Book Chapter & Symposium Paper Citations and Abstracts

This chapter provides an overview of the state-of-the-science as related to the phytoassessment techniques used in environmental biomonitoring and the hazard assessment process for chemicals. The emphasis is on freshwater angiosperms and bryophytes. Algal species, which are presented in-depth in another chapter, will be discussed in a few cases for comparison only. The discussion will include aquatic, wetland, and to a lesser extent, terrestrial plants, in the context of the laboratory and field assessment techniques used to assess their environmental condition.

Folmar, Leroy C. 1999. Assays for Endocrine Disrupting Chemicals: Beyond Environmental Estrogens. In: Environmental Toxicology and Risk Assessment: Standardization of Biomarkers for Endocrine Disruption and Environmental Assessment. 8th Volume, ASTM STP 1364. D.S. Henshel, M.C. Black, and M.C. Harrass, Editors. American Society for Testing and Materials, West Conshohocken, PA. Pp. 59-94. (ERL,GB 1043).

Recent popular and scientific articles have reported the presence of estrogenic and other hormone mimicking chemicals in the environment and their potential for causing reproductive dysfunction in humans and wildlife. The purpose of this session was to present the best available, if not standard, analytical methods to assay for the effects of xenobiotic chemicals on a broad range of endocrine-mediated events, including reproduction, growth, development and stress responses in aquatic vertebrate and invertebrate animals.

McKenney, Charles L., Jr. 1999. Hormonal Processes in Decapod Crustacean Larvae as Biomarkers of Endocrine Disrupting Chemicals in the Marine Environment. In: Environmental Toxicology and Risk Assessment: Standardization of Biomarkers for Endocrine Disruption and Environmental Assessment. 8th Volume, ASTM STP 1364. D.S. Henshel, M.C. Black, and M.C. Harrass, Editors. American Society for Testing and Materials, West Conshohocken, PA. Pp. 119-135. (ERL,GB 1057).

Knowledge of endocrine control of the complex larval developmental processes in insects (metamorphosis) has led to the introduction of insect hormones and their analogues as insecticides known as insect growth regulators (IGRs) with the largest group being juvenile hormone analogues (JHAs). Developmental and metabolic alterations in estuarine crustacean larvae induced by JHAs suggest that these compounds may be interfering with an endocrine system using JH-like compounds. These responses of crustacean larvae during the metamorphic process can be used in the development of biomarkers for the environmental impact of these types of compounds and other potential endocrine disrupting chemicals on estuarine biota.

Davis, William P., Michelle R. Davis and David A. Flemer. 1999. Observations on the Regrowth of Subaquatic Vegetation Following Transplantation: A Potential Method to Assess Environmental Health of Coastal Habitats. In: Seagrasses: Monitoring, Ecology, Physiology, and Management. Stephen A. Bortone, Editor. CRC Press, Boca Raton, FL. Pp. 231-238. (ERL,GB 1060).

In 1991, experimental transplantings of Vallisneria americana (tapegrass, vallisneria, or wildcelery) were initiated at selected sites which lacked grass beds along the north shore of Perdido Bay, located on the Alabama-Florida border. Abatement of organic and color-staining components had been implemented to improve the water quality of effluent discharged by a pulp mill into the headwaters of Elevenmile Creek, a stream entering this low salinity estuary. This study was designed to assess whether previous in situ habitat conditions (e.g., light exclusion, water or sediment toxicity) had prevented natural recruitment of aquatic grasses or if other factors, (e.g. propagule transport) existed which might limit or delay Vallisneria colonization or growth. Different experimental transplanting configurations were employed in order to observe success in establishment of beds and assess our ability to measure plant growth among the varying micro-habitats and substrates. The initial transplanting, in 1991, consisted of two plants each, spaced at 40 cm centers in four 6 x 1 m parallel row-plots. These plants subsequently spread rapidly by runners merging the rows into a continuously expanding grass bed. Second and third trials conducted in 1995, were planted in a cross-shaped configuration, which has emerged as our preferred design. The growth of these transplants indicated Vallisneria grass beds were recruitment limited, rather than constrained by prevailing conditions of water quality/toxicity, light reduction or unsuitable substrate during the study period. Our experience may represent a fundamental method for routine utilization of the responses of submerged aquatic vegetation (SAV) to assess a broad range of questions concerning habitat and water quality of potential sites for habitat restoration.

Martin, Eugene L. and Tyler A. Kokjohn. 1999. Cyanophages. In: Encyclopedia of Virology, vol. 1. 2nd edition. Allan Granoff and Robert G. Webster, Editors. Academic Press, London, UK. Pp. 324-332. (ERL,GB X923).

The cyanophages are a group of DNA viruses that attack host organisms found within the cyanobacteria or blue-green algae, a group of oxygenic photosynthetic procaryotes. A continuing dichotomy has occurred as to the nomenclature and taxonomy of these microorganisms. Many of the existing genera and species were mainly described on the basis of morphological characteristics obtained from field-collected samples, and not from axenic cultures. It has been argued that in cell size and morphological complexity the blue-green algae more closely resemble the green algae and other micro-algae than the other bacteria and that their dual photosystems are almost identical with that of the eucaryotic algae and higher green plants rather than with anything known in the anoxygenic photosynthetic bacteria. Detailed physiological and genetic studies have been used to delineate this group of microorganisms more completely. Their multilayered cell wall closely resembles the cell wall structure of gram-negative eubacteria. On the basis of 16S and 5S rRNA nucleotide base sequence data, the blue-green algal procaryotes have been assigned to the eubacteria, a group distinct from eucaryotes (e.g. algae) and the archaebacteria. Other characteristics that have been anaylzed include analysis of pigments (chlorphyll a and phyobilins), chemoheterotrophic/photoheterotrophic capabilities, N2-fixation ability, DNA base composition, DNA/DNA hybridization and modes of asexual and sexual reproduction. Of considerable importance is the fact that the basic cell structure of this group is procaryotic which is synonymous with bacteria. Therefore, while blue-green algae and the cyanobacteria are reasonably compatible terms, cyanobacteria will be used here. In Volume 3 of Bergey's Manual Castenholz and Waterbury have divided the cyanobacteria into five morphological groups which are summarized in Table 1. This is the classification scheme that will be used for this article.

Nelson, Marcia K., Foster L. Mayer and Mary G. Henry. 1999. Summary of Workshop Sessions. In: Ecotoxicology and Risk Assessment for Wetlands. M.A. Lewis, F.L. Mayer, R.L. Powell, M.K. Nelson, S.J. Klaine, M.G. Henry, and G.W. Dickson, Editors. SETAC Press, Pensacola, FL. Pp. 343-350. (ERL,GB X948).

Important aspects of the effect of contaminants on wetland ecological structure and function, in both natural and constructed systems, were reviewed and evaluated in a Society of Environmental Toxicology and Chemistry (SETAC) Workshop, Ecotoxicology and Risk Assessment for Wetlands, held 30 July-3 August 1995. Experts from many disciplines in the scientific community examined influences of chemical and nonchemical stressors on wetland ecosystems, as well as wetland processes that affect contaminant fate and effects. This special publication summarizes the accomplishments of the workshop and represents an up-to-date compilation of information about several types of wetlands, focusing on identifying creative contaminant treatment solutions, critical issues regarding the fate and effect of contaminants with associated risk, and areas for future research and development.

Kelsch, Thomas, Rebecca L. Powell, Kenneth R. Dixon, Anne Fairbrother, Judy C. Helgen, Stephen J. Klaine, Foster L. Mayer, Gary A. Pascoe, Jennifer L. Shaw and Russell F. Theriort. 1999. Workgroup IV Synopsis: Regulatory Issues and Risk Assessment. In: Ecotoxicology and Risk Assessment for Wetlands. M.A. Lewis, F.L. Mayer, R.L. Powell, M.K. Nelson, S.J. Klaine, M.G. Henry, and G.W. Dickson, Editors. SETAC Press, Pensacola, FL. Pp. 275-314. (ERL,GB X950).

The discussions in this workgroup started with an identification and brief explanation of U.S. regulations pertaining to wetlands. The Framework for Ecological Risk Assessment Forum was then reviewed in relation to the unique aspects of conducting a wetland assessment. Assessment and measurement endpoints as well as the development of conceptual models for conducting ecological risk assessment were discussed. Issues surrounding exposure and effects characterization, including spatial and temporal relationships, frequency and duration of contact, direct and indirect effects, and modeling of systems, were covered. The ecological significance of the data and their interpretation were also talked about. The importance of nontoxicant stressors to wetlands and the difficulty of separating them from chemical stressors were recognized. Finally, the workgroup finished with a review of 4 regulatory programs and how the ecological risk assessment thought process can and is being used to assist in management decisions. It was concluded that the ecological risk assessment approach is data-driven and that the proper assessment depends on our ability to characterize wetland specific hydrological, biogeochemical, and biological functions as they relate to the exposure and effects of toxicants. Our limited understanding of how wetlands function and the effects of stressors on many wetland organisms make it necessary to improve and refine existing ecological risk assessment methods for use in these unique environments. Various recommendations were developed to identify and fill technical data gaps and to develop methods and models to process the data at various spatial and temporal scales.

Boesch, Donald F., Michael A. Lewis, William H. Mckee, Douglas Morrison, Pasquale F. Roscigno, Geoffrey I. Scott and Kevin Summers. 1999. Workgroup III Synopsis: Contaminant Fate and Effects in Coastal and Estuarine Wetlands. In: Ecotoxicology and Risk Assessment for Wetlands. SETAC Press, Pensacola, FL. Pp. 207-242. (ERL,GB X951).

Wetlands of the ocean coasts and estuaries are characterized by the influence of frequent water-level fluctuations as effected by astronomic tides as well as by meterologically forced changes in the level of coastal waters. Some coastal wetlands experience extremely wide water-level fluctuations (several meters) predictably twice a day, while others experience only micro tides, and wind events may be the dominant control of water level. Coastal and estuarine wetlands also contain variable concentrations of dissolved salts from the ocean. Tidal flooding and salinity result in profound differences in the structure and function of coastal and estuarine wetlands in comparison to inland, freshwater wetlands. In addition to tidal wetlands, this chapter addresses those wetlands in the upper reaches of estuaries that are influenced by the tides but do not experience measurable salinity (i.e., tidal freshwater wetlands). Here we consider coastal and estuarine wetlands inhabited by emergent, vascular plants, including salt and brackish marshes and mangrove swamps.

Mihaich, Ellen M., Jay Gooch, Peter deFur, William H. Benson, Charles Tyler, Linda Birnbaum, Richard T. Di Giulio and Donald E. Tillitt. 1999. Reproductive and Developmental Effects of Contaminants in Oviparous Vertebrates: Workshop Introduction. In: Reproductive and Developmental Effects of Contaminants in Oviparous Vertebrates. Richard T. Di Giulio and Donald E. Tillitt, Editors. SETAC Press, Pensacola, FL. Pp. 1-7. (ERL,GB X953).

Concern has arisen in recent years about the potential for effects on reproduction and development in both human and wildlife populations. As a consequence, considerable attention has been given to various aspects of this broad issue by research scientists, environmental managers, and the general public. This workshop brought together experts from the fields of reproductive and developmental biology, environmental toxicology and chemistry, ecology and risk assessment in order to discuss and evaluate a key subset of this issue that has great ecological significance - effects of chemicals on both terrestrial and aquatic oviparous (i.e., egg-laying) vertebrates. The workshop focused on contaminant exposure, mechanisms of effects on reproduction and development, organismal outcomes, ecological ramifications, and a discussion of ecological risk assessment focused on oviparous vertebrates. While environmental stressors other than chemical contamination also can impair reproduction, this workshop was focused on contaminant interactions and effects in oviparous vertebrates because they have unique sensitivities to contaminants as a result of their life-history strategy. For example, maternal transfer of contaminants to eggs and the subsequent effects of these contaminants on development have provided hallmark examples of ecological risk from this mechanism of toxicity and route of exposure. It was also our intention that these discussions would provide for a clearer focus on reproductive and developmental effects of contaminants on those species that hold the greatest promise for use in prospective and retrospective ecological risk assessments, including species commonly used in today's toxicity testing methods. This focus brought additional clarity to areas in which research could provide the tools needed to better protect living resources.

Benson, William H., Richard T. Di Giulio, Donald E. Tillitt, Linda Birnbaum, Peter deFur, Jay Gooch, Ellen M. Mihaich and Charles Tyler. 1999. Reproductive and Developmental Effects of Contaminants in Oviparous Vertebrates: Workshop Summary, Conclusions, and Recommendations. In: Reproductive and Developmental Effects of Contaminants in Oviparous Vertebrates. Richard T. Di Guilio and Donald E. Tillitt, Editors. SETAC Press, Pensacola, FL. Pp. 403-416. (ERL,GB X954).

Oviparous vertebrates generally occupy important niches in aquatic as well as terrestrial systems, and reproductive and developmental effects on these species can be of relatively great ecological significance. Because these organisms have critical windows of development, they may be particularly susceptible to toxic perturbation resulting from episodic exposure to environmental contaminants. In addition, oviparous vertebrates that occupy higher trophic levels may be especially vulnerable to persistent organic chemicals by means of trophic transfer. In the context of oviparous vertebrates, the workshop focused on the processes that control contaminant exposure, basic physiological processes that control reproduction and development, toxicological mechanisms of contaminant exposure, and ecological ramifications. In addition, the workshop included critical discussions of laboratory and field approaches for determining exposure and effect, and the integration of this information into ecological risk assessments focused on reproductive and developmental contaminants. The common theme that surfaced through deliberations that took place at the workshop was that the life-cycle characteristics of oviparous vertebrates were the single most significant factor in defining an organism's vulnerability to the reproductive and developmental effects of contaminants. Morever, the overriding demographic attributes of life-history strategies influence life-cycle characteristics, chemical exposure, and toxicity in a way that impacts factors that are critical to determining the risks associated with chemical exposure. This final chapter integrates the research gaps and recommendations identified during the workshop into a single set of workshop conclusions and recommendations.

Denslow, Nancy D., Christopher J. Bowman, Gillian Robinson, H. Stephen Lee, Ronald J. Ferguson, Michael J. Hemmer and Leroy C. Folmar. 1999. Biomarkers of Endocrine Disruption at the mRNA Level. In: Environmental Toxicology and Risk Assessment: Standardization of Biomarkers for Endocrine Disruption and Environmental Assessment. 8th Volume, ASTM STP 1364. D.S. Henshel, M.C. Black, and M.C. Harrass, Editors. American Society for Testing and Materials, West Conshohocken, PA. Pp. 24-35. (ERL,GB X978).

A large number of estrogen-mimicking, anthropogenic chemicals capable of disrupting normal reproductive function have been identified. The ubiquitous distribution of these compounds, many as components of complex industrial or municipal waste, has spurred an effort to develop methods to screen for chemicals which disrupt normal endocrine regulation of reproduction. We have developed assays that both allow exposure of animals in vivo and measure the response at the level of gene activation. We have developed a probe for measuring the induction of vitellogenin mRNA by Northern Blot in livers of sheepshead minnows treated with 17-b-estradiol. We have also developed a strategy for using Differential Display Polymerase Chain Reaction for determining gene induction profiles following exposure to estradiol. These methods should be adaptable to a variety of structurally diverse estrogen mimics.

Guillette, Louis J., Jr., Andrew A. Rooney, D. Andrew Crain and Edward F. Orlando. 1999. Steroid Hormones as Biomarkers of Endocrine Disruption in Wildlife. In: Environmental Toxicology and Risk Assessment: Standardization of Biomarkers for Endocrine Disruption and Environmental Assessment. 8th Volume, ASTM STP 1364. D.S. Henshel, M.C. Black, and M.C. Harrass, Editors. American Society for Testing and Materials, West Conshohocken, PA. Pp. 254-270. (ERL,GB X979).

Xenobiotic compounds introduced into the environment by human activity have been shown to adversely affect the endocrine system of wildlife. Various species exhibit abnormalities of (1) plasma sex steroid hormones, (2) altered steroid synthesis from the gonad in vitro and (3) altered steroidogenic enzyme function. These endpoints are sensitive and relatively easy to measure quantitatively with reliability and precision. These observations have led to the conclusion that sex steroid hormones could be markers of exposure to, and altered function from, endocrine disrupting contaminants (EDCs). However, there are serious limitations in the use of steroid hormones as generalized markers of EDC exposure. Steroid hormones exhibit seasonal, ontogenetic, gender and species-specific variation. Moreover, the regulation of sex steroid plasma concentrations is a relatively complex phenomenon capable of short-term (minutes - hours) alteration due to environmental inputs, such as acute stress -- an activational response. Alterations in steroid synthesis and degradation also can be a response to altered embryonic development due to EDC exposure - an organizational response. If steroid hormones are to be used as biomarkers, then closely controlled, well designed sampling has to be performed. Additionally, an appreciation of the variation possible in endocrine responses among the species to be studied must be obtained.

Mihaich, Ellen M., Jay Gooch, Peter deFur, William H. Benson, Charles Tyler, Linda Birnbaum, Richard T. Di Giulio and Donald E. Tillitt. 1999. Reproductive and Developmental Effects of Contaminants in Oviparous Vertebrates: Workshop Introduction. In: Reproductive and Developmental Effects of Contaminants in Oviparous Vertebrates. Richard T. Di Guilio and Donald E. Tillitt, Editors, Editors. SETAC Press, Pensacola, FL. Pp. 1-7. (ERL,GB X1009).

The purpose of this book is to disseminate the critical discussions on reproductive and developmental effects in oviparous vertebrates that occurred during the SETAC Pellston Workshop in Fairmont, Montana in July 1997. The workshop brought together experts from fields of reproductive and developmental biology, environmental toxicology and chemistry, ecology, and risk assessment. These individuals were selected to achieve balance among academia, government, and the private sector. In the context of oviparous vertebrates, the workshop focused on the routes of contaminant exposure and the mechanisms of effect on reproduction and development, organismal outcomes, and ecological ramifications. The workshop included discussions of laboratory and field approaches to link exposure and effect and to integrate this information into ecological risk assessments focused on contaminants in which reproductive and developmental effects are the primary concern. There are numerous reasons why the workshop focused on oviparous vertebrates. The oviparous lifestyle has particular nuances that may predispose such species to early life-stage exposures and to developmental effects. These effects may occur during larval development or during the juvenile or adult stage, depending upon the species. Exposures at early-life stages may lead to alterations in key developmental processes, as well as increased susceptibility to chemical insults as adults. Exposures at maturity could also disrupt normal reproductive physiology.

Benson, William H., Richard T. Di Giulio, Donald E. Tillitt, Linda Birnbaum, Peter deFur, Jay Gooch, Ellen M. Mihaich and Charles Tyler. 1999. Reproductive and Developmental Effects of Contaminants in Oviparous Vertebrates: Workshop Summary, Conclusions, and Recommendations. In: Reproductive and Developmental Effects of Contaminants in Oviparous Vertebrates. EPA/600/J-02/313. Richard T. Di Guilio and Donald E. Tillitt, Editors, Editors. SETAC Press, Pensacola, FL. Pp. 403-416. (ERL,GB X1010).

The workshop was successful in advancing the state of the science, as well as in bringing together a broad base of experience and viewpoints to advance integrations of approaches to understanding basic chemical and physiological processes, toxicological effects and mechanisms, ecological principles, and risk assessment issues related to reproductive and developmental effects of environmental contaminants. It was clear that the demographic attributes of life-history strategies influence life-cycle characteristics, chemical exposure, and toxicity in a manner affecting characteristics that define the risk to chemical exposure. Traditional approaches of toxicity testing methods and biological and chemical monitoring have contributed greatly to our current knowledge of reproductive and developmental effects and to our ability to assess and regulate the impacts of environmental contaminants. It was the intent of the workshop organizers to focus on reproductive and developmental effects of contaminants on those oviparous vertebrates that hold promise for use in ecological risk assessments. By providing this focus, the organizers intended to bring additional clarity to areas in which new research can provide the tools needed to better manage and protect ecological resources. A mechanistic understanding of environmental fate and reproductive and developmental effects of contaminants is attainable, but it must be considered a long-term goal. Continued progress toward this goal will enable researchers to demonstrate the link between contaminant exposure, basic physiological processes, toxicological effects, ecological consequences, and assessment of risk. Additional fundamental knowledge is essential to explain the mechanisms of reproductive and developmental effects and the processes governing the chemical fate and bioavailability of causative agents. As costs associated with compliance to regulations increase, regulators, as well as the regulated community, must make the most effective use of funds allocated for preventing or reducing deleterious impacts on environmental quality. Decisions based on a more complete mechanistic understanding of cause-and-effect relationships will be less likely to vary with technological trends and will be more defensible, while allowing economic growth to occur in a climate of ecologically meaningful environmental stewardship and maintenance of environmental quality.

Swanell, Richard P.J., David Mitchell, D. Martin Jones, Stuart Petch, Ian M. Head, Alyson Willis, Kenneth Lee and J.E. Lepo. 1999. Bioremediation of Oil-Contaminated Fine Sediments. In: Proceedings of the 1999 International Oil Spill Conference "Beyond 2000: Balancing Perspectives". American Petroleum Institute, Washington, DC. Pp. 751-756. (ERL,GB X1026).

Bioremediation of oil contamination has been shown to be effective for cobble and sandy shorelines. To assess the operational limitations of this technology, this project studied its potential to treat buried oil in fine sediments. The effectiveness of bioremediation by nutrient enrichment with water-soluble mineral fertilizers was quantified experimentally with a randomised block design with three replicate blocks. Each block consisted of an untreated control plot, a plot treated with fertilizer alone, an oiled plot, and an oiled plot treated with fertilizer. The sediment in each plot was retained in mesh enclosures and buried at a depth of 0.15 m. Weathered and emulsified Arabian Light crude oil was applied to the appropriate plots at 3.7 kg.m-2. Bioremediation success was monitored by examining in situ CO2 production rates; changes in residual hydrocarbons normalized to 17a(H), 21b(H)-hopane; and response of hydrocarbon-degrading microorganisms. Fertilizer treatments significantly increased the biodegradation of petroleum hydrocarbons (p = 0.0001) in the buried sediments. These conclusions were supported by in situ CO2 production data. Microbiological analyses showed that nutrient addition increased the numbers of hydrocarbon-degraders on the oiled plots tenfold. The results clearly showed that bioremediation can treat oil buried in fine sediment following a spill incident.

Ingersoll, Christopher G., Tom Hutchinson, Mark Crane, Stanley Dodson, Ted DeWitt, Andreas Gies, Marie-Chantal Huet, Charles L. McKenney, Jr., Eva Oberdorster, David Pascoe, Donald J. Versteeg and Oliver Warwick. 1999. Laboratory Toxicity Tests for Evaluating Potential Effects of Endocrine-Disrupting Compounds. In: Endocrine Disruption in Invertebrates: Endocrinology, Testing, and Assessment. Peter L. deFur, Mark Crane, Christopher G.Ingersoll and Lisa J. Tattersfield, Editors. SETAC Press, Pensacola, FL. Pp. 107-197. (ERL,GB X1071).

The scope of the Laboratory Testing Work Group was to evaluate methods for testing aquatic and terrestrial invertebrates in the laboratory. Specifically, discussions focused on the following objectives: 1) assess the extent to which consensus-based standard methods and other published methods for conducting toxicity tests with invertebrates in the laboratory can be used to detect and assess endocrine-disrupting compounds (EDCs); 2) identify the strengths and weaknesses in these methods for use in the ecological risk assessment of EDCs; 3) suggest potential improvements to existing methods and endpoints, and where appropriate, recommend the development of new approaches; and 4) develop a prioritized list of short-term and long-term research needs. During the workshop, 2 additional objectives were identified: 5) evaluate the use of reference compounds to help identify species, life stages, and endpoints potentially responsive to EDCs and to help in the development of standardized tests; and 6) identify groups of organisms that could be evaluated in transgenerational (multigenerational) exposures to detect ecologically relevant effects of EDCs on progeny of exposed organisms.