L. D. Wike, F. D. Martin, M. H. Paller
Westinghouse Savannah River Company
Aiken, SC

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Environmental impact can be difficult to assess, especially at the ecosystem level. Any impact assessment methodology that can give cost effective and timely results is highly desirable. Rapid bioassessment (RBA) is cost effective and produces timely results. Several types of RBA have been used at the Savannah River Site (SRS) to assess stream conditions, including the Index of Biotic Integrity (IBI) based on fish community characteristics, and various techniques using aquatic macroinvertebrate species diversity and abundance. In an attempt to broaden the applicability of the RBA concept, we have also begun to develop RBA techniques for seep-fed wetlands and terrestrial habitats. These techniques will focus on vertebrate and macroinvertebrate assemblages for seep-fed wetlands and arthropod assemblages for terrestrial habitats. In situ bioassay is another technique that could be used for rapid and economical assessment of the effects of anthropogenic disturbance. We propose the development of two methods of in situ bioassay that can address bioavailability of constituents of concern. The use of caged bioassay organisms can be applied to terrestrial systems such as capped or existing waste sites using the common house cricket. Another proposed bioassay could use a resident species, such as the imported red fire ant, which is found in disturbed habitats and open areas such as waste sites. Combining in situ techniques with RBA methodologies has the potential to provide a comprehensive assessment of chemical and physical impacts to a wide range of ecosystem types.

The use of biological data to assess environmental quality (i.e., bioassessment) is increasingly favored by regulatory agencies because it explicitly and directly evaluates the ecological effects of environmental disturbances (Barbour et al. 1999). Because newer bioassessment methods generate useful, accurate results comparatively rapidly and economically, they are sometimes referred to as rapid bioassessment protocols (RBAs). One of the first RBAs to gain widespread acceptance in the United States was the Index of Biotic Integrity (IBI), which uses fish assemblage data to assess the ecological health of streams (Karr et al. 1986). The IBI has been adapted for use throughout the United States and in a number of foreign countries (Klemm et al. 1993). Other bioassessment methods based on fish, macroinvertebrate, and algal assemblages are now widely used to assess the ecological health of streams (Barbour et al. 1999). To date RBA methods have not been well developed for terrestrial ecosystems.

In situ bioassay has the potential to avoid some of the inherent difficulties found in applying RBA techniques to terrestrial systems, but at the expense of not providing an integrated assessment of local ecosystem health. Organisms need to be chosen carefully to integrate local conditions and to reflect any movement of constituents of concern into the food chain. Insects or other macroinvertebrates would be preferred because of their small size and home range and for ease of body burden analysis.

In the United States, bioassessment results are usually expressed in the form of a multimetric index composed of varying numbers of metrics, each of which represents a biological attribute that is sensitive to pollution or other types of environmental disturbance (e.g., species diversity, number of sensitive species, percentage of tolerant species, etc.). The score assigned to each individual metric expresses its deviation from expectations of undisturbed conditions in a comparable habitat. These scores are aggregated into a single index score that reflects overall ecological health. Because comparisons with local undisturbed reference conditions are critical, multimetric indices must be adjusted to account for differences in species composition among geographic regions and habitats (Hughes et al. 1987). Multimetric indices are popular because they are easy to explain yet scientifically defensible and they have a direct ecological relevance that is understandable even by non-specialists (Karr and Chu 1997).

The IBI has been adapted for SRS streams where it has been shown to accurately discriminate undisturbed sites from sites affected by habitat degradation and chemical pollution (Paller et al. 1996). An analogous RBA technique employing macroinvertebrate data collected from artificial substrates has also proven useful for stream assessments (Paller and Specht 1997). Multimetric index results can be enhanced by combining them with other types of information. Habitat data can help determine if index results are affected by physical (e.g., erosion) or chemical (e.g., presence of contaminants) factors. Because many types of contaminants bioaccumulate, tissue contaminant data from selected receptors (e.g., fish or amphibians) can assist in determining exposure to bioavailable contaminants. At the SRS, fish and invertebrate based multimetric indices have been combined with habitat, fish tissue contaminant, and fish necropsy data to provide comprehensive assessments of the cumulative effects of waste site contaminants and National Pollutant Discharge Elimination System discharges on stream biota (Paller and Dyer 2000). Multimetric indices recently have been developed for lakes and estuaries (Gerritsen et al. 1998) and are now being developed to assess the ecological health of wetlands (Adamus et al. 2001). Because wetlands are diverse environments that support a variety of organisms, proposed indices for wetlands may encompass macroinvertebrates, vegetation, amphibians, fish, or birds (Adamus 1996; Danielson 1998). The most appropriate assemblage depends on the wetland type. However, inclusion of more than one assemblage can produce more complete and accurate results (Paller 2001).

At the SRS, wetland habitats termed "seeps" exist where shallow groundwater outcrops from hillsides. When located down gradient from contaminated seepage basins, the groundwater that feeds these seeps can contain a variety of potentially toxic constituents (Haselow et al. 1990). These seeps are the initial point of contact between surface ecological receptors and emerging seepage basin contaminants. Because organisms in the seeps encounter the highest contaminant concentrations, impacts are more likely to be manifested in the seeps than elsewhere.

Ongoing studies at the SRS include disturbed seeps as well as undisturbed seeps that can serve as a reference for comparison with the disturbed seeps. A variety of passive and active sampling methods have been employed to determine the most efficient and cost-effective biological sampling protocols for seeps. Physical and chemical data have also been collected from the seeps to more fully characterize them. Data collected during the early and late spring 2002 are currently being analyzed to detect ecologically important variables that differ between the disturbed and undisturbed seeps. These variables will form the basis for a multimetric biological index composed of community, population, and organism level metrics. Data reporting will include two formats; one typical of technical reports read by scientific specialists and a more concise format more easily used for environmental decision making. The latter format will utilize straightforward graphical representations of data (e.g., sun ray plots, pie charts, box-and-whisker plots), text, site picture(s), and map(s) to summarize and integrate information. Other types of data (e.g., fish tissue contaminant data, water chemistry data) will also be incorporated into this report where pertinent to provide a more complete assessment of ecological conditions.

We hope that research conducted on the SRS will help fill a gap in the existing method of assessing subsurface contaminants: failure to systematically and effectively assess the presence or extent of ecological impact of subsurface contaminants that emerge to the surface and the spatial extent of these impacts. This type of information can play a critical role in the risk-based evaluation of mitigation options.

We also expect RBA to help address the potential risk of existing terrestrial waste sites and aid in evaluating the effectiveness of containment at remediated sites. Beginning in 1996, pitfall trap arrays have been used to sample various terrestrial habitats at SRS including old fields, pine plantations, upland hardwood, sandhills and mesic hardwood sites. These data, all from summer sampling events, are currently being analyzed for patterns that will facilitate the partitioning of habitat type and disturbance, allowing the evaluation of ecosystem health through a set of RBA-type metrics.

In situ bioassay could be accomplished in two ways, use of a suitable species already existing in the habitat to be examined or the controlled exposure of experimental animals to the area to be evaluated. The imported red fire ant (Solenopsis invicta) is a ubiquitous organism in much of the southern parts of the United States. It is usually found in disturbed and early successional habitats, which are typical of waste sites. Single-queen colony mounds can go as deep as 1.5 m and have as many as 500,000 individuals. Foraging fire ants may venture as much as 40 m from the nest and will consume almost any item or organism of any nutritive value within their area. This position in the food chain combined with their intimate association with the soil within a relatively small area makes the fire ant an ideal organism for in situ bioassay. The problem with using fire ants for bioassay is in the difficulty of collecting pure samples for constituent analysis.

Three methods of collection are considered here; a passive sampler, a commercially available active sampler, and a large scale elutriator. Each method has advantages and liabilities. The passive sampler and the active sampler share the disadvantage of only sampling workers and soldier caste ants. The elutriator would sample all castes and life stages but is available at this time only as a partially tested design.

Caged bioassay has been used successfully for aquatic systems and could be applied to terrestrial systems using the readily available common house cricket (Acheta domestica). Cages made of plastic pipe and screen placed on control and experimental sites would be allowed to "grow in" to the local ecosystem. Common house crickets are herbivorous and will be kept in the cages and allowed to feed for a period of time determined by their life span and then removed for analysis. In addition to the caged animals on experimental sites and control sites, further control would come from analysis of a subsample of animals at the beginning of the experiment and a sample of animals kept in laboratory conditions.

The most thorough approach to impact assessment is to concomitantly employ several assessment tools that utilize different taxonomic groups and multiple levels of biological organization. Because they provide an excellent summation of the status of ecologically important endpoints, RBA methods should be included in environmental assessments whenever possible. However, they reflect existing damage and may not be sensitive to incipient problems that have yet to reach thresholds that result in detectable community level changes. This liability can be at least partly offset by combining RBA techniques with other analyses that emphasize the organismal level of organization. Something as simple as analyzing the tissues of ecologically important species for constituents of concern can provide information concerning exposure to contaminants that may eventually affect population and community structure. Use of more than one RBA technique is advisable because different taxonomic groups possess physiological and ecological differences that can affect their responses to environmental perturbations. The use of multiple taxonomic groups ensures a more comprehensive and accurate assessment, especially when degradation is not severe, as it may be in the incipient stages of a developing problem.

Bioassessment protocols are best developed for streams and shallow rivers - habitats where community boundaries are well defined, taxonomy is well known, and sampling methods are relatively efficient and practical. They are more limited for other types of aquatic habitats and most limited for terrestrial habitats. Terrestrial habitats can pose particular problems because of patchiness associated with recovery from multiple disturbances and steep environmental gradients in soil moisture and composition. Changes in community structure associated with environmental patchiness can be confounded with changes in community structure associated with toxicity or other types of environmental degradation. As a result, terrestrial bioassessment often focuses on contaminant levels or biochemical markers in sentinel species rather than on community level indices (Lower and Kendall 1990). Such approaches fail to provide a community perspective and may present practical difficulties because sentinel species (e.g., keystone avian species) may be rare or protected. Efforts at the SRS seek to fill some of the gaps in terrestrial bioassessment by developing a multimetric index based on arthropod assemblages that can be supplemented with relatively simple arthropod bioassays.

The use of multiple sources of information to investigate environmental problems has obvious scientific advantages but presents potential problems in terms of economy and the need to clearly integrate findings for decision making purposes. Properly designed RBAs that emphasize collection of key data using efficient sampling protocols can help alleviate this problem, as can simple field bioassays. Well designed reporting formats that clearly and concisely present key findings can help ensure that ecological data plays an important role in the decision making process.

1. Adamus, P.R., T.J. Danielson, and A. Gonyaw. 2001. Indicators for monitoring biological integrity of inland, freshwater wetlands, a survey of North American technical literature (1990-2000). EPA 843-R-01. U.S. Environmental Protection Agency, Washington, DC.
2. Adamus, P.R. 1996. Bioindicators for assessing ecological integrity of prairie wetlands. EPA/600/R-96/082. U.S. Environmental Protection Agency, Environmental Research Laboratory, Corvallis, OR.
3. Barbour, M.T., J. Gerritsen, B.D. Snyder, and J.B. Stribling. 1999. Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers: Periphyton, Benthic Macroinvertebrates and Fish, Second Edition. EPA 841-B-99-002. U.S. Environmental Protection Agency, Office of Water, Washington, DC.
4. Danielson, T. J. 1998. Wetland Bioassessment Fact Sheets. EPA843-F-98-001. U.S. Environmental Protection Agency, Office of Wetlands, Oceans, and Watersheds, Wetlands Division, Washington, DC.
5. Gerritsen, J., R.E. Carlson, D.L. Dycus, C. Faulkner, G.R. Gibson, J. Harcum, and S.A. Markowitz. 1998. Lake and reservoir bioassessment and biocriteria, technical guidance document. EPA 841-B-98-007. U.S. Environmental Protection Agency, Washington, DC.
6. Haselow, J.S., M. Harris, B.B. Looney, N. V. Halverson, and J. B. Gladden. 1990. Analysis of soil and water at the Four Mile Creek Seepline near the F&H Areas of SRS (U). WSRC-RP-90-00591. Westinghouse Savannah River Company, Aiken, SC.
7. Hughes, R.M., E. Rexstad, and C.E. Bond. 1987. "The relationship of aquatic ecoregions, river basins, and physiographic provinces to the ichthyographic regions of Oregon." Copeia 1987:423-432.
8. Karr, J.R., K.D. Fausch, P.L. Angermeier, P.R. Yant, and L.J. Schlosser. 1986. Assessing biological integrity in running waters: A method and its rationale. Special publication 5. Illinois Natural History Survey, Champaign, IL.
9. Karr, J.R., and E.W. Chu. 1997. "Biological monitoring, essential foundation for ecological risk assessment." Human and ecological risk assessment 3:933-1004.
10. Klemm, D.J., Q.J. Stober, and J.M. Lazorchak. 1993. Fish field and laboratory methods for evaluating the biological integrity of surface waters. U.S. Environmental Protection Agency, EPA/600/R-92/111. Cincinnati, OH.
11. Lower, W.R. and R.J. Kendall. 1990. "Sentinel species and sentinel bioassay." In: McCarthy, J. F.; Shugart, L.R., eds. Biomarkers of environmental contamination. Boca Raton, FL: CRC Press: 309-332.
12. Paller, M.H. 2001. "Comparison of fish and macroinvertebrate bioassessments from South Carolina coastal plain streams." Aquatic Ecosystem Health and Management 4:175-186.
13. Paller, M.H., M.J.M. Reichert, and J.M. Dean. 1996. "The use of fish communities to assess environmental impacts in South Carolina coastal plain streams." Transactions of the American Fisheries Society 125:633-644.
14. Paller, M.H., and W.L. Specht. 1997. "A multimetric index using macroinvertebrate data collected with artificial substrates." Journal of Freshwater Ecology 12:367-378.
15. Paller, M.H., and S.A. Dyer. 2000. Biotic integrity of streams in the Savannah River Site integrator operable units. Westinghouse Savannah River Company, Aiken, SC.