No abstract

Volatile Organic Compounds (VOCs) are the most common subsurface environment contaminants usually in the form of Non-Aqueous Phase Liquids (NAPL) through Leaking Underground Storage Tanks (LUSTs) and pipelines, accidental spills, land disposal sites, and industrial waste impoundments. VOCs are toxic, mutagenic and carcinogenic. Hence, VOCs in subsoil pose a serious threat of groundwater contamination. Organic compounds, owing to their persistence and volatility, present unique environmental problems in the vadose zone of soils. The uncertainty in transport mechanisms and subsoil environment pose a serious challenge in developing transport model for VOC compounds. Apart from advection and dispersion, VOC also undergo several complex chemical reactions such as adsorption, degradation, volatilization and ionic exchange. The transport mechanisms and transport modeling studies for VOCs are largely based on extensive field studies and relevant laboratory experiments. The focus here is to review the role of transport mechanisms and modeling aspects of organic compounds in petroleum fuels and other such liquids and liquid wastes that have the potential to migrate through subsoil to groundwater and also to atmosphere by vapor diffusion.

Water being the principal potential source of enlivening the plants on earth and without it, it is the end for the life of living beings on earth. Though about two third of the world is of water but there is a scarcity of water for drinking for living beings as well as for plant watering. Inefficient watering of plants making water table fall and in many zones world wide becoming drought prone resulting in famine, mal-nutrition and suicides. Farmers being largely unscientific and unskilled mostly in developing countries using water inappropriately thereby agricultural yield is below its optimum level as well as land becoming saline due to washing of excess pesticides, fertilizers and water logging and becoming unfit for further farming. Hence it is proposed in this paper a novel approach to determine the efficient water requirement of agricultural fields for farming in a most scientific and cost effective manner and to design a ultra low cost moisture sensor using computer and thereby to manage the water resources more appropriately in agricultural farms for the plants irrigation and its results are presented.

This paper presents the transport of volatile organic compounds (VOC) through contaminated subsoil to groundwater using one dimensional vadose zone transport model, VLEACH. The model is applied using field specific data for a typical Toluene at Fuel pumping station and Transformer dumping yard. Laboratory column leaching studies were conducted to assess the mass flow rate of Toluene flux through subsoil and compared with VLEACH model output. The research also focused on the sensitivity of the model output with the varying input parameters, one at a time, across its maximum range of values identified from the study area. The observed Toluene fluxes are not consistent with the experimentally input concentrations and may not be valid due to its lower density of 0.865 g/ml. Hence, liquid phase transport of Toluene for experimental column leaching studies is not suitable. The sensitivity analysis results reveals that, model output is a function of fractional organic carbon content as well as water content.