Publications by authors named "Marta T Lukasewycz"
In the early stages of risk assessments for sites with contaminated sediments, predictions of risks are often complicated or limited by sparse or inadequate bioaccumulation data. These limitations often require risk assessors to estimate bioaccumulation relationships in order to complete the assessments of risk. In the present study, the errors are evaluated with the simple (direct) application of field measured biota-sediment accumulation factors (BSAFs) to other species at a specific location, and to the same species and/or other species at other locations within a site and to other sites.
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- Chemical concentration quotients show significant differences in the distribution of pollutants like PCBs, PCDDs, PCDFs, and PAHs between water and sediment in southern Lake Michigan, with values varying by up to 100 times.
- Apparent disequilibrium levels were found to be greater for PAHs and PCDDs compared to PCBs, indicating more complex interactions with organic carbon in the environment.
- Adjustments to equilibria calculations, considering black carbon effects, suggest that while some chemical classes align with expected equilibrium, others show notable divergences that highlight the complexity of contaminant interactions in aquatic environments.
For aquatic, avian, and mammalian species, dioxin equivalency values (TEQs) were computed for Aroclor, Clophen, Kanechlor, Chlorofen, Sovol, Delor, Phenoclor, and Chinese polychlorinated biphenyl (PCB) mixtures by using World Health Organization toxicity equivalency factors (TEFs) and compound-specific compositional data for PCBs, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) for the individual mixtures. The TEQs were similar across the different PCB product lines for mixtures of similar chlorine content. Depending on the PCB mixture, the polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) in the mixture contributed anywhere from 0 to 96% of the total TEQs, and the impact of PCDD/Fs was greatest for the fish TEQs.
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- This approach, known as the hybrid bioaccumulation modeling approach, combines mechanistic bioaccumulation models to project field-measured biota-sediment accumulation factors (BSAFs) and bioaccumulation factors (BAFs) to different ecological contexts.
- It uses food web models to compare two different sets of ecological conditions: one for the ecosystem where the measurements were taken and another for the target ecosystem to which the data is being applied.
- The hybrid method showed improved alignment between the actual measured values and the predicted BSAFs and BAFs when extrapolating data for various fish species across different locations in Lake Michigan and the Hudson River.
Accurate measurement of organic carbon (OC) and black carbon (BC) in sediments requires the complete removal of coexisting inorganic carbonates from the sample before instrumental analysis. The removal of carbonates from sediments is achieved with acidification, which causes the dissolution and decomposition of carbonates with accompanying effervescence. This effervescence, or the lack of it, is commonly used as an indicator for the presence or absence of carbonates.
View Article and Find Full Text PDFComparison of biota-sediment accumulation factors across ecosystems.
Environ Sci Technol
August 2005
Article Synopsis
- Sets of biota-sediment accumulation factors (BSAFs) for fish show consistent linear relationships when compared across different ecosystems, indicating that individual BSAF rankings remain stable regardless of ecosystem type.
- This consistency holds true for both metabolized and non-metabolized nonionic organic chemicals in fish.
- Differences in BSAF values across ecosystems can occur due to variations in ecosystem conditions, including factors like trophic levels, diets of organisms, and how chemicals distribute between sediments and water.
Article Synopsis
- A study determined biota-sediment accumulation factors (BSAFs) for PCBs, PCDDs, and PCDFs in lake trout and sediment from southern Lake Michigan using advanced chromatography techniques.
- BSAFs for PCBs ranged from <0.1 to 18, while PCDDs and PCDFs ranged from <0.001 to 0.32, with specific chemical structures influencing accumulation potential.
- The findings highlight variations in bioaccumulation rates related to fish age and slight metabolism differences, suggesting the need for further toxicity testing of certain PCDFs due to their measured BSAFs and unknown effects.