Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Includes bibliographical references (p. 92-104).

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This research is part of an overall program to develop and use a suite of acute and sublethal toxicity biomarkers, and testing protocols for use in assaying potential effects of complex mixtures of xenobiotics such as found in soils containing agricultural biocides and petrochemical wastes dredged sediments, and hazardous waste sites (HWS). The purpose of this study was to evaluate four biomarkers of sublethal pathology that could be used in an integrative model of multiple toxicity endpoints with the earthworm Lumbricus terrestris.

A process for disposing of pesticide rinsewater generated from the rinsing of application equipment is being developed at Virginia Polytechnic Institute and State University. This process involves the sorption of pesticides onto an organic matrix followed by degradation in a composting environment. We are now evaluating the hazards that might be associated with land-applying composted pesticide waste. Diazinon was the first pesticide selected for evaluation, which consisted of two studies. The first used the earthworm species Eisenia foetida to evaluate the toxicity of soil amended with composted diazinon waste. The second study determined the bioavailability of delta-2-14C-diazinon and its degradation products to E. foetida in soil amended with composted delta-2-14C-diazinon. Results from the first study indicate that uncomposted diazinon sorbent and 30-day composted diazinon sorbent were toxic to E. foetida at sublethal and lethal levels. However, E. foetida exposed 60-day composted diazinon sorbent did not experience mortality or demostrate sublethal effects commonly associated with acetylcholinesterase inhibition. Earthworms exposed to diazinon that was uncomposted or composted for 30 days in the radiolabelled study experienced higher mortality than in the field study. After 30 and 60 days of composting 14C-diazinon became unextractably incorporated into organic matter and very little was mineralized. Earthworms were shown to accumulate radioactivity when exposed to soil amended with 60- day composted delta-2-14C-diazinon. The majority of this radioactivity was unextractably bound to earthworm tissue and that which was extractable contained only trace levels of delta-2-14C-diazinon. Based on the absence of toxicity in the field study and the low levels of 14C-diazinon present in earthworm tissues, 60 days of composting appears to greatly reduce the hazard that diazinon rinsate poses to E. foetida. / Master of Science

Objectives were to: (1) assess toxicity of polychlorinated biphenyls on Eisenia foetida, in terms of survival (LC5O/LD5O), and suppression of coelomocytes to form secretory (SR) and erythrocyte rosettes (ER) with, and to phagocytize rabbit erythrocytes; and (2) compare results with those of Lumbricus terrestris to assess relative sensitivities to PCB. Using 5-d filter paper contact exposure protocol, LC50 and LD50 were 30.4 cg/cm2 and 4450 cg/g dry mass, respectively. Nominal PCB exposure concentrations of 5.0 and 10.0 pg/cm2 resulted in tissue levels of 1389 and 2895 pg/g dry mass causing a significant reduction in SR formation by 18 and 52%, respectively. ER formation and phagocytosis were reduced significantly (52 and 61%) only at the higher tissue concentration. Compared to reported data on lethality and immunomodulation in L. terrestris, E. foetida appears to be more resistant.

The research presented herein provides information on coelomocyte (leukocyte) collection, function and immunotoxicity from polychlorinated biphenyls (PCB) in the earthworm Lumbricus terrestris. Research was undertaken as part of an overall goal to develop a well-documented and scientifically valid non-mammalian surrogate immunoassay with the earthworm Lumbricus terrestris to assess immunotoxic potential of xenobiotics. The principal objectives were to: (1) Develop an extrusion model for analyzing immunotoxicity of xenobiotics; (2) determine if coelomocytes can be collected repeatedly without obvious harm to the earthworm or change in immune response of the coelomocytes harvested and (3) validate the response sensitivity profiles of a panel of biomarkers {differential and total cell counts, erythrocyte rosette (ER) and secretory rosette (SR) formation with, and phagocytosis of antigenic rabbit red blood cells} in earthworms after acute exposure to a known mammalian and L. terrestris immunotoxin, the PCB Aroclor 1254.

This research evaluated the potential of activation and attachment, as sequential companion biomarkers of phagocytosis by earthworm, Lumbricus terrestris, immunoactive coelomocytes for use in immunotoxicology. The potential was assessed by exposing earthworms to sublethal concentrations of CuSO4 and Arochlor 1254®, chemicals used as reference or standard immunotoxicants.

Growing concerns over climate change is driving research aimed at determining ways of retaining soil carbon (C) within managed northeastern forests. Earthworms are exotic to the state of Vermont and the current extent of earthworm community presence in the state's forests, as well as the long term impact these communities will have on soil C storage, is still unknown. Current research suggests that earthworms have conflicting effects on the C cycle of soils, simultaneously enhancing mineralization through soil mixing, while protecting C through the stabilization of microaggregate (mA) structures. The mA soil fraction represents a pool of physically stable structures capable of maintaining occluded C for long periods of time. To date, studies investigating earthworm effects on mA formation and occluded C have rarely been done in undisturbed forest soils. Earthworms were found in 10 of 18 forest sites utilized in a statewide Vermont earthworm survey, and community presence correlated with thinner forest floor depths. For 8 sites, the impact of earthworm presence on the quantity of C within water stable mA was investigated. Earthworm presence correlated with greater total C in the top 20 cm of mineral soil, highlighting the relocation of the forest floor noted in all 18 sites. A small, but significant, decrease was noted in the proportion of bulk soil mA, however through C enrichment from the forest floor, there was a significant increase in the pool of mA-associated C. A paired mesocosm study was also conducted, utilizing the endogeic earthworm species Aporrectodea tuberculata, placed in an earthworm-free, undisturbed forest soil. Findings from this study corroborated the correlations noted in the field with significant, though small, decreases in the proportion of bulk soil mA. The larger macroaggregate fraction was increased by about 4 times under earthworm influence. The C enrichment of mA structures occluded within the macroaggregate fraction accounted for approximately 95% of the total increase in mA-associated C, and 50% of the total C integrated into the mineral soil. It can be assumed that the C preferentially occluded within the mA structures by earthworm ingestion will experience longer mean residence time relative to bulk soil C. We conclude that, for the forest soils investigated, earthworm communities decreased the proportion of mA slightly but that the pool of physically stabilized C was increased through mA turnover. Forest soils usually experience low soil mixing and therefore typically contain high proportions of mA, though the quantity of C within these structures varies. Due to mA restructuring within the earthworm gut, it is unlikely that earthworm community expansions will alter the proportion of mA in forest soils, however the quantity of C present within these structures is likely to increase. The individual site investigated in the controlled study was particularly low in mineral soil C, and therefore the long-term presence of earthworms would likely result in an increase to mineral C storage. However, this result may not be applicable for forests with high levels of mineral soil C prior to earthworm invasion.

Coelomocyte migration responses, both random and chemotatic, were examined in the earthworm Lumbricus terrestris. Coelomocyte random migration patterns towards non-stimulatory, non-chemotatic solutions were described. Migration responses to immunostimulatory agents lipopolysaccharides (LPS), N-formly-methionyl-leucyl-phenylalanine (FMLP), sheep erythrocytes, Saccharomyces cerevisiae, Aeromonas hydrophila, Eisenia fetida and Rhabditis pellio were characterized. Chemotaxis was reported to LPS, FMLP, sheep erythrocytes, S. cerivesae and E. fetida. Bio-indicator potential of chemotaxis is discussed relative to variability in migration responses.