Modeling wildlife exposure to toxic chemicals: Trends and recent advances

Pastorok, Robert A.; Butcher, Matthew; Nielsen, R. Dreas

doi:10.1080/10807039609383627

“…21,2002 M.E. Toal et al Measured body weights (to the nearest gram) of a population of wood mice in a mixed deciduous woodland (Marley Wood, Oxfordshire, UK [26]) were converted to age (in days) using Equation 5 for the spring and autumn periods. According to Equation 5, wood mouse body weight reaches an asymptote (21 g) after approximately 155 d, thus making age differentiation impossible after this time.…”

Section: Scenario A: Predator Preys On Small Mammals Of Identical Agementioning

confidence: 99%

“…Exposure can occur through various routes, but consumption of contaminated prey items is thought to be the main route of exposure for terrestrial predators [1]. A number of algorithms exist to estimate daily oral intake of contaminants by birds of prey and mammalian predators [2][3][4][5][6][7]. These algorithms use a range of information on dietary preferences, ingestion rates, physiological parameters, allometric relationships, and toxicological data to estimate dose rates to predators.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, dose estimates require quantitative data on both the pollutant burdens in prey and the feeding rates of predators. Ingestion rates have been estimated for various predators [8][9][10][11][12][13][14] and pollutant concentrations in prey are usually derived by direct chemical analysis or by using bioaccumulation factors [5]. When estimating dose to predators using conventional dose algorithms, the term prey pollutant concentration is usually assumed to represent prey body tissue pollutant concentration.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modeling Cadmium Dynamics in the Guts and Tissues of Small Mammals: Dose Implications for Predators

Toal¹,

Walker²,

Shore³

2002

Environ Toxicol Chem

0

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Predators that consume contaminated small-mammal prey are exposed to pollutants present in both the prey tissues and the prey gut. However, the contribution of the prey gut and its contents to the contaminant intake of the predator is often ignored. This study developed a two-compartment model of the dynamics of Cd in a model prey species, the wood mouse (Apodemus sylvaticus). The results from the Cd dynamics model were used to calibrate a revised predator dose estimation methodology that accounted for contaminant uptake by a predator from both prey tissues and guts. The dose to the predator predicted by the revised methodology was compared to that predicted by conventional dose calculations, which account for contaminants in prey tissues only. The conventional approach underestimated Cd dose to a model predator by a factor of 1.2- to 10-fold, depending on prey age and predator behavior. Thus, accounting for the contaminant burden in the prey gut as well as in the tissues can markedly increase dose estimates to predators, and this is likely to be true for most low-bioavailability pollutants. This study has major implications for ecological risk assessment involving food chain transfer of low-bioavailability xenobiotics to predators.

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“…More complex models are also used in which chemical exposure processes, assimilation in tissues, or trophic transfer are represented mechanistically [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Testing of metal bioaccumulation models with measured body burdens in mice

Torres

¹

,

Johnson

²

2001

Enviro Toxic and Chemistry

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Estimates of chemical accumulation in prey organisms can contribute considerable uncertainty to predictive ecological risk assessments. Comparing body burdens calculated in food web models with measured tissue concentrations provides essential information about the expected accuracy of risk indices. Estimates of arsenic, cadmium, copper, lead, and nickel body burdens in house mice (Mus musculus) inhabiting a seasonal wetland were generated with two small mammal bioaccumulation models. Published soil-to-small mammal bioaccumulation regression models produced accurate estimates of arsenic and lead body burdens but failed to adequately predict copper and nickel levels in mice. Incorporating conservative prediction intervals in the regression models shows potential for successful applications in screening-level risk assessments. A simple mechanistic cumulative ingestion bioaccumulation model overpredicted lead levels in mice generally by less than one order of magnitude but greatly overpredicted concentrations of arsenic, copper, and nickel. Better estimates of absorption and elimination of ingested metals and knowledge of specific arthropod taxa in house mouse diets are likely to improve the accuracy of the cumulative ingestion model. Applying Monte Carlo simulations to the soil-small mammal regression models generated probabilistic estimates of body burdens that were consistent with deterministic results. However, deterministic minimum and maximum predictions of the ingestion model were excessively conservative (widely spaced) relative to lower and upper probabilistic percentiles. Metal levels predicted in individual mice on the basis of mouse-specific parameter values and exposures were not significantly more accurate than bioaccumulation predictions for the sitewide population.

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“…Thus, dose estimates require quantitative data on both the pollutant burdens in prey and the feeding rates of predators. Ingestion rates have been estimated for various predators [8–14] and pollutant concentrations in prey are usually derived by direct chemical analysis or by using bioaccumulation factors [5]. When estimating dose to predators using conventional dose algorithms, the term prey pollutant concentration is usually assumed to represent prey body tissue pollutant concentration.…”

Section: Introductionmentioning

confidence: 99%

Modeling cadmium dynamics in the guts and tissues of small mammals: Dose implications for predators

Toal

¹

,

Walker

²

,

Shore

³

2002

Enviro Toxic and Chemistry

3

0

View full text Add to dashboard Cite

Predators that consume contaminated small-mammal prey are exposed to pollutants present in both the prey tissues and the prey gut. However, the contribution of the prey gut and its contents to the contaminant intake of the predator is often ignored. This study developed a two-compartment model of the dynamics of Cd in a model prey species, the wood mouse (Apodemus sylvaticus). The results from the Cd dynamics model were used to calibrate a revised predator dose estimation methodology that accounted for contaminant uptake by a predator from both prey tissues and guts. The dose to the predator predicted by the revised methodology was compared to that predicted by conventional dose calculations, which account for contaminants in prey tissues only. The conventional approach underestimated Cd dose to a model predator by a factor of 1.2- to 10-fold, depending on prey age and predator behavior. Thus, accounting for the contaminant burden in the prey gut as well as in the tissues can markedly increase dose estimates to predators, and this is likely to be true for most low-bioavailability pollutants. This study has major implications for ecological risk assessment involving food chain transfer of low-bioavailability xenobiotics to predators.

show abstract

Modeling wildlife exposure to toxic chemicals: Trends and recent advances

Cited by 29 publications

References 51 publications

Modeling Cadmium Dynamics in the Guts and Tissues of Small Mammals: Dose Implications for Predators

Modeling Cadmium Dynamics in the Guts and Tissues of Small Mammals: Dose Implications for Predators

Testing of metal bioaccumulation models with measured body burdens in mice

Modeling cadmium dynamics in the guts and tissues of small mammals: Dose implications for predators

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