Concentrations, Source Identification, and Lung Cancer Risk Associated with Springtime PM2.5-Bound Polycyclic Aromatic Hydrocarbons (PAHs) in Nanjing, China.

This study concentrated on the pollution level, sources, and lung cancer risk of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) in spring in Nanjing, China. The PM2.5 samples were collected in spring of the year 2016 in Nanjing. Sixteen United States Environmental Protection Agency priority PAHs were extracted and analyzed after sampling. The mean concentrations of PAHs and BaPeq were 3.98 ± 1.01 and 0.29 ± 0.08 ng/m3, respectively, which is a low level among results from regions worldwide. The diurnal variations of PAHs and BaPeq concentrations showed a relatively high level in the early morning, at the morning rush time of work and traffic transportation, and in the evening traffic peak hours. According to the results of diagnostic ratios, PAHs originated mainly from traffic exhaust, especially diesel vehicle emissions. In a single day, the highest inhalation exposure level was focused between 4 a.m. and 6 a.m., whereas the time between 12 a.m. to 2 p.m. in a day had the lowest exposure dose. Due to the inhalation exposure, the median values of incremental lung cancer risk in spring were estimated to be 7.08 × 10-9, 5.29 × 10-9, 3.53 × 10-8, 5.21 × 10-9, 7.21 × 10-9, 5.24 × 10-9, 3.01 × 10-8, and 5.40 × 10-9 for boys, male adolescents, male adults, male seniors, girls, female adolescents, female adults, and female seniors, respectively, indicating low potential lung cancer risk.

Pollution characteristics, sources and lung cancer risk of atmospheric polycyclic aromatic hydrocarbons in a new urban district of Nanjing, China.

This paper focused on the pollution characteristics, sources and lung cancer risk of atmospheric polycyclic aromatic hydrocarbons (PAHs) in a new urban district of Nanjing, China. Gaseous and aerosol PM2.5 (particulate matter with aerodynamic diameter smaller than 2.5µm) samples were collected in spring of 2015. Sixteen PAHs were extracted and analyzed after sampling. Firstly, arithmetic mean concentrations of PAHs and BaPeq (benzo[a]pyrene equivalent) were calculated. The mean concentrations of PAHs were 29.26±14.13, 18.14±5.37 and 48.47±16.03ng/m3 in gas phase, particle phase and both phases, respectively. The mean concentrations of BaPeq were 0.87±0.51, 2.71±2.17 and 4.06±2.31ng/m3 in gas phase, particle phase and both phases, respectively. Secondly, diagnostic ratios and principal component analysis were adopted to identify the sources of PAHs and the outcomes were the same: traffic exhaust was the predominant source followed by fuel combustion and industrial process. Finally, incremental lung cancer risk (ILCR) induced by whole year inhalation exposure to PAHs for population groups of different age and gender were estimated based on a Monte Carlo simulation. ILCR values caused by particle phase PAHs were greater than those caused by gas phase PAHs. ILCR values for adults were greater than those for other age groups. ILCR values caused by total (gas+particle) PAHs for diverse groups were all greater than the significant level (l0-6), indicating high potential lung cancer risk. Sensitivity analysis results showed that cancer slope factor for BaP inhalation exposure and BaPeq concentration had greater impact than body weight and inhalation rate on the ILCR.

Human health risk assessment of DDTs and HCHs through dietary exposure in Nanjing, China.

In a market based study in Nanjing, a typical southeast city in China, the most common consumed 23 kinds of foods from eleven different categories (vegetable, fruit, fish, pork, livestock meat, chicken, egg, milk, oil, rice and flour) were sampled in November 2015. The concentrations of DDTs and HCHs in foods were analyzed using gas chromatography with mass spectrometer detector. The residual amounts of DDTs and HCHs in foods were 0.95-3.53 ng g-1 and 0.32-1.96 ng g-1, respectively. The highest residual of ∑10OCPs was 4.75 ng g-1 in livestock meat and the lowest was 1.31 ng g-1 in flour. Estimated daily intakes of both DDTs and HCHs for children were higher than other age groups regardless of the gender. With respect to food categories, the consumption of vegetables generated higher dietary exposure of DDTs and HCHs than other food categories for all age categories, which accounted for 20.21%-29.18% of the total. The daily intakes of γ-HCH and DDTs for all population groups were far below the acceptable amounts suggested by the Food and Agriculture Organization of the United Nations/World Health Organization. Health risk assessment indicated that there was no obvious non-cancer risk for local residents, whereas the cancer risk was estimated to be from 10-6∼10-4, being higher than the acceptable risk level and lower than the priority risk level. Among residents of different gender and age, females showed higher risk than males in all age groups, and children were the most vulnerable age group to health risk.

Pollution level, inhalation exposure and lung cancer risk of ambient atmospheric polycyclic aromatic hydrocarbons (PAHs) in Taiyuan, China.

Passive air samplers were deployed to collect both gas and particulate phase polycyclic aromatic hydrocarbons in Taiyuan between 2009 and 2010. Annual average concentrations of BaP equivalent concentration (B[a]P(eq)) in background, rural and urban areas were 2.90 ± 0.29, 23.2 ± 30.8 and 27.4 ± 28.1 ng/m(3), respectively, with higher concentration in the winter than in other seasons. The median B[a]P(eq) concentrations of annual inhalation exposure were estimated to be in the range of 103-347 ng/d for all population groups in rural as well as in urban areas. The median values of incremental lifetime cancer risk (ILCR) induced by whole year inhalation exposure for all groups were basically larger than 10(-6), with higher values in winter than in other seasons and in urban than in rural area. In the same season and area, the ILCR of adults was larger than other age groups and that of females was a little higher than males.

Health risk assessment on dietary exposure to polycyclic aromatic hydrocarbons (PAHs) in Taiyuan, China.

Twenty-five kinds of seven categories of foods were sampled in December 2008 and the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined. The highest level of total PAHs was detected in pork (195.30ng/g) whereas the lowest concentration was found in milk (8.73ng/g). The median values of B[a]P equivalent (B[a]P(eq)) daily exposure doses for children, adolescents, adults and seniors of male were estimated to be 392.42, 511.01, 571.56 and 532.56ng/d, respectively, whereas those for the above population groups of female were found to be 355.16, 440.51, 487.64 and 444.85ng/d, respectively. The incremental lifetime cancer risk (ILCR) values at the 22.1th, 26.1th, 12.7th, 24.9th, 22.7th, 27.0th, 12.9th, and 25.5th percentiles for male children, male adolescents, male adults, male seniors, female children, female adolescents, female adults and female seniors, respectively, were larger than 10(-6), indicating high potential carcinogenic risk, and were larger than 10(-4) at the 74.5th, 78.7th, 60.6th, 77.4th, 75.3th, 79.5th, 60.8th and 77.9th percentiles for the above groups, respectively, which implied significant cancer risk. Sensitivity analysis found that the two variables of oral cancer slope factor of benzo(a) pyrene (SF) and the daily dietary PAH exposure level (ED) had the greater impact than that of body weight (BW) on the ILCR.

[Enhanced coagulation and NOM fractionation study of a typical southern water].

Systematic studies on enhancing normal treatment processes were performed in order to remove aquatic organic matter economically and efficiently. Enhanced coagulation and polymer coagulant-aid coagulation were compared through jar tests and on-spot experiment (Pilot-scale and full-scale experiment). Fractionations of raw water and water after treatments of above two strategies were performed based on selective adsorption of resin DAX-8. It was found that matters causing UV absorbance at 254 nm were well removed by above two treatments; removals of which could be achieved 90% or more. Hydrophobic bases and acids fractions were more removed under enhanced conditions with removals 66% and 35% respectively; while hydrophilic fraction could be better removed by about 45% using polymer coagulant aids. But the whole removals of the two strategies were almost equal.