Bioaccumulation Potential of Persistent Organic Chemicals in Humans

Abstract

A model was used to explore the influence of physicalchemical properties on the potential of organic chemicals to bioaccumulate in humans. ACC-HUMAN, a model of organic chemical bioaccumulation through the agricultural and aquatic food chains to humans, was linked to a level I unit world model of chemical fate in the physical environment and parametrized for conditions in southern Sweden. Hypothetical, fully persistent chemicals with varying physical-chemical properties were distributed in the environment, and their bioaccumulation to humans was calculated. The results were evaluated using the environmental bioaccumulation potential (EBAP), defined as the quotient of the chemical quantity in a human divided by the quantity of chemical in the whole environment. Since the latter is closely related to emissions, EBAP is potentially a more useful tool for comparative risk assessment of chemicals than currently used medium-specific measures such as the fish-water bioaccumulation factor. A high environmental bioaccumulation potential, defined as > 10% of the maximum EBAP, was found for chemicals with 2 < log KOW < 11 and 6 < log KOA < 12. While these chemical partitioning properties clearly influenced bioaccumulation at each trophic level, these effects tended to equalize over the food web. The fact that the transfer from the environment as a whole to humans was quite uniform over a large chemical partitioning space suggests that these partitioning properties are relatively unimportant determinants of human exposure compared to other factors such as the substance's persistence in the environment and in the food web.

Difficult socio-economic circumstances and the utilization of risk information: A study of Mexican agricultural workers in the USA

“…Most participants in this study were living in poverty, but there was still sufficient variability in the severity of economic circumstances, although within a restricted range, to examine the effects of economic differences and interpretations of these circumstances on risk information utilization. The risk information presented to participants in the study reflected the type of scientific evidence frequently used by experts to quantify and communicate the risk of an environmental chemical (Feldman 1995, Czub andMcLachlan 2004).…”

Octanol/Air Partition Coefficients of Volatile Methylsiloxanes and Their Temperature Dependence

“…8 Substances with low log K OA values (<5) can be readily eliminated from mammals through respiration, while those with high log K OA values could be biomagnified significantly in arctic terrestrial food-chains. 7,8 The high bioaccumulation potential in humans is predicted for persistent organic chemicals with log K OA values ranging from 6 to 12. 8 Volatile methylsiloxanes (VMS) such as hexamethyldisiloxane (L 2 ), octamethyltrisiloxane (L 3 ), decamethyltetrasiloxane (L 4 ), octamethylcyclotetrasiloxane (D 4 ), decamethylcyclopentasiloxane (D 5 ), and dodecamethylcyclohexasiloxane (D 6 ) are relatively stable in air.…”

“…7,8 The high bioaccumulation potential in humans is predicted for persistent organic chemicals with log K OA values ranging from 6 to 12. 8 Volatile methylsiloxanes (VMS) such as hexamethyldisiloxane (L 2 ), octamethyltrisiloxane (L 3 ), decamethyltetrasiloxane (L 4 ), octamethylcyclotetrasiloxane (D 4 ), decamethylcyclopentasiloxane (D 5 ), and dodecamethylcyclohexasiloxane (D 6 ) are relatively stable in air. Based on the currently available data, their half-lives in air are greater than 2 days.…”

The precautionary principle and chemicals management: The example of perfluoroalkyl acids in groundwater

“…However, BCF FISH may not be conservative for higher organisms in food webs where there is significant biomagnification of the chemical arising from dietary exposure. Furthermore, for slowly metabolized chemicals with low air-water partition coefficients, BCF FISH may not be conservative with respect to airbreathing organisms because elimination via respiration of air is slower than elimination via respiration of water (Czub and McLachlan, 2004). For PFAAs, elimination occurs through different mechanisms in aquatic and terrestrial species: In mammalian species it is governed by renal and biliary clearance (Harada et al, 2007;Han et al, 2012), whereas in fish PFAAs can also be eliminated via the respiratory system (i.e.…”