged between 6.58 - 124.51 Cfu/100 mL, 0.52 - 37.56 Cfu/100 mL, 0.07 - 5.00 Cfu/100 mL, 0 - 2.07 Cfu/100 mL for Total Bacteria Count (TBC), Total Coliform Count (TCC), Faecal Coliform Count (FCC) and Total Fungal Count (TFC) respectively, which showed no effective quality control system. Incremental lifetime cancer risk (ILCR) assessment revealed a carcinogenic health risk to the populace drinking this water. The study concludes that water stored under sunlight for a long period is not good for human consumption and therefore adequate monitoring by the appropriate agencies is emphasized.

Shift in Peaks of PAH‐Associated Health Risks From East Asia to South Asia and Africa in the Future

AbstractLung cancer risk from exposure to ambient polycyclic aromatic hydrocarbons (PAHs) is expected to change significantly by 2050 compared to 2008 due to changes in climate and emissions. Integrating a global atmospheric chemistry model, a lung cancer risk model, and plausible future emissions trajectories of PAHs, we assess how global PAHs and their associated lung cancer risk will likely change in the future. Benzo(a)pyrene (BaP) is used as an indicator of cancer risk from PAH mixtures. From 2008 to 2050, the population‐weighted global average BaP concentrations under all RCPs consistently exceeded the WHO‐recommended limits, primarily attributed to residential biofuel use. Peaks in PAH‐associated incremental lifetime cancer risk shift from East Asia (4 × 10−5) in 2008 to South Asia (mostly India, 2–4 × 10−5) and Africa (1–2 × 10−5) by 2050. In the developing regions of Africa and South Asia, PAH‐associated lung cancer risk increased by 30–64% from 2008 to 2050, due to increasing residential energy demand in households for cooking, heating, and lighting, the continued use of traditional biomass use, increases in agricultural waste burning, and forest fires, accompanied by rapid population growth in these regions. Due to more stringent air quality policies in developed countries, their PAH lung cancer risk substantially decreased by ∼80% from 2008 to 2050. Climate change is likely to have minor effects on PAH lung cancer risk compared to the impact of emissions. Future policies, therefore, need to consider efficient combustion technologies that reduce air pollutant emissions, including incomplete combustion products such as PAH.

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.

Assessment of health risk and burden of disease induced by exposure to benzene, toluene, ethylbenzene, and xylene in the outdoor air in Tehran, Iran.

The health risk and burden of disease induced by exposure to benzene, toluene, ethylbenzene, and xylene (BTEX) in the outdoor air in Tehran, 2019 were assessed based on the data of five fixed stations with weekly BTEX measurements. The non-carcinogenic risk, carcinogenic risk, and disease burden from exposure to BTEX compounds were determined by hazard index (HI), incremental lifetime cancer risk (ILCR), and disability-adjusted life year (DALY), respectively. The average annual concentrations of benzene, toluene, ethylbenzene, and xylene in the outdoor air in Tehran were 6.59, 21.62, 4.68, and 20.88 μg/m3, respectively. The lowest seasonal BTEX concentrations were observed in spring and the highest ones occurred in summer. The HI values of BTEX in the outdoor air in Tehran by district ranged from 0.34 to 0.58 (less than one). The average ILCR values of benzene and ethylbenzene were 5.37 × 10-5 and 1.23 × 10-5, respectively (in the range of probable increased cancer risk). The DALYs, death, DALY rate (per 100,000 people) and death rate (per 100,000 people) induced by BTEX exposure in the outdoor air in Tehran were determined to be 180.21, 3.51, 2.07, and 0.04, respectively. The five highest attributable DALY rates in Tehran by district were observed in the districts 10 (2.60), 11 (2.43), 17 (2.41), 20 (2.32), and 9 (2.32), respectively. The corrective measures such as controlling road traffic and improving the quality of vehicles and gasoline in Tehran could reduce the burden of disease from BTEX along with the health effects of other outdoor air pollutants.

Synergistic cancer risk assessment from PM1 bound metals and PAHs in the Indo-Gangetic Region

The atmospheric particulate matter (PM) contains a significant amount of human carcinogens such as metals and Polycyclic Aromatic Hydrocarbons (PAHs). Previous studies have clearly shown that these carcinogens pose serious health issues due to the inhalation of particulate matter. Since the synergistic roles of these carcinogens are rarely considered, these studies frequently underestimate the health risk to humans. The current research aims to bridge this information gap by estimating the synergistic carcinogenic risk assessment owing to PM1 bound metals and PAHs across the densely populated Indo-Gangetic Plain (IGP). The carcinogenic risk assessment was conducted in accordance with the USEPA guidelines on these various PM1 bound components. The Incremental Lifetime Cancer Risk (ILCR) due to heavy metals, such as Lead (Pb) and Chromium (Cr), was found beyond the acceptable limit (> 10−4). The risk due to PM1 bound USEPA PAHs was also significantly higher (> 10−5). This study further estimated the potential toxicity from broad domain of environmental PAHs present in ambient air by considering relevant estimation factors from existing literature. The projected risk from these diverse environmental PAHs was of the order 10−4. Further, source identification of PAHs based on diagnostic isomer ratios revealed that diesel exhaust, biomass burning, and coal combustion are the dominant PAHs sources. Moreover, the exposure to these pollutants is higher in winter and post-monsoon periods. Overall, the synergistic carcinogenic risk found from metals and PAHs was of the order 10−3. In a nutshell, inhalation of PM1 bound heavy metals and PAHs at IGP can result in the development of 1000 cancer cases per million population, which is the highest value compared to other parts of the world. The present study demands immediate policy interventions not only for the reduction of particulate pollution, but also for the reduction of carcinogenic species from the ambient air in order to improve human health.

Polycyclic aromatic hydrocarbons (PAHs) in Egyptian red sea sediments: Seasonal distribution, source Identification, and toxicological risk assessment

This study investigated the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in sediments from the shoreline of the Red Sea. 16 PAH concentrations ranged from 1.43 to 4990.69 µg/g dry weight to 1.64 to 6397.69 µg/g dry weight during spring and autumn, respectively. Most sites with the highest PAH concentrations were (4–6 rings) compounds. The sources of PAHs were analyzed using principal component analysis (PCA) and diagnostic ratios between combinations of PAHs. The results indicated that the pyrogenic source was the primary source of PAHs. The results showed that surface sediment from all sample sites presents low to sporadic toxicity concerns to marine organisms. Total carcinogenicity and mutagenicity of eight priority PAHs ranged from 0.03 to 863.96 and 0.09 to 1197.85 µg/g dry weight, respectively (TEQBaP and MEQBaP). BaP accounted for most of the influence among the eight carcinogenic PAHs and could be employed as a particular PAH toxicity indicator. Using the toxic equivalent quotient (TEQcarc) and incremental lifetime cancer risk (ILCR) to estimate human health risk, it has been determined that sediment contaminated with PAHs in some study area stations may possess the capacity to cause cancer, particularly in children. The ecological risk posed by PAHs was evaluated using a risk quotient (RQ). The RQPAHs estimated for the samples revealed that the study region was at a high-risk level. Anthropogenic hydrocarbon inputs that were more pronounced in locations connected to maritime activity are described in this study. Further monitoring studiesencompassing different environmental matrices about PAHs pollution and their toxicological relevance should be conducted.

Potential microbial mechanisms underlying the effects of rising atmospheric CO2 levels on the reduction and methylation processes of arsenic in the paddy soil

Many studies have demonstrated that climate change affects the biogeochemical cycle of pollutants, but the mechanisms of arsenic (As) biogeochemical processes under high CO2 levels are unknown. Here, rice pot experiments were carried out to explore the underlying mechanisms of the impacts of elevated CO2 on the reduction and methylation processes of As in paddy soils. The results revealed that elevated CO2 might increase As bioavailability and promote As(V)-to-As(III) transformation in the soil as well as higher As(III) and dimethyl arsenate (DMA) accumulation in rice grains, thus increasing health risk. In As-contaminated paddy soil, two key genes involved in the biotransformation of As (arsC and arsM) and associated host microbes were identified as being significantly promoted by increasing CO2 levels. Elevated CO2 enriched the soil microbes harboring arsC (Bradyrhizobiaceae and Gallionellaceae), which aided in the reduction of As(V) to As(III). Simultaneously, elevated CO2 enriched soil microbes harboring arsM (Methylobacteriaceae and Geobacteraceae), allowing As(V) to be reduced to As(III) and then methylated to DMA. The findings of the Incremental Lifetime Cancer Risk (ILTR) assessment suggested that elevated CO2 exacerbated the individual adult ILTR from rice food As(III) consumption by 9.0 % (p < 0.05). These findings show that elevated CO2 aggravates the exposure risk of As(III) and DMA in rice grains by changing microbial populations involved in As biotransformation in paddy soils.

Toxic elements in children's multivitamin-multimineral supplements and the health risks they pose

This work aimed to determine the levels of toxic elements (As, Cd, Hg, and Pb) and their risks in children's multivitamin-multimineral (CMVM) supplements. An inductively coupled plasma-mass spectrometer (ICP-MS) was used to quantify the studied elements. The mean concentrations and ranges (μg/kg) of the toxic elements in the CMVM products were as follows: As (32.4, 5.3–90); Cd (58.2, 6–129); Hg (42.2, 6–108); and Pb (231,8.6–541). The estimated oral daily intakes (EODI) were determined to be in the range of 0.01–0.31 μg/day, 0.01–0.64 μg/day, 0.02–0.53 μg/day, and 0.01–2.36μg/day for As, Cd, Hg, and Pb, respectively. All the EODI values were below the tolerable intake limits set for each element. The chronic non-cancer risks associated with oral exposure to studied elements were evaluated using the target hazard quotient (THQ) and the hazard index (HI). The THQ and HI values were below 1, indicating that these products were safe for consumption by children. The potential cancer risks associated with exposure to As and Pb through the consumption of CMVM products were determined using the Incremental Lifetime Cancer Risk (ILCR) and the total cancer risks (TCR). The ILCR and TCR values were below the threshold value of 1 × 10–4, indicating that the risk of developing cancer was very low and ignorable.

Estimation of Polycyclic Aromatic Hydrocarbons in Groundwater from Campania Plain: Spatial Distribution, Source Attribution and Health Cancer Risk Evaluation.

The aim of this study was to evaluate the concentrations of polycyclic aromatic hydrocarbons (PAHs) in 1168 groundwater samples of the Campania Plain (Southern Italy), taken using a municipal environmental pressure index (MIEP), and to analyze the distribution of these compounds to determine source PAHs using ratios of isomers diagnostic. Lastly, this study also aimed to estimate the potential health cancer risk in groundwaters. The data indicated that the highest concentration of PAHs was found in groundwater from Caserta Province and the contents of BghiP, Phe, and Nap were detected in the samples. The spatial distribution of these pollutants was evaluated using the Jenks method; moreover, the data indicated that incremental lifetime cancer risk ILCRingestion ranged from 7.31 × 10-20 to 4.96 × 10-19, while ILCRdermal ranged from 4.32 × 10-11 to 2.93 × 10-10. These research findings may provide information about the Campania Plain's groundwater quality and aid in the development of preventative measures to lessen PAH contamination in groundwater.

Straw return decreases polycyclic aromatic hydrocarbon (PAH) accumulation in winter wheat and human health risk by enhancing PAH dissipation in rhizosphere soil

Straw return in situ, a common agronomic measure in China, has been widely used not only to increase crop yields and improve soil nutrients but also to remove polycyclic aromatic hydrocarbons (PAHs) from agricultural soils. Nevertheless, the safety risks of food crops (i.e., human health risk of wheat grains) grown in PAHs-contaminated agricultural soils amended with crop straw remain uncertain. A pot experiment was conducted in a PAHs-contaminated agricultural soil cultivated with winter wheat under different ratios of corn straw addition (0% (control, CK), 1%, 2.5%, and 5%, weight/weight). Results showed that corn straw addition significantly (P < 0.05) decreased PAH concentrations in rhizosphere soil, roots, straws, and grains by 48.32%–50.01%, 11.85%–42.67%, 9.78%–28.03%, and 14.16%–31.67%, respectively, compared with CK, whereas the transfer factors of PAHs from roots to straws were significantly (P < 0.05) increased. A correlation heatmap showed that PAH concentrations in roots, straws, and grains were positively (P < 0.01) correlated with those in rhizosphere soil. These indicated that corn straw decreased PAH accumulation in winter wheat due to the increase of PAH dissipation in the rhizosphere soil, although it enhanced PAH transfer in winter wheat. The incremental lifetime cancer risk (ILCR) model indicated that corn straw significantly (P < 0.05) decreased the human health risk of winter wheat grains by 29.73%–45.05%. Overall, corn straw apparently reduced PAH accumulation in winter wheat, ecological risk, and human health risk via enhancing PAH dissipation in the rhizosphere soil. These findings provide an important scientific basis and theoretical guidance for agricultural safety production.