Health risk assessment and source study of PAHs from roadside soil dust of a heavy mining area in India

Accumulation, sources, and health risks of phthalic acid esters (PAEs) in road dust from heavily industrialized, urban and rural areas in southern Iran

In this research, a total of 51 road dust samples were collected from three districts (Asaluyeh, Bushehr, and Goshoui) in the south of Iran from April to June 2022 and analyzed for the concentration of 7 phthalic acid esters (PAEs) compounds. Asaluyeh was considered as an industrial area (near gas and petrochemical industries), Bushehr as an urban area, and Goshoui as a rural area (far from pollution sources). The PAEs concentration of the street dust samples was determined using a mass detection gas chromatography (GC/MS). The mean ± SD levels of ƩPAEs in samples from industrial, urban, and rural sources were 56.9 ± 11.5, 18.3 ± 9.64, and 5.68 ± 1.85 μg/g, respectively. The mean concentration levels of ƩPAEs was significantly (P < 0.05) higher in samples from the industrial area than urban and rural areas. The mean levels of di(2-Ethylhexyl) phthalate (DEHP) in industrial, urban, and rural areas were 20.3 ± 8.76, 4.59 ± 1.71, and 2.35 ± 0.98 μg/g, respectively. The results of the PCA analysis indicate that the likely major sources of PAEs in the road dust in the studied areas are the application of various plasticizers in industry, solvents, chemical fertilizers, waste disposal, wastewater (e.g., agricultural, domestic, and industrial), and the use of plastic films and plastic-based irrigation pipes in greenhouses. As well as, it was found that the non-cancer risk of exposure to dust-bound PAEs was higher for children than for adults. These values were <1 for both age groups (children and adults) and the exposure of inhabitants to PAEs in road dust did not pose a notable non-cancer risk. The cancer risk from exposure to DEHP in road dust was below the standard range of 10-6 in all three areas. Further studies that consider different routes of exposure to these contaminants are needed for an accurate risk assessment. Moreover, since higher PAEs level was found in industrial area, decision-makers should adopt strict strategies to control the discharging of pollution from industries to the environment and human societies.

Occurrence, distribution and risk assessment of polycyclic aromatic hydrocarbons in soils around main water source areas of Beijing, China

Polycyclic aromatic hydrocarbons (PAHs) in urban environments have been globally concerned due to their significant health impacts on residents. However, little is known about potential risks of PAHs from centralized water source areas. In the present study, 326 soils samples from the main water source areas of Beijing were collected and the occurrence, source appointment, and risks of PAHs were systematically investigated based on the monitoring results from high-performance liquid chromatography (HPLC). The total PAHs (∑16 PAHs) concentrations ranged from 5.70 to 1512 ng/g with median value of 44.2 ng/g, in which 4-ring and 5-ring groups were the major components. PAHs concentrations in the cultivated land were significantly higher than other areas, which could reflect significant impact of soil organic matter and total nitrogen contents on the spatial variations of PAHs. Further source identifications through positive matrix factorization model (PMF) revealed that biomass (22.5%), coal (21.4%), gasoline (17.6%) and diesel (16.4%) combustion were dominant sources of soil PAHs in the study area. Moreover, the risk assessment indicated that total ecological and health risk of PAHs were negligible, but individual PAH, including pyrene and benzo(b)fluoranthene, should be concerned due to their potential risks in several monitored stations located in the secondary protection area of four reservoirs. Our study provided new insights into environmental risks of soils in main water source areas from PAHs and could be helpful for organic micropollutant controlling and drinking water safety in rapidly urbanizing cities.

Distribution, sources, and health risk of polycyclic aromatic hydrocarbons and their derivatives in the watershed: the case of Yitong River, China

Polycyclic aromatic hydrocarbons (PAHs) and substituted PAHs (SPAHs) are persistent organic pollutants prevalent globally, and SPAHs have received widespread attention in recent years due to their stronger toxicity and carcinogenicity compared to PAHs. There is a lack of systematic examination of PAHs and their derivatives in watersheds. Thus, to clarify the current status, possible sources, and potential risks of PAHs and their derivatives in watersheds, a study was conducted on Yitong River in China. The results showed that the concentrations of ∑PAHs, ∑OPAHs, and ∑NPAHs ranged from 297.9-1158.3 ng/L, 281.1-587.2 ng/L, and 65.7-269.1 ng/L, respectively. Diagnostic ratio analysis showed that the PAHs were mainly derived from petroleum sources, agricultural waste, and coal combustion. Nitrated PAHs (NPAHs) were mainly derived from liquid combustion sources, and oxygenated PAHs (OPAHs) were derived mainly from petroleum source emissions and atmospheric deposition. The exposure risk model of PAHs revealed that 86% of the studied sites would pose carcinogenic risks after dermal contact. The contaminant causing a major carcinogenic risk was DahA, and none of the sites produced non-carcinogenic risks. The lifetime carcinogenic risk of NPAHs was 8.85 × 10^-10-1.44 × 10^-4, and some surface waters presented with potential carcinogenic risks.

Health risk assessment and source apportionment of potentially toxic metal(loid)s in windowsill dust of a rapidly growing urban settlement, Iran

Rapid industrialization and urbanization have resulted in environmental pollution and unsustainable development of cities. The concentration of 12 potentially toxic metal(loid)s in windowsill dust samples (n = 50) were investigated from different functional areas of Qom city with the highest level of urbanization in Iran. Spatial analyses (ArcGIS 10.3) and multivariate statistics including Principal Component Analysis and Spearman correlation (using STATISTICA-V.12) were adopted to scrutinize the possible sources of pollution. The windowsill dust was very highly enriched with Sb (50 mg/kg) and Pb (1686 mg/kg). Modified degree of contamination (mC_d) and the pollution load indices (PLI_zone) indicate that windowsill dust in all functional areas was polluted in the order of industrial > commercial > residential > green space. Arsenic, Cd, Mo, Pb, Sb, Cu, and Zn were sourced from a mixture of traffic and industrial activities, while Mn in the dust mainly stemmed from mining activities. Non-carcinogenic health risk (HI) showed chronic exposure of Pb for children in the industrial zone (HI = 1.73). The estimations suggest the possible carcinogenic risk of As, Pb, and Cr in the dust. The findings of this study reveal poor environmental management of the city. Emergency plans should be developed to minimize the health risks of dust to residents.

Pollution Characteristics, Source Apportionment, and Health Risk Assessment of Potentially Toxic Elements (PTEs) in Road Dust Samples in Jiayuguan, Hexi Corridor, China

The sources of potentially toxic elements (PTEs) in road dust are complex and potentially harmful to humans, especially in industrial cities. Jiayuguan is the largest steel-producing city in Northwest China, and this study was the first to conduct a related study on PTEs in road dust in this city, including the pollution characteristics, source apportionment, and health risk assessment of PTEs in road dust. The results showed that the highest concentration of PTEs in the local road dust samples were Mn, Ba, Zn, and Cr. The enrichment factor (EF) of Se was the highest, and it was "Very high enrichment" in areas other than the background area, indicating that the local Se was more affected by human activities. The geoaccumulation index (I_geo) of Se was also the highest, and the pollution level was 5 in all areas except the background area, indicating that the local Se was more polluted and related to coal combustion. The sources of PTEs in local road dust samples mainly included geogenic-industrial sources, coal combustion, traffic sources, and oil combustion. For the non-carcinogenic risk, the hazard index (HI) of each element of children was higher than that of adults, and the sum of the HI of each element was greater than 1, indicating that there was a non-carcinogenic risk under the combined influence of multiple elements, which was especially obvious in industrial areas. For the carcinogenic risk, the cancer risk (CR) of Cr at a certain point in the industrial area exceeded 10^-4, which was a carcinogenic risk, and the Cr in this area may be related to the topsoil of the local abandoned chromate plant.

Uncertainty health risk assessment and regional control of drinking water: a case study of Hanyuan County, southwest mountainous area, China

To evaluate the health risks of drinking water in Hanyuan County, 96 samples of peripheral drinking water were collected from 30 sites in the area. The samples were then analyzed for chemical properties including Fe, Mn, NH₃-N, [Formula: see text], F^-, Pb, Hg, As, Cr(VI), Cd, and so on. The health risks of ten trace elements in drinking water were probabilistically assessed using the health risk assessment model and Monte Carlo simulation. On this basis, sequential indicator simulations were used to classify the health risk levels of drinking water in the region, to conduct hierarchical management and control. The results showed that except for [Formula: see text], all other indicators met World Health Organization standards and China's drinking water sanitation standards. Drinking water presents a specific carcinogenic risk to adults, and the cumulative contribution of As and Cr(VI) exceeds 95%, and has a specific non-carcinogenic risk to children if the cumulative contribution of F^-, [Formula: see text], and As exceeds 90%. Grade I, II, and III non-carcinogenic risk areas accounted for 0.89%, 24.72%, and 74.39% of the total area of Hanyuan County, respectively, while grade I, II, and III carcinogenic risk areas accounted for 27.71%, 45.56%, and 26.73% of the total Hanyuan County area, respectively. Finally, according to the health risk characteristics of each control area, corresponding zoning control suggestions were proposed.

Concentration, source apportionment and potential carcinogenic risks of polycyclic aromatic hydrocarbons (PAHs) in roadside soils

PAHs are organic pollutants that have carcinogenic and mutagenic impacts on human health and are a subject of great concern. The soil-bound polycyclic aromatic hydrocarbons (PAHs) in the urban areas can be very lethal to human health. The concentrations, sources, and possible cancer risks of 15 PAHs were analysed by collecting roadside soil samples in Lucknow, India. The range of ∑₁₅PAHs was found to be 478.94 ng/g to 8164.07 ng/g with a mean concentration of 3748.23 ng/g. The highest contribution (32.5%) was found to be from four-ring PAHs, followed by six-ring (24.5%) and five-ring (16.7%) PAHs. The source apportionment through diagnostic ratios ANT/(ANT + PHE) against FL-2/(FL-2+PYR) highlighted the dominance of petroleum, wood, coal, and grass combustion as sources of PAHs in the study area. Source apportionment was also done through positive matrix factorization, confirming the dominance of 'vehicular emissions' (49%), followed by 'coal and biomass combustion' (∼39%), and 'leakages, volatilization and petroleum combustion' (∼12%) as potential sources. The results from lifetime cancer risks (ILCR) varied in the range of 7.5 × 10^-4 and 1.3 × 10 × ^-2 illustrating 'high cancer risk'. The total cancer risk susceptibility of children was found to be 31% more than that of adults. The highest risk associated with toxic equivalent concentration (TEQ) was found at site S8 highlighting the impact of the presence of an international airport, and huge traffic load. The present study will prove to be useful for information related to human exposure to PAHs content in soil in the study area and as baseline study for policy makers, stakeholders, and researchers.

Profiling of seasonal variation in and cancer risk assessment of benzo(a)pyrene and heavy metals in drinking water from Kirkuk city, Iraq

Water samples at 13 sites were analyzed to evaluate heavy metals (cobalt, lead, manganese, copper) and benzo(a)pyrene using 2 methods of analysis (high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) kits). The Lesser Zap River is the main tributary of the Tigris and is used as a main source of drinking water in Kirkuk city through the General Kirkuk project. Risk evaluation for benzo(a)pyrene and lead in water samples was accomplished by Monte Carlo simulation. The highest concentrations of B(a)P were recorded at sites S7 and S5, with levels of 0.192 and 0.122 µg L^-1 detected by HPLC and ELISA, respectively. The WHO guidelines for benzo[a]pyrene in drinking water recommend 0.7 µg L ^-1, and none of the samples surpassed this level; moreover, B(a)P levels exceeded EPA standards in 2014 (0.01 µg L^-1), particularly when the liquid-liquid extraction method with HPLC was used. Carcinogenic risks for human adults and children exist and are highest during the rainy season as compared with the carcinogenic risk during the dry season and risks for children exceed those of adults. This indicates that the 2^nd round of sampling (winter season) harbors more carcinogenic risk than the 1^st round of sampling (dry season).

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.

Remediation of soils and sediments polluted with polycyclic aromatic hydrocarbons: To immobilize, mobilize, or degrade?

Polycyclic aromatic hydrocarbons (PAHs) are generated due to incomplete burning of organic substances. Use of fossil fuels is the primary anthropogenic cause of PAHs emission in natural settings. Although several PAH compounds exist in the natural environmental setting, only 16 of these compounds are considered priority pollutants. PAHs imposes several health impacts on humans and other living organisms due to their carcinogenic, mutagenic, or teratogenic properties. The specific characteristics of PAHs, such as their high hydrophobicity and low water solubility, influence their active adsorption onto soils and sediments, affecting their bioavailability and subsequent degradation. Therefore, this review first discusses various sources of PAHs, including source identification techniques, bioavailability, and interactions of PAHs with soils and sediments. Then this review addresses the remediation technologies adopted so far of PAHs in soils and sediments using immobilization techniques (capping, stabilization, dredging, and excavation), mobilization techniques (thermal desorption, washing, electrokinetics, and surfactant assisted), and biological degradation techniques. The pros and cons of each technology are discussed. A detailed systematic compilation of eco-friendly approaches used to degrade PAHs, such as phytoremediation, microbial remediation, and emerging hybrid or integrated technologies are reviewed along with case studies and provided prospects for future research.

Human Health Assessment of Sixteen Priority Polycyclic Aromatic Hydrocarbons in Contaminated Soils of Northwestern Algeria

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental organic contaminants generated by incomplete combustion of organic materials that are widely distributed in soils.

OBJECTIVES

This study represents the first attempt to examine the health toxicity of 16 detected PAHs in contaminated soil, via different exposure pathways to populations in northwestern Algeria.

METHODS

The toxicity equivalency quotients (TEQ) of PAHs were evaluated. The carcinogenic risk assessment of incremental lifetime cancer risk (ILCR) from ingestion, inhalation, and dermal exposure pathways to each PAH in soil are described.

RESULTS

Incremental lifetime cancer risk values were in the upper limit of the tolerable range (10^-6-10^-4) for adults and children. The total cancer risk of PAH-contaminated soils for children, adolescents and adults was 2.48×10^-5, 2.04×10^-5 and 3.12×10^-5mg.kg^-1d^-1, respectively. The highest potential cancer risks were identified for adults and children, with adolescents having the lowest risks. Across exposure pathways, the dermal contact and ingestion pathways had the greatest contributions to the carcinogenic risk of human exposure to PAHs.

CONCLUSIONS

Further research and guidelines are needed for risk assessments of PAHs in agricultural, residential/urban, and industrial areas, and further risk assessments should include risks posed by exposure through air.

COMPETING INTERESTS

The authors declare no competing financial interests.

Levels, Sources, and Health Damage of Dust in Grain Transportation and Storage: A Case Study of Chinese Grain Storage Companies

A large amount of mixed dust exists in grain, which can easily stimulate the respiratory system and cause diseases. This study explored contamination levels and health effects of this grain dust. A total of 616 dust samples from different stages and types of grain were collected in China—in Hefei (Anhui), Shenzhen (Guangdong), Chengdu (Sichuan), Changchun (Jilin), and Shunyi (Beijing)—and analyzed using the filter membrane method and a laser particle size analyzer. A probabilistic risk assessment model was developed to explore the health effects of grain dust on workers in the grain storage industry based on the United States Environmental Protection Agency risk assessment model and the Monte Carlo simulation method. Sensitivity analysis methods were used to analyze the various exposure parameters and influencing factors that affect the health risk assessment results. This assessment model was applied to translate health risks into disability-adjusted life years (DALY). The results revealed that the concentration of dust ranged from 25 to 70 mg/m3, which followed normal distribution and the proportion of dust with a particle size of less than 10 μm exceeded 10%. Workers in the transporting stage were exposed to the largest health risk, which followed a lognormal distribution. The average health risks for workers in the entering and exiting zones were slightly below 2.5 × 10−5. The sensitivity analysis indicated that average time, exposure duration, inhalation rate, and dust concentration made great contributions to dust health risk. Workers in the grain storage and transportation stage had the health damage, and the average DALY exceeded 0.4 years.

WITHDRAWN: Impact of basic medical insurance fund risk on the health risk assessment of urban residents

Ahead of Print article withdrawn by publisher.

Polycyclic aromatic hydrocarbons (PAHs) in indoor environments are still imposing carcinogenic risk

Polycyclic aromatic hydrocarbons (PAHs) are among the most health-relevant air pollutants. Herein, we conducted meta-analysis and experimental validation to evaluate PAHs in our surroundings and carcinogenic risks. We summarized the occurrence of PAHs in outdoors and indoors from 131 studies with 6,766 samples collected in different countries in 1989-2019. The global weighted-median concentration in outdoor air, indoor air and dust of ΣPAHs were 142 ng/m³, 369 ng/m³ and 10,201 ng/g; respectively. ΣPAHs have decreased in indoor air but remained steady in outdoor air and indoor dust. More carcinogenic PAHs in indoor/outdoor air was observed in Asia, while in dust was North America. Monte-Carlo simulation further showed indoor sources for children's exposure from dust and air can exceed outdoor. To further validate the health effect of PAHs from indoors, 15 more recent indoor dust samples were collected to examine their mutagenicity. The results showed that ΣPAHs were found to be significantly correlated with mutagenicity potency in the dust sample metabolically activated with liver S9 subcellular fraction and likely accounted for 0.42-0.50 of the mutagenic activity. Our findings indicated that PAHs are still likely to have carcinogenic activity in indoor environments and exposure risk of children to indoor dust should be emphasized.

PAH7 concentration reflects anthropization: A study using environmental biomonitoring with honeybees

Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants, mainly due to anthropogenic emission. In this study, we used honeybees as bioindicators of PAHs pollution in 36 industrial sites distributed in 14 French departments, covering more than 950 km² area of biomonitoring. Honeybees were sampled three times a year (spring, summer and autumn), during a period covering 2016 to 2019. Cluster and Principal Component Analysis allowed to classify sites in semi-natural, agricultural and urban lands according to their land use. We found that the higher the level of anthropization, the higher the concentration of PAH7 (PAH7: Benzo[a]Pyrene, Benzo[a]Anthracene, Benzo[b]Fluoranthene, Benzo[j]Fluoranthene, Benzo[k]Fluoranthene, Indeno[1,2,3-c,d]Pyrene and Dibenz[ah]Anthracene). We have found that 5 out of 20 compounds analyzed are significantly impacted by the landscape context (BjF, BaA, Chr, BbF and CPP). We observed significantly more 3-ringed PAHs in the autumnal samples than in the summer ones, but there was no seasonal effect on the PAH7 concentration. Moreover, diagnostic ratios show that high temperature processes are the main origin of PAHs, even in semi-natural environments.

Ingestion and Dermal Cancer Risk via Exposure to Polycyclic Aromatic Hydrocarbon-Contaminated Soils in an Oil-Producing Community, Niger Delta, Nigeria

There is an intrinsic link between polycyclic aromatic hydrocarbons (PAHs) accumulated in soils and increased health risk to humans after exposure to contaminated soil via ingestion, inhalation of particulates carrying PAHs, and direct contact with polluted soils. However, the assessment of PAH contamination in most developing countries fails to consider health risk assessment. Therefore, a comprehensive study was conducted to determine the concentration, source, toxicity, and human health risks of 16 PAHs in an urban area in Warri, Delta State, in the Niger Delta region of Nigeria. The results showed varying contamination levels for PAH in soil samples from all sampling points, with benzo[a]anthracene (BaP; at 338.81 μg/kg) being the most abundant at all 9 sampling stations. The highest total concentration of PAH was observed at station 5 (1230.98 μg/kg), which was closest to a flow station. Further comparison with PAH contamination standards showed that soils from stations 1 and 2 were weakly contaminated (<600 μg/kg), and soil samples from stations 3, 4, 6, 7, and 9 were moderately contaminated (<1000 μg/kg). Soil samples from stations 5 and 8 were observed to be heavily contaminated (>1000 μg/kg). The BaP estimates for soil samples obtained for stations 3 to 9 were higher than the BaP soil screening value (15 μg/kg), indicating a carcinogenic potential of soil samples. The results also showed that the incremental lifetime cancer risk estimates for PAH in the soil for adults and children were above the recommended threshold (10^-4 ) for ingestion and dermal contact, implying that exposure to contaminated soil could lead to cancers in adults and children. Currently, there are no regional or national standards for PAHs in soil that would indicate an increased likelihood for human exposure and subsequent health issues. Environ Toxicol Chem 2021;40:261-271. © 2020 SETAC.

The occurrence and distribution of polycyclic aromatic hydrocarbons, bisphenol A and organophosphate flame retardants in indoor dust and soils from public open spaces: Implications for human exposure

Global concern exists regarding human exposure to organic pollutants derived from public open spaces and indoor dust. This study has evaluated the occurrence of 18 polycyclic aromatic hydrocarbons (PAHs), 11 organophosphorus flame retardants (OPFRs) and bisphenol A (BPA). To achieve this, a new simple, efficient and fast multi-residue analytical method based on a fully automated pressurised liquid extraction (PLE) and subsequent quantification by gas chromatography coupled to electron ionization-mass spectrometry (GC-EI-MS) in selected ion monitoring (SIM) mode was developed. The developed method was applied to indoor dust (12 sampling households) and soil derived from two public open spaces (POSs). Among all compounds studied, PAHs were the most ubiquitous contaminants detected in POS soils and indoor dust although some OPFRs and BPA were detected in lower concentrations. An assessment of the incremental lifetime cancer risk (ILCR) was done and indicated a high potential cancer risk from the POS sites and some of the indoor dust sampled sites. However, key variables, such as the actual exposure duration, frequency of contact and indoor cleaning protocols will significantly reduce the potential risk. Finally, the ingestion of soils and indoor dust contaminated with OPFRs and BPA was investigated and noted in almost all cases to be below the USEPA reference doses.

Profiling and potential cancer risk assessment on children exposed to PAHs in playground dust/soil: a comparative study on poured rubber surfaced and classical soil playgrounds in Seoul

Children can get affected by polycyclic aromatic hydrocarbons (PAHs) while they interact with play area soil/rubber surfacing and exposed to PAHs by dermal contact, inhalation and hand-to-mouth activity. A comparative study has been conducted on PAHs profiling and probable cancer risk of children from PAHs present in uncovered playground surface soil and poured rubber surfaced playground dust. Surface soil and dust samples have been collected from 14 different children parks around the Korea University campus, Seoul, Republic of Korea. Concentrations of 16 PAHs in the soils/dust were found to be in a range of 2.82-57.93 μg g^-1. Profiling of the PAHs from the playground soils/dust reveals 3-ring PAHs are dominating with 79.9% of total PAHs content, on an average. The diagnostic ratio analysis confirms that vehicular exhaust and fossil fuel burning are likely the main sources of high molecular weight carcinogenic PAHs, whereas low molecular weight PAHs have pyrogenic origin. The probabilistic health risk assessment using Monte Carlo simulations for the estimation of the 95% cancer risk exposed to the PAHs from the surfaced playgrounds shows a little higher value than the USEPA safety standard (1.3 × 10^-5). Sensitivity analysis revealed exposure duration and relative skin adherence factor for soil as the most influential parameters of the assessment. Noticeably, cancer risk is approximately 10 times higher in poured rubber surfaced playgrounds than in uncovered soil playgrounds.

Impact of traffic volumes on levels, patterns, and toxicity of polycyclic aromatic hydrocarbons in roadside soils

Vehicular exhaust is one of the important sources of polycyclic aromatic hydrocarbons (PAHs) in urban areas, and roadside soils can be directly contaminated with PAHs released from traffic emissions. In this study, roadside soils were collected at 10 sites in Ulsan, the largest industrial city in South Korea, to investigate the relationship between the traffic volume and the contamination characteristics of PAHs. The total concentrations of 16 US EPA priority PAHs (∑16 PAHs, mean: 1079 ng g-1) and organic-matter-normalized ∑16 PAHs (mean: 224 ng g-1 OM) were positively correlated with traffic volumes (Pearson correlation, r = 0.88 and 0.78, p < 0.01). The levels of carcinogenic PAHs were significantly higher at the high traffic sites than at the low traffic sites. High traffic sites (>25 000 vehicles per day) located at intersections showed elevated concentrations of indicator compounds (e.g., phenanthrene, fluoranthene, pyrene, and benzo[ghi]perylene) for gasoline and diesel exhaust. The diagnostic ratios also suggested a strong influence of the traffic emissions on the roadside soils, not only at urban sites but also at rural ones. Consequently, roadside soils and road dust (which are expected to be much more contaminated with PAHs than roadside soil) can act as important non-point sources of air and water pollution. The cancer risk from exposure to PAHs in the roadside soils was in an acceptable range, but continuous monitoring is required to evaluate the influence of increasing traffic on the environment and human health.