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Bioaccumulation of metals in earthworms.

Yu, Shuo.

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Bioaccumulation of metals in earthworms.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Bioaccumulation of metals in earthworms./
Author:	Yu, Shuo.
Description:	173 p.
Notes:	Source: Dissertation Abstracts International, Volume: 71-02, Section: B, page: 0900.
Contained By:	Dissertation Abstracts International71-02B.
Subject:	Environmental Health. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3393268
ISBN:	9781109604351

Bioaccumulation of metals in earthworms.
Yu, Shuo.

Bioaccumulation of metals in earthworms. - 173 p.

Source: Dissertation Abstracts International, Volume: 71-02, Section: B, page: 0900.

Thesis (Ph.D.)--The Ohio State University, 2010.

Contamination of soil with metals poses a risk to ecosystem health, particularly to organisms that are in direct contact with the soil (i.e., plants, soil invertebrates). Earthworms are often used as test organisms in laboratory and field studies in order to estimate metal risk in contaminated soils. 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.

ISBN: 9781109604351Subjects--Topical Terms:

578282
Environmental Health.

Bioaccumulation of metals in earthworms.
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020 $a 9781109604351
035 $a (UMI)AAI3393268
035 $a AAI3393268
040 $a UMI $c UMI
100 1 $a Yu, Shuo. $3 1682764
245 1 0 $a Bioaccumulation of metals in earthworms.
300 $a 173 p.
500 $a Source: Dissertation Abstracts International, Volume: 71-02, Section: B, page: 0900.
500 $a Adviser: Roman P. Lanno.
502 $a Thesis (Ph.D.)--The Ohio State University, 2010.
520 $a Contamination of soil with metals poses a risk to ecosystem health, particularly to organisms that are in direct contact with the soil (i.e., plants, soil invertebrates). Earthworms are often used as test organisms in laboratory and field studies in order to estimate metal risk in contaminated soils. 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.
520 $a 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.
520 $a 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.
520 $a Future bioaccumulation tests should report earthworm species and use standardized methods to measure critical soil properties (i.e., clay content, pH, organic matter) in order to produce reliable results and make comparison with other studies. Also, use of earthworms in ecological risk assessment should take into consideration pre-exposure histories of the test organisms, and a prolonged test period may be required for a comprehensive understanding of uptake kinetics and compartmentalization. Laboratory toxicity and bioaccumulation models along with measurements of key soil properties could be used as a screening tool to evaluate metal bioavailability in the baseline ecological risk assessment.
590 $a School code: 0168.
650 4 $a Environmental Health. $3 578282
650 4 $a Environmental Sciences. $3 676987
690 $a 0470
690 $a 0768
710 2 $a The Ohio State University. $b Environmental Science. $3 1676894
773 0 $t Dissertation Abstracts International $g 71-02B.
790 1 0 $a Lanno, Roman P., $e advisor
790 $a 0168
791 $a Ph.D.
792 $a 2010
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3393268