ABSTRACT
Hexachlorobenzene (HCB) has been widely used as a fungicide and is also a by-product of several industrial processes, such as solvent manufacturing. Its lipophilic and hydrophobic nature, besides its low rate of chemical and biological degradation, can lead to its bio-accumulation and bio-magnification throughout the food net. Therefore, its detection and quantification in organisms and environment are extremely important, and this creates the need for efficient methodologies allowing for its detection and quantification for environmental contamination studies, in a low-cost way. The present study compared different methods of HCB extraction from estuary and sea sediments and waters, assessing the advantages of each method. The recovery tests were performed with samples of estuary and sea sediments, and waters previously treated with HCB in mixture with 14C-HCB as a radiotracer, and the radiocarbon in the extracts was quantified by liquid scintillation counting (LSC). The recovery of 14C-HCB from waters was compared by hexane extraction in C18 cartridges and liquid-liquid extraction, also using hexane. The recovery of 14C-HCB from the sediments was tested with the mixture hexane:acetone and microwave energy. The solid phase (C18) extraction was the best method for water extraction, accounting for 88.3% and 83.4% of recovery, respectively, from estuary and seawater. The microwave extraction recovered 99.5% and 99.9% of14C-HCB, respectively from estuary and sea sediments. The cost/benefit ratio indicates the C-18 solid phase extraction for waters and the microwave extraction for sediments as the best recovery methods, which allow for good detection of HCB in pollution studies.
KEY WORDS
Recovery; 14C-HCB; different matrices; cost/benefit ratio