To study potential ecological impacts of CO2 leakage to shallow groundwater and soil/sediments from geologic CO2 sequestration (GCS) sites, this work investigated the viability and metal reduction of Shewanella oneidensis MR-1 under CO2 stress. While MR-1 could grow under high-pressure nitrogen gas (500 psi), the mix of 1% CO2 with N2 at total pressures of 15 or 150 psi significantly suppressed the growth of MR-1, compared to the N2 control. When CO2 partial pressures were over 15 psi, the growth of MR-1 stopped. The reduced bacterial viability was consistent with the pH decrease and cellular membrane damage under high pressure CO2. After exposure to 150 psi CO2 for 5 h, no viable cells survived, the cellular contents were released, and microscopy images confirmed significant cell structure deformation. However, after a relatively short exposure (25 min) to 150 psi CO2, MR-1 could fully recover their growth within 24 h after the stress was removed, and the reduction of MnO2 by MR-1 was observed right after the stress was removed. Furthermore, MR-1 survived better if the cells were aggregated rather than suspended, or if pH buffering minerals, such as calcite, were present. To predict the cell viability under different CO2 pressures and exposure times, a two-parameter mathematical model was developed.

The spatio-temporal varying characteristics of dissolved inorganic nitrogen, reactive phosphate (RP), chemical oxygen demand (COD), and dissolving oxygen (DO) in Tianjin coastal seawater were investigated based on observation from May 1996 to October 2006. The concentrations of dissolved inorganic nitrogen (DIN), RP and COD ascended gradually and their varying ranges were 0.103–2.432, 0.009–0.12, and 0.8–2.9 mg L−1, respectively. While DO in seawater decreased from 8.9 to 6.1 mg L−1 gradually. Those indicated that human-induced eutrophication occurred and the seawater quality deteriorated. The spatial distributions of DIN, RP and COD were largely uniform, where isopleths generally descended from estuarine zones and bays to the central areas and from northern area to southern area, indicating that continental input is the dominant source of those pollutants. Especially, peak zones of those pollutants usually appeared near estuaries, Tianjin harbors, and dumping site of dredged sediment, which indicates that the urban and industrial sewage, shipping waste, dredged soil were the main sources for those contaminants in seawater.

Considering the large amounts of PAHs emitted into the ambient air in China, it is urgent to take preliminary health risk assessment of citizens through inhalation exposure to PAHs in China. The incremental lifetime cancer risk (ILCR) model was used to get the risk level of Tianjin citizens as an example, and Monte Carlo simulation was adopted to deal with the uncertainty. Exposure analysis found that the average values of B[a]P equivalent (B[a]Peq) daily exposure doses for children in the indoor, traffic and outdoor settings were estimated to be 2,446.8, 478.4, and 321.6 ng day−1, respectively. And those for adults were 3,344.1, 794.9, and 519.0 ng day−1, respectively. Much attention must be paid to indoor exposure, as it contributes more than 70% of the B[a]Peq daily exposure dose. ILCR falls within the range of 10−5–10−3, which is higher than the acceptable risk level of 10−6, and lower than the priority risk level (10−3). So this risk should be compared with those of other public health issues in the purpose of risk management. Sensitivity analysis found that the two variables, indoor air PAHs concentration distribution and the cancer slope factor (CSF) of BaP, contribute about 89% of the total risk uncertainty. Thus they are considered as the two main factors influencing the accuracy of the PAHs health risk assessment.

Nineteen road dust samples were collected during 2005 in different parts of the urban area of Anshan, Liaoning Province, China, and 11 polycyclic aromatic hydrocarbons (PAHs) species were quantitatively analyzed using GC–MS. The results indicated that the total average concentration of PAHs over the investigated sites ranged from 48.73 to 638.26μg/g, with a mean value of 144.25μg/g, higher than the concentrations measured in previous studies. PAHs concentrations were higher with high molecular weight homologues (4–6 rings PAHs), accounting for 83.24–96.98%, showing combustion of petroleum fuels was a potential source. Organic carbon in road dust was considered one of the important factors that influenced the concentrations of PAHs in this study, and it was found that concentrations of total PAHs were correlated with those of organic carbon in road dust. The results of diagnostic ratios analysis showed traffic emission (gasoline or diesel) was one of the most important sources of road dust PAHs. Principal component analysis (PCA) indicated that the major sources of road dust PAHs might be emission from traffic, steel industry, cooking and coal combustion.

In China, traffic policemen have to stand for several hours a day at the road intersections with high vehicle flows. To assess their exposure to airborne carcinogenic polycyclic aromatic hydrocarbons (PAHs) during their working time, a preliminary study was conducted to measure the personal exposure level to PAHs. And a probabilistic incremental lifetime cancer risk (ILCR) model together with the benzo[a]pyrene (BaP) toxic equivalents (BaPeq) method was used to conduct health risk assessment. Personal exposure monitors (PEM) were carried by traffic policemen to collect PM10 samples during their daily work in Tianjin, China. Meanwhile, PM100 samples were collected at the roadsides and on campus of Nankai University as comparison. PAHs species were quantitatively analyzed by GC/MS. Experimental results showed that the concentrations of total PAHs, BaP and BaPeq were much higher at the road intersections (867.5, 26.2, 82.4 ng m−3), where the traffic policemen stand during their work time, than those at the roadsides (46.6, 1.5, 5.7 ng m−3), and on campus (19.5, 0.7, 2.4 ng m−3). According to the risk assessment results, the occupational risk falls within the range from 10−6 to 10−3. On the basis of sensitivity analysis results, further research should be directed to give better characterization of the yearly concentration distribution of PAHs and the cancer slope factor (CSF) of BaP in order to improve the accuracy of the health risk assessment.