WP15 Soil Ecotoxicology and Risk Assessment|
Wednesday, 16 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall
WP151 (JOH-1117-814397) Are Songbirds at Risk from Lead Exposure at Small Arms Ranges: an Application of the Spatially Explicit Exposure Model?
Start time: 8:00 AM
Johnson, M1, Wickwire, W2, Parsons, P3, Burmistrov, D2, Menzie, C2, 1 US Army Center for Health Promotion and Preventive Medicine, Aberdeen Proving Ground, MD, USA2 Menzie-Cura & Associates, Winchester, MA, USA3 Wadsworth Center, New York State Dept. of Health, Albany, NY, USA
Use of small arms during training is an important activity associated with the development and proficiency of soldiers. Consequently, many installations have ranges dedicated to this purpose that have high soil levels of lead. It has been proposed that the copper-jacket surrounding the lead core of the bullets hastens the oxidation of the metal facilitating transport. Many of these ranges are no longer used and have become habitat for wildlife. To address the potential for adverse effects from lead exposure in songbirds, a multi-level approach was used. An integrative soil sampling procedure was used and incorporated into the Spatially Explicit Exposure Model (SEEM) for two small arms range sites. Additional site-specific data included lead analysis of nestling food items, blood lead levels, nest site location and characteristics, and fecal samples. Territorial males were also spot mapped to determine likelihood of breeding activity. These data were used to refine and compare model inputs and results, respectively. Additionally, population data were used to assist in model result interpretation. Although analytical data were limited, this approach provides the means to evaluate risk to songbirds from lead at small arms ranges.
WP152 (BLU-1117-845479) Assessing the validity of enzyme bioassays for screening bioavailable metals in mining impacted soils.
Start time: 8:00 AM
Blumenstein, E1, Ranville, J1, Choate, L2, Ross, P1, 1 Colorado School of Mines, Golden, CO, USA2 United States Geological Survey, Lakewood, CO, USA
Mine tailings piles and abandoned mine soils, also known as mining impacted soils (MIS), are often contaminated by a suite of toxic metals which were released in the mining process. Traditionally, regulatory testing of MIS has been conducted with a Toxicity Characteristic Leaching Procedure (TCLP) (USEPA Method 1311). The TCLP simulates the leaching a waste will undergo if disposed of in a sanitary landfill. Unfortunately, the TCLP is not a good measure of determining what will happen to MIS left in the surface environment. Many of the heavy metals present in MIS may not be in bioavailable forms. Additionally, the bioavailability of metals in mining influenced waters (MIWs), including MIS leachates, is influenced by three primary parameters: the concentration of the metal, the competition with other ions (calcium and magnesium), and complexation with other solution species (alkalinity and organic matter). Enzymatic bioassays may provide a measure of metal bioavailability that is easier, less costly, more time-effective, and more accurate than the TCLP. This study evaluated the commercially available enzymatic toxicity assay MetPLATETM test kit. The MetPLATETM assay uses a modified strain of the Escherichia coli bacteria as the test organism. When the E. coli bacteria are not stressed by metals, the enzyme -galactosidase is produced, which hydrolyzes an added chromogenic substrate. Conversely, when the E. coli bacteria are stressed, lesser amounts of substrate or no substrate at all is hydrolyzed. The inhibition of the enzyme is measured colorometrically with a 96-well spectrophotometer. This study indicated that the bioavailability of heavy metals present in MIS leachate, as is the case for MIW, is dependent upon concentration, competition, and complexation. These results were obtained by examining Cu and Zn toxicity under different levels of hardness, alkalinity, and DOC in MIS leachates.
WP153 (PER-1117-758177) Determining fertilizer contribution to bioavailable and total metal concentrations in agricultural soils and plants.
Start time: 8:00 AM
Perez, A.1, 2, Anderson, K.1, 2, 1 Food Safety and Environmental Stewardship Program2 Oregon State University, Corvallis, OR, USA
Fertilizers may contain variable concentrations of metals (and metalloids) including arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg), and nickel (Ni). These metals may accumulate and pose a risk to soil and aquatic biota via off site transport and to human health through plant uptake. This research aims to determine the bioavailable and total metal concentrations in agricultural soils amended with heavy metal rich fertilizer and total metal concentration in the edible portion of wheat and/or potato plants. Diffusive Gradient Thin Films (DGT) were used to estimate labile metal concentrations in saturated soils from four agricultural research plots in Oregon. Site to site variation of metal concentration, effects of multiple fertilizer doses, and estimated Kdl in distinct soil systems was investigated. Preliminary results suggest Cd, Ni, and Hg may be enriched in potatoes while total soil Cd increased with treatment.
WP154 (GAL-1117-817961) Toxicty and bioaccumulation of phenanthrene in Eisenia andrei.
Start time: 8:00 AM
Galvis, P1, Lanno, R1, 1 Ohio State University, Columbus, OH, USA
Ecological soil screening levels (EcoSSLs) are screening values that can be used routinely to identify contaminants of concern in soils that may require further evaluation in a baseline risk assessment. This study examines the effect of five different soils on the chronic toxicity and bioaccumulation of phenanthrene (PHE) by Eisenia andrei. When developing EcoSSLs, it is important to establish soil physical and chemical characteristics that affect bioavailability since these are key factors affecting adsorption, uptake and toxicity of contaminants in soil. The five different soils used in this study (Kirkland clay loam, Perkins sandy loam, Richfield clay loam, Sassafras sandy loam and Webster clay loam) exhibited a wide range of physical/chemical characteristics (pH - 4.0-7.3; % organic carbon - 0.4-2.4; % clay content - 12-36%). A second goal was to compare different methods to measure the potentially bioavailable fraction of PHE in each soil. Soils were amended with different PHE concentrations and toxicity was assessed by monitoring reproductive effects such as cocoon production, hatchability, and number of hatchlings. PHE bioavailability was assessed by measuring body burdens of PHE in earthworm tissues, using solid phase microextraction fiber (SPME) and C18 empore disks to extract PHE from soil. To determine PHE uptake in earthworms, soils were spiked at a no effect concentration (NOEC). The bioavailable fraction of PHE was established by measuring body burdens and tracing PHE concentrations in soil over time using SPME and C18 empore disks extractions. The results of the study will be used to develop a model of the effects of soil physical/chemical characteristics on the bioaccumulation and toxicity of PHE in earthworms.
WP155 (TSA-1117-816214) Development of soil-to-earthworm bioaccumulation models for energetic compounds and metabolites.
Start time: 8:00 AM
Tsao, C.L.1, Sample, B.E.1, Johnson, M.S.2, 1 CH2M HILL, Sacramento, CA, USA2 US Army Center for Health Promotion and Preventive Medicine, Aberdeen Proving Ground, MD, USA
Concentrations of contaminants in tissue are needed to estimate exposure of birds and mammals. In the absence of measured data, models are used. Empirical models based on measured relationships are better than models based on chemical characteristics (i.e., Kow). We developed soil-to-earthworm tissue bioaccumulation models for 8 energetic compounds [HMX, perchlorate, RDX, TNT, and its metabolite (2,4-DANT, 2,6-DANT, 2-ADNT, and 4-ADNT)]. Data were extracted from from 7 journal papers and the gray literature.. Results from the studies were pooled by chemical in soil and by parent/metabolites in earthworms to determine existence of linear relationships between the chemical concentrations in soil and in earthworm whole-body tissues. . Four chemicals (RDX, perchlorate, 2-ADNT, and 4-ADNT) had statistically significant log-linear relationships between soil to earthworms; inversely proportional relationships were found for RDX and perchlorate in soil to earthworms. For the remaining chemical-to-tissue combinations, summary statistics of BAFs (ratio of soil to tissue) were generated. Among all the chemicals examined, 3 chemicals pairs: (HMX in soil to HMX in earthworms, TNT-to-TNT, and TNT-to-4ADNT) had median soil-to-tissue BAFs of less than one; the remaining chemical pairs (HMX/HMX, perchlorate/perchlorate, RDX/RDX, TNT/2-ADNT, TNT/2,4-DANT, 2,4-DANT/2,4-DANT, and 2,6-DANT/2,6-DANT] all had median uptake values of greater than one.
WP156 (CAI-1117-828515) Arsenic transport and transformation in Golf course soils: field and laboratory experiments.
Start time: 8:00 AM
Cai, Yong1, Chen, Zhangrong1, Jaramillo, Alejandro 1, Snyder, George 2, Chen, Ming2, Cisar, John3, 1 Department of Chemistry & Biochemistry and Southeast Environmental Research Center, Florida International University, Miami, FL 33199, USA2 Everglades Research and Education Center, University of Florida, Belle Glade, FL 33430, USA3 Fort Lauderdale Research and Education Center, University of Florida, Ft. Lauderdale, FL 33314
The impact of extensively used arsenic-containing herbicides on ground water beneath golf courses has become a topic of interest. Although currently used organoarsenicals are less toxic, their application into the environment may produce the more toxic inorganic arsenicals. Over the last few years, our research team has been conducting studies to understand the key factors and processes controlling arsenic transport and transformation in Florida golf course soils. This paper will summarize the results from our field and laboratory experiments. The results from the field experiments conducted at the Fort Lauderdale Research and Education Center, University of Florida showed that the substrate composition significantly influenced arsenic mobility and arsenic species transformation in the percolate water. Arsenic species transformation occurred in soil, resulting in co-occurrence of four arsenic species, arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in percolate water. The clay coatings on the soil particles and the addition of peat in the soil changed the arsenic bioavailability, which in turn controlled the microorganism-mediated arsenic transformation. The adsorption kinetics of AsV and MMA to soil substrate were characterized using equilibrium batch experiments. Heterogeneous colloid-binding characteristics of arsenic were also evaluated using equilibrium dialysis technique. A three-component equilibrium model was proposed to describe the partitioning of arsenic species in the water, colloidal, and soil system, and to estimate the arsenic distribution coefficients among these three phases. Column experiments were conducted to simulate arsenic transport through golf course soils in the presence and absence of soil-derived colloids. The transport and transformation of arsenic species is influenced by a combination of microbial and physicochemical properties and processes. Arsenic species transformation occurred under the column conditions and had a significant impact on arsenic transport for both arsenic species tested (AsV and MMA).
WP157 (KIM-1117-741779) Additivity of phytotoxicity in soybean in response to soil Cu and Zn.
Start time: 8:00 AM
Kim, B.1, McBride, M.2, 1 Cornell University, Ithaca, New York, USA2 Cornell University, Ithaca, New York, USA
Cu and Zn are essential micronutrients for plant growth. However, because of continued usage in feed additives and pesticides, annual loadings of these metals on agricultural land often far exceed plant requirements, potentially causing phytotoxicity. Most studies have investigated separately Cu and Zn toxicity to plants, whereas the additivity and interactivity of phytotoxicity of the two metals has not been fully studied. In the present study, a long-term field experiment has been designed to address the question of interaction over a wide range of Cu and Zn concentrations. The field experiment was conducted on two soils of different texture, a sandy loam and a silty clay loam, to investigate the role of soil properties in controlling metal bioavailability, and thus toxicity to plants. Aqueous solutions of Cu and Zn sulfates were sprayed on the soils with mixing, to reach a final soil concentration range from 0 to 400 mg/kg Cu and Zn. The metal-spiked soils, transferred to plastic pots, were allowed to age in the field for two years before planting soybeans. For the characterization of soil properties, organic matter contents and pH were measured, and the amount of total and bioavailable Cu and Zn in the soils were estimated by HF microwave digestion and 0.01 M CaCl2-extraction, respectively. Cu and Zn uptake into the soybeans was measured after HNO3 microwave digestion of the above-ground plant tissue. Cu and Zn concentrations in the plant tissues were highly correlated with the amount of CaCl2-extractable Cu and Zn in the soils, but the absolute amounts of both bioavailable metals and metal concentrations in the plants differed between the soils. The results of statistical analyses (SAS for windows V8) suggested that the CaCl2-extractable amounts of Cu and Zn in the soils were significant variables (p < 0.0001) for the estimation of metal toxicity to soybean plants. Based on these findings, a quantitative relationship between CaCl2-extractable Zn (at each Cu addition level) and plant yield (dry weight) in both soils was formulated to predict the phytotoxic level of Zn in soybean plants depending on the Cu concentration in the soil. Therefore, it can be concluded that the phytotoxic effects of Cu and Zn in soybean plants is additive to different degrees in the two soils, and that its intensity is influenced by soil characteristics.
WP158 (VAN-1117-791490) Incorporation of bioavailbility for the derivation of ecologically relevant effects threshold concentrations in soils: an European experience.
Start time: 8:00 AM
Van Sprang, P1, Smolders, E2, Waegeneers, N2, Oorts, K2, Heijerick, D1, Vandenbroele, M1, Vangheluwe, M1, Marchini, S3, Schoeters, I4, 1 European Center for Risk Assessment (EURAS), Gent, Belgium2 University of Leuven, Leuven, Belgium3 Instituto Superiore di Sanita, Roma, Italy4 European Copper Institute, Brussels, Belgium
In the framework of a voluntary Copper Risk Assessment initiative, copper specific information on environmental toxicity/deficiency and on environmental exposure/fate for key environmental compartments (water, sediment, soil) was compiled in order to assess the potential impact of copper to the environment. Since existing concepts and methodologies as laid down in the Technical Guidance Document have been mainly developed for organic compounds and are as such less suitable to assess the true potential impact of metals on the ecological quality of ecosystems, an innovative approach have been developed to derive an ecologically relevant environmental effects threshold concentrations (PNEC) for copper to the terrestrial ecosystem. The proposed methodology encompasses the development of an extensive quality screened database containing chronic toxicity data for different terrestrial taxonomic groups and takes the effect of metal speciation on copper toxicity fully into account by the use of newly developed chronic regression models for 3 different trophic levels (microbial processes, invertebrates and higher plants). As such the terrestrial copper effects database can be easily normalised towards the geochemical conditions prevailing in the EU soils under scrutiny. The statistical best fitting approaches that were used for the derivation of the soil PNECs from the species sensitivity distributions and the in-depth sensitivity comparison with field toxicity data will be further discussed. Finally, the conservatism and remaining uncertainty considered for the final PNEC setting derivation will be highlighted and a way forward in order to reduce the uncertainties associated with metal risk assessments in general will be proposed.
WP159 (CIA-1117-832450) Successful development of site-specific ecological risk-based clean-up goals for metals-contaminated sites at Aberdeen Proving Ground.
Start time: 8:00 AM
Ciarlo, M1, Powell, M1, Neubauer, R1, Paul, J2, 1 EA Engineering, Science, and Technology, Sparks, MD, USA2 US Army Aberdeen Proving Ground, APG, MD, USA
Ecological risk assessments (ERA) were performed for a number of hazardous waste sites at Aberdeen Proving Ground, Maryland where metals were identified as the primary chemicals of concern. Sources of these metals include batteries, scrap metal, and photographic wastes. The ERAs for these sites used site-specific bioavailability data from Sequential Extraction Procedure (SEP) analyses to refine exposure estimates and to identify chemicals responsible for observed toxicity in bioassays. In wildlife exposure models, SEP-based estimates of bioavailable metals concentrations were used as exposure point concentrations. To compliment these estimates, site-specific bioaccumulation data was also derived from field collection of fish tissue and from earthworm and rye grass bioaccumulation bioassays. Together, the bioavailability and bioaccumulation data provided more realistic, site-specific estimates of wildlife exposures. For lower trophic level receptors, the results of earthworm, rye grass, minnow, and amphipod bioassays were examined for statistically significant correlations with bioavailable concentrations of metals; this information was used to refine the list of chemicals potentially responsible for observed toxicity. As part of risk management, the site-specific data from the assessment was used to develop bioaccumulation and bioavailability factors and regressions. These were used with food web models and literature-based benchmarks to set effects-threshold exposure point concentrations for use in risk management.
WP160 (JOH-1117-833143) Critical body residues in earthworms (Eisenia foetida): effects of soil concentration, aging and soil type.
Start time: 8:00 AM
Burcea, L.1, Friedel, C.1, Bhaitarai, D.1, Brunkow, P.2, Johnson, K.1, 3, 1 Environmental Sciences Program, Southern Illinois University Edwardsville, Edwardsville, IL, USA2 Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL, USA3 Department of Chemistry, Southern Illinois University Edwardsville, Edwardsville, IL, USA
Current environmental site assessments evaluate total soil concentrations and fail to account for the contaminant′s actual bioavailability at the site. Confounding the issue in these site assessments is that the contaminan′s chemical properties and bioavailability change with time. Site assessments need to be based on bioavailable contaminant levels in soil rather than total soil concentrations. Unfortunately, conventional methods used to assess toxicity of contaminants are based on an organism′s exposure to total chemical concentrations. This laboratory measure of toxicity has often times been criticized in the field due to many variable external factors. An approach that integrates the variability in a contaminant′s bioavailability in the field is needed. One such approach is based on critical body residues (CBR) which are a measure of toxicity based on tissue residues in an organism at contaminated sites. In theory, the toxic dose of the contaminant at the receptor should be a constant for a particular species regardless of external factors such as aging and bioavailability. Our study was conducted with soils fortified with dieldrin that were aged for 0, 90, and 1040 days. Standardized 14 day earthworm (Eisenia foetida) toxicity test were conducted in soils ranging in concentration from 0- to 500 ug/g to evaluate two measures of toxicity, LD50s and CBRs. The LD50s changed with aging and were 80.3-, 99.8-, and 125.0 ug/g, respectively, for each time point. An ANOVA was performed on the tissue concentrations from all of the deceased earthworms from each soil concentration and time point. There were no statistical differences in CBRs between concentration and time points. However, regression analysis indicated a statistically positive relationship between CBR and soil concentration. While traditional toxicity testing indicated decreasing toxicity, CBRs remained constant. As such CBRs may be a more promising tool to assess contaminant toxicity and risk in field situations.
WP161 (HOU-1117-839819) Bioaccumulation of Dioxins in Earthworms.
Start time: 8:00 AM
Houkal, Dana1, Hummell, Roy 1, 1 Malcolm Pirnie, Seattle, WA, USA
Mammals and birds are primarily exposed to soil-borne dioxins and furans through the ingestion of soil-dwelling invertebrates. U.S. EPA uses this exposure pathway to develop their ecological soil screening levels. We report the results of a field investigation to develop site-specific earthworm bioaccumulation factors for dioxin congeners. The acid insoluble residue method was used to improve the estimation of dioxin body burdens in earthworms. Our results are compared to other published earthworm bioaccumulation data for dioxins and likely sources of variability among these factors are described.
WP162 (STE-1117-841554) The Use of Control Performance Data for QA/QC of Chronic Plant and Invertebrate Toxicity Tests.
Start time: 8:00 AM
Olaveson, K1, Stephenson, G1, Feisthauer, N1, Crumb, J1, 1 Stantec Consulting Ltd., Guelph, Ontario, Canada
Current toxicity test methods in terrestrial ecotoxicology recommend the use of reference toxicant tests to determine if changes are occurring in laboratory culture test organism sensitivity to a standard reference chemical. A change in sensitivity might affect their acceptability for use in toxicity testing. Reference toxicity tests involve significant time to set up, monitor, process, and analyze the data. They are either conducted on a regular basis or are conducted concurrently with a toxicity test. These tests require significant space (e.g., growth chambers) and materials in order to be conducted. This testing is in addition to regular toxicity testing that occurs in a laboratory. We have investigated the use of control performance data as an alternative QA/QC check for laboratory toxicity testing. The results from the experimental control treatment from tests conducted in our laboratory were combined into a warning chart for comparison of control performance over time. The benefit of using the control performance data is that the time, space and materials spent producing QA/QC data is reduced. Similar to reference toxicity testing, the use of control performance data allows for comparisons of test results over time. It is important to ensure that all data being used in the comparison of control performance data were generated under the same conditions (e.g., same soil, test duration, test conditions, and endpoints) because differences in any of these test characteristics could influence the response of the test organisms in the control treatment. Control performance charts for toxicity tests conducted in artificial soil, which is a fine sandy loam soil formulated from constituents, were produced for: Eisenia andrei (adult survival, number of progeny produced, and mean individual progeny dry mass), Onychiurus folsomi (adult survival, and number of progeny produced), and four plant species, including barley, alsike clover, perennial ryegrass, and red fescue (shoot length, root length, shoot dry mass, and root dry mass). The performance control charts indicate the variability associated with tests repeated over time and are a useful QA/QC tool.
WP163 (GUR-1117-818368) Analysis of physiological and molecular biomarkers in a multi-process phytoremediation system.
Start time: 8:00 AM
Gurska, J1, Huang, X-D1, Lampi, M1, Greenberg, B1, 1 University of Waterloo, Waterloo, Ontario, Canada
Phytoremediation is the use of plants to remediate contaminated soils, sediments and/or ground water. It is pertinent at sites where contaminants can come in contact with the roots of plants and be degraded, immobilized or sequestered. A significant aid to phytoremediation process are bacteria which reside within the area surrounding the root (rhizosphere. Multiple techniques affect contaminant removal, and of particular interest to us, is the removal of persistent petroleum hydrocarbons from the soil. A recently developed multi-process system includes the use of naturally occurring plant growth promoting bacteria (PGPR). This system has proven to be more effective than traditional, single-component remediation tactics. It would be beneficial to understand the dynamics of interaction between PGPR, plants and contaminants throughout this process. Though in the recent years a greater understanding has been achieved regarding uptake and metabolism of organic compounds, the actual mechanisms of degradation of petroleum hydrocarbons by the plants are still under speculations. Currently plants under investigation include fall rye (Lolium multiflorum) and tall fescue ( Festuca arundinacea). The overall health of the plants and changes in the photosynthetic capacity were monitored using Pulse Amplitude Modulated (PAM) fluorometry. It was found that plants under hydrocarbon stress conditions exhibit changes in photosynthetic parameters such as photochemical and non-photochemical quenching. PGPR were found to alleviate some of these effects. Additionally the ability to inhabit a contaminated environment results in molecular changes; PGPR could contribute to these changes as well. Genetic expression under stress conditions with and without PGPR are being evaluated using differential display PCR (ddPCR). By identifying genes whose expression is modulated by hydrocarbon exposure with or without PGPR, the mechanisms underlying detoxification with the use of plants might be further elucidated.
WP164 (AEL-1117-818936) Use of Microtox® to predict heavy metal concentrations in urban residential soils.
Start time: 8:00 AM
Aelion, C1, Davis, H1, 1 University of South Carolina, Columbia, South Carolina, USA
Clusters of developmental delay and mental retardation (DD/MR) were identified in children born in Greenville County, South Carolina. Although it is difficult to identify one factor that causes the observed DD/MR outcome, exposure of pregnant women to environmental contaminants such as heavy metals can induce DD/MR in infants through a variety of pathways. Because it is impractical and expensive to measure the concentrations of individual metals in large numbers of environmental samples, the general toxicity test, Microtox® Toxicity System, was used to identify highly toxic soils. Approximately 200 soil samples were collected from residential areas in Greenville County and analyzed to determine an effective concentration (EC50) of soil required to kill 50% of the luminescent bacteria test organisms (Vibrio fischeri). Lower EC50 values denote greater toxicity. A subset of 56 high and low toxicity soil samples was then analyzed by inductively coupled plasma emission spectrophotometry for arsenic, lead, and chromium (EPA method 6010) which are known toxins. Significant negative correlations were found between the Microtox® EC50 values and soil metal concentrations (-0.6022, p<0.0001 for arsenic; -0.6201, p<0.0001 for chromium; -0.3006, p=0.0244 for lead). The Microtox® test was effective in identifying soils with elevated concentrations of arsenic, chromium, and lead, even in residential neighborhoods where limited soil toxicity was expected. This screening tool appears to be a good surrogate for environmental exposure and a first step for quantifying environmental exposure and determining its possible association with DD/MR in these children.
WP165 (KIL-1117-825971) Risk assessment of a CCA-contaminated site in Southern Finland.
Start time: 8:00 AM
Kilpi-Koski, J.1, Karjalainen, A-M.1, Penttinen, O-P.1, 1 University of Helsinki, Lahti, Finland
Contaminated sites pose great hazards for ecosystems and inhabitants. In Finland about 20 000 contaminated sites have been identified. The wood preserving industry is regarded as one of the most severe polluters e.g. with the use of the inorganic impregnation chemical CCA (chromated copper arsenate). In this study an old impregnation area in Hartola, Southern Finland, was investigated. Timber was treated there with CCA during the summers of 1958-1966 and even preliminary research with the field-portable X-ray fluorescence meter revealed severe metal contamination in the upper layer of soil. Later laboratory analyses on AAS confirmed additional metal contamination of groundwater and drinking water wells. To conduct a risk assessment of this polluted area both bioaccumulation and toxic effects of CCA were studied. Earthworm (Dendrobaena octaedra) reproduction and mortality tests and lettuce (Lactuca sativa) seed germination test were used to evaluate the biological effects of polluted soil. Duckweed (Lemna minor) and a water flea (Daphnia magna) were exposed to the contaminated well water. Since arsenic accumulating wood horsetail (Equisetum sylvaticum) grows abundantly at the study site, metal concentrations from roots and stems were determined using AAS. In addition, effective concentration (EC50) of As, Cu and Cr for earthworms will be determined with spiked soil samples in the laboratory using the critical body residue approach. An ecological risk assessment (ERA) based on the result of the above testing procedures will be carried out according to a draft of Finnish ERA guideline.
WP166 (PHI-1117-720665) Toxicity of Selenium to the Soil Invertebrate Folsomia candida in Sassafras Sandy Loam Soil.
Start time: 8:00 AM
Phillips, C.1, Checkai, R.1, Simini, M.1, Kuperman, R.1, Higashi, R.2, Fan, T.3, Sappington, K.4, 1 U.S. Army, APG, MD, USA2 University of California, Davis, CA, USA3 University of Louisville, Louisville, KY, USA4 U.S. Environmental Protection Agency, Washington, DC, USA
The U.S. Environmental Protection Agency (USEPA) is developing Ecological Soil Screening Levels (Eco-SSLs) for chemicals that are often found in soil at Superfund hazardous waste sites. Currently, information gaps in the toxicity database prevent development of Eco-SSLs for selenium. We investigated the effects of selenium to a soil invertebrate using an adaptation of the International Standardization Organization (ISO) test for the collembolan Folsomia candida. The ISO test was modified for use with a natural soil, Sassafras Sandy Loam (SSL) [Fine-loamy, siliceous, mesic Typic Hapludult] at pH 7.1, with sand:silt:clay ratio 70:13:17, and 1% organic matter. Selenium was added as sodium selenate, and weathered/aged in soil via alternating moist/dry cycles for 21 days. At the initiation and conclusion of each test, soil from each treatment level was collected, lyophilized, and stored at -40oC. Soils were analyzed for selenium by liquid chromatography/inductively-coupled Argon plasma mass spectrometry (LC/MS), following nitric:perchloric digestion. Nonlinear regression models were used to correlate ecotoxicity data with selenium concentrations, retained primarily as SeO4 in this soil. Preliminary results showed that the EC20 and EC50 values for juvenile production were 4.7 and 10.9 mg kg-1, respectively. Results of this study will undergo quality assurance by the Eco-SSL Task Group before inclusion in the Eco-SSL database, and will be delivered as input toward developing an Eco-SSL for selenium and soil invertebrates.
WP167 (AAA-1117-743876) Investigations into the less-than-additive toxicity of binary combinations of petroleum hydrocarbon distillates to the earthworm Eisenia andrei.
Start time: 8:00 AM
(McCann) Cermak, J.1, Stephenson, G.1, 2, Roy, J.3, Birkholz, D.4, Dixon, D.1, 1 University of Waterloo, Waterloo, Ontario, Canada2 Stantec Consulting, Guelph, Ontario, Canada3 Imperial Oil Ltd., Calgary, Alberta, Canada4 EnviroTest Laboratories, Edmonton, Alberta, Canada
Canadian standards for petroleum hydrocarbons in soil have been developed for different boiling point distillates of crude oil. These standards are based on the toxicity, as total petroleum hydrocarbon concentration in the soil within the boiling point ranges, to soil-dwelling organisms (invertebrates, plants) and do not take into consideration the effect the presence of petroleum hydrocarbons in multiple boiling point ranges might have on toxicity. The interaction effect of petroleum hydrocarbons on toxicity was investigated using binary combinations of petroleum distillates and the earthworm Eisenia andrei. Earthworms were exposed to various combinations of the distillates over 28-days. The results indicate that the distillate toxicity is less-than-concentration-additive when a second distillate is present concurrently. To investigate the less-than-additive toxicity further, uptake studies were conducted with individual and binary combinations of distillates and E. andrei. Earthworms were exposed to non-lethal concentrations of the distillates and sampled over a 16- or 64-day duration. Tissue samples were collected, extracted, subjected to gel permeation chromatography and separated on an alumina column to obtain both an aliphatic and aromatic fraction. These fractions were analyzed by gas chromatography-FID to obtain the total concentration of aliphatics and aromatics. The results of the uptake studies will be discussed in relation to the toxicity test results.
WP168 (FEI-1117-755200) Use of Sphagnum peat to optimize contaminated soil characteristics for chronic earthworm ecotoxicity assessments.
Start time: 8:00 AM
Feisthauer, N.1, Stephenson, G.1, Crumb, J.1, Olaveson, K.1, 1 Stantec Consulting Ltd., Guelph, Ontario, Canada
Site-specific ecotoxicity testing of contaminated soils provides useful information for the assessment of risk to terrestrial organisms. The most commonly tested earthworm species are Eisenia andrei and E. fetida. Both are compost worms, and their natural habitat is moist, highly organic fine-textured soils. However, the physicochemical characteristics of site soils often constitute a suboptimal habitat for survival, growth and reproduction of earthworms. Soil contaminated with petroleum hydrocarbons as a result of oil drilling activities are often very clayey subsurface soils with little organic matter. Earthworm reproduction is usually very poor in these contaminated soils and in uncontaminated reference soils that have similar physicochemical characteristics to the site soils, but are free of contamination. Since the soil physicochemical characteristics have a strong influence on earthworm reproduction, the effect on reproduction attributable to soil petroleum hydrocarbon contamination often cannot be determined. As a result, 63-day E. andrei reproduction tests were conducted with uncontaminated reference and petroleum hydrocarbon-contaminated site soils amended with a soil conditioner that would decrease soil bulk density and provide more organic matter but would not otherwise change the physicochemical characteristics of test soils. The soil conditioner was buffered (CaCO3) sphagnum peat. It is well tolerated by earthworms and is relatively inert since earthworms do not use it as a food source. Reference and site soils were amended with 0, 1.25, 2.5, 5 and 10% peat. Total and bioavailable concentrations of petroleum hydrocarbons were determined in amended and non-amended soils. Significant increases in earthworm reproduction occurred in the reference and contaminated soils at the 2.5% peat treatment, relative to reproduction in the 0% treatments. Preliminary test results suggest that amending site soils that are suboptimal for earthworm reproduction with buffered peat is an effective method to discriminate effects on earthworm reproduction that are attributable to soil physicochemical characteristics versus contaminants in soil.
WP169 (PAR-1117-808618) Elucidating the Bioavailability and Ecotoxicity of Soil Hydrocarbons in Laboratory Earthworm Toxicity Tests.
Start time: 8:00 AM
Parkerton, T1, Letinski, D1, Febbo, E1, Manning, R1, Jager, T2, 1 ExxonMobil Biomedical Sciences, Annandale, NJ, USA2 Department of Theoretical Biology, Vrije University Amsterdam, Amsterdam, Netherlands
To provide an improved understanding of the bioavailability and ecotoxicity of hydrocarbons spiked to natural soil, a series of acute toxicity and bioaccumulation experiments were performed with selected aliphatic and aromatic hydrocarbons (decalin, pentamethylheptane, phenanthrene and n-hexadecane) using the manure worm, Eisenia fetida. During toxicity tests, disposable polydimethylsiloxane (PDMS) fibers were added to test chambers to simulate partitioning of soil hydrocarbons to worm lipid. Observed toxicity results were compared to measured concentrations of test substances in soil, PDMS fibers and earthworms. Observed LC50s for the different hydrocarbons differed by more than two orders of magnitude when expressed in terms of soil concentration. Normalization of toxicity data to internal concentrations in the worms reduced differences between test compounds. The ability of PDMS fibers to mimic accumulation of test substances in worms differed between hydrocarbons. To gain insights into the differences observed in PDMS fiber and worm concentrations, a kinetic mass balance model was developed and applied to the soil test system. Model results are discussed and used to provide recommendations regarding use of PDMS fibers as a biomimetic extraction device in soil toxicity tests.
WP170 (CIA-1117-832060) Ecological risk assessment using bioaccumulation and bioavailability data at two small arms firing ranges.
Start time: 8:00 AM
Ciarlo, M1, Hinckley, D1, Neubauer, R1, Paul, J2, 1 EA Engineering, Science, and Technology, Sparks, Maryland, USA2 U.S. Army Aberdeen Proving Ground, APG, Maryland, USA
An ecological risk assessment (ERA) was performed at two small arms firing ranges at Aberdeen Proving Ground, Maryland. The initial assessment was based on standard food web models and benchmarks. Advanced stages of the assessment used site-specific toxicity data from rye grass, earthworm, minnow, amphipod, and frog bioassays to evaluate risks to lower trophic level receptors. To aid in evaluating risks to higher trophic level receptors, food-item bioaccumulation data was collected for worms and plants through bioassays, and for frogs through field collection of tissue. Bioavailability of metals in soil and sediment was evaluated using Sequential Extraction Procedures. Bioaccumulation and bioavailability data were used to refine wildlife exposure estimates and identify chemicals potentially associated with toxicity observed in the bioassays. This site-specific data proved important since bioavailability varied with soil parameters, and since uptake factors at the site differed considerably from literature-based factors. The risk characterization identified the receptors at risk and identified antimony, copper, lead, and zinc as chemicals of concern. Data from the assessment was then used to develop effects-threshold exposure point concentrations for use in risk management.
WP171 (POS-1116-600159) Integrated Risk Assessment (IRA) helps to decide on land deposition of slightly contaminated sediments.
Start time: 8:00 AM
Posthuma, L1, de Zwart, D1, Harmsen, J2, Cuypers, C3, van Noort, P3, 1 RIVM, Lab for Ecological Risk Assessment, Bilthoven, Netherlands2 Alterra, Wageningen, Netherlands3 RIZA, Lelystad, Netherlands
Slightly contaminated sediments are a large problem in rural areas of the Netherlands. Up till the 1980s, this material was spread on adjacent land as fertilizer. Increasing focus on contaminations suggested the presence of risks associated to this approach. This triggered the development of risk management policies. So-called sediment classes (0 = clean, 4=highly contaminated) were defined on the basis of sediment risk assessments. Currently, this generic classification system is considered an insufficient method to address the problem. The Dutch government has decided that risk management should be focused more on site characteristics and local land use, rather than on a generic view on sediment quality alone. This triggered works of the three Dutch governmental research institutes RIVM, RIZA and Alterra on the Integrated Risk Assessment of sediment deposition on land. The research is based on a systems approach. That is: exposure modeling yields the change of concentrations that is to be expected from local sediment deposition. Exposure scenarios further yield the expected real exposure of humans, of agricultural products, and of organisms in the soil ecosystem. By combination of these predicted real exposures with the sensitivities of the different receptors, the approach yields a set of possible risk levels, including the risks induced by whole mixtures. Eventually, by looking at stand-still and/or those sets of risk levels, deposition policies can be formulated by assigning one out of three labels to a sediment. That is: a sediment can be (1) Always deposited on land, irrespective of land use and local soil characteristics, (2) Never deposited on land, since this would always induce unacceptable risks, or (3) Sometimes deposited on land, e.g. when the local soil is already slightly contaminated or when there is no unacceptable increase of risk. This contribution presents IRA results and policy options obtained by this approach.
WP172 (KUP-1117-641264) Toxicity benchmarks for positive chemical control in soil invertebrate toxicity testing using light-textured natural soils.
Start time: 8:00 AM
Kuperman, R.1, Simini, M.1, Phillips, C.1, Checkai, R.1, 1 U.S. Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD, USA
A positive chemical control is required in toxicity testing with soil invertebrates to validate the condition of the test species, and reliability and precision of results. Agricultural pesticides are recommended by International Standardization Organization (ISO) as positive chemical controls in definitive toxicity tests with soil invertebrates in standard artificial soils. These reference toxicants include Carbendazim for earthworms (ISO/11268-2) and enchytraeids (ISO/16387), and Phenmedipham or Parathion for collembola (ISO/11267). Reference toxicity benchmarks for these, established by international ring tests conducted with OECD artificial soil, cannot be used for validating test results in natural soils or with alternative test species, due to contrasting chemical toxicities in natural soils, and differences in species-specific sensitivities. Limited worldwide availability and potential variability in product formulations, including concentrations of active and inert ingredients, further complicate use of pesticides as positive controls. We investigated the toxicity of an inorganic agricultural nutrient as an alternative reference toxicant, boric acid (H3B03), to the soil invertebrates Eisenia fetida, Enchytraeus crypticus, and Folsomia candida. The respective ISO protocols were modified for toxicity testing in Sassafras sandy loam soil, having physico-chemical properties (including relatively low pH 5.2 and organic matter 1.2%, and high sand content 71%) that support relatively high bioavailability of many organic and inorganic chemicals. Interim benchmarks for boric acid determined by nonlinear regression analyses of toxicity data for E. fetida, E. crypticus, and F. candida, yielded LC50 (adult survival) values of 880, 203, and 69 mg/kg, respectively; EC50 values 181 and 99 mg/kg for cocoon production and juvenile production by E. fetida; and EC50 values 56 and 72 mg/kg for juvenile production for E. crypticus and F. candida, respectively. These toxicity benchmarks require confirmation by additional testing to assess their variability and robustness before recommending their use in toxicity testing with other light-textured natural soils.
WP173 (KEL-1117-822563) Effect of species differences and interactions on the bioaccumulation of weathered p,p'-DDE from soil.
Start time: 8:00 AM
Kelsey, J1, White, J2, 1 Muhlenberg College, Allentown, PA, USA2 The Connecticut Agricultural Experiment Station, New Haven, CT, USA
The impact of species differences and interactions among the earthworms Eisenia foetida and Lumbricus terrestris and the plants Cucurbita pepo and Cucurbita maxima on the uptake of weathered p,p'-DDE from soil was determined. In four field-weathered soils, the BAF for Eisenia foetida, an epigeic species (surface habitat), was approximately 10-fold higher than those for Lumbricus terrestris, an anecic species (deep habitat) and Aporrectodea caliginosa, an endogeic species (habitat within the soil profile). Root concentrations of the compound in the two plants were the same, but translocation to stems and leaves was approximately an order of magnitude higher in C. pepo than C. maxima. Although some combinations of earthworm and plant species caused significant changes in the p,p'-DDE burden in both organisms, the effects were species specific. Contaminant bioconcentration in C. pepo was increased slightly by E. foetida and by 3 fold when the plant was grown with L. terrestris. Eisenia foetida had no effect on the contaminant BCF by C. maxima, but L. terrestris caused a 2-fold reduction in p,p'-DDE uptake by the plant. Contaminant levels in E. foetida and L. terrestris were unaffected by C. pepo. When grown with C. maxima, the concentration of p,p'-DDE decreased by approximately 4 fold and 7 fold in E. foetida and L. terrestris, respectively. These data suggest total chemical concentration alone is not a reliable indicator of the toxicological significance of a contaminated soil, and that species-specific differences and interactions significantly impact overall exposure and risk.
WP174 (CHE-1117-827531) Arsenic transport and speciation in soils used in Golf Course - Column Experiments.
Start time: 8:00 AM
Chen, Zhangrong1, Cai, Yong 1, Snyder, George2, Cisar, John3, 1 Department of Chemistry and Biochemistry and Southeast Environmental Research Center, Florida International University, Miami, FL 33199, USA2 Everglades Research and Education Center, University of Florida, Belle Glade, FL 33430, USA3 Fort Lauderdale Research and Education Center, University of Florida, Ft. Lauderdale, FL 33314
The fate of arsenic contaminant in soil depends on many factors, including adsorption, transformation, and transport. Knowledge of these phenomena is important for risk assessment and remediation feasibility studies. The purpose of this study was to investigate arsenic transport and transformation in porous soil media with a specific focus on the impact of soil-derived heterogeneous colloids. Column techniques can be considered as useful tools both to perform transport experiments and to obtain equilibrium adsorption data without much perturbation of the actual solid/liquid interface. In this study, column experiments were conducted in the laboratory to simulate arsenic transport through golf course soils in the presence and absence of soil-derived colloids under saturated conditions with continuously monitoring pH and Eh changes for the column systems. The transport and transformation of arsenic species is influenced by a combination of microbial and physicochemical properties and processes. Arsenic species transformation occurred under the column conditions and had a significant impact on arsenic transport for both arsenic species tested (arsenate, As(V), and monomethylarsinic acid, MMA). On the other hand, the association of arsenic species to soil-derived chemicals also influenced arsenic transport and bioavailability, further affected microbial involved arsenic species transformation. Arsenic breakthrough curves were not correlated with Fe and Al breakthrough curves using soil (with 10% volume of Canadian sphagnum peat moss)-derived colloid solution as influent, indicating that arsenic mainly associated with other soil-derived particles/chemicals and not with Fe and Al-containing colloids in the presence of peat derivatives in the influent solution.
WP175 (PAT-1118-078417) Uptake of Antimony, Copper, and Lead into Plants at Small Arms Firing Ranges in Central California.
Start time: 8:00 AM
Pattanayek, M1, DeShields, B1, Dimundo, G1, Navarro, N2, 1 Blasland Bouck and Lee (BBL) Inc., Petaluma, CA, USA2 U.S. Army Corps of Engineers (USACE), CA, USA
Studies have been conducted at small arms firing ranges at Fort Ord, California to evaluate the uptake of antimony, copper, and lead into plants from soil and to provide data for conducting ecological risk assessments. Plant samples have been collected over the past decade from locations representing no, low, moderate, and high bullet cover range areas; from bermed, no-berm, and multi-use ranges; and from different soil type areas. Several plant species have been collected, including iceplant, California croton, buckwheat, coyote brush, coffeeberry, ceanothus, chamise, and three species of manzanita. Vegetative, reproductive, and/or whole plant tissue samples were analyzed for antimony, copper, and lead. Co-located soil samples were also collected and regression analyses were conducted to evaluate whether plant species, bullet cover, range-type, soil type affected the uptake of metals in plants. The highest concentrations of metals were found in plant samples collected from high bullet cover zones, with a significant decrease in tissue concentrations in areas of lesser bullet cover. Antimony and lead uptake trends were similar and correlations were considered good across the various species. Copper uptake trends were not similar for the various species. Uptake of metals were generally higher in multi-use ranges, but were similar across different soil types. Site-specific biota uptake factors (BAFs) or regressions were developed which were used in estimating exposures and risks to plants and wildlife. Additionally, standard in vitro bioavailability tests for lead were conducted on plant tissues. The in vitro tests showed that bioaccessibility is similar across most tissue concentrations of lead, with a slight increase in bioavailability with increasing tissue lead concentration.
WP176 (LEE-1122-019318) Assessment of radon potential of soil-gas and groundwater in the Okchon zone, Korea.
Start time: 8:00 AM
Je, Hyun-Kuk1, Lee, Jin-Soo2, Chon, Hyo-Taek2, 1 Samdoo Co., Ltd., Gyunggi-do 462-120, Korea, South Korea2 School of Civil, Urban and Geosystem Engineering, Seoul National University, Seoul 151-744, Korea, South Korea
Making the geogenic radon potential map in Korea is a research project supported by the Korean Ministry of Commerce, Industry and Energy. The objectives of this study were to develop a radon risk grade and to apply risk assessment for dose exposure by radon radioactivity. The study area is located in the central part of Korea, called the Okchon zone (about 5,100 km2), which occur in a 80km wide, northeast-trending belt that extends across the Korean Peninsula. The Okchon zone is underlain by metasedimentary rocks of unknown age that are composed mainly of black slate, phyllite, mica schist, shale, and limestone. Soil-gas samples of 280 points were typically collected by augering a hole and placing steel probe 50 to 70 cm below the soil surface of each site with a systematic sampling density of 2.5x2.5 km2. Soil-gas sample of 160 ml was extracted into the RDA200 (alpha-scintillation type), and radon concentration was calculated by use of the Morse (1976) 3-minute method. Ground waters were taken at 102 private houses and vaporized by degassing pump. Radon concentration of water samples was analyzed by RAD7 (alpha-scintillation type) with 20-minute. Regional radon surveys indicate a wide range of radon activities for soils (126-2,542 pCi/L) and ground waters (82-2,950 pCi/L). About 10 percent of soil-gas samples exceeded 1,000 pCi/L and 90 percent of ground water samples exceeded the MCL (maximum contaminant level) of drinking water, 300 pCi/L, which proposed by U.S. Environmental Protection Agency in 1999. Radon concentration of soil-gas and ground water was classified as bedrock geology, based on 1/50000 digitized geological map and field research. For soil-gas measurements, mean value of radon concentration was decreased in the order of Black shale-slate (621 pCi/L) > Granite (583 pCi/L) > Gneiss (493 pCi/L) > Phyllite (493 pCi/L) > Limestone (480 pCi/L) > Schist (476 pCi/L). And for groundwater measurements, mean value of radon concentration was decreased in the order of Black shale-slate (1,067 pCi/L) > Granite (989 pCi/L) > Schist (661 pCi/L) > Phyllite (611 pCi/L) > Limestone (386 pCi/L).