Perfluorinated compounds in a coastal industrial area of Tianjin,China

Perfluorinated compounds (PFC) in water, sediment, soil, and biota from the coastal industrial area of Tianjin, China, were measured to provide baseline information and to determine possible sources and potential risk to wildlife. Perfluorooctanesulfonate (PFOS) was the predominant PFC with maximum concentrations of 10 ng/L in water, and 4.3, 9.4, and 240 ng/g dw in sediment, soil, and fish, respectively. Perfluorooctanoate (PFOA) concentration in water ranged from 3.0 to 12 ng/L. Perfluoroundecanoate (PFUnA) and Perfluorododecanoate (PFDoA) were detected in solid matrices, respectively, at concentrations of 相似文献   

Receptor-mediated in vitro bioassay for characterization of Ah-R-active compounds and activities in sediment from Korea

Sediment extracts of stream sediments, collected from inland areas of Lake Shihwa (LSI) and Masan Bay (MBI), were screened for their abilities to induce aryl hydrocarbon receptor (Ah-R) mediated gene expression in vitro. Cell viability assay was also performed to examine cytotoxic effects on the Ah-R-mediated activities of sediment samples. Over 80% (30 out of 36) of sediment raw extracts (REs) induced significant Ah-R-mediated activities in the H4IIE-luc cell bioassays. Ah-R-mediated activities of sediment REs from LSI locations (mean=58%-TCDD-max; n=21) were greater than those of sediment REs from MBI locations (mean=35%-TCDD-max; n=15), in general. Seven (mean+/-SD=100+/-14%-TCDD-max) of 21 sediment REs from LSI showed Ah-R-mediated activities comparable to that (set to, 100%-TCDD-max) elicited by 1240 pM TCDD. Whereas, in MBI, only two REs from M1 (93%-TCDD-max) and M9 (82%-TCDD-max) showed significantly great responses that comparable to maximum response of TCDD standard curve. Sample potencies relative to the TCDD standard (TCDD-EQs) were estimated based on full dose-response characteristics of REs and TCDD-EQs were found to be 14-868 pg TCDD/g, dw and 17-275 pg TCDD/g, dw, in LSI and MBI, respectively. A range of TCDD-EQ20-80 of samples, based on multiple estimates of relative potency (REP20-80), did not vary greatly (2-4-fold) in the H4IIE-luc bioassays, which indicated relatively low degree of uncertainties in point estimates of REP for sediment REs examined. Acid-treatment of REs samples improved quantitative biological responses of samples followed by decreases in cytotoxicity identified by MTT cell viability assays.     

Polychlorinated biphenyls,polycyclic aromatic hydrocarbons and alkylphenols in sediments from the Odra River and its tributaries,Poland

Concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), nonylphenol (NP) and octylphenol (OP) were measured in sediments collected during June–August 1998 along the Odra River and its tributaries (Warta, Obrzyca, Barycz, Kaczawa and Bóbr Rivers) in Poland. In addition, raw and treated sewage sludge collected from Gdańsk, Poland, were analyzed for the target compounds. Concentrations of PCBs in sediments varied widely, ranging from 2.7 to 412?ng/g, on a dry weight basis (dry wt). PAHs were the predominant compounds in sediments with concentrations ranging from 150 to 19?000?ng/g, dry wt. The distribution of concentrations of PAHs was more homogenous than that of PCBs. NP concentrations in sediments ranged from <1 to 762?ng/g, while that of OP from <1 to 9.8?ng/g, dry wt. Measured concentrations of target analytes in sediments of the Odra River and its tributaries were comparable to or greater than those reported for riverine sediments in other eastern European countries. Concentrations of total PCBs, PAHs and NP in raw and treated sewage sludge collected from a sewage treatment plant in Gdańsk, Poland, were in the ranges of 203–284, 11?720–13?880 and 6760–99?600?ng/g, dry wt, respectively. Primary treatment of sewage did not appear to reduce PCB or PAH concentrations, although NP and OP concentrations were much less in treated sludge than in raw sludge. This is one of a few studies that document concentrations of PCBs, PAHs and NP in sediments of the Odra River and its tributaries in Poland.     

Effect of water content on transient nonequilibrium NAPL-gas mass transfer during soil vapor extraction

The effect of water content on the volatilization of nonaqueous phase liquid (NAPL) in unsaturated soils was characterized by one-dimensional venting experiments conducted to evaluate the lumped mass transfer coefficient. An empirical correlation based upon the modified Sherwood number, Peclet number, and normalized mean grain size was used to estimate initial lumped mass transfer coefficients over a range of water content. The effects of water content on the soil vapor extraction SVE process have been investigated through experimentation and mathematical modeling. The experimental results indicated that a rate-limited NAPL-gas mass transfer occurred in water-wet soils. A severe mass transfer limitation was observed at 61.0% water saturation where the normalized effluent gas concentrations fell below 1.0 almost immediately, declined exponentially from the initiation of venting, and showed long tailing. This result was attributed to the reduction of interfacial area between the NAPL and mobile gas phases due to the increased water content. A transient mathematical model describing the change of the lumped mass transfer coefficient was used. Simulations showed that the nonequilibrium mass transfer process could be characterized by the exponent beta, a parameter which described the reduction of the specific area available for NAPL volatilization. The nonequilibrium mass transfer limitations were controlled by the soil mean grain size and pore gas velocity, were well described by beta values below 1.0 at low water saturation, and were well predicted with beta values greater than 1.0 at high water saturation.