Passive Partitioning of Polychlorinated Biphenyls between Seawater and Zooplankton, a Study Comparing Observed Field Distributions to Equilibrium Sorption Experiments

Abstract

From previous studies, it remains unclear whether polychlorinated biphenyls (PCBs) are biomagnified in zooplankton or if concentrations are simply governed by passive partitioning. In this study, in the Gullmar Fjord on the Swedish west coast, field-determined lipid-normalized partition coefficients (log Klip) were compared to equilibrium partition coefficients from laboratory sorption experiments with dead and preserved zooplankton. There was no significant difference between the linear regressions of log Klip-log Kow (analysis of covariance [ANCOVA], p < 0.05) for field and laboratory-determined partition coefficients, supporting passive partitioning being the dominant uptake pathway for PCBs in the Gullmar Fjord zooplankton. The field-observed partition coefficients were also suggestive of passive partitioning, as all field-log Klip-log Kow regressions were significant (p < 0.05, r2 = 0.74-0.95) and apparently linear. Further, there was generally no positive correlation between apparent biomagnification factors (BMF; concentration in zooplankton [pg/kgoc]/concentration in phytoplankton [pg/kgoc]) and trophic level (on the basis of delta15N). The in-situ organic carbon (-oc)-normalized concentrations in zooplankton (>200 microm) were not statistically different from oc-normalized concentrations in phytoplankton (0.7-50 microm), which supports the absence of significant biomagnification.

Macondo‐1 well oil‐derived polycyclic aromatic hydrocarbons in mesozooplankton from the northern Gulf of Mexico

“…Several processes (e.g. exchange with water through passive partitioning, ingestion of contaminated food, and production of fecal pellets and eggs), occurring simultaneously, may affect the final body burden of PAHs derived from oil spills [Sobek et al, 2006;Berrojalbiz et al, 2011]. Moreover, all of these processes may vary as a function of ambient temperature and seasonality [Hallanger et al, 2011b].…”

Influence of season, location, and feeding strategy on bioaccumulation of halogenated organic contaminants in Arctic marine zooplankton

“…Based on empirical studies, passive partitioning between seawater and zooplankton is the controlling factor for HOC concentrations in zooplankton [12,13]. Furthermore, these studies concluded that biomagnification does not occur in zooplankton, because no increase in HOC concentrations with increasing trophic positions was observed [12][13][14].…”

“…Furthermore, these studies concluded that biomagnification does not occur in zooplankton, because no increase in HOC concentrations with increasing trophic positions was observed [12][13][14]. Trophic positions are calculated from the ratio of heavier to lighter stable isotope of nitrogen ( [15].…”

“…Bioconcentration factors can be predicted mathematically for lipid-soluble compounds from a chemical's octanol water partitioning coefficient (K OW ) [24], assuming lipid-water equilibrium between the organism and the surrounding water and a 1:1 linear relationship between log K OW and log bioconcentration factor [23]. However, whether the relationship between log bioconcentration factor (or BAF) and log K OW is linear [12,22], or curvilinear [7,25], and whether the relationship is indeed 1:1, are subjects of ongoing debate. Field-derived BAFs are sensitive to variation in seawater HOC concentrations [26], and a common feature of all BAF field studies is high variation in BAF values seen among seasons and geographical areas [27].…”

“…Field-derived BAFs are sensitive to variation in seawater HOC concentrations [26], and a common feature of all BAF field studies is high variation in BAF values seen among seasons and geographical areas [27]. Field studies have reported linear relationships between log K OW and BAFs that both deviate [7,9], and coincide with the 1:1 relationship line [12].…”