Bioaccumulation and differential partitioning of polychlorinated biphenyls in freshwater, planktonic food webs

Abstract

Abstract:The planktonic food chain phytoplankton -zooplankton -young-of-the-year roach (Rutilus rutilus) was studied in 19 lakes in southern Sweden to investigate the bioaccumulation of polychlorinated biphenyls (PCBs). The SPCB concentrations did not steadily increase with increasing trophic level. The SPCB concentrations in zooplankton (400 ng·g lipid -1 ) were lower than in both phytoplankton (660 ng·g lipid -1 ) and fish (890 ng·g lipid -1 ), which did not differ significantly. Lipid content explained 40% of the total variation in dry weight normalised SPCB concentrations in the samples. The PCBs were differentially partitioned between the trophic levels. The logBMFs (biomagnification factors, concentration in predator/concentration in prey) were a function of the logK ow of the PCB congeners. The logBMF zoo/phyto values were < 0 for all PCB congeners on a lipid weight basis, and the logBMF fish/zoo values were < 0 for PCB congeners with logK ow > 6. We conclude that no PCBs had higher lipid-normalised concentrations in zooplankton than in phytoplankton and the most lipophilic PCBs had moderately higher concentrations in roach than in zooplankton. PCBs with logK ow > 6 decreased in concentration from phytoplankton to zooplankton to roach. We suggest that the concept of biomagnification did not apply to the planktonic food chain investigated in these lakes.Résumé : Nous avons étudié la chaîne alimentaire planctonique phytoplancton -zooplancton -jeune gardon (Rutilus rutilus) dans 19 lacs du sud de la Suède afin d'analyser la bioaccumulation des polychlorobiphényles (PCB). Les concentrations de SPCB n'ont pas augmenté de façon constante avec l'augmentation du niveau trophique. Les concentrations de SPCB dans le zooplancton (400 ng·g lipides -1 ) étaient plus faibles que dans le phytoplancton (660 ng·g lipides -1 ) et chez les poissons (890 ng·g lipides -1 ), concentrations qui ne différaient pas de façon significative. La teneur en lipides expliquait 40% de la variation totale des concentrations normalisées de SPCB en poids sec dans les échantillons. Les PCB étaient répartis de façon différentielle entre les niveaux trophiques. Le log FBA (facteurs de bioamplification, concentration chez le prédateur/concentration chez les proies) était une fonction du log K ow des congé-nères de PCB. Le log FBA zoo/phyto était < 0 pour tous les congénères de PCB en fonction du poids en lipides, et le log FBA poisson/zoo était < 0 pour les congénères de PCB dont le log K ow > 6. Nous concluons qu'aucun PCB n'avait une concentration normalisée dans les lipides plus élevée chez le zooplancton que chez le phytoplancton, et que les concentrations de PCB les plus lipophiles étaient modérément plus élevées chez le gardon que chez le zooplancton. On observait une diminution de la concentration de PCB dont le log K ow > 6 en passant du phytoplancton au zooplancton puis au gardon. La notion de bioamplification ne semblait donc pas s'appliquer aux organismes de la chaîne alimentaire planctonique étudiés dans ces lacs.[Traduit par la Réd...

Bioaccumulation of 14C-PCB 101 and 14C-PBDE 99 in the marine planktonic copepod Calanus finmarchicus under different food regimes

“…minimum were 6-18 times higher than in the C. finmarchicus feeding on them. Our experimental data support result from field studies where higher BAF values for PCBs were found in the size fraction of the collected material defined as phytoplankton, than in the size fraction defined as zooplankton (Berglund et al, 2000;Kannan et al, 1995). We have no obvious explanation to this reduced accumulation with increasing trophic level.…”

“…Most ecotoxicological studies on phyto-and zooplankton are done in the field and are based on size fractionation of the plankton, equating size ranges to trophic levels (Berglund et al, 2000;Harding et al, 1997;Hargrave et al, 2000;Sobek et al, 2004). It is generally found that the bioaccumulation of polychlorinated biphenyls (PCBs) and other HOCs increase linearly with K ow for the compounds, even though the slope and the yintercept may vary.…”

Persistent organic pollutants in river food webs: influence of trophic position and degree of heterotrophy

“…These biomagnification factors are low compared with other studies on piscivorous fish (3-5; Russell et al 1995) or planktivorous fish (1-3; Hoekstra et al 2003). However, the results are similar to those found in planktonic food chains in lakes (Berglund et al 2000) where there was no biomagnification in the first trophic transfer between zooplankton and phytoplankton and only an increase (biomagnification factors = 1.5-3.0) in concentrations of the PCBs with log K OW > 6.5 in the second trophic transfer between zooplankton and planktivorous young-of-the-year roach (Rutilus rutilus). Thus, PCBs were magnified on a dry weight basis but not on a lipid weight basis in the first trophic transfer between periphyton and detritus, and invertebrates and the biomagnification factors were independent of the K OW values of the PCBs.…”

“…However, like lipids, the organic carbon fraction could not predict PCB concentrations within each of the two compartments in this study. Lipid content has been shown to accurately predict PCB accumulation in both fish and invertebrates (Kucklick and Baker 1998;Berglund et al 2000). Therefore, we used dry matter and lipid rather than carbon-normalized PCB concentrations for all compartments when testing food chain bioaccumulation and biomagnification factors in our food chains.…”

Bioaccumulation of PBDE congener 2,2′,4,4′-tetrabromodiphenyl ether by Heterosigma akashiwo in response to different nutrient concentrations

“…Microalgae can easily accumulate POPs, which are then transferred to higher trophic levels through the food chain because of their high lipid content and small size. The bioaccumulation of POPs by microalgae is influenced by the properties of organic compounds (such as molecular structure and hydrophobicity), and by algal lipids, which are variable between species and influenced by environmental factors (Stange & Swackhamer 1994, Berglund et al 2000, Carlson & Swackhamer 2006. Several studies reported the bioconcentration of POPs, such as PCBs, by microalgae in nutrientlimited conditions (Halling-Sørensen et al 2000, Datta 2001, Lynn et al 2007.…”