| مستخلص: |
Polychlorinated biphenyls (PCBs) are a group of synthetic organic chemicals that enrich the food chain via biomagnification where the highest levels have been detected in cetaceans. While several studies have reported cetaceans as sentinels of environmental pollution, information on the contamination status of PCBs in cetaceans found stranded along Philippine coasts has been very limited over the past decades. An important contributory factor to this paucity is the challenging analytical method for the analysis of PCBs in lipid-rich biological tissues due to lipid interferences that can affect gas chromatographic systems especially column efficiency and lifetime. Thus, a modified method consisting of a series of three cleanup steps -- involving isolation column chromatography, gel permeation chromatography (GPC), and solid-phase extraction (SPE) using silica gel following Soxhlet extraction, plus macro- and micro-concentration prior to gas chromatographic/mass spectrometric analyses -- was used. Recovery of added analytes corresponding to appropriate concentration ranges and repeatability of data values were excellent as values obtained were within the established performance criteria of 40-120% recovery, including a 106% mean recovery for the QC material (FAPAS T05100QC -- Oily Fish) and < 30% RSD for an analyte concentration of 1 µg kg-1. Thus, the modified cleanup technique in conjunction with GC/MS detection is proven suitable for its intended use. Thirty-eight (38) congeners (PCBs-8, -12, -19, -18, -33, -38, -35, -37, -52, -44, -57, -74, -79, -78, -81, -77, -104, -99, -123, -118, -114, -126, -155, -153, -162, -167, -156, -157, -169, -188, -189, -202, -195, -194, -205, -208, -206, and -209) were detected in cetacean blubber (n = 15) ranging from 21.7 ng g-1 lipid weight (in an adult female dwarf sperm whale (Kogia sima) found in Camarines Sur) to 1460 ng g-1 lipid weight (in an adult male rough-toothed dolphin (Steno bredanensis) found in Zambales. [ABSTRACT FROM AUTHOR] |
