Enhancing ecotoxicological modeling and assessment. Body Residues and Modes Of Toxic Action

McCarty, L.S.; Mackay, Donald

doi:10.1021/es00046a001

Cited by 570 publications

(569 citation statements)

References 33 publications

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“…Effective lethal body burdens (LBB50s) were calculated for naphthalene and pyrene as products of aqueous BCFs (Table 2) and LC free 50 values ( Table 3). The LBB50 values were 18 and 11 mmol kg À1 fresh wt for naphthalene and pyrene, respectively (Table 3), and thereby slightly higher than the range of 2 to 8 mmol kg À1 fresh wt proposed earlier [35]. These results are in agreement with other results of the present study indicating partitioning of the PAHs to the hydrophobic waxy layer covering the cuticle of F. candida.…”

Section: Toxicity Experimentssupporting

confidence: 91%

Uptake and toxicity of polycyclic aromatic hydrocarbons in terrestrial springtails—studying bioconcentration kinetics and linking toxicity to chemical activity

Schmidt

Smith

Holmstrup

et al. 2012

Enviro Toxic and Chemistry

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Abstract-Passive dosing applies a polymer loaded with test compound(s) to establish and maintain constant exposure in laboratory experiments. Passive dosing with the silicone poly(dimethylsiloxane) was used to control exposure of the terrestrial springtail Folsomia candida to six polycyclic aromatic hydrocarbons (PAHs) in bioconcentration and toxicity experiments. Folsomia candida could move freely on the PAH-loaded silicone, resulting in exposure via air and direct contact. The bioconcentration kinetics indicated efficient uptake of naphthalene, anthracene, and pyrene through air and (near) equilibrium partitioning of these PAHs to lipids and possibly the waxy layer of the springtail cuticle. Toxicities of naphthalene, phenanthrene, and pyrene were related to chemical activity, which quantifies the energetic level and drives spontaneous processes including diffusive biouptake. Chemical activity-response relationships yielded effective lethal chemical activities (La50s) well within the expected range for baseline toxicity (0.01-0.1). Effective lethal body burdens for naphthalene and pyrene exceeded the expected range of 2 to 8 mmol kg À1 fresh weight, which again indicated the waxy layer to be a sorbing phase. Finally, chemical activities were converted into equilibrium partitioning concentrations in lipids yielding effective lethal concentrations for naphthalene and phenanthrene in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg À1 lipid). Passive dosing was a practical approach for tightly controlling PAH exposure, which in turn provided new experimental possibilities and findings. Environ. Toxicol. Chem. 2013;32:361-369. # 2012 SETAC

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Section: Toxicity Experimentssupporting

confidence: 91%

Uptake and toxicity of polycyclic aromatic hydrocarbons in terrestrial springtails—studying bioconcentration kinetics and linking toxicity to chemical activity

Schmidt

Smith

Holmstrup

et al. 2012

Enviro Toxic and Chemistry

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“…It is well established that there are inherent problems associated with using exposure concentrations in water (ecotoxicology) or air or food (mammalian toxicology) as expressions of relative toxicities of organic chemicals and that IECs or body burdens can be more reliable for expressing relative toxicities (14,16). As long ago as 1939, Ferguson illustrated how "the disturbing effect of phase distribution" obscures the interpretation of toxicity data (17).…”

Section: Raidar Assessment Factors For Dsl Chemicals and Popsmentioning

confidence: 99%

Policies for Chemical Hazard and Risk Priority Setting: Can Persistence, Bioaccumulation, Toxicity, and Quantity Information Be Combined?

Arnot

Mackay

2008

Environ. Sci. Technol.

138

132

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Existing methods used to screen chemical inventories for hazardous substances that may pose risks to humans and the environment are evaluated with a holistic mass balance modeling approach. The model integrates persistence (P), bioaccumulation (B), toxicity (T), and quantity (Q) information for a specific substance to assess chemical exposure, hazard, and risk. P and B are combined in an exposure assessment factor (EAF), P, B, and T in a hazard assessment factor (HAF), and P, B, T, and Q in a risk assessment factor (RAF) providing single values for transparent comparisons of exposure, hazard, and risk for priority setting. This holistic approach is illustrated using 200 Canadian Domestic Substances List (DSL) chemicals and 12 United Nations listed Persistent Organic Pollutants (POPs). Priority setting results are evaluated with those of multiple category-based screening methods employed by Environment Canada and applied elsewhere that use cutoff criteria in multiple categories (P, B, and T) to identify hazardous chemicals for more comprehensive evaluations. Existing methods have categorized the DSL chemicals as either higher priority (requiring further assessment; screened in) or lower priority (requiring no further action at this time; screened out). The priority setting results of the cutoff-based categorization are largely inconsistent with the proposed integrated method, and reasons for these discrepancies are discussed. Many chemicals screened out using existing methods have equivalent or greater risk potential than chemicals screened in. Decisions for screening assessments using binary classification on the basis of cutoff criteria can be flawed, and complementary holistic methods for priority setting evaluations such as the one proposed should be considered.

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“…The critical body residue (CBR) is defined as the threshold concentration of a substance in an organism that marks the transition between no and adverse effects (McCarty and Mackay, 1993;Hickie et al, 1995). This concept suggests that as long as 'the exposure concentration' is below a certain threshold level, organisms are able to store the accumulated metals in detoxified forms.…”

Section: Regression Summarymentioning

confidence: 99%

Differences in metal sequestration between zebra mussels from clean and polluted field locations

et al. 2009

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a b s t r a c tOrganisms are able to detoxify accumulated metals by, e.g. binding them to metallothionein (MT) and/or sequestering them in metal-rich granules (MRG). The different factors involved in determining the capacity or efficiency with which metals are detoxified are not yet known.In this work we studied how the sub-cellular distribution pattern of cadmium, copper and zinc in whole tissue of zebra mussels from clean and polluted surface waters is influenced by the total accumulated metal concentration and by its physiological condition. Additionally we measured the metallothionein concentration in the mussel tissue. Metal concentration increased gradually in the metal-sensitive and detoxified sub-cellular fractions with increasing whole tissue concentrations. However, metal concentrations in the sensitive fractions did not increase to the same extent as metal concentrations in whole tissues. In more polluted mussels the contribution of MRG and MT became more important. Nevertheless, metal detoxification was not sufficient to prevent metal binding to heat-sensitive low molecular weight proteins (HDP fraction). Finally we found an indication that metal detoxification was influenced by the condition of the zebra mussels. MT content could be explained for up to 83% by variations in Zn concentration and physiological condition of the mussels.

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Enhancing ecotoxicological modeling and assessment. Body Residues and Modes Of Toxic Action

Cited by 570 publications

References 33 publications

Uptake and toxicity of polycyclic aromatic hydrocarbons in terrestrial springtails—studying bioconcentration kinetics and linking toxicity to chemical activity

Uptake and toxicity of polycyclic aromatic hydrocarbons in terrestrial springtails—studying bioconcentration kinetics and linking toxicity to chemical activity

Policies for Chemical Hazard and Risk Priority Setting: Can Persistence, Bioaccumulation, Toxicity, and Quantity Information Be Combined?

Differences in metal sequestration between zebra mussels from clean and polluted field locations

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