Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


osu1259697144.pdf (1.15 MB)

ETD Abstract Container

Abstract Header

Bioaccumulation of Metals in Earthworms

Yu, Shuo
http://rave.ohiolink.edu/etdc/view?acc_num=osu1259697144

Abstract Details

2009, Doctor of Philosophy, Ohio State University, Environmental Science.
Bioaccumulation is a direct biological measure of metal bioavailability since it measures the actual amount of metal taken up by the earthworm and integrates all of the effects of biotic (e.g., earthworm behavior) and abiotic (e.g., soil pH) modifying factors over the duration of the exposure period. This dissertation used earthworms as a model to examine the effects of various factors on bioaccumulation of cadmium (Cd) in soil.Chemical bioaccumulation factors (BAF) are considered a simple tool to estimate the bioaccumulation of contaminants in a particular organism in a specific medium. However, there can be considerable uncertainty associated with the application of BAF to metals in soil systems. In this study, data from a comprehensive review of studies reporting bioaccumulation of Cd by earthworms was used to perform statistical analyses on factors that affected variation in Cd BAF. Seventy-five papers from 1973 to 2006 with 727 observations from both lab and field studies were reviewed. Data on earthworm species, deputation time, earthworm tissue Cd, and soil properties including pH, organic matter content, clay content, cation exchange capacity (CEC), soil texture, and total soil Ca and Cd, were included in our data set. Due to inconsistent reporting of chemical/physical soil properties, statistical analyses of the more commonly reported variables (i.e., species, depuration time, and experiment type [field vs. laboratory]) were first performed using a generalized linear model (GLM). Because earthworm species was the only significant factor among the commonly reported variables, effects of soil properties on Cd BAF were subsequently evaluated on a subset of the data set using multiple linear regressions of residual values from the GLM. The two most significant parameters affecting mean Cd BAF in earthworms were earthworm species and soil matrix properties. Soil clay content, soil pH, and organic matter content independently comprised 61.3%, 6.0%, and 0.4% of the soil property effect on Cd BAF, respectively. Covariance among the three soil property parameters accounted for the remaining 32.3% of the soil matrix effect. Acclimation of earthworms to cadmium (Cd) levels exceeding background concentrations may result in the development of Cd-tolerance mechanisms and allow the accumulation of Cd with minimum adverse effects. In this study, earthworms (Eisenia andrei) were acclimated by exposure to 20 mg/kg Cd in Webster soil for 28 days. A 224-day bioaccumulation test was subsequently conducted with both acclimated and unacclimated worms exposed in Webster soils spiked with 20 mg/kg and 100 mg/kg Cd. Uptake kinetics and subcellular compartmentalization of Cd were examined. Results suggest that acclimated earthworms accumulated more Cd and required longer time to reach steady state than unacclimated worms. Most of the Cd was present in the metallothionein (MT) fraction. Cadmium in the MT fraction increased approximately linearly with time, and required a relatively longer time to reach steady state, while Cd in the cell debris and granule fractions quickly reached steady state. Cadmium in the cell debris fraction is considered potentially toxic, but low steady state concentrations observed in this study suggested no adverse effects occurred.
Roman Lanno (Committee Chair)
Nicholas T. Basta (Other)
Susan W. Fisher (Other)
Timothy J. Buckley (Other)
Environmental Science
Cadmium; earthworm; bioaccumulation

Recommended Citations

Citations

  • Yu, S. (2009). Bioaccumulation of Metals in Earthworms [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259697144

    APA Style (7th edition)

  • Yu, Shuo. Bioaccumulation of Metals in Earthworms. 2009. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1259697144.

    MLA Style (8th edition)

  • Yu, Shuo. "Bioaccumulation of Metals in Earthworms." Doctoral dissertation, Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259697144

    Chicago Manual of Style (17th edition)

osu1259697144
2,176
© 2009, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.