Premium
Assessing the effects of modifying factors on pentachlorophenol toxicity to earthworms: Applications of body residues
Author(s) -
Fitzgerald Dean G.,
Warner Kathryn A.,
Lanno Roman P.,
Dixon D. George
Publication year - 1996
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620151227
Subject(s) - eisenia fetida , pentachlorophenol , lumbricus terrestris , toxicity , chemistry , bioassay , environmental chemistry , toxicology , ecotoxicology , dry weight , earthworm , zoology , biology , botany , ecology , organic chemistry
This study examined the toxicokinetic relationship between critical body residues (CBRs) of pentachlorophenol (PCP) at lethality, soil PCP concentrations, and modifying factors of toxicity such as body size, species, temperature, and soil type during 28‐d bioassays with earthworms. Eisenia fetida (0.2–0.4 g) were exposed to PCP at 15 and 24°C in artificial soil and at 24°C in Brookston clay. Lumbricus terrestris (3.3–4.6 g) and Eudrilus eugeniae (1.5–2.7 g) were exposed in artificial soil at 15 and 24°C, respectively. Soil PCP concentrations ranged from 0 to 6.75 mmol PCP/kg soil (dry weight), and body residues were measured by gas chromatography following cryoextraction of freeze‐dried earthworms. Comparisons of toxicity were made using incipient lethal levels (ILLs) and CBRs at lethality. The equations estimated by nonlinear curve fitting of a one‐compartment, first‐order kinetics model provided a good fit to the observed data for all species, temperatures, and soil types at which tests were conducted. Incipient lethal levels for L. terrestris (0.72 mmol/kg soil) and E. eugeniae (0.63 mmol/kg soil) were similar and significantly higher than those for all E. fetida treatments. Incipient lethal levels for E. fetida exposed to PCP in artificial soil at 15 and 24°C were similar and lower than the ILL for E. fetida exposed to PCP in Brookston clay. The toxicity half‐lives were similar for all E. fetida treatments but were higher than for the larger worms, L. terrestris and E. eugeniae , which were similar. Mean CBRs at lethality for E. fetida tested in artificial soil at 24°C ranged from 0.33 to 0.74 mmol/kg (wet weight) over the range of soil PCP exposure concentrations from 0.12 to 3.75 mmol PCP/kg. Mean CBRs for E. fetida exposed to PCP at 24°C in Brookston clay ranged from 0.51 to 1.59 mmol PCP/kg (wet weight) over the same range of soil PCP concentrations and were not significantly different. Critical body residues for E. fetida (15°C), L. terrestris , and E. eugeniae tested in artificial soil at 2.10 mmol PCP/kg ranged between 0.34 and 0.80 mmol PCP/kg. Residues in surviving worms were either similar to or lower than those in dead worms. Similar CBRs in three species of earthworms differing 10‐fold in body size, and for E. fetida exposed to PCP concentrations ranging over more than two orders of magnitude in two different soil types, demonstrate that body residues can act to more effectively integrate the relationship between test organism, exposure, and mortality than soil toxicant concentrations alone.