Monitoring of BTEX hydrocarbons in soil atmosphere by new activated carbon cloth passive sampler without a membrane
The development and evaluation of a new passive sampler without a membrane and its applicability as an environmental monitor for benzene, toluene, ethylbenzene and xylenes (BTEX) in soil atmosphere is reported. The sampler was deployed at the ground surface and beneath (60 cm) the surface level and measured soil-air fluxes of organic contaminants coming to the surface by the passive sampling element - activated carbon cloth (ACC). The effect of relative humidity on the multicomponent vapour phase adsorption by ACC sampler's performance was determined. Also, a few field demonstrations were conducted at fuel-contaminated sites. The samplers were quantitativety analyzed by liquid extraction and gas chromatography with a flame ionization detector. It was shown that the ACC passive sampler offers a cost efficient new method of monitoring of organic vapours originating from soil and groundwater contamination. The ACC passive sampler can accurately measure fluxes over both long and short periods. High adsorption capacity and fast adsorption kinetic rate of activated carbon cloth as well as the absence of diffusive membrane in the construction of the sampler allows the cloth to collect sufficient amount of analyte for analysis at very low concentrations (ppb). The method is inexpensive and practical and can be readily duplicated by others using off-the-shelf equipment and normally available laboratory skills.