Black carbon and ecological factors affect in situ biota to sediment accumulation factors for hydrophobic organic compounds in flood plain lakes. Environ Sci Technol
ABSTRACT Ecological factors may play an important role in the bioaccumulation of polychlorobiphenyls (PCBs) and polyaromatic hydrocarbons (PAHs). Geochemical and bioaccumulation behavior of these chemicals also appears to be related to the presence of black carbon (BC) in sediment. In situ PCB and PAH biota to sediment accumulation factors (BSAF) for benthic invertebrates, as well as 6h Tenax-extractable (fast-desorbing) concentrations and lake characteristics (including BC in sediment), were determined for different seasons in chemically similar but ecologically different lakes (fish-dominated turbid, algae-dominated turbid, and macrophyte-dominated). BSAFs could be explained with a model including a term for Freundlich sorption to BC and a term for uptake from fast-desorbing concentrations in ingested sediments. Freundlich coefficients for in situ sorption to BC (KF) were calculated from slow desorbing fractions and BC contents and agreed well with literature values for KF. Furthermore, in contrast to BSAFs based on total extracted concentrations, Tenax-based BSAF showed a strong positive correlation with log Kow. We therefore argue that BC caused slow desorption and limited BSAFs in these lakes. Seasonal and lake effects on BSAFs were detected, while the differences between oligochaetes and other invertebrates were small for PCBs and within a factor of 10 for PAHs. BSAFs for pyrogenic PAHs were much lower than for PCBs, which was explained by stronger sorption to BC and lesser uptake from ingested sediment.
Full-textDOI: · Available from: Gertjan Zwolsman, Aug 20, 2015
- SourceAvailable from: Mojca Kos Durjava
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- "This can be partly explained by the steric hindrance that restricts permeation of the large and very hydrophobic organic compounds through the cell membrane (Shaw and Connel, 1982). Also the low water solubility and binding to surfaces would cause these compounds to bind to dissolved organics and particles (Moermond et al., 2005). As there are no available experimental values of log Kow covering all selected congeners, we plot logBCF against ALOGP which is an estimation of log Kow (Ghose and Crippen, 1986). "
ABSTRACT: Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in textiles, foams and plastics. Highly bioaccumulative with toxic effects including developmental neurotoxicity estrogen and thyroid hormones disruption, they are considered as persistent organic pollutants (POPs) and have been found in human tissues, wildlife and biota worldwide. But only some of them are banned from EU market. For the environmental fate studies of these compounds the bioconcentration factor (BCF) is one of the most important endpoints to start with. We applied quantitative structure-activity relationships techniques to overcome the limited experimental data and avoid more animal testing. The aim of this work was to assess the bioaccumulation of PBDEs by means of QSAR. First, a BCF dataset of specifically conducted experiments was modeled. Then the study was extended by predicting the bioaccumulation and biomagnification factors using some experimental values from the literature. Molecular descriptors were calculated using DRAGON 6. The most relevant ones were selected and resulting models were compared paying attention to the applicability domain.Chemosphere 06/2012; 89(4):433-44. DOI:10.1016/j.chemosphere.2012.05.081 · 3.50 Impact Factor
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- "This may suggest that sorption for the first mentioned range is hydrophobicity driven partitioning, whereas surface adsorption prevails for the more bulky compounds at higher LogK OW . Individually modeled LogK F,BC values for PCBs were one order of magnitude lower than those for PAHs, which agrees with earlier reported BC sorption constants for these compound classes (Jonker and Smedes, 2000; Lohmann et al., 2005; Moermond et al., 2005). "
ABSTRACT: Contaminated sediments can be remediated by adding carbonaceous materials (CM), e.g. activated carbons (AC). Here, we analyze published datasets from AC amendment trials to identify variation in the effectiveness of AC in reducing porewater concentrations of hydrophobic organic contaminants (HOCs). The analysis uses a model that separates the contribution of HOC sorption to AC by parameterzing the sorption contributions by amorphous organic matter and black carbon (BC). It appears that sorption to BC increased with LogK(OW), whereas sorption to AC showed a relatively narrow range of affinity properties with a median Freundlich LogK(F,)(AC) value of 7.2 (μg/kg(AC))/(μg/L)(n) (IQR = 7.0-7.5) for polychlorinated biphenyls (PCBs) and 8.6 (IQR = 8.3-8.8) for polycyclic aromatic hydrocarbons (PAHs). Estimated Freundlich exponents were n(F,)(AC) = 0.74 for PCBs and 0.82 for PAH. Sorption to AC was stronger than to BC for chemicals below LogK(OW) = 6.3-6.6. For HOC risk reduction this is favorable, because chemicals with low K(OW) show generally higher bioavailable concentrations.Environmental Pollution 02/2012; 161:23-9. DOI:10.1016/j.envpol.2011.09.043 · 3.90 Impact Factor
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- "Two of the five aquatic studies performed in the ADW floodplains addressed toxicant accumulation in biota exposed to floodplain lake sediments. Moermond et al. (2004) reported elevated ΣPCB levels in mixed invertebrates samples and detected 15 individual PCB congeners and 13 individual PAHs in mixed invertebrates samples and in oligochaetes originating from three polluted floodplain lakes (Moermond et al., 2005). Accordingly, Van der Geest and Paumen (2008-this issue) measured significant copper accumulation in oligochaetes exposed to contaminated ADW sediment in whole sediment bioassays. "
ABSTRACT: The aim of this paper was to collect evidence for the effects of contaminants on biota in a highly dynamic river Rhine floodplain. To this purpose we reviewed the results of circa 10 studies performed in this floodplain. The floodplain was contaminated with elevated levels of cadmium, copper, PAHs, and PCBs and high levels of zinc which were at some sites above legislative values. The results showed that the present contaminants were accumulated by the floodplain inhabiting organisms, but meanwhile population and community effects were ambiguous. Only for the mayfly Ephoron virgo clear effects were detected at the level of the single floodplain. The absence of clear population and community effects is puzzling since at lower contaminant concentrations adverse effects were detected in other environments. Factors that may mask toxic effects include flooding and food quality and quantity. We conclude that given the site specific conditions, being an open, eutrophic system with a highly dynamic flooding pattern, assessment of the contribution of toxicants to observed population density or biomass and community composition requires 1] an increase in number of replicates; 2] a larger scale of investigation and 3] comparison to stable systems with comparable contamination levels.Science of The Total Environment 12/2008; 406(3):455-61. DOI:10.1016/j.scitotenv.2008.05.058 · 4.10 Impact Factor