Validation of a Method for the Analysis of PAHs in Bulk Lake Sediments Using GC-MS

Abstract

This work presents the validation procedures of an analytical method to determine the 16 PAHs from the US EPA's priority pollutants list in sediment samples using ultrasonic extraction coupled to gas chromatography-mass spectrometry. The extraction techniques are altered by the construction of an extraction flask adapted to the ultrasonic bath that greatly reduces losses and increases extraction efficiency of the volatile compounds, especially naphthalene. Cleanup procedures are also altered to change the polarity of the solvent mixture that contributes to reducing the elution of undesirable compounds. The PAH spiked sediment at 100 microg/kg level shows recovery rate of 68% to 108%. A certified reference material has been analyzed for those compounds showing results conforming to certified values. The optimized procedure is applied to sediment samples from different areas across Southeast Brazil and presents the results from the Ibirité Reservoir (MG, Brazil), a eutrophic water body. The total PAH concentration in these sediment samples varies between 103.96 and 180.87 microg/kg (dry weight). As the detected concentrations are relatively low, the acute toxicity detected in sediment and its pore water is not due to these compounds, but to high concentrations of ammonia, copper, and nickel according to TIE procedures.

Distribution of polycyclic aromatic hydrocarbons in sediments of Akaki River, Lake Awassa, and Lake Ziway, Ethiopia

“…They reflect the input from point and non-point sources of contamination (Yamada et al 2009;Hahladakis et al 2013;Yohannes et al 2013a, b). Properties, such as high toxicity, high stability, high lipophilicity, electrochemical stability, and adsorption to sediments, make PAHs a potentially dangerous group of chemicals.…”

“…The use of GC-MS for determination of PAHs is based on a favorable combination of greater selectivity, resolution, and sensitivity (Alvarez-Aviles et al 2007;Yamada et al 2009;Denis et al 2012). However, due to the complex nature of the sediments, prior to introduction into the analytical system, a sample preparation (extraction and cleanup) process is needed (Shu et al 2000;Alvarez-Aviles et al 2007;Yamada et al 2009). Sample extraction is a critical step in the determination of PAH because these compounds are strongly sorbed to the matrix; consequently, their extraction is time-consuming and, in many cases, causes quantification errors (Yamada et al 2009).…”

Direct Analysis of Polyaromatic Hydrocarbons in Soil and Aqueous Samples Using Condensed Phase Membrane Introduction Tandem Mass Spectrometry with Low-Energy Liquid Electron Ionization

“…PAHs are mutagenic, carcinogenic, and bioaccumulative, and as a result are listed as priority pollutants by the United States Environmental Protection Agency (U.S. EPA) . While all PAHs are highly hydrophobic (log K ow 3–7), they are globally distributed throughout air, water, − sediments, − and biota . The complexity of samples contaminated with PAHs often requires extensive sample preparation and cleanup prior to analysis, with procedures that differ significantly depending upon the sample matrix.…”

“…Soils, sediments, and biota are often a sink for PAHs because of favorable organic partitioning behavior. Soxhlet extraction has long been employed to isolate PAHs from complex solid samples due to high extraction recovery. ,,, However, the time (up to 16 h) and large solvent quantities required has led to alternative, greener techniques, including microwave, , sonication, , supercritical fluid, , and pressurized solvent extractions . While these techniques provide improvements, they still involve considerable sample pretreatment and cleanup in advance of analysis.…”

Biostimulation strategies : For in situ biodegradation of complex aromatic contaminant mixtures in groundwater

“…Detailed information about different methods used for aromatic hydrocarbon determination and their quantification was reviewed by AlSalka et al (2010). Each one of the discussed methods has its advantages and drawbacks, but main focus on method selection should be based on the aim of the experiment and also other factors such as sample preparation, cost and analysis time (Yamada et al, 2009). In aromatic hydrocarbon bioremediation research, one needs a single method that is comprehensive for all relevant compounds present in the pollution mixture often encountered in remediation projects.…”