Environmental behavior of pahs in dianchi lake distributions, sources and risk assessment of poly cyclic aromatic hydrocarbons in surface sediments from Dianchi Lake,China

Polycyclic aromatic hydrocarbons [PAHs] in the priority controlling list of US EPA were systematically evaluated in surface sediments in Dianchi Lake and its estuaries. Total PAH concentrations [IPAHs] varied from 210 to 11,070 ng/gdry weight [d.w] in Dianchi Lake, and from 230 to 12,271 microg/g d.w. in the estuaries. IPAHs in sediments from Caohai section were higher than those from Waihai section. The occurrences of PAHs in the Lake were closely related to the distributions of rivers, indicating that the river runoff was an important pathway of PAHs into the Lake. Compared with the US Sediment Quality Guidelines [SQGs], IPAHs in most area were below the effect range low [ERL], which implied that the adverse biological effects would occur rarely. The toxic equivalent concentrations of potentially carcinogenic PAHs [TEQ[carc]] varied from 19to967ngTEQ/gd.w., and the higher values were found in northern Caohai area. The proportions of the toxic equivalent quantity [TEQ[carc]] to the total TEQs in sediments were all above 96%, suggesting that the carcinogenicity of PAHs could be occurred. Significantly positive correlations between total organic carbon [TOC] and less molecular weight PAHs [2, 3-ring] [LPAHs] were observed in the Lake. Diagnostic ratios showed that the primary source of PAHs in Dianchi Lake and most estuaries is biomass combustion, but is petroleum combustion or petrogenic origin in several other estuaries

Investigation of the heavy metal contamination of the sediments from the yellow river wetland nature reserve of Zhengzhou, China

Heavy metal pollution in the sediment of the Yellow River draws wide attention in the recent years. The Yellow River wetland nature reserve of Zhengzhou is one of the major wetlands of the river and located at the beginning of the lower reach. In this article, we aimed to investigate the degree and the sources of the metal pollution in the reserve. Metals as Cu, Pb, Cr, Cd and Mn in the sediment were monitored using flame atomic absorption spectrometry. The index of geo-accumulation [I[geo]] and the modified degree of contamination [mC[d]] were developed to evaluate individual metal pollution and overall enrichment impact of the elements. Compared with sediment quality guidelines, the effect of Cr and Pb are more serious than others. I [geo] values show Pb pollution are moderate at the Xinzhai, Langchenggang and Nansutan sites, and mC[d] analysis indicate the whole contamination at the Wantan, Langchenggang and Nansutan sites was low. Principal component analysis indicated that the first factor was Cu, Mn and Cd, mainly from soil erosion and the irrational use of phosphate fertilizers; the second Pb from fossil fuel burning; and the third Cr from weathering process. We conclude that Pb contamination is serious in the reserve, and the main sources of the metal are crude oil consumption and coal combustion of the brick kilns around. We also draw a conclusion that it is vital to evaluate contamination degree with both individual elements and overall average

14,15-Epoxyeicosatrienoic acid induces the proliferation and anti-apoptosis of human carcinoma cell

Epoxyeicosatrienoic acids [EETs], which are cytochrome P450 epoxygenase metabolites of arachidonic acid, have anti-inflammatory effects, modulate smooth muscle proliferation, and inhibit smooth muscle migration. This study was designed to determine whether exogenous EETs have any effect on the cell proliferation and apoptosis of carcinoma cell as well as the possible signaling pathways of EETs in this regulation. The effects of EETs on the proliferation and anti-apoptosis of human carcinoma cells were measured by MTT assay and flowcytometric analysis, and the regulation of PPARy, epithelial growth factor receptor [EGFR], extracellular signal-regulated kinase [ERK], phosphatidylinositol 3 [PI3]-Kinase/AKT pathways was investigated by reverse transcriptase polymerase chain reaction [RT-PCR] and western blot analysis. Results of this study suggested that 14, 15-EET may activate the expression of PPARy in Tea-8113 cells. 14,15-EET may stimulate cell proliferation, and increase the percentage of cells during S-G2-M phase in Tea-8113 cells significantly. The levels of EGFR, ERK, and PI3 kinase/AKT proteins were significantly induced by treatment of 14, 15-EET and 14,15-EET/ AUDA, but no significant changes were observed by addition of GW9662. These findings suggest that exogenous 14,15-EET has potent inhibitory effect on proliferation, and could induce apoptosis in Tea-8113 cell, and these changes are related to the expression of PPARganna, the activation of EGFR, ERK, and PI3 kinase/AKT proteins

Effect of aging on bioavailability of copper on the fluvo aquic soil

The bioavailability of copper in contaminated soils has received more attention due to the safety concern of food chain. The bioavailability of metals is determined by its fractions which are affected by the soil properties and its aging time. This paper focused on the aging effect on the bioavailability of copper added to the soil. The garden soil [fluvo aquic soil] was treated with 100mg/kg and 1000 mg/kg of CuSO4 and incubated for 14, 21, 28, 42, 63, 120, 200, 300 and 400 days in the laboratory respectively. The sequential extraction procedure was used to characterize copper bioavailability in the soil. Meanwhile, the barley was cultured on the same soil incubated and its toxicity was assessed according to the guideline of International Organization for Standardization. The findings show that the exchangeable and carbonate-bound copper decreased with the aging time after addition of CuSO4 in to soil. Meanwhile, the percentages of Fe-Mn oxides and organic bound copper increased. The residual copper was changed little during the aging course. The copper fractions became stable in soils after 60 days. The kinetic equations showed that the Power function and the Elovich equation were fitted well to the experimental data, and the r2 values ranged from 0.840 to 0.982 and 0.741 to 0.975 respectively. The barley test showed that the barley root length was more sensitive to reflect copper toxicity than the shoot biomass. And the exchangeable and carbonate-bound copper were significantly correlated with the barley root length