Toxicokinetics of Polycyclic Aromatic Hydrocarbons in Eisenia Andrei (Oligochaeta) Using Spiked Soil

Abstract

Abstract-The accumulation of four polycyclic aromatic hydrocarbons ([PAHs]; phenanthrene, pyrene, fluoranthene, and benzo[a]pyrene) was tested in the earthworm Eisenia andrei in a spiked artificial soil medium. A typical peak in the body residues was observed for all PAHs around day 7, which could not be explained from changes in the total soil concentration. It is argued that the most likely cause of this peak is a decrease in the concentration in pore water, the main bioavailable phase for earthworms. This decrease is caused by biodegradation while the low rate of mass transfer from the solid state precludes replenishment. To describe the data, bioavailability was assumed to decline exponentially in time, but the shape of the accumulation curves suggests a more abrupt change. Estimates of the uptake rate (k 1 ) are similar for all PAHs when expressed on soil solution basis (approximately 2,000 L/kg/d); the elimination rate (k 2 ) shows a decrease with K ow as expected, but the values tend to be slightly lower than literature data. The dynamic bioconcentration factors (k 1 /k 2 ) agree well with an equilibrium partitioning between soil water and the phases inside the organism.

Multigeneration Exposure of the Springtail Folsomia candida to Phenanthrene: From Dose−Response Relationships to Threshold Concentrations

“…In contrast, from the fifth generation onward, BSAFs were around 2 or lower, and no significant effects of phenanthrene on survival and reproduction were observed for the remaining exposure concentrations. These BSAF values are high compared to field studies on PAHs (38,39) but in the range of laboratory studies on aquatic and terrestrial invertebrates exposed to several PAHs (including phenanthrene), in which PAH availability is expected to be high (31,39).…”

Toxicity, bioaccumulation and metabolism of pesticides in the earthworm

“…However, many environmental factors greatly influence the effects of a pesticide on earthworms; soil properties such as pH and organic matter content, 11,22) dissolved organic carbon in pore water, 23) adsorptiondesorption hysteresis with sequestration in the soil, 12,[24][25][26] and microbial degradation. 20,27,28) Detailed kinetic analysis that assumes compartments of pore water, soil particles and biota has been applied to understand the behavior of a chemical in such a complex system based on the equilibrium partitioning (EP) theory. [28][29][30] Recently, a cylindrical soil monolith treated with organophosphorus and pyrethroid insecticides has been utilized to examine their effects on enzymatic activities by considering earthworm ecology.…”

“…20,27,28) Detailed kinetic analysis that assumes compartments of pore water, soil particles and biota has been applied to understand the behavior of a chemical in such a complex system based on the equilibrium partitioning (EP) theory. [28][29][30] Recently, a cylindrical soil monolith treated with organophosphorus and pyrethroid insecticides has been utilized to examine their effects on enzymatic activities by considering earthworm ecology. 31) However, these approaches are too complicated to concisely examine the effects of many pesticides.…”

“…28,102) The combination of the slow mass transfer of PAHs from the soil-sorbed phase to pore water with its microbial biodegradation therein is likely to result in these profiles. The partition of a chemical between water and the earthworm is proportional to log K ow similarly to that between water and soil, and so no dependency of BSAF on log K ow is predicted by the EP theory.…”

Comparative chronic toxicity of homo- and heterocyclic aromatic compounds to benthic and terrestrial invertebrates: Generalizations and exceptions

“…This, together with the low organic carbon content of the soil, could lead to an overestimation of the pore water concentration in the soil. Another explanation could be the faster depletion in the soil compared to water-saturated sediment, which could limit the availability of the compounds to the test organisms (Jager et al, 2000). These considerations underline the fundamental problems in research on scarcely studied heterocyclic PAC and PAC transformation products: although there is an urgent need for insight in their fate, effects and risk, it is still hard to find reliable values for their physicochemical properties and accurately estimate their availability in soil and sediment.…”