Measurement of polychlorinated biphenyls (PCBs) in fish tissue and prediction of toxicity
Fish is often contaminated with PCBs, which are particularly toxic to fetuses, infants and children. Since methods currently used for the analysis of these compounds are expensive, time consuming and labor intensive, the aim of this dissertation was to develop rapid and low-cost methods that estimate PCBs and address the different aspects of this measurement. The objectives were: (1) to develop and validate a rapid and low cost method for the analysis of total PCB in fish tissue equivalent to the conventional gas chromatography/electron capture detection (GC/ECD) method; (2) to identify the significant predictors of Toxicity EQuivalents (TEQ) in fish tissue which would serve as the basis for the development of methods that could measure these compounds and predict TEQ; (3) to develop a rapid, low-cost method that could quantify these predictors to estimate TEQ in fish tissue. An extraction and cleanup method for fish samples prior to enzyme-linked immunosorbent assay (ELISA) for the estimation of total PCB was developed in the range of 0.05 to 5.0 ppm. The method was validated by analyzing fish samples collected from waterbodies around Indiana by ELISA and the conventional GC/ECD method. Total PCB estimated by ELISA was not significantly different from GC/ECD (p>0.05). EPA National Fish Tissue Study (2003) data were used to determine the significant predictors of TEQ. The strongest predictive model (p<0.0001, R2=0.97) included PCB-118, PCB-126, 2,3,7,8-TCDD, 1,2,3,6,7,8-HxCDD, 2,3,4,7,8-PeCDF, but the required limit of detection for these congeners is 0.1 ppt. However, the most practical model from a method development standpoint (p<.0001, R2=0.68) included PCB-138, PCB-153 and PCB-118, and required a limit of detection of 1000 ppt. Therefore, an analytical procedure to estimate TEQ was developed to measure PCB-138, PCB-153 and PCB-118 in fish tissue using solid phase microextraction (SPME) coupled to dual column GC/ECD from 1 to 100 ppb. Fish samples collected from waterbodies around Indiana were analyzed using SPME-GC/ECD and gas chromatography/mass spectrometry (GC/MS) to validate the method. The data obtained for PCB-118, PCB-138 and PCB-153 by the two methods were significantly correlated (p<0.05). Also, TEQ estimated using data obtained from the two methods were not significantly different (p<0.05).
Santerre, Purdue University.
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