Preliminary hazard assessment of polychlorinated biphenyls, polybrominated diphenyl ethers, and polychlorinated dibenzo-p-dioxins and dibenzofurans to Yangtze finless porpoise in Dongting Lake, China

Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis), a protected endangered species, is the sole freshwater subspecies of finless porpoise, living only in the middle and lower reaches of the Yangtze River, China, and its appended lakes. Its population has decreased sharply to 1,400 because of human activities, including environmental contamination. In the present study, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in the blubber, liver, kidney, stomach, small intestine, and brains of five individual Yangtze finless porpoises collected from 1998 to 2004. The results showed PCB concentrations ranged from 0.06 to 1.89 mu g/g lipid weight in the organs and consisted mainly of penta-, hexa-. and decachlorinated biphenyls. The PBDE concentrations were between 5.32 and 72.76 ng/g lipid weight. Tetra-, penta-, and hexabrominated diphenyl ethers were the major homologues. The PCDD/F concentrations ranged from 65 to 1,563 pg/g lipid weight, and their predominant homologues were penta- and hexachlorinated dibenzofurans and hepta- and octachlorinated dibenzo-p-dioxins. The hazard quotients (HQs) based on toxic equivalency were determined to be greater than one in all individuals for PCBs, for PCDD/Fs, and for PCBs and PCDD/Fs In addition, HQs would be higher if PBDEs were included. The results suggest that reduction of environmental contamination may contribute greatly to protecting this highly endangered species.

Using the RBFN model and GIS technique to assess wind erosion hazard of inner Mongolia, China

Soil wind erosion is the primary process and the main driving force for land desertification and sand-dust storms in and and semi-arid areas of Northern China. While many researchers have studied this issue, this study quantified the various indicators of soil wind erosion, using the GIS technology to extract the spatial data and to construct a RBFN (Radial Basis Function Network) model for Inner Mongolia. By calibrating sample data of the different levels of wind erosion hazard, the model parameters were established, and then the assessment of wind erosion hazard. Results show that in the southern parts of Inner Mongolia wind erosion hazards are very severe, counties in the middle regions of Inner Mongolia vary from moderate to severe, and in eastern are slight. Comparison of the results with other research shows conformity with actual conditions, proving the reasonability and applicability of the RBFN model. Copyright (C) 2007 John Wiley & Sons, Ltd.