Bioavailability to Earthworms of Aged DDT, DDE, DDD, and Dieldrin in Soil

Abstract

A study was conducted to determine the bioavailability of several pesticides that have persisted for various periods in soils in the field and the laboratory. Based on the concentrations or the percentages of the compound in soil samples that were found in the earthworm Eisenia foetida, ca. 30, 12, 34, and 20% of DDT, DDE, DDD, and a total of the three compounds were bioavailable in a soil treated in the field with DDT 49 years earlier. Only 28 or 43% of dieldrin aged for 49 years was bioavailable based on concentrations in E. foetida or percentages of the compound assimilated by the worms, respectively. Comparably low percentages of DDT, DDE, and DDD but not dieldrin were assimilated by the worms from samples of soil from a waste-disposal site receiving the insecticide ca. 30 years earlier. Aging for 190 days in Kendaia loam in the laboratory markedly reduced the availability to E. foetida of DDT and DDE but not DDD. The amounts of aged or unaged DDT, DDE, and DDD but not dieldrin that were removed from the soils by solid-phase extraction with Tenax TA beads were generally greater with increasing amounts assimilated by the earthworms. The results show that aging markedly reduces the bioavailability of these compounds.

Wintering area DDE source to migratory white-faced ibis revealed by satellite telemetry and prey sampling

“…Estimates of the half-life of DDT range from 2 -17 years (Extoxnet 1994), and that of DDE for 15 years. Nash and Woolsen (1967) found that 39% of an original application remained in soil 17 years later, while Morrison et al (2000) reported that 30% of DDT applied in one soil type 49 years earlier was still bio-available to earthworms. Setmire et al (1993) found DDE concentrations in biota from freshwater rivers and drains around the Salton Sea and Imperial Valley to be the highest documented in California, and ibis had some of the highest concentrations in birds from the valley.…”

Toxicity, bioaccumulation and metabolism of pesticides in the earthworm

“…ablity by the formation of unextractable bound residues, 98,99) the uptake of pesticides even from the bound fraction of exhaustively extracted soils showed their partial release during digestion. 24,100,101) The EP theory has been successfully introduced to describe the bioaccumulation (BSAF) of pesticides in aquatic species, 30) while its application to the earthworm is still limited for polychlorinated aromatics and PAHs.…”

Persistence and Changes in Bioavailability of Dieldrin, DDE, and Heptachlor Epoxide in Earthworms Over 45 Years

“…Alexander (2000) argued that because regulatory agencies do not take aging into account, toxic exposures are being over estimated in assessments and he cited his laboratory studies on earthworms in aged soils in support of his argument (Morrison et al 2000;Kelsey et al 2005). In contrast, Gaw et al (2012), studying the accumulation of DDE in Aporrectodea caliginosa in aged horticultural soils under laboratory conditions, concluded that DDE remains biologically available to earthworms and to animals that prey on earthworms.…”