Total Incremental Lifetime Cancer Risk Research Articles

Effect through inhalation on human health of PM1 bound polycyclic aromatic hydrocarbons collected from foggy days in northern part of India

We investigated the health risk from 16 polycyclic aromatic hydrocarbons (PAHs) adsorbed on submicron particles and also reported their concentrations, spatial distribution and possible sources during foggy days at Kanpur. Twenty-four urban foggy day’s samples gathered from Kanpur, an urban center in North India and most densely populated city in the Indo-Gangetic plain of India, were examined for 16 PAHs (2–6 rings).The mean concentration of PM1 was found to be 160.16±37.70μg/m3. ∑16PAHs concentrations were 529.17ng/m3 with a mean of 33.07ng/m3. The compounds of higher molecular weight (4–6 rings) added to 70.67% of ∑PAHs mass concentration in the foggy day’s samples. The results of source identification by using principle component analysis (PCA) and diagnostic ratios proposed that the primary sources of PAHs were vehicular emission (primarily driven by diesel fuel) and coal combustion and the secondary source. Exposure to total PAHs in the ambient air resulted in, 95% probability total Incremental Lifetime Cancer Risk (TILCR) 3.57×10−5 for adults and 2.08×10−5 for children or (∼35 cancer case per million in adults and ∼20 cancer case per million in children) due to inhalation in terms of ILCR were higher than the baseline value of acceptable risk (one cancer case per million people) suggesting moderate health risk to resident human population.

Polycyclic aromatic hydrocarbons in urban soils from kindergartens and playgrounds in Bratislava, the capital city of Slovakia

One of the most urgent environmental problems in the world is contamination of soils by a variety of chemical pollutants in urban regions. The main goal in this study was to determine concentrations of 16 polycyclic aromatic hydrocarbons (Σ16PAHs) in soils in kindergartens and playgrounds because children are most often exposed to the soil surface. Totally, 61 surface soil samples (0–10 cm) were collected from the city of Bratislava and analyzed for basic soil properties and PAHs. The concentrations of Σ16PAHs ranged from 45 to 12,151 μg/kg with a mean concentration of 2,064.8 μg/kg and correlated positively with total organic carbon contents of the soils (Spearman r = 0.272, p < 0.034). There were significant differences in PAH concentrations between the old inner part of the city and the younger outer part. Kindergartens and playgrounds with more contaminated soils are located in the oldest part of the city (i.e., city center). Source apportionment using PAH diagnostic ratios indicated that traffic was likely the primary source of PAHs in soils, but wood or coal combustion from domestic heating as an additional contamination source could not be excluded. The benzo(a)pyrene equivalent concentrations for carcinogenic PAHs (BaPtpe) in 21 % of the soil samples were higher than the Canadian risk-based soil criterion. Nevertheless, total incremental lifetime cancer risks of PAHs ranged from 7.39 × 10−9 to 2.79 × 10−6, indicating negligible risk for the health of children even in the most contaminated soils.

Concentrations, Source and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Soils from Midway Atoll, North Pacific Ocean

This study was designed to determine concentrations of polycyclic aromatic hydrocarbons (PAHs) in soil samples collected from Midway Atoll and evaluate their potential risks to human health. The total concentrations of 16 PAHs ranged from 3.55 to 3200 µg kg−1 with a mean concentration of 198 µg kg−1. Higher molecular weight PAHs (4–6 ring PAHs) dominated the PAH profiles, accounting for 83.3% of total PAH mass. PAH diagnostic ratio analysis indicated that primary sources of PAHs in Midway Atoll could be combustion. The benzo[a]pyrene equivalent concentration (BaPeq) in most of the study area (86.5%) was less than 40 µg kg−1 BaPeq and total incremental lifetime cancer risks of PAHs ranged from 1.00×10−10 to 9.20×10−6 with a median value of 1.24×10−7, indicating a minor carcinogenic risk of PAHs in Midway Atoll.

Distribution, sources and potential risk of HCH and DDT in soils from a typical alluvial plain of the Yangtze River Delta region, China

Spatial distribution, sources and potential health risks of organochlorine pesticides (OCPs), including hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), in surface soils (n = 544) collected from a typical alluvial plain of the Yangtze River Delta region, China, were elucidated. Concentrations of ΣHCH and ΣDDT in soils ranged from less than the limit of detection (<LOD) to 99.0 ng g(-1), dry weight (dw) (mean 3.23 ng g(-1) dw) and <LOD to 600 ng g(-1) dw (mean 88.8 ng g(-1) dw), respectively. Historical applications of HCH and DDT were the major sources of the residue in soils. HCH was mainly distributed in Anthrosols in the southern part of the watershed, while DDT was mainly distributed in Cambosols in the northern part. The 95 % cumulative probability incremental lifetime cancer risks (ILCRs) of different age groups such as children, youths, and adults all exceeded the acceptable risk level of 10(-6) recommended by USEPA for carcinogenic chemicals. The spatial distributions of ∑ILCRs were consistent with concentrations of OCPs in soils, while they were slight different for the different age groups. Adult females had the greatest risk of OCPs in soils, followed by children, while youths had the least risk. The ingestion of OCPs in soils was the more important route of exposure compared with dermal and inhalation exposures. The concentration of OCPs in soils, the particulate emission factor, the fraction of dermal exposure ratio, and the soil ingestion rate were the major contributing variables to total ILCRs according to sensitivity analyses.

Source apportionment and risk assessment of polycyclic aromatic hydrocarbons in the atmospheric environment of Alexandria, Egypt

In this study, three receptor models [factor analysis/multiple linear regression (FA/MLR), positive matrix factorization (PMF) and UNMIX] were applied seasonally to investigate the source apportionment of PAHs in the atmospheric environment of Alexandria, and a lifetime cancer risk was assessed. ∑44 (gas+particle) PAH concentrations varied from 330 to 1770ngm−3 and 170–1290ngm−3 in the summer and winter seasons respectively. PAH concentrations at the industrial sites were significantly higher than at the traffic and residential sites during the winter season (p<0.001). Summer PAH concentrations were significantly higher than the winter season at the traffic sites (p=0.027). Results obtained from the three receptor models were comparable. Vehicle emissions, both diesel and gasoline contributed on average 36.0–49.0% and 19.0–34.0% respectively, natural gas combustion 11.0–27.0% and, during the summer only, also evaporative/uncombusted petroleum sources 8.00–18.0%. Seasonal trends were found for the gasoline emission source. Overall, PMF and UNMIX models afforded better source identification than did FA/MLR. The lifetime cancer risk assessment showed that incremental lifetime cancer risks (ILTCRs) were greater than the acceptable level of 10−6 through dermal and ingestion routes at all the investigated sites and through the inhalation route at the industrial and traffic sites only. Total ILTCRs (6.64×10−3–4.42×10−2) indicated high potential risks to the local residents.

Health risk assessment for vehicle inspection workers exposed to airborne polycyclic aromatic hydrocarbons (PAHs) in their work place

Inhalatory and dermal exposures of on-duty vehicle inspection workers to polycyclic aromatic hydrocarbons (PAHs) in Beijing were investigated from April 18 to May 17, 2011. Exposure levels to particulate PAHs for the vehicle inspection workers at gasoline, bus and diesel lines were found to be 56.07 ng m(-3), 111.72 ng m(-3) and 199.80 ng m(-3), respectively. A probabilistic risk assessment framework was integrated with the toxic equivalence factors (TEFs) and the incremental lifetime cancer risk (ILCR) approaches to quantitatively estimate the exposure risk for vehicle inspection workers of the three work lines. The median values of inhalation risk were estimated to be 3.7 × 10(-7), 5.0 × 10(-7) and 1.37 × 10(-6), respectively, while the median dermal ILCR values were 7.05 × 10(-6), 6.98 × 10(-6) and 1.28 × 10(-5), respectively for gasoline, bus, and diesel inspection workers. Total ILCR was higher than the acceptable risk level of 10(-6), indicating unacceptable potential cancer risk.

Assessing hazardous risks of human exposure to temple airborne polycyclic aromatic hydrocarbons

We proposed an integrated probabilistic risk assessment framework based on reported data to quantify human health risks of temple goers/workers to airborne polycyclic aromatic hydrocarbons (PAHs) from incense burning in typical Taiwanese temples. The framework probabilistically integrates exposure, human respiratory tract, and incremental lifetime cancer risk (ILCR) models to quantitatively estimate size-dependent PAHs exposure in human lung regions and cancer risks for temple goers (moderate and high exposures) and temple workers (extreme exposure). Our results show that the ILCRs are greater than the acceptable level of 10 −6 for extreme and high exposure groups through inhalation route. The result also indicates that the higher ILCRs (10 −6 to 10 −4) are found in ingestion and dermal contact routes for temple goers/workers. For personal extreme exposure to carcinogenic PAH in the temple, 95% probability total ILCR (TILCR) (9.87 × 10 −4 to 1.13 × 10 −3) is much greater than the range of 10 −6 to 10 −4, indicating high potential health risk to temple workers. For temple goers with high and moderate exposure groups, however, the 95% probability TILCRs were estimated from 6.44 × 10 −5 to 7.50 × 10 −5 and 5.75 × 10 −6 to 6.99 × 10 −6, respectively. This study successfully offers a scientific basis for risk analysis due to incense burning to enhance broad risk management strategies for temple indoor air quality.

Probabilistic risk assessment for personal exposure to carcinogenic polycyclic aromatic hydrocarbons in Taiwanese temples

To assess how the human exposure to airborne carcinogenic polycyclic aromatic hydrocarbons (PAHs) during working in or visiting a typical Taiwanese temple, we present a probabilistic risk model, appraised with reported empirical data. Two approaches are applied, one based on animal-derived benzo[ a]pyrene (B[ a]P) toxic equivalents (B[ a]P eq) of individual PAHs and one is assumed that the potency of PAH mixtures is linked to their B[ a]P level. The model integrates probabilistic exposure profiles of total-PAH and particle-bound PAH levels inside a temple from a published exploratory study with probabilistic incremental lifetime cancer risk (ILCR) models taking into account inhalation and dermal contact pathways, to quantitatively estimate the exposure risks for three age groups of adult, adolescent, and child. Risk analysis indicates that 90% probability inhalation ILCRs for three age groups have orders of magnitude around 10 −7–10 −6; whereas for the dermal contact ILCRs ranging from 10 −5 to 10 −4, indicating high potential cancer risk. All 90% probabilities of B[ a]P- and B[ a]P eq-based total ILCRs are larger than 10 −6, indicating unacceptable probability distributions for three age groups. Sensitivity analysis indicates that to increase the accuracy of the results efforts should focus on a better definition of probability distributions for inhalation cancer slope factor, inhalation rates, and particle-bound PAH-to-skin adherence factor. We estimate risk-based visiting frequency advice for adult, adolescent, and child to a temple ranging from 5 to 7, 17 to 23, and 48 to 65 year −1, respectively, based on an average 3 h residence time.