PMC:2854002 / 20920-23212 JSONTXT

{"project":"MyTest","denotations":[{"id":"19961220-17948791-28495514","span":{"begin":1408,"end":1410},"obj":"17948791"},{"id":"19961220-12564897-28495515","span":{"begin":1716,"end":1718},"obj":"12564897"}],"namespaces":[{"prefix":"_base","uri":"https://www.uniprot.org/uniprot/testbase"},{"prefix":"UniProtKB","uri":"https://www.uniprot.org/uniprot/"},{"prefix":"uniprot","uri":"https://www.uniprot.org/uniprotkb/"}],"text":"Figure 2a−d show the relationships among estimated and measured PCB biolipid concentrations in sediment dwelling organisms. Figure 2a shows that estimated data derived from KOW values, sediment TOC, and solid phase concentration according to eq 3 overestimate measured biolipid concentrations by a median factor of 33. By contrast, estimates in Figure 2b where data are derived from eqs 5, 6, and 7 that distinguish between sorption to AOC and BC agree within a median factor of 6 as reported Table 2. The correlation coefficient is improved from 0.83 to 0.93 when sorption to AOC and BC are both considered. Again, the BC-corrected relationship performs well in the higher PCB concentration range, but underpredicts biolipid concentrations in the lower PCB concentration range. Consequently, the slope for the data in Figure 2b is greater than 1. Predicting biolipid concentrations from bioavailability measurements such as the PCB mass fraction desorbed, measured via a Tenax bead extraction and shown in eq 4, or using actual measured free aqueous concentrations according to eq 2 instead of solid phase concentrations, gives much better agreement with measured data. This is shown in Figure 2c and d and reflected by the median factor of 1 for the ratio of estimated to measured biolipid concentrations and fitted slopes in the log−log plots close to unity. The relationship presented by Landrum et al. (20) using the PCB mass fraction desorbed from sediment within 6 h, f6h, has only been validated for oligochaetes, but apparently also yields reasonable predictions for the marine species Neanthes arenaceodentata and Leptocheirus plumulosus discussed here. Figure 2d confirms the contention of Kraaij et al. (27) that measured pore-water concentrations work better than sediment concentrations in estimating equilibrium biolipid PCB concentrations. Leptocheirus plumulosus is a particle-browsing amphipod whereas the polychaete Neanthes arenaceodentata and the oligochaete Lumbriculus variegatus ingest the fine sediment fraction. While different feeding strategies may result in different PCB exposure pathways and may explain some of the smaller differences in Figure 2c and d, the data suggest that the relationships are quite robust for three different sediment dwelling organisms."}

{"project":"2_test","denotations":[{"id":"19961220-17948791-28495514","span":{"begin":1408,"end":1410},"obj":"17948791"},{"id":"19961220-12564897-28495515","span":{"begin":1716,"end":1718},"obj":"12564897"}],"text":"Figure 2a−d show the relationships among estimated and measured PCB biolipid concentrations in sediment dwelling organisms. Figure 2a shows that estimated data derived from KOW values, sediment TOC, and solid phase concentration according to eq 3 overestimate measured biolipid concentrations by a median factor of 33. By contrast, estimates in Figure 2b where data are derived from eqs 5, 6, and 7 that distinguish between sorption to AOC and BC agree within a median factor of 6 as reported Table 2. The correlation coefficient is improved from 0.83 to 0.93 when sorption to AOC and BC are both considered. Again, the BC-corrected relationship performs well in the higher PCB concentration range, but underpredicts biolipid concentrations in the lower PCB concentration range. Consequently, the slope for the data in Figure 2b is greater than 1. Predicting biolipid concentrations from bioavailability measurements such as the PCB mass fraction desorbed, measured via a Tenax bead extraction and shown in eq 4, or using actual measured free aqueous concentrations according to eq 2 instead of solid phase concentrations, gives much better agreement with measured data. This is shown in Figure 2c and d and reflected by the median factor of 1 for the ratio of estimated to measured biolipid concentrations and fitted slopes in the log−log plots close to unity. The relationship presented by Landrum et al. (20) using the PCB mass fraction desorbed from sediment within 6 h, f6h, has only been validated for oligochaetes, but apparently also yields reasonable predictions for the marine species Neanthes arenaceodentata and Leptocheirus plumulosus discussed here. Figure 2d confirms the contention of Kraaij et al. (27) that measured pore-water concentrations work better than sediment concentrations in estimating equilibrium biolipid PCB concentrations. Leptocheirus plumulosus is a particle-browsing amphipod whereas the polychaete Neanthes arenaceodentata and the oligochaete Lumbriculus variegatus ingest the fine sediment fraction. While different feeding strategies may result in different PCB exposure pathways and may explain some of the smaller differences in Figure 2c and d, the data suggest that the relationships are quite robust for three different sediment dwelling organisms."}