Showing papers on "Aquatic toxicology published in 1989"

Biochemical responses in aquatic animals: A review of determinants of oxidative stress

Abstract: The study of biochemical responses in aquatic animals comprises a vigorous area of inquiry within ecotoxicology for a number of reasons, including the perceived need for basic research in the field, the desire for highly sensitive biomarkers useful for biomonitoring and the particular concern for elevated rates of neoplasia observed in some aquatic systems. In this paper, an approach only recently investigated by aquatic toxicologists will be described and reviewed in detail. This approach is based on theories of oxyradical generation and subsequent oxidative stress in biological systems. Of particular concern to environmental toxicologists with respect to these phenomena are the abilities of a number of common and diverse compounds to undergo enzymatically facilitated redox cycling in cells and thereby generate oxyradicals under aerobic conditions. Mechanisms of oxyradical generation, toxicological consequences of these processes and endogenous antioxidant defense systems are described. In addition, methodologies for studying these phenomena are discussed and recent studies demonstrating their applicability to aquatic toxicology are reviewed.

Principles of fish nutrition

Abstract: Principles of fish nutrition , Principles of fish nutrition , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Aquatic organisms and pyrethroids

Abstract: Under laboratory conditions, in water without particulate matter, pyrethroid insecticides have a high toxicity to fish and some aquatic invertebrates. The pyrethroids are of very low water solubility/high lipophilicity, and therefore are rapidly and strongly adsorbed to particulate material. In the adsorbed state their bioavailability to aquatic organisms is greatly reduced. Consequently, under field conditions the aquatic impact of these insecticides is likely to be much less than might be predicted by laboratory acute or chronic toxicity test data. Over the past 10 years a large number of aquatic field studies have been carried out with pyrethroids, in natural farm ponds, streams and lakes and also in mesocosms (experimental ponds and enclosures). Recent investigations, to meet the requirements of the United States Environmental Protection Agency, have been most extensive. These studies, done in replicated experimental ponds of at least 0-04 ha, each require at least 20 man-years of effort. Following agricultural applications of the pyrethroid insecticides, spray-drift or run-off may cause minor effects upon some aquatic organisms. Algae, microorganisms, annelids, gastropods and fish are all unaffected, but some impact may occur upon certain zoo-plankton and on aquatic stages of insects. However, with products for which realistic field studies have been reported, the effects are mostly transient and are unlikely to cause adverse changes in the populations or productivity of aquatic ecosystems.

Toxicology of Synthetic Pyrethroids in Aquatic Organisms: An Overview

Abstract: The aquatic toxicology of the photostable synthetic pyrethroid insecticides as it affects two important groups of susceptible organisms — fish and aquatic insects — is discussed. The sensitivity of these aquatic species to the pyrethroids is dependent on several factors, including toxicokinetics, target site (nervous system), sensitivity and possible secondary mechanisms of action, as well as chemical and physical properties of the aquatic medium that influence toxicity and bioavailability. Uptake rates and routes of fenvalerate greatly affected the toxicity of fenvalerate to mosquito larvae. LD50 values were determined for cuticular and dietary exposure routes by utilizing radiolabeled fenvalerate at the respective LC50 concentrations in the two media (water and food). Fenvalerate was sixfold more toxic to mosquito larvae by the cuticular route. Technical fenvalerate was more toxic to larvae than was the emulsifiable concentrate formulation. Addition of different concentrations of humic acid to the water reduced the toxicity to the larvae. Review and analysis of relevant literature are integrated into a discussion of the principles and details of aquatic toxicology of the pyrethroids.

Aquatic toxicity test for enchytraeids

Abstract: It is the purpose of this report to present a simple method for testing the toxicity of chemical substances by using enchytraeids in an aquatic environment. Up to eight different environmental chemicals were applied to various species, mainly of the genus Enchytraeus. The results were compared with those achieved for D. magna. Significant differences, however, between the LC50 values of the various enchytraeid species and the LC50 values for enchytraeids and daphnids could not be observed. For E. cf. buchholzi the toxicological sensitivity of discrete ontogenetic stages was tested. The Aquatic Enchytraeid Test results were compared with those obtained from the Terrestrial Enchytraeid Test. It was found that in soil a chemical could be 600 times less toxic than in water, although the same species (E. albidus) was used in both environments. Even more pronounced were the discrepancies between the terrestrial and aquatic toxicities when the LC50 values for earthworms and daphnids were compared.

Pollutant toxicity to aquatic animals--methods of study and their applications.

Abstract: The toxicity of water pollutants to aquatic animals is reviewed, with particular emphasis on methods for measuring lethal toxicity, factors influencing toxicity, the measurement of chronic and sublethal toxicity, and the role of toxicological data in formulating water quality standards. Methods for measuring lethal toxicity are well established and have been applied to a wide range of fish and invertebrate species. Their applications and limitations are discussed. The measurement of sublethal toxicity employs very diverse techniques ranging from biochemical to the use of experimental ecosystems. Profitable techniques are those which possess one or more of the characteristics: sensitivity, specificity, ecological relevance. A large data base now exists on the toxicity of pollutants to aquatic species, singly and in combination, and on the effects of environmental conditions, and interspecific and intraspecific biotic factors. Toxicological data and information from field studies are complementary, and their use in formulating water quality standards for the preservation of aquatic life is discussed.

Factors influencing bioaccumulation of sediment-associated contaminants by aquatic organisms, factors related to sediment and water. Environmental effects of dredging. Technical note No. 2

Abstract: PURPOSE: This is the second technical note in a series of four which outlines and describes the principal factors` that determine uptake and retention of chemicals by aquatic organisms. The first three notes describe factors related to contaminants, sediment and water, and biota. The fourth note is a glossary and bibliography. The information contained herein is intended to assist Corps of Engineers environmental personnel in activities requiring a working knowledge of concepts and terminology in the subject of chemical uptake, retention, and elimination by aquatic organisms exposed to contaminated sediments.

Toxicity of Jet A (aviation fuel) selected aquatic organisms. Technical report, August 1987-February 1988

Abstract: JP8 (jet propulsion) is an aviation fuel being considered for replacement of diesel fuel used in the generation of smoke on the battlefield. JP8 is projected to be more economical and also be used as a fuel for the ground machinery used in the transport and dissemination of JP8. Also, fog oil has naphthene constituents above the Occupational Safety and Health Administration (OSHA) standards. JP8 trailing and testing could lead to contaminating surrounding aquatic ecosystems through runoff or wind transport. Therefore, the toxicity of JP8 to aquatic organisms must be known. Jet A (aviation fuel) was substituted for JP8 due to availability and similar distillation procedure. The aquatic toxicity of the soluble fraction of Jet A (aviation fuel) was examined. Acute 48-hr bioassays were performed using the water flea, Daphnia magna, and 96-hr growth inhibition bioassays were performed using a green unicellular alga, Selenastrum capricornutum. All tests were conducted according to guidelines set by the U.S. Environmental Protection Agency (EPA) and the American Society for Testing and Materials (ASTM). The 48-hr EC50 for D. magna was 3.1 mg/L. The 96-hr IC50 for S. capricornutum was 4.2 mg/L.

Biomonitoring of Waste Effluents - An Overview For Environmental Sanitarians

Abstract: In the early seventies it was a problem to conduct routine wastewater effluent testing at many municipal sewage treatment facilities because of a lack of equipment and the availability of trained personnel. During this time sanitarians in many states played a key role in training and assisting plant operators to establish routine effluent monitoring programs. Effluent testing and monitoring during the early 1970’s was focused on biochemical oxygen demand and other eutrophying characteristics of the waste. Concern about the toxic effects of wastewater developed as increasing numbers of chemical substances were identified in waste effluents. In 1972 the Federal Water Pollution Control Act was amended, establishing as a national policy “that the discharge of toxic pollutants be prohibited.” The enactment of the Toxic Substances Control Act (TSCA) in 1976 directed the Environmental Protection Agency (EPA) to determine whether the disposal of a chemical substance presented a toxic risk to the environment. Traditional chemical analysis cannot provide information concerning the changes in toxicity of a chemical substance due to characteristics of the receiving stream (e.g. temperature, pH). In addition, traditional analysis of complex mixtures is difficult and cannot be used to predict synergistic effects with other chemical constituents. The need to improve the evaluation of waste effluents for toxic effects on aquatic organisms was recognized by the EPA when it issued a national policy statement in 1984 entitled “Policy for the Development of Water QualityBased Permit Limitations for Toxic Pollutants”. In it’s policy statement the EPA established the use of biological techniques for effluent toxicity testing. Specific language in the 1984 national policy statement included: “In addition to enforcing specific numerical criteria, EPA and the States will use biological techniques and available data on chemical effects to asses toxicity impacts”. The use of biological monitoring as part of the National Pollutant Discharge Elimination System (NPDES) permit was also included: “effluent toxicity data in conjunction with other data can be used to control priorities, assess compliance with state water quality standards, and set permit limitations to achieve those standards.” As more State water quality authorities adopt EPA recommendations for toxicity testing, local sanitarians will need to have a greater knowledge of biomonitoring techniques and methods. Biomonitoring is defined as the use of organisms for evaluating the toxicological impact of wastewater effluents on receiving waters. Organisms used in aquatic toxicity tests range from fish and protozoans to bacteria and algae. Table 1 provides a summary of organisms commonly used in toxicity testing of waste effluents.

Tentative Identification of Organic Compounds at the Westside Wastewater Treatment Plant (High Point, NC) and Implications for Aquatic Toxicity

Abstract: After identifying an acute toxicity problem, the North Carolina Division of Environmental Management required the High Point Westside Wastewater Treatment Plant (Westside WWTP) to institute periodic biomonitoring and reduce whole effluent toxicity. This research was undertaken to provide additional information through a broad spectrum, chemical-specific approach to toxicity reduction in which potential toxicants are identified. wesEsi.de WWTP samples deEermined as acutely "toxictf or %on-toxicfv by Daphnia pulex bioassay, effluents from six categories of industrial dischargers, and a domestic wastewater sample were analyzed for organic chemicals using continuous solvent extraction of wastewater samples and broad spectrum GC/MS analysis. An extensive data base was developed which includes aquatic toxicity data for 60 compounds and tentatively identified compounds in WWTP samples (82 out of 123 peaks were identified) and industrial effluents (about 50 for each) ranked according to their potential for contribution to toxicity. The study suggests that many compounds found in Westside WWTP influent and effluent are of industrial origin because they occur in both industrial samples and Westside WWTP samples. Treatment does not remove some organic compounds exhibiting significant toxicity to aquatic organisms and shown to be present in tttoxicvv effluents and industrial samples. Toxicity of Westside WWTP influent and effluent may be caused by a variety of industrial organic compounds in concentrations that alone would not be sufficient to produce a t o x i c effect but, because they may all produce toxicity by a non-specific mode of action (narcosis), together they may produce a toxic effect. Reconmendations for further analyses include confirmation of identifications using additional mass spectral techniques, determination of estimated or empirical aquatic toxicities and further toxicity characterization procedures that can remove groups of suspect toxicants selectively.

Toxicity of Jet A (Aviation Fuel) Selected Aquatic Organisms

Abstract: : JP8 (jet propulsion) is an aviation fuel being considered for replacement of diesel fuel used in the generation of smoke on the battlefield JP8 is projected to be more economical and also be used as a fuel for the ground machinery used in the transport and dissemination of JP8 Also, fog oil has naphthene constituents above the Occupational Safety and Health Administration (OSHA) standards JP8 trailing and testing could lead to contaminating surrounding aquatic ecosystems through runoff or wind transport Therefore, the toxicity of JP8 to aquatic organisms must be known Jet A (aviation fuel) was substituted for JP8 due to availability and similar distillation procedure The aquatic toxicity of the soluble fraction of Jet A (aviation fuel) was examined Acute 48-hr bioassays were performed using the water flea, Daphnia magna, and 96-hr growth inhibition bioassays were performed using a green unicellular alga, Selenastrum capricornutum All tests were conducted according to guidelines set by the US Environmental Protection Agency (EPA) and the American Society for Testing and Materials (ASTM) The 48-hr EC50 for D magna was 31 mg/L The 96- hr IC50 for S capricornutum was 42 mg/L