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Analysis of complex samples in environmental matrices poses extreme challenge for analytical chemists as the number of known and unknown compounds are numerous and have varying physical and chemical properties. The introduction, over the past decade, of comprehensive two-dimensional (2D) gas chromatography (GC × GC) paired with mass spectrometry (MS) has tremendously changed the analytical profiles of ultra-trace levels of organic pollutants from different environmental media. This review article provides a summary of selected articles using comprehensive 2D GC/MS-based methodologies from January 2014 to August 2019. The applications of various MS detectors, such as single (Q) and triple (QqQ) quadrupole, low resolution and high resolution time-of-flight (TOF), and the hybrid (quadrupole TOF-MS), coupled to GC × GC, and their benefits for analyzing persistent and emerging organic pollutants when applied to different environmental matrices were discussed. Emphasis was given to reviewing some applications of GC × GC-electron capture detector (ECD) and GC × GC-μECD within the specified period as these detectors have improved selectivity and sensitivity toward halogenated (bromine and chloride) compounds found in ultra-trace levels of environmental media.

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In Liberia, waste management is one of the main challenges faced by municipal authorities, environmental technicians and public health practitioners in their quest to maintain a clean, safe and healthy environment. The construction and operation of a sanitary landfill ensures adequate waste management and, by extension, the protection of both the environment and human receptors. This study presents the results of geotechnical investigations conducted on soils from two sedimentary units of Liberia: Paynesville Sandstone and Farmington River Formation. The intent of the study was to assess the suitability of the soil for use as landfill liner. Three soil samples were collected from each of the two sedimentary units and, using B.S 1377 (1990), soils characteristics such as particle size distribution, permeability, liquid limit, plastic limit, plasticity index and hydraulic conductivity were measured and presented as mean values. Hydraulic conductivity of a sanitary landfill liner is the most important parameter to consider in materials selection. The results of hydraulic conductivity obtained from the study showed that only the samples from Farmington River Formation met the USEPA (1994) and CGRM (2007) requirement of ≤ 1x10-9 m/sec suitable for use as landfill liner. The mean soil permeability results for the Paynesville Sandstone and Farmington River Formation were 2.5 mL/hr and 0.05 mL/hr respectively; implying that the samples from the Paynesville Sandstone are more permeable and, thus, more susceptible to leaching and groundwater contamination if used as a bottom liner in a landfill design. Based on the findings of this research, it can be concluded that the sample from the Farmington River Formation is more suitable for use as a natural material for landfill liner. The quality of the sample should, however, be improved by addition of small amounts of bentonite.