[Historical Changes and Responses to Human Activities of Polycyclic Aromatic Hydrocarbons in Lake Sediments from Northern China During the Past 100 Years].

Polycyclic aromatic hydrocarbons (PAHs) are of concern globally because of their carcinogenic, teratogenic, mutagenic, and bio-accumulative effects. Northern China is one of the regions in China with a high density of lakes; however, the lake aquatic environment is becoming seriously deteriorated, especially from PAH pollution due to the intensification of human activities during the past 100 years. Therefore, the spatial distribution and historical changes in PAHs in lake sediments from northern China were analyzed to indicate their response to anthropogenic emissions and pollution reduction actions. The ω(PAHs) in lake sediments ranged from 18.2 to 1205.0 ng·g-1, and low molecular weight PAHs were the dominant compounds. PAH concentrations increased from the 1950s to a peak level in the 2000s, which was induced mainly by increased energy consumption and rapid economy development, with PAH levels decreasing subsequently in the last 10 years due to craft improvement of wastewater treatment plants and the promotion of new energy policies. Spatially, PAHs pollution in Northeast and North China was more serious than that in Northwest China due to the higher level of economic development and energy consumption. Source apportionment results revealed that historical PAH emissions transferred from biomass combustion to a mixture of coal and petroleum combustion. In addition, the results of ecological risk assessment showed that the synthetic sediment quality index (SeQI) of northern China ranged from 36 to 75, and North and Northeast China posed higher ecological risk than that in Northwest China, with phenanthrene (Phe), acenaphthylene (Ace), acenaphthylene (Acy), and dibenzo(a,h)anthracene (DahA) as the main risk contributors.

[Screening of Priority Pollutants and Risk Assessment for Surface Water from Shengjin Lake].

Shengjin Lake, which serves as an important National Nature Reserve, is suffering from chemical pollution due to rapid industrial and agricultural development in the circumjacent basin. Therefore, 168 anthropogenic toxic chemicals were determined to examine their spatial distribution and identify priority pollutants using a ranking system based on occurrence(O), persistence(P), bioaccumulation(B), ecological risk(E), and human health risk(H). Ecosystem and human health risks were also assessed. The spatial distribution of pollutants indicated that higher concentrations occur in the upper lake area compared to the middle and lower lake areas because of Jiang Dam. According to the derived priority pollutant list, phthalate esters(PAEs), organochlorine pesticides(OCPs), and heavy metals(HMs) are high-priority pollutants; polychlorinated biphenyls(PCBs), polycyclic aromatic hydrocarbons(PAHs), and volatile organic compounds(VOCs) are medium-priority pollutants; and antibiotics(ANTs) are low-priority pollutants. The ecology risk quotient(RQ) of the high-priority pollutants ranged from 4.3 to 15.9, indicating severe ecology risk to the aquatic organism, and higher risks were found in the upper lake areas. Additionally, the human health risk assessment revealed negligible carcinogenic risks associated with high-priority pollutants. The comprehensive ranking system established in this study can be applied to other lake basins by altering the measured concentrations to screen for priority pollutants, offering a scientific foundation for identifying priority control pollutants for watershed management.

Deposition and regional distribution of HCHs and p,p'-DDX in the western and southern Tibetan Plateau: records from a lake sediment core and the surface soils.

Tibetan Plateau is the world's highest plateau, which provides a unique location for the investigation of global fractionation of organochlorine pesticides (OCPs). In this study, deposition and regional distribution of HCHs and p,p'-DDX in the western and southern Tibetan Plateau were investigated by the records from a sediment core of Lake Zige Tangco and 24 surface soils. Concentration of ΣHCHs in the surface soils of the western Tibetan Plateau was much higher than that of the southern part. Maximum fluxes of α-, ß-, and δ-HCH in the sediment core were 9.0, 222, and 21 pg cm(-2) year(-1), respectively, which appeared in the mid-1960s. Significant correlations were observed between concentrations of α- and ß-HCH in both the surface soils and the sediment core. Concentrations of both α- and ß-HCH increased with the inverse of the average annual temperature of these sites. γ-HCH became the dominant isomer of HCHs after the late 1970s, and reached the maximum flux of 160 pg cm(-2) year(-1) in the early 1990s. There were no significant correlations between concentrations of γ-HCH and the other isomers in both the surface soils and the sediment core. The results suggested that there was input of Lindane at scattered sites in this area. In contrast to ΣHCHs, concentration of Σp,p'-DDX in the surface soils of the southern part was much higher than that of the western part. Maximum flux of Σp,p'-DDX was 44 pg cm(-2) year(-1), which appeared in the mid-1960s. Local emission of p,p'-DDT was found at scattered sites. This study provides novel data and knowledge for the OCPs in the western and southern Tibetan Plateau, which will help understand the global fractionation of OCPs in remote alpine regions.

[Ichthyofauna and its community diversity in volcanic barrier lakes of Northeast China].

Based on the investigations of fish resources in Jingpo Lake and Wudalianchi Lakes in 2008-2011 and the historical data, this paper analyzed the characteristics of ichthyofauna and its community diversity in volcanic barrier lakes of Northeast China. The ichthyofauna in the volcanic barrier lakes of Northeast China was consisted of 64 native species, belonging to 47 genera, 16 families, and 9 orders, among which, one species was the second class National protected wild animal, four species were Chinese endemic species, and five species were Chinese vulnerable species. In the 64 recorded species, there were 44 species of Cypriniformes order and 37 species of Cyprinidae family dominated, respectively. The ichthyofauna in the volcanic barrier lakes of Northeast China was formed by 7 fauna complexes, among which, the eastern plain fauna complex was dominant, the common species from the South and the North occupied 53.1%, and the northern endemic species took up 46.9%. The Shannon, Fisher-alpha, Pielou, Margalef, and Simpson indices of the ichthyofauna were 2.078, 4.536, 0.575, 3.723, and 0.269, respectively, and the abundance distribution pattern of native species accorded with lognormal model. The Bray-Curtis, Morisita-Horn, Ochiai, Sørensen, and Whittaker indices between the communities of ichthyofauna in the volcanic barrier lakes of Northeast China and the Jingpo Lake were 0.820, 0.992, 0.870, 0.862 and 0.138, respectively, and those between the communities of ichthyofauna in the volcanic barrier lakes and the Wudalianchi Lakes were 0.210, 0.516, 0.838, 0.825, and 0.175, respectively. The ichthyofauna in volcanic barrier lakes of Northeast China was characterized by the mutual infiltration between the South and the North, and the overlap and transition between the Palaeoarctic realm and the Oricetal realm. It was suggested that the ichthyofauna community species diversity in the volcanic barrier lakes of Northeast China was higher, the species structure was more stable, but the species richness trended to decrease.

Quantitative structure retention relationship studies for predicting relative retention times of chlorinated phenols on gas chromatography.

A new method of quantitative structure-retention relationship (QSRR) studies was reported for predicting gas chromatography (GC) relative retention times (RRTs) of chlorinated phenols (CPs) using a DB-5 column. Chemical descriptors were calculated from the molecular structure of CPs and related to their gas chromatographic RRTs by using multiple linear regression analysis. The proposed model had a multiple square correlation coefficient R2 = 0.970, standard error SE = 0.0472, and significant level P = 0.0000. The QSRR model also reveals that the gas chromatographic relative retention times of CPs are associated with physicochemical property interactions with the stationary phase, and influenced by the number of chlorine and oxygen in the CP mOlecules.