Diffusive-Gas Transport of Volatile Organic Carbons from a Source in an Unsaturated (Vadose) Zone
Journal Title: IOSR Journal of Environmental Science, Toxicology and Food Technology (IOSR-JESTFT) - Year 2019, Vol 13, Issue 1
Abstract
In the absence of pressure gradients, conditions prevalent in the batch experiments, gas –phase diffusion dominates migration of volatile pollutants in the unsaturated zone. Gas –phase diffusion in the unsaturated zone is affected by partitioning into soil-water, onto air-water and into or onto solid. The process spreads only the contaminants in the gas phase where contaminants with low mass fraction fa in the soil gas diffuse more slowly depending on the soil and chemical properties on the diffusing substance. This study shows Non-aqueous phase liquids (NAPL) compounds with higher mass fraction (Isooctane (0.82), n-hexane (0.78), methylcyclopentane (0.54)) diffuse to a longer distance (1.75m, 1.30m, 1.50m) than those with low mass fraction (toluene (0.04), m-xylene (0.04), octane (0.09), (60m, 60m and 51 m respectively) from a source zone. The diffusion coefficient D’ calculated was also higher for these compounds; 0.05, 0.05, 0.05 and 0.00, 0.00 and 0.001 respectively. At transient diffusion described by the sorption- affected diffusion coefficient, compounds with higher vapour pressure as Isooctane, n-hexane, methylpentane showed higher mass fraction in soil gas, a phenomena that accounts for their higher diffusion rate hence longer distance attained before attenuated. The results obtained shows isooctane travel the most distance (1.3 m) before been attenuated to 1 % of the original concentration of a source zone, a reason attributed to it recaltricant and slow degradation nature.
Authors and Affiliations
Edward Membere, Emmanuel Johnson
Effect of Sprouting Time on the Nutrient and Anti-Nutrient Properties of Cowpea (Vigna Unguiculata)
In this study the effect of sprouting time (0h, 24h, 48h, 72h, 96h and 120h) on the nutritional, and anti-nutritional properties of cowpea was investigated. Cowpea seeds were sprouted in the laboratory under room conditi...
Assessment of Noise, Temperature, Light Intensity And Their Impacts on Workers In Footwear And Leather Products Industries of Bangladesh
Noise, temperature and light intensity are invisible indoor environmental trepidations that affect the quality of life and productivity of the industries. The study was carried out in twenty footwear and leather products...
Pollution In Nigerian Auto-Mechanic Villages: A Review
The increasing number of malfunctioning automobiles withsubsequent increase in emission levels and waste handling is an environmental concern in Nigeria. The spills from lubricants, gasoline, diesel and byproducts of use...
Chemical Composition And Nutritional Value Of Composite Wheat Flours (Triticumaestivum) And Two Varieties Of Taro Corms (Colocasiaesculenta) Cultivar Fouê And Cultivar Yatan
The aim of this study, was to evaluate nutritive potential of composite flours of wheat (Triticumaestivum) and taro corms (Colocasiaesculenta) cv fouê and yatan. Moisture and ash contents of composite flours of wheat and...
Phytoremediation Potential of Some Indigenous Herbaceous Plant Species Growing on Metalliferous Mining Sites At Nahuta, Bauchi State, Nigeria
Heavy metals constitutes a serious threats because unlike most organic pollutants they are not easily degraded through natural process and therefore remain in the environment for a very long time. Soil contamination resu...