Total Incremental Lifetime Cancer Risk Research Articles

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.

Polycyclic aromatic hydrocarbons in soil-turfgrass systems in urban Shanghai: Contamination profiles, in situ bioconcentration and potential health risks

Abstract Previous studies on the distribution patterns and health risks of polycyclic aromatic hydrocarbons (PAHs) from cities were focused on soils, leaving the soil-plant system less investigated. In this study, PAHs in the soil-turfgrass system in the urban area of the megacity Shanghai were investigated. The results indicated that total PAH concentrations in soils and turfgrasses ranged from 163.02 to 14,289.30 ng g−1 and 45.15 to 1076.98 ng g−1, respectively. On average, four- and three-ring PAHs such as fluoranthene (14.4%) and pyrene (12.4%) were dominant in soils and naphthalene (37.1%) was especially enriched in turfgrasses. The significant differences in compositional profiles of PAHs between soils and turfgrasses implied selective uptake and translocation of PAHs by turfgrasses from soils. The in situ bioconcentration factors (BCFs) of ∑ 16 PAHs in turfgrasses ranged 0.004–1.3, with ryegrass the highest. BCFs decreased significantly with increasing PAH concentrations in soils, suggesting that turfgrass-assisted PAH removal vial root uptake may be more efficient in slightly contaminated soils. Source appointment results indicated that PAHs in Shanghai were majorly derived from fossil fuel/biomass combustion, vehicular emissions and coking. The incremental lifetime cancer risk (ILCR) analysis generally showed a potential cancer risk for adults (total ILCRs > 1 × 10−6 for all sites) and children (total ILCRs > 1 × 10−6 for most sites) especially through dermal contact with soil. Some sites showed total ILCR values above 1 × 10−4, indicating high health risks for both. The results are informative for contamination prevention and control in urban soils from Shanghai and will provide guidance for further exploration of the phytoremediation potential of turfgrasses.

Spatio-temporal variation and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface dust of Qom metropolis, Iran.

The objective of this research was to determine seasonal variation, distribution, potential health risk, and source identification of 16 polycyclic aromatic hydrocarbons (PAHs) in the surface dust of eight urban areas of Qom. The total levels of 16 PAHs ranged from 364.83 to 739.26ngg-1, with an average of 478.27ngg-1. Sites 1 and 8 showed the highest (491.33ngg-1) and lowest (465.08ngg-1) concentrations of PAHs, respectively. The PAHs demonstrated the highest and the lowest levels in autumn (553.41ngg-1) and summer (402.30ngg-1), respectively. Naphthalene (Nap) showed the highest amounts in all of the areas (75.57ngg-1). Source apportionment indicated that vehicular emissions and combustion of fossil fuels (liquid fossil fuel, crude oil, and gas) are the main sources of the PAHs. Toxic equivalency quantities (TEQs) index exhibited a mean concentration of 47.41ngg-1, and benzo[a]pyrene (BaP) and dibenzo[a,h]anthracene (DBA) together contributed more than 80% of TEQ, indicating high risk potential of these compounds. Total incremental lifetime cancer risk (ILCR) presented higher value (2.62 × 10-7) for children than for adults (2.53 × 10-7), one-fold lower than the threshold (10-6). The spatial ILCR for the study areas and seasons showed the highest cancer risk in site 2 and winter. Taken together, the carcinogenic risk of PAHs to children and adults, respectively, through direct ingestion and dermal contact pathways illustrated values close to the baseline, suggesting that more attention should be paid to the issue in the study area.

Source Apportionment and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Black Carbon Monitored in Port Harcourt, Rivers State, Nigeria

The purpose of this study was to determine concentrations of polycyclic aromatic hydrocarbons (PAHs) in air samples in Port Harcourt metropolis, Rivers State, Nigeria, evaluate their potential risks to human health and identify pollution sources by characterizing the PAHs. Sixteen polycyclic aromatic hydrocarbons were measured with a total concentration range of 0 to 9,589 mg/kg in the rainy season and 0.46 to 131mg/kg range in the dry season. High molecular weight PAHs dominated the PAH profiles accounting for 91% in dry season and 45% in the wet season. The overall assessment of the ratios of LMW to HMW of minimum, maximum and mean concentrations indicated pyrogenic sources. Benzo (a) pyrene equivalent (BaPeq) analysis showed that benzo (a) pyrene, DiBenzo (a,h) antracene and Indeno (1.2.3-cd) pyrene contributed the highest cancer toxicity with 94% and 85% in wet and dry seasons, respectively. The total incremental lifetime cancer risks of PAHs ranged from 0 to 4.90 with a median value of 3.37 x10-2 in wet season; while in the dry season, ILCR of PAHs ranged from 1.62 x10-5 to 7.42x10-3 with a median value of 1.15 x 10-3 . These values showed pervasive pollution indicating a major carcinogenic risk of PAHs. Mean ILCR in wet season was 3.37 x10-2 (33,700 x10-6 ) meaning 1 in every 30 persons in the study area is estimated to develop cancer. In the dry season, mean ILCR was 1.15 x10-3 (1,150 x10-6 ) meaning 1 in every 870 persons in the study area is estimated to develop cancer.

Polycyclic aromatic hydrocarbons (PAHs) and esophageal carcinoma in Handan-Xingtai district, North China: a preliminary study based on cancer risk assessment.

Extremely high risk of esophageal carcinoma (EC) occurs in Handan-Xingtai district of North China. In spite of various preventive measures and epidemiological investigations that have been conducted for years, incidence and mortality of EC are still in the highest level of China. The etiology of EC remains unclear in the region. Previous studies of our research group proposed that polycyclic aromatic hydrocarbons (PAHs) that derived from numerous coal gangue dumps and atmospheric particulates were major contaminants in these regions. In consideration of mutagenic, teratogenic, and carcinogenic characteristics of PAHs, the authors hypothesized that severe exposure to PAHs could preform as a causative factor for EC. Therefore, four data sets documented in our previous studies were employed in this paper. To quantitatively evaluate the carcinogenic risk imposed by sixteen priority PAHs, incremental lifetime cancer risks (ILCRs) via three exposure pathways were calculated. The results showed that total ILCRs for adult group ranged from 2.08E-05 to 8.63E-02, with an average of 2.00E-02. Total ILCRs for childhood group ranged from 1.09E-05 to 4.48E-02, with an average of 1.04E-02. Total ILCR value of 94% samples exceeded 10-4, indicating a particularly high carcinogenic risk to local residents. Furthermore, ingestion and dermal contact conducted as principal pathways of exposing to PAHs for each population group, rather than inhalation. It can be speculated that severely exposing to PAHs may be a pathogenesis of EC in Handan-Xingtai district. The rigorous supervise and governance are imperative to avoid severe exposure to PAHs that derived from coal gangue dumps.

Exposure to Heavy Metals in Soot Samples and Cancer Risk Assessment in Port Harcourt, Nigeria

Background.Port Harcourt is an oil-rich city in Nigeria's Niger delta region. For over two years, Port Harcourt experienced black soot deposition in the environment. In November 2016, residents woke up to black soot covering cars, clothes, houses, plants, etc. Soot concentrations continued to increase until the first quarter of 2017. After public outcry, the frequency and concentration of soot deposition began to decline.Objective.The present study was carried out to determine the presence and levels of heavy metals in soot along with a cancer risk assessment of heavy metals exposure in Port Harcourt, Nigeria.Method.Three residential locations were sampled: Aba road, Woji and Iwofe. Sampling was performed from 6:00 am to 6:00 pm, to simulate the estimated duration that most residents who do not work in offices are exposed to soot in places such as the open market and business areas. Five heavy metals (iron (Fe), nickel (Ni), chromium (Cr), cadmium (Cd) and lead (Pb)) were investigated. The data obtained were subjected to Pearson correlation and one-way analysis of variance using SPSS software to test the correlation and significant differences between metals concentrations.Results.Lead was found to have a significant correlation with Cd (0.808), indicating that both metals originated from the same source. Concentrations of heavy metals were higher than control values and the World Health Organization's specifications for ambient air. Chromium concentrations were the lowest. The order of concentration of heavy metals was Fe > Pb > Cd > Ni > Cr.Conclusions.Non-carcinogenic and carcinogenic health risks of these heavy metals were evaluated using the target hazard quotient (THQ) and the incremental lifetime cancer risk (ILCR). Obtained ILCR values were within the acceptable limits for cancer risks. However, the total ILCR values for Cd and Pb for children were 3 times higher than those for adults. This is a source of concern as their prevalence in ambient air puts children and residents in Port Harcourt metropolis at risk of various types of cancers.Competing Interests.The authors declare no competing financial interests.

Multiple exposure pathways and health risk assessment of heavy metal(loid)s for children living in fourth-tier cities in Hubei Province

In the past, most research focused on the children living near a typical contaminated area but ignored the health risks of children living in the fourth or fifth tier cities without typical contaminated sources. These cities are now facing a series of problems, such as serious environmental pollution, undeveloped health system and so on. Furthermore, the development of modern logistics for food delivery has altered lifestyles that directly impact diets and eating patterns. In this study, multiple exposure pathways and health risks of children to heavy metal(loid)s were studied based on questionnaire-based surveys and field sampling of soil, dust, fine particulates, drinking water and food. We found that Pb, Cd and Mn levels in environmental samples were very high indicating a serious pollution problem. Inhalation exposure via aerosol particles was the most important pathway and was greater than exposure by food ingestion. The hazard index for Mn via aerosol particles was >1 even at the 5th percentile and Mn levels in urine was 10 times higher than those of people living in typical contaminated areas. The total incremental lifetime cancer risk (ILCR) for all metal(loid)s was also higher than the threshold at the 95th percentile. This study highlights health risks to children living in fourth tier cities and the importance of air pollution control to protect heavy metal exposure for children.

Characteristics of PM2.5-bound PAHs at an Urban Site and a Suburban Site in Jinan in North China Plain

The PM2.5 samples at an urban site (JN) and a suburban site (QXT) were simultaneously collected in a heavily polluted city in North China Plain (Jinan) from March to December in 2016, and eighteen polycyclic aromatic hydrocarbons (PAHs) were analyzed. The annual average ∑PAHs concentrations were 39.8 ± 36.6 and 23.6 ± 14.0 ng m–3 at JN and QXT, respectively, with the highest concentrations observed during winter. PHE and CHY were the two most abundant PAHs, accounting for 31.1% at JN and 34.2% at QXT. Source apportionment analyses from the results of Principal Component Analysis (PCA) revealed that coal/biomass combustion and vehicle emission were the major PAH sources in PM2.5. The ratio of LMW + MMW (LMW: low molecular weight; MMW: middle molecular weight) PAHs to ∑PAHs at JN was significantly lower (p < 0.001) than that at QXT, indicating coal/biomass burning made more significant contribution to suburban area than that to urban area. Conversely, vehicle emission worked more effectively to urban area. The total benzo[a]pyrene (BaP) equivalent concentration (BaPeq) of PAHs (gas + particle phases) was 9.66 times higher than the standard value (1.00 ng m–3) and mainly originated from PAHs in particles (93.1%) with the highest contributor of Benzo(a)pyrene (BaP, 60.8%) at the urban site of Jinan in winter. The total incremental lifetime cancer risk (ILCR) assessment suggested that all age groups may have potential health risk at JN in winter except for infant. The Concentration Weighted Trajectory (CWT) model indicated that local emission and short-distance transport were the main sources of PAHs during spring and winter, and long-range transport played a key role on PAH concentrations in summer and autumn.

Polycyclic Aromatic Hydrocarbons (PAHs) in Urban Street Dust of Huanggang, Central China: Status, Sources and Human Health Risk Assessment

ABSTRACT Twenty-one street dust samples were collected in Huanggang City, Hubei Province, Central China. Sixteen priority polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography–mass spectrometry (GC-MS). Concentrations of ∑16PAHs ranged from 622.97 µg kg–1 to 4340.67 µg kg–1 with an average of 1862.10 µg kg–1. Among these PAHs, high-molecular-weight PAHs (four to six rings), which are the predominant PAH contributors in street dust, accounted for 55%–73% of the total PAHs. Mean concentrations of the PAHs among the four functional districts followed the order: education district > traffic area > business district > residential area. However, the individual PAH concentrations exhibited weak correlations with the total organic carbon. Based on the isomer ratios of the PAHs, biomass and coal combustion, and petroleum input were two key factors controlling PAH levels in this study. At a 95% confidence interval, the total incremental lifetime cancer risks for children, adolescents and adults approximated 10–6–1.5 × 10–5. These values were higher than the baseline value for acceptable risk (10–6), indicating a potential carcinogenic risk.

Polycyclic aromatic hydrocarbons in street dust of Marvdasht city, SW Iran: concentration, health risk assessment and source apportionment

The status, health risk and sources of street-dust-borne polycyclic aromatic hydrocarbons (PAHs) were investigated in Marvdasht city. The total concentration of 15 PAHs ranged from 932.85 to 5030 μg kg-1 with a mean of 2185.7 μg kg-1. The PAHs contained 2-6 rings and the level of five carcinogenic PAHs generally accounted for 5-40% of total concentration. The statistical analysis and diagnostic ratios demonstrated that the main emission source of PAHs is traffic. The toxic equivalent concentrations (TEQs) of PAHs in street dust ranged from 12.91 to 1160.88 μg kg-1, with a mean of 257.18 μg kg-1. High correlation coefficients (r > 0.9, p < 0.01) between benzo[a]pyrene, dibenzo[a,h]anthracene, benzo[g,h,i]perylene, indene and toxicity equivalent concentrations of street dust indicated that these PAHs are predominant contributors to TEQ. The results of total incremental lifetime cancer risk (ILCR) demonstrated that Marvdasht's residents are potentially exposed to high cancer risk via dust ingestion and dermal contact.

Effect of residential air cleaning interventions on risk of cancer associated with indoor semi-volatile organic compounds: a comprehensive simulation study

Human exposure to multiphase semi-volatile organic compounds (SVOCs) via multiple routes has been associated with health risks. Residential air cleaning interventions remove SVOCs adsorbed on airborne particles, which subsequently affects indoor concentrations of SVOCs in other phases. We aimed to investigate the effect of residential air cleaning interventions on the overall cancer risk associated with multiphase SVOCs. We simulated concentrations of eight multiphase SVOCs (including seven polycyclic aromatic hydrocarbons [PAHs] and di(2-ethylhexyl) phthalate [DEHP]) using a kinetic partition mass balance model for three exposure scenarios: naturally ventilated residences without intervention (scenario 1), naturally ventilated residences with portable air purifiers (scenario 2), and mechanically ventilated residences with air filtration units (scenario 3). We converted indoor concentrations of the individual PAHs into indoor concentrations of equivalent benzo[a]pyrene (BaPeq) using the BaP cancer potency equivalent factor for each PAH. We estimated indoor exposure to SVOCs via inhalation, dermal absorption, and ingestion. For each scenario, we calculated the incremental lifetime cancer risk (ILCR) associated with indoor exposure to each SVOC via the three routes and the total ILCR (all three routes combined). Mean total ILCRs associated with exposure to BaPeq were 4·42 × 10-6 (SD 2·84) for scenario 1, 2·36 × 10-6 (1·53) for scenario 2, and 4·88 × 10-6 (4·86) for scenario 3. Mean total ILCRs associated with exposure to DEHP were 3·61 × 10-6 (3·60) for scenario 1, 7·51 × 10-7 (5·34) for scenario 2, and 1·48 × 10-5 (2·02) for scenario 3. Ingestion of settled dust was the most important contributor to the total ILCR for both BaPeq and DEHP in all the studied scenarios. The large-scale use of mechanical ventilation systems in urban residences in China needs to be evaluated owing to their potential exacerbation of the cancer risks associated with common indoor SVOCs. National Key Project of the Ministry of Science and Technology and Natural Science Foundation of China.

Application of biochar to soils may result in plant contamination and human cancer risk due to exposure of polycyclic aromatic hydrocarbons

Biochars are added to soil to improve agronomic yield. This greenhouse- and field-scale study evaluated polycyclic aromatic hydrocarbon (PAH) contamination in 35 commercial and laboratory-produced biochars, and assessed the effects of biochar amendment of soils on PAH accumulation in vegetables and the risk for cancer. The total and bioavailable PAH concentrations in biochars varied from 638 to 12,347 μg/kg and from below the detection limit (BDL) to 2792 μg/kg, respectively. PAH formation in biochars decreased with increasing production temperature (350–650 °C). Root exudates enhanced PAH release from biochars. The total PAH concentrations in eight edible vegetables growing in biochar-amended soil varied according to biochar and vegetables type from BDL to 565 μg/kg. A health risk assessment framework was integrated with the benzo[a]pyrene toxic equivalency quotient and the incremental lifetime cancer risk (ILCR) to estimate the exposure risk for human beings via ingestion of PAH-contaminated vegetables. The total ILCR for adults was above 10−6, which suggests a risk to human health from direct exposure to PAHs in vegetables grown in biochar-amended soil. These results demonstrate that biochar application may lead to contamination of plants with PAHs, which represents a risk to human health. The PAH levels in biochars produced using different conditions and/or feedstocks need to be evaluated and biochars should be pretreated to remove PAHs before their large-scale agronomic application.

Distribution, fate and risk assessment of PAHs in water and sediments from an aquaculture- and shipping-impacted subtropical lake, China

The spatial-temporal distribution of polycyclic aromatic hydrocarbons (PAHs), their source, and potential health risks were determined in overlying water and surface sediments from Chinese Lake Guchenghu, adjacent commercial mitten crab ponds and the connected Wushen Canal to assess the contamination profile of the area. The total PAHs concentrations in sediment and water were 86.7–1790 ng g−1 dry weight (dw) and 184–365 ng L−1 in summer and 184–3140 ng g−1 dw and 410–1160 ng L−1 in winter. Two- and 3-ring PAHs were the predominant compounds in water, while PAHs with 4–6 rings dominated in the sediment at both upstream and downstream sites. PAHs concentrations in water and sediment correlated significantly. Diagnostic ratios and positive matrix factorization (PMF) analyses indicated a strong influence of pyrogenic sources, principally biomass combustion and vehicle emission, on the concentrations of PAHs. The distribution, source identification, and mean effects range median quotients (mERMQ) analyses suggested that the most contaminated area was located downstream and upstream of the Wushen Canal, followed by Lake Guchenghu and a commercial crab pond area. From an ecological point of view, PAHs posed a potential risk to drinking water sources as the concentrations exceeded the guideline value of 0.05 μg L−1. The risk posed by sediment PAHs appeared to be low except for the downstream sites, which showed a low to medium ecotoxicological risk. The total incremental lifetime cancer risks ranged between 10−7 and 10−5, indicating a potential health risk for the local population when exposed to sediment from the area.

Human health risk assessment of ground water contaminated with petroleum PAHs using Monte Carlo simulations: A case study of an Indian metropolitan city

Underground pipelines are frequently used to transport petroleum fuels, through industrial as well as residential zones. Chennai is one of the four largest metropolitan cities of India. The region of interest in this study is located in the northern part of the Chennai. Ground water of this area was contaminated with polyaromatic hydrocarbons (PAHs) from the leaking oil storage tanks and pipe lines. Health risk assessment was conducted for exposure to PAHs in the ground water using incremental life time cancer risk (ILCR) models coupled with benzo[a]pyrene toxic equivalent method. The exposure pathways considered in this study were direct water ingestion and dermal contact under residential scenario. Exposure input parameters were transformed to statistical parameters using lognormal/uniform distributions and resultant probabilities of cancer risk were estimated by performing Monte Carlo simulations. Preliminary remediation goals were predicted using the combination of the cancer risk models of all the exposure routes with the consideration of high-safety risk of 1-in-1 million. Results showed that the cancer risk is predominantly contributed (greater than 98%) by dermal exposure than the oral in both adults and children. The total ILCR is found to be greater than a low safety risk of 1-in-10,000 with higher probability percentages (>90%). The 95th percentile values of the risk were presented in order to address the need for remediation. Appropriate remedial and treatment methods for the subject site were proposed. The results of the study will be useful for the regulatory boards and policy makers in India in understanding the actual impact of the contamination on receptors, setting up final remediation goals and deciding on a specific remedial method.

Polycyclic aromatic hydrocarbons (PAH) in Portuguese educational settings: a comparison between preschools and elementary schools

ABSTRACTThe aim of this study was to determine levels and risks due to inhalation exposure to polycyclic aromatic hydrocarbons (PAH) in different educational settings, namely for 3- to 5- year-old and 6- to 10-year-old children. Eighteen PAH (16 priority designated by US Environmental Protection Agency (USEPA) and dibenzo[a,l]pyrene and benzo[j]fluoranthene) were simultaneously collected in indoor and outdoor air at two Portuguese preschools (PS1–PS2) and five elementary schools (ES1–ES5) from March to May 2014. Indoor concentrations at PS and ES were significantly different, with total levels (∑PAHs) 0.721–15.9 ng/m3 at PS1–PS2 and 5.03–23.6 ng/m3 at ES1–ES5. The corresponding outdoor concentrations were, respectively, 1.22–32.7 ng/m3 and 2.6–31.5 ng/m3. Polycyclic aromatic hydrocarbons with 2–3 aromatic rings were predominantly emitted by indoor sources, while compounds with 4–6 aromatic rings were mainly generated by infiltration of ambient PAH pollution to indoors. Excess lifetime risks of lung cancer exceeded the World Health Organization (WHO) designated guideline of 10–5 in both types of schools (15–42-fold at PS; 15–52-fold at ES). However, total (sum of indoor and outdoor exposure) incremental lifetime cancer risks (ILCR) were below the USEPA level of 10–6 at all studied institutions and thus considered negligible. Finally, ILCR due to indoor exposure represented 60–75% and 70–85% of the total ILCR at PS and ES, respectively, thus indicating the need for development and implementation of indoor air quality guidelines in educations settings.

Polycyclic aromatic hydrocarbons in urban street dust: sources and health risk assessment.

Urban street dust samples from 49 sampling sites in Xuzhou (China) were collected and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs) using gas chromatography/mass spectrometry. The organic matter and total carbon contents were also determined. The results showed that total PAHs concentrations varied from 2174 to 24,499ng/g with a mean value of 6616ng/g, organic matter content varied from 3.1 to 8.7% with a mean value of 5.8%, total carbon content varied from 13.2 to 24.2%, with a mean value of 19.9%. Total carbon content was found to show a significant correlation with total PAHs concentration, but such a relationship with total PAHs concentration was only weakly identified for organic matter content. Source Apportionment Techniques indicated pyrogenic sources were the main source of PAHs in urban street dust. The total incremental lifetime cancer risk, including dermal contact, ingestion and inhalation exposure pathways, was estimated to be 4.12×10-6 and 3.98×10-6 for children and adults, respectively.

The status of organochlorine pesticide contamination in the soils of the Campanian Plain, southern Italy, and correlations with soil properties and cancer risk

The distribution, inventory, and potential risk of organochlorine pesticides (OCPs), including Hexachlorocyclohexanes (HCHs) and Dichlorodiphenyltrichloroethanes (DDTs), and their correlation with soil properties and anthropogenic factors were investigated in soils of the Campanian Plain. The total concentrations of HCHs and DDTs ranged from 0.03 to 17.3 ng/g (geometric mean: GM = 0.05 ng/g), and 0.08–1231 ng/g (GM = 14.4 ng/g), respectively. In general, the concentration of OCPs in farmland and orchards was higher than on land used for non-agricultural purposes. There are significant differences in the concentration of OCPs in the soils across the region, more specifically, the Acerra-Marigliano conurbation (AMC) and Sarno River Basin (SRB) are recognized as severely OCP-contaminated areas. The recent application of technical HCHs and DDTs in large quantities appears unlikely in light of the ratio of α-HCH/β-HCH and p,p′-DDT/p,p′-DDE, and the prohibition of the use of these chemicals in Italy nearly forty years ago. The clear correlation between the concentration of DDTs and organic carbon suggests a typical secondary distribution pattern. The mass inventory of OCPs in soils of the Campanian Plain is estimated to have a GM of 17.3 metric tons. There is no clear evidence linking the impact of geographical distribution of OCPs on the incidence of cancer, and the 95% confidence interval of total incremental lifetime cancer risk (TILCR) data falls below the internationally accepted benchmark value of 1 × 10−5.

Source apportionment and risk assessment of PM1 bound trace metals collected during foggy and non-foggy episodes at a representative site in the Indo-Gangetic plain

The concentration, spatial distribution and source of 13-PM1 bound trace metals (Fe, Cu, Mn, Cr, Zn, Cd, Ni, K, Mg, Na, Ca, Pb and V) and adverse health effects of 5-PM1 bound trace metals (Mn, Zn, Ni, Cr and Cd) collected during foggy and non-foggy episodes are presented. Twenty-four samples from each period (foggy and non-foggy episodes) were collected from Kanpur, a typical densely populated city and the most polluted representative site in the Indo-Gangetic plain of India, and were analyzed for carcinogenic (Ni, Cr and Cd) and non-carcinogenic metals (Mn and Zn). The average mass concentration of PM1 during foggy and non-foggy episodes was found to be 160.16±37.70 and 132.87±27.97μg/m3. Source identification via principle component analysis suggested that vehicular emission and anthropogenic, industrial and crustal dust were the dominant sources in this region. During both episodes the decreasing order of hazard quotient (Hq) for adult and children was as Mn>Cr>Cd>Ni>Zn. In a non-foggy episode the hazardous index (Hi) values of these 5 trace metals were found to be ~3.5 times higher than a foggy episode's exposed population, respectively. In a foggy episode, due to the exposure to total carcinogenic trace metals (Ni, Cr and Cd) present in the ambient air, 95% probability total incremental lifetime cancer risks (TIlcR) were ~687 cancer cases and ~402 cancer cases per million in the adult population and children population respectively. These cancer cases were ~1.6 times higher than a non-foggy episode's exposed population.

Lagdo Dam Flood Disaster of 2012: An Assessment of the Concentrations, Sources, and Risks of PAHs in Floodplain Soils of the Lower Reaches of River Niger, Nigeria

The concentrations of the USEPA 16 priority polycyclic aromatic hydrocarbons (PAHs) in soils of the floodplain of the lower reaches of River Niger, Nigeria, were investigated following the Lagdo Dam flood disaster of 2012. The aim was to provide information on the extent of contamination, sources, and risks of PAHs in these soils. The concentrations of Σ16 PAHs in the floodplain soils ranged from 812 to 10,700 μg kg. The benzo(a)pyrene (BaP) toxic equivalence and incremental lifetime cancer risk (ILCR) factors were used to evaluate the risk of human exposure to PAHs in these soils. The concentrations of benzo(a)pyrene carcinogenic equivalence (BaP) and benzo(a)pyrene mutagenic equivalence (BaP) ranged from not detected to 4090 μg kg and not detected to 4150 μg kg, respectively. The total ILCR for children and adults was calculated as the summation of the individual risks through the three routes of exposure, (ingestion, dermal, and inhalation of vapor or dust). The values obtained indicate that there are 6450 and 4480 chances in one million equally exposed persons to develop the risk of cancer for children and adults, respectively, which were higher than the USEPA acceptable guideline value of one cancer case in one million (10) equally exposed persons. The PAHs source evaluation, using the diagnostic ratios and principal component analysis (PCA), indicated that the major sources of PAHs in these soils were fossil fuel combustion, gas flaring, wood combustion, traffic emissions, and input from petroleum.