Investigation of gasoline distributions within petrol stations: spatial and seasonal concentrations, sources, mitigation measures, and occupationally exposed symptoms.

We measured levels of VOCs and determined the distributions of benzene concentrations over the area of two petrol stations in all three seasons. Using the concentrations and sampling positions, we created isoconcentration contour maps. The average concentrations ranged 18-1288 µg m(-3) for benzene and 12-81 µg m(-3) for toluene. The contour maps indicate that high-level contours of benzene were found not only at the fuel dispenser areas but also at the storage tank refilling points, open drainage areas where gasoline-polluted wastewater was flowing, and the auto service center located within the station area. An assessment of the benzene to toluene ratio contour plots implicates that airborne benzene and toluene near the fuel dispenser area were attributed to gasoline evaporation although one of the studied stations may be influenced by other VOC sources besides gasoline evaporation. Additionally, during the routine refilling of the underground fuel storage tanks by a tank truck, the ambient levels of benzene and toluene increased tremendously. The implementation of source control by replacing old dispensers with new fuel dispensers that have an efficient cutoff feature and increased delivery speed can reduce spatial benzene concentrations by 77%. Furthermore, a questionnaire survey among 63 service attendants in ten stations revealed that headache was the most reported health complaint with a response rate of 32%, followed by fatigue with 20%. These prominent symptoms could be related to an exposure to high benzene concentrations.

Cloning, characterization, and expression of vitelline protein BI and its encoding gene in the liver fluke, Fasciola gigantica.

A cDNA containing a 813 bp open reading frame encoding vitelline protein BI (FgVPBI) of Fasciola gigantica was cloned. FgVPBI has 96% sequence identity with VPBI of Fasciola hepatica and 84% identity with VPBII F. hepatica. It is far less similar to eggshell precursor proteins of other trematode species, for example, 29% identity with C. sinensis. Northern blot hybridization of total RNA from adult parasites demonstrated a FgVPBI transcript with a size of 1,000 nucleotides. FgVPBI mRNA is localized in the vitelline cells in both vitelline glands and intrauterine eggs. Recombinant FgVPBI was expressed as a 31.5 kDa protein in Escherichia coli and used for production of a polyclonal antiserum in rabbits. The FgVPBI antiserum detected immunoblotted rFgVPBI and native eggshell precursor protein at molecular weights of 31.5 kDa and 31 kDa, respectively. Immunolocalization showed strong staining in the cytoplasm of vitelline cells, in eggshell globules and the shells of eggs.