UV light device for vertical screening of contaminated soil samples with petroleum hydrocarbon

Abstract Petroleum hydrocarbons in light non-aqueous phase liquid (LNAPL) can generate significant contaminations when released into the ground. The identification, delimitation and understanding of their interactions with the hydro-stratigraphical media are essential in geo-environmental site characterization. The investigations of LNAPL contaminated sites in Brazil are mostly carried out with monitoring wells, which has limitations to identify LNAPL. The site characterization techniques based on the emission of ultraviolet light (UV), commercially known as UVOST and OIP works better to identify and provide qualitative LNAPL data. A bench testing campaign was conducted to evaluate the performance of an alternative, low-cost UV light device for identifying the presence of LNALP contamination in soil samples. This device creates a dark environment and uses UV light at different wavelengths combined with different color filters. Three different soils (organic, fine-medium sand and well-sorted medium sand), three products of petroleum hydrocarbons (lubricating oil, gasoline and diesel) and deionized water were combined. A total of 54 Bench tests was performed for hydrocarbon detection to assess the applicability of the alternative, low-cost UV light device. The UV-C light with a red colour filter provided the best results for identifying soil contamination. It was found the UV light device is more efficient when using different wavelengths associated with more than one colour filter. The application of this system has been broadened as it has now become more efficient for use with different combinations of soil types and LNAPL sources.