R7 AM Soil Ecotoxicology and Risk Assessment|
Thursday, 17 November 2005: 8:00 AM - 11:40 AM in 327-329
655 (VAN-1117-664052) Terrestrial toxicity testing of metal contaminated soils from Sudbury, Ontario.
Start time: 8:00 AM
Van der Vliet, L1, Princz, J1, Gilbertson, M2, Scroggins, R1, 1 Environment Canada, Ottawa, Ontario, Canada2 C. Wren & Associates, Guelph, Ontario, Canada
An ecological risk assessment in Sudbury will examine and evaluate the possible risks associated with airborne metal particulate emissions resulting from past smelting operations. Terrestrial toxicity testing was undertaken to support decision-making in the ecological risk assessment in Sudbury. Soil was collected from two pre-selected sites within the Sudbury area. The site soil was collected from a reference site with a low background concentration of metals and from a site with a high concentration of metals; both soils were acidic. The survival, growth, and reproduction of the test species (Folsomia candida and Eisenia andrei, red clover, northern wheatgrass) were assessed in these soils, both with and without partial pH neutralization. The pH adjustment of the soils would aid in the determination of the influence of low soil pH on the toxicity of the soils. Folsomia candida were not sensitive to soil acidity or to metal contamination levels. Eisenia andrei were highly sensitive to soil pH, and the results demonstrated that even in the absence of metal contamination, earthworm reproduction was very low in the pH unadjusted reference soil. When soil pH was adjusted to reduce the effects of acidity, earthworm reproduction in the contaminated soil was significantly lower than the reference soil, showing sensitivity to elevated metal levels. Red clover and northern wheatgrass were sensitive to low pH and metal contamination levels, and root growth (root length, root dry weight) proved to be the most sensitive endpoint. Unlike earthworms, both plant species were able to emerge and grow in the low pH reference soil. However, both plants showed increased growth in soils that had been pH adjusted. Growth in reference soil was greater than in soil with elevated metals when comparing plants in the same pH treatment, demonstrating that both species of plants were sensitive to metal contamination. To focus future testing of other metal-contaminated sites, we recommend the continued use of a battery of test organisms to capture varying sensitivity as demonstrated by the test organisms.
656 (ROE-1117-660815) Soil properties affect the toxicity of tributyltin-oxide (TBT-O) to earthworms, springtails, and plants.
Start time: 8:20 AM
Roembke, J.1, Jaensch, S.1, Junker, T.1, Pohl, B.1, Scheffczyk, A.1, Schallnass, H-J.1, 1 ECT Oekotoxikologie GmbH, Floersheim, Germany
Environmental risk assessment of chemicals in the soil relies mainly on tests with OECD artificial soil. Chemical bioavailability in artificial soil can contrast with bioavailability in natural soils and produce ecotoxicological results that are not representative of species exposure conditions in the field. We initially evaluated reproduction and growth of earthworms and collembolans, and early seedling growth of a dicotyledonous plant species in nine natural soils, having a wide range of physico-chemical properties, and in OECD soil. Soils that supported reproduction and growth of the test species were than used to investigate the toxicity of the biocide tributyltin-oxide. Interim results showed that natural soils sustained greater toxicity of TBT-O to earthworms (EC50 values varied from 0.5 to 4.7 mg/kg soil dry weight (DW)) compared with toxicity in OECD soil (EC50 = 13.4 mg/kg DW). Collembolans were less sensitive to TBT-O than earthworms in natural soils with EC50 values ranging from 23.4 to 177.4 mg/kg DW. In contrast with earthworms, the toxicity of TBT-O to collembolans in OECD soil (EC50 of 104.0 mg/kg DW) was within the range of EC50 values established for natural soils. Phytotoxicity tests revealed even greater difference between the exposure effects in natural soils (EC50 ranged from 5.4 to 189.2 mg/kg DW) and in OECD soil (EC50 of 535.5 mg/kg DW) when compared with results of the earthworm tests. Our data also show that EC50 values were more robust endpoint compared to EC10 values based on comparisons of coefficients of variation. These preliminary results show that toxicity testing should include studies with natural soils in addition to OECD soil to better reflect the exposure in the field. Alternatively, the inclusion of a safety factor may be recommended for risk assessment to adjust the EC50 values established in artificial soil thus insuring a better protection of soil organisms.
657 (DUS-1117-716268) Impact of Thermal Shock on the Enzyme Activity of a Copper-Contaminated Soil.
Start time: 8:40 AM
Dussault, M1, Becaert, V.1, Sauve, S2, Deschenes, L1, 1 NSERC Industrial Chair in Site Remediation and Management, Chemical Engineering Department, École Polytechnique de Montréal, Montreal, Quebec, Canada2 Environmental Chemistry Laboratory, Chemical Department, Université de Montréal, montreal, quebec, canada
The aim of this study is to establish the relationship between soil physicochemical parameters and copper speciation and ecotoxicity to the microbial flora by monitoring the soil functional recovery capacity following a thermal stress. The recovery of protease and -glucosidase activity following a simulated heat wave perturbation (17 hrs, 60°C) was monitored over a 4-day period. Concurrently, Cu2+ activity, total dissolved Cu content, soluble anions and DOC were analyzed before thermal stress and after the recovery period. The study was conducted on a natural soil with adjusted organic matter content (% O.M. : 2, 5, 8) and pH (5, 6 and 7). In order to obtain different copper concentrations (0, 250 and 750 mg/kg), 3 wet/dry cycles followed by a lixiviation were performed. An increase in DOC from 42% to 100% was observed in the soil samples having undergone a thermal stress. Moreover, results showed that protease activity in uncontaminated soil samples was stimulated by the thermal stress, reaching an average of twice that of the baseline level after 2 days. In contrast, the recovery of contaminated soil reached just over half the activity of its corresponding thermally unperturbed soil, for any O.M. content. For glucosidase activity, a better recovery rate was observed in 750 mg Cu/kg-contaminated soils than in 250 mg Cu/kg-contaminated soils. Finally, results indicate that a significant variation in basic enzyme activity occurred in all samples over a period as short as 4 days. This observation highlights the importance of assessing the temporal evolution of enzyme activity.
658 (AAA-1117-742954) The uptake of aliphatic and aromatic compounds from petroleum hydrocarbon-contaminated soil by the earthworm Eisenia andrei.
Start time: 9:00 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 variability in the proportion of aliphatics and aromatics within petroleum products, nor differences in the bioavailability and/or toxicity of these compounds. A study was conducted using the earthworm Eisenia andrei to investigate the uptake and elimination kinetics of aliphatics and aromatics from soil spiked with individual boiling point distillates of crude oil. Earthworms were exposed to non-lethal concentrations of the distillates and sampled over a 16- or 64-day duration. On day 8 or 16, some earthworms were transferred to clean soil and sampled over an eight-day period in order to determine the elimination kinetics. Both soil and 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. Samples were also selected for gas chromatography-mass spectroscopy analysis to determine major compounds within the sample. The results of these analyses will be discussed in relation to toxicity test results and their implications for risk assessment.
Start time: 9:20 AM
659 (SAM-1117-754133) Evaluation of Ecological Risks at the Old Skeet Range, Naval Weapons Station Seal Beach, California.
Start time: 10:00 AM
Sample, B1, Arenal, C1, 1 CH2M HILL, Sacramento, CA, USA
: Screening ecological risk assessments (ERAs) for the Old Skeet Range at Naval Weapons Station Seal Beach, California, identified potential risks from lead and antimony. Portions of the site lie within a National Wildlife Refuge and provide habitat for two federal T&E species (light-footed clapper rail and Beldings savannah sparrow). A baseline ERA was performed. Given screening results and up to 154000 mg/kg lead in soil, ecological risks were assumed. ERA focused on spatial delineation of risks and identification of potential cleanup levels. Assessment endpoints included plants, invertebrates, aquatic birds, terrestrial birds and mammals, and T&E species. Data collected included co-located soil or sediment and biota samples, bird and mammal liver tissue, and soil and sediment for bioaccessibility analyses. Site-specific plant and sediment invertebrate bioassays were also conducted. Concentrations of lead and antimony produced dietary estimates that exceeded toxicity thresholds for all bird and mammal receptors in some samples. Measured lead in livers of birds and mammals exceeded background but not effect thresholds. Estimated lead in livers of birds and mammals suggest risk at some sampling locations. Lead as shot exists in concentrations that present risks to birds. Toxicity attributable to lead and antimony was observed in the site-specific sediment bioassays. Results of plant bioassays were confounded by salt phytotoxicity. Lead and antimony exceeded literature-based plant and invertebrate toxicity values in some samples. Point-by-point risk results were used to develop two remediation footprints, one based on the most sensitive receptor (Beldings savannah sparrow) and the other based on the next most sensitive set of receptors. Based on several considerations (e.g., potential for significant habitat disruption and destruction), comparative analyses of the effects and benefits of different remedial alternatives were recommended. In particular, an evaluation weighing the relative benefits of remediation strategies versus damage to sensitive habitat is warranted.
660 (PEI-1117-793720) Metal toxicity in soils: towards a new generation of toxicity models.
Start time: 10:20 AM
Peijnenburg, Willie1, Koster, Marijke1, Vijver, Martina2, 1 RIVM - Laboratory for Ecological Risk Assessment, Bilthoven, Netherlands2 Institute of Environmental Sciences (CML), University of Leiden, Leiden, Netherlands
Biotic ligand models (BLMs) are increasingly used for assessing the risks of metals in the aquatic environment. It may be hypothesized that the basic principles underlying aquatic BLMs also apply to terrestrial organisms. However, possibly due to the complex interactions of metals with the various soil constituents and due to difficulties encountered in univariately modifying the soil, development of terrestrial BLMs is still in its early stages of development. Several approaches towards assessing the truly bioavailable metal fraction in soil, responsible for toxic effects will be presented in our contribution. These include commonly used toxicity assays with spiked field soils in which various metal pools are quantified, bioassays in artificial quartz sand, and toxicity studies along aged field gradients. In addition, mixture effects are quantified on the basis of bioavailable metal pools and insight in the factors modifying toxicity and the mechanisms of toxicity. To quantify and qualify the abovementioned aspects, the often used terrestrial earthworm Aporrectodea caliginosa is used. The models developed were validated in field soils, contaminated with metals during prolonged periods of time or containing enhanced natural background levels of metals. After discussion of the results, application in regulatory use of the approaches taken will be highlighted and future research directions indicated concerning the development of tools on accurate metal risk assessment.
661 (ALL-1117-734858) Development of Terrestrial Biotic Ligand Models for Copper and Nickel Toxicity in Soils: Application for Plant, Invertebrate, and Microbial Tests.
Start time: 10:40 AM
Thakali, S1, Allen, H1, Di Toro, D.1, Ponizovsky, A1, Rooney, C2, Zhao, F2, McGrath, S2, Criel, P3, Janssen, C3, Oorts, K4, Smolders, E.4, 1 Center for the Study of Metals in the Environment, University of Delaware, Newark, DE, USA2 Agriculture and Environment Division, Rothamsted Research, Harpenden, Hertfordshire, UK3 Ghent University, Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent, Belgium4 Laboratory for Soil and Water Management, K.U.Leuven, Faculty of Agricultural and Applied Biological Sciences, Leuven, Belgium
Terrestrial Biotic Ligand Models (TBLM) were developed based on data for Cu and Ni speciation and bioassays carried out on non-calcareous soils (11 for Cu and 10 for Ni) of the European Union. Metal activity was calculated using the WHAM VI model with total (added + background) Cu or Ni, soil organic matter, pH and soil solution concentrations of alkali and alkaline earth metals as inputs. The TBLM approach considers Cu2+ or Ni2+ in soil solution to be in equilibrium with metal in the soil. The metal ions react with the biotic ligand, the receptor site for the organism. Other ions, principally H+, Ca2+ and Mg2+, compete with the Cu2+ or Ni2+ to ameliorate their toxicity. The same extent of biological effect is exerted for a specific bioassay test endpoint and metal at the same fraction of biotic ligand sites occupied by the Cu or Ni, irrespective of the soil chemistry. A comparison of the TBLM approach to that of considering total metal or free metal ion activity indicates that the TBLM provides an appropriate means to normalize and compare toxicological results among soils.
662 (SEM-1117-548407) Integration of bioavailability, ecological and ecotoxicological lines-of-evidence into ecological risk indexes for contaminated soil assessment.
Start time: 11:00 AM
Semenzin, E1, 2, Critto, A1, Carlon, C2, Mesman, M3, Schouten, A3, Rutgers, M3, Giove, S4, Marcomini, A1, 1 Interdepartmental Centre IDEAS - Ca' Foscari University, Venice, Italy2 Consorzio Venezia Ricerche, Marghera, Venice, Italy3 Laboratory for Ecological Risk Assessment, National Institute for Public Health and the Environment, RIVM, Bilthoven, The Netherlands4 Department of Applied Mathematics, Ca' Foscari University, Venice, Italy
According to the Weight of Evidence (Burton et al., 2002) and the TRIAD (RIVM, 2000) approaches, combining the information provided by the Lines of Evidence (LoEs) belonging to three investigation legs (chemistry/bioavailability, ecology and ecotoxicology), a site-specific Ecological Risk Assessment framework was defined, including three tires of investigation. Specific methodologies and tools were developed in order to select the most suitable LoEs to be applied to the case study and to integrate their results. A comparison procedure, based on Multi Criteria Analysis (MCA) and expert judgment, provided a comparison of 62 bioavailability tools, 21 ecological observations and 40 ecotoxicological tests. The obtained ranks supported the selection of the most suitable set of tests to be applied to the ACNA di Cengio contaminated mega-site (Italy), for each investigation tier. Moreover, for the integration of the LoEs results, a specific Weight of Evidence procedure was defined aiming at assessing the impairment occurring on the terrestrial ecosystem due to soil contamination. Specific integrated risk indexes and an evaluation matrix were developed in order to support the quantitative and qualitative impairment analysis for selected terrestrial ecosystem function and soil biodiversity. Due to the complexity of the procedures (including expert judgments, comparative and weighting criteria, chemical, ecological and ecotoxicological knowledge of the soil system), MCA methods have been included in order to handle different sources of information and avoid their loss. The proposed methodology has been implemented in the ERA-MANIA DSS, a decision support system preliminarily applied to the ACNA site (Italy); additional applications could be useful to test the system in different conditions.
663 (GIL-1117-758928) Multiple lines of evidence to assess metals in forested areas of Sudbury, Ontario.
Start time: 11:20 AM
Gilbertson, M-K1, Hearne, K1, Wren, C1, 1 C. Wren and Associates, Guelph, Ontario, Canada
The Ecological Risk Assessment (ERA) in Sudbury will evaluate the possible risk from airborne particulate emissions from the chemicals of concern (COCs) which are nickel, copper, cobalt, arsenic, lead and selenium. An area of uncertainty in the ERA is whether the soils in the Sudbury area are inhibiting the recovery of a self-sustaining forest ecosystem. Field and laboratory studies were conducted in 2004-2005 to determine whether the concentrations of the COCs present in the Sudbury soils pose an unacceptable risk to plants, invertebrates or microbial activity. This risk will be determined using a battery of single species terrestrial toxicity tests, field-based ecological measurements and soil chemistry. Soil toxicity testing methods are often used in the assessment of contaminated sites. Many of the existing tests are not designed for use in large forested areas in northern conditions. As a result, we have applied a battery of soil toxicity tests, including some experimental and some established methods. The results of the soil chemistry, toxicity testing and ecological characterization will be integrated to determine whether the concentrations of metals in the soil are inhibiting the recovery of a self-sustaining forest system. The approach that will be used to integrate the ecological information, soil chemistry and toxicity assessment will be presented and discussed. This information will address important data gaps that currently exist, and will significantly decrease the uncertainty associated with the final risk assessment.