Trimethylbenzoic acids as metabolite signatures in the biogeochemical evolution of an aquifer contaminated with jet fuel hydrocarbons

Evolution of trimethylbenzoic acids in the KC-135 aquifer at the former Wurtsmith Air Force Base (WAFB), Oscoda, MI was examined to determine the functionality of trimethylbenzoic acids as key metabolite signatures in the biogeochemical evolution of an aquifer contaminated with JP-4 fuel hydrocarbons. Changes in the composition of trimethylbenzoic acids and the distribution and concentration profiles exhibited by 2,4,6- and 2,3,5-trimethylbenzoic acids temporally and between multilevel wells reflect processes indicative of an actively evolving contaminant plume. The concentration levels of trimethylbenzoic acids were 3-10 orders higher than their tetramethylbenzene precursors, a condition attributed to slow metabolite turnover under sulfidogenic conditions. The observed degradation of tetramethylbenzenes into trimethylbenzoic acids obviates the use of these alkylbenzenes as non-labile tracers for other degradable aromatic hydrocarbons, but provides rare field evidence on the range of high molecular weight alkylbenzenes and isomeric assemblages amenable to anaerobic degradation in situ. The coupling of actual tetramethylbenzene loss with trimethylbenzoic acid production and the general decline in the concentrations of these compounds demonstrate the role of microbially mediated processes in the natural attenuation of hydrocarbons and may be a key indicator in the overall rate of hydrocarbon degradation and the biogeochemical evolution of the KC-135 aquifer.     

MOVEMENT AND WAYFINDING IN THE KING SAUD UNIVERSITY BUILT ENVIRONMENT: A LOOK AT FRESHMAN ORIENTATION AND ENVIRONMENTAL INFORMATION

One potentially significant, yet hardly investigated, criterion for postoccupancy evaluation is the legibility of a setting—the degree to which a building or group of buildings facilitate the ability of users to find their way around. Legibility is one of the foundation concepts of environmental psychology, yet it has not often been considered enough as a guiding principle in design. The purpose of this paper is to analyse spatial orientation and wayfinding problems encountered by newcomers (freshman students) at the King Saud University (KSU) campus, Saudi Arabia, and to test/relate this to Lynch's elements of the image of cities. The analysis draws on previous research findings, theories, and more general observations, as well as observations made of wayfinding performance and map sketching by 30 high-school students likely to soon enroll at the university. Many specific problems with orientation and the architectural legibility of the buildings are identified and discussed. Emphasis is placed upon physical-setting variables that are likely to affect the ease with which spatial orientation and wayfinding are accomplished. These include the following facets of the KSU built environment: degree of differentiation; degree of visual access; and complexity of spatial layout.Legible buildings within which people can effectively maintain their orientation and find their way, according to this research, are in no way simplistic, dull, or boring; on the contrary, settings must possess distinctive landmarks and regions which, along with understandable path networks, allow users to know where they are and how to make their way to desired destinations. Coherent and legible environments are important in the lives of the people who use them. The movement of people through buildings and the factors that influence whether or not they are able to find their way need to continue to be of significance to both researchers and practitioners.