scholarly journals Single‐species acute lethal toxicity tests are not predictive of relative population and community effects of two salinity types

2021 ◽  
Author(s):  
Ben J. Kefford ◽  
Ross V. Hyne ◽  
Andrew J. Brooks ◽  
Jonathan P. Bray ◽  
Mark Shenton ◽  
...  
Keyword(s):  
Single Species ◽  
Toxicity Tests ◽  
Community Effects ◽  
Relative Population ◽  
Lethal Toxicity

Ability of Standard Toxicity Tests to Predict the Effects of the Insecticide Diflubenzuron on Laboratory Stream Communities

1982 ◽  
Vol 39 (9) ◽  
pp. 1273-1288 ◽  
Author(s):  
Stephen R. Hansen ◽  
Ronald R. Garton
Keyword(s):  
Quality Criteria ◽  
Single Species ◽  
Toxicity Tests ◽  
Exact Nature ◽  
Interspecies Interactions ◽  
Community Effects ◽  
Test Species ◽  
Stream Communities ◽  
Freshwater Animal ◽  
Laboratory Stream

We assessed the ability of a standard set of freshwater single-species toxicity tests to predict accurately effects of the insecticide diflubenzuron (1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)urea) on complex laboratory stream communities. The single-species tests complied with requirements prescribed for establishing freshwater quality criteria and included nine freshwater animal acute tests, five freshwater animal chronic tests, and one freshwater algal test. The stream communities were stocked from a natural source, equilibrated for 3 mo and then treated with diflubenzuron for 5 mo. Effects on these stream communities were assessed at the functional group level using biomass and diversity for the analysis. The single-species tests adequately predicted the concentrations of diflubenzuron which affected these stream communities; the most-sensitive test species, insects and crustaceans, were up to an order of magnitude more sensitive than the observed community effects. The single-species tests were less successful in predicting the exact nature of the community level effects. Those effects resulting from direct lethality to component species were clearly predicted; indirect effects due to altered interspecies interactions could only be predicted with an a priori knowledge of the system's trophic dynamics.Key words: toxicity, diflubenzuron, streams, community effects, toxicity testing

Use of Biomonitoring to Control Toxics in the United States

1988 ◽  
Vol 20 (10) ◽  
pp. 101-108 ◽  
Author(s):  
Nelson A. Thomas
Keyword(s):  
Water Quality ◽  
Chronic Toxicity ◽  
National Policy ◽  
Single Species ◽  
Field Studies ◽  
The United States ◽  
Toxicity Tests ◽  
Toxic Pollutants ◽  
Receiving Waters ◽  
Biological Field

A biomonitoring program has been developed in support of the National Policy for the Development of Water Quality-Based Permit Limitations for Toxic Pollutants. The program focuses on the use of laboratory toxicity tests on aquatic plants and animals to predict ecosystem impact caused by toxic pollutants. Both acute and chronic toxicity tests were developed to test effluents and ambient waters. Laboratory and biological field studies were conducted at nine sites. Single species laboratory toxicity tests were found to be good predictors of impacts on the ecosystem when two or more species were used. Biomonitoring can be undertaken either on effluents and/or on the receiving waters. In that toxicity related to seeps, leachates and storm sewers has often been found upstream from dischargers, it is beneficial to conduct both effluent and ambient biomonitoring.

scholarly journals Why are mayflies (Ephemeroptera) lost following small increases in salinity? Three conceptual osmophysiological hypotheses

2018 ◽  
Vol 374 (1764) ◽  
pp. 20180021 ◽  
Author(s):  
Ben J. Kefford
Keyword(s):  
Turnover Rate ◽  
Ph Regulation ◽  
Research Effort ◽  
Ion Homeostasis ◽  
Single Species ◽  
Toxicity Tests ◽  
Future Prospects ◽  
Theme Issue ◽  
Vital Functions ◽  
Rate Of Increase

The salinity of many freshwaters is increasing globally as a result of human activities. Associated with this increase in salinity are losses of Ephemeroptera (mayfly) abundance and richness. The salinity concentrations at which Ephemeroptera decline in nature are lower than their internal salinity or haemolymph osmolality. Many species also suffer substantial mortality in single species laboratory toxicity tests at salinities lower than their internal salinity. These findings are problematic as conventional osmoregulation theory suggests that freshwater animals should not experience stress where external osmolality is greater than haemolymph osmolality. Here I explore three hypotheses to explain salt sensitivity in Ephemeroptera. These conceptual hypotheses are based on the observations that as the external sodium ion (Na + ) concentration increases so does the Na + turnover rate (both uptake and elimination rates increase). Sulphate ( ) uptake in mayflies also increases with increasing external although, unlike Na + , its rate of increase decreases with increasing external . The first hypothesis is premised on ion turnover being energetically costly. The first hypothesis proposes that individuals must devote a greater proportion of their energy to ion homeostasis at the expense of other uses including growth and development. Lethal levels of salinity presumably result from individuals not being able to devote enough energy to maintain ion homeostasis without critical loss of other vital functions. The second hypothesis is premised on the uptake of Na + exchanged for (an outgoing) H + , leading to (localized) loss of pH regulation. The third hypothesis is premised on localized Na + toxicity or poisoning with increased Na turnover as salinity increases. None of the proposed hypotheses is without potential problems, yet all are testable, and research effort should be focused at attempting to falsify them. This article is part of the theme issue ‘Salt in freshwaters: causes, ecological consequences and future prospects’.

Effects of sediment-spiked lufenuron on benthic macroinvertebrates in outdoor microcosms and single-species toxicity tests

2016 ◽  
Vol 177 ◽  
pp. 464-475 ◽  
Author(s):  
T.C.M. Brock ◽  
D.A. Bas ◽  
J.D.M. Belgers ◽  
L. Bibbe ◽  
M-C. Boerwinkel ◽  
...  
Keyword(s):  
Benthic Macroinvertebrates ◽  
Single Species ◽  
Toxicity Tests

scholarly journals Comparative Aquatic Toxicity of Gold Nanoparticles and Ionic Gold Using a Species Sensitivity Distribution Approach

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Tarryn L. Botha ◽  
Tanyn E. James ◽  
Victor Wepener
Keyword(s):  
Gold Nanoparticles ◽  
Aquatic Toxicity ◽  
Single Species ◽  
Species Sensitivity Distribution ◽  
Toxicity Tests ◽  
Species Sensitivity ◽  
Sensitivity Distribution ◽  
Hazardous Concentration ◽  
Toxic Potential ◽  
Ionic Gold

Gold nanoparticles (nAu) are used in drug delivery systems allowing for targeted cellular distribution. The effects of increased use and release of nanoparticles into the environment are not well known. A species sensitivity distribution (SSD) allows for the ecotoxicological hazard assessment of a chemical based on single species toxicity tests. Aquatic toxicity needs to be related to particle characterization in order to understand the effects. The behaviour of nAu in the medium changed as the concentration increased. The toxic potential of ionic gold and nAu was expressed as a hazardous concentration where 5% of species will be harmed (HC5). The HC5 for nAu was much higher (42.78 mg/L) compared to the ionic gold (2.44 mg/L). The differences between the hazard potentials of nAu and ionic gold were attributed to the nAu not releasing any Au ions into solution during the exposures and following an aggregation theory response. Exposures to ionic gold on the other hand followed a clear dose dependent response based on the concentration of the ionic metal. Although SSDs present an indication of the relative hazard potential of nanoparticles, the true worth can only be achieved once other nanoparticle characteristics and their behavior in the environment are also considered.

A comparison between toxicity tests using single species and a microbial process

Chemosphere ◽  
1999 ◽  
Vol 38 (14) ◽  
pp. 3277-3290 ◽  
Author(s):  
Patrick van Beelen ◽  
Arja K. Fleuren-Kemilä
Keyword(s):  
Single Species ◽  
Toxicity Tests ◽  
Microbial Process

scholarly journals Community Confounding In Joint Species Distribution Models

2021 ◽  
Author(s):  
Justin J. Van Ee ◽  
Jacob S. Ivan ◽  
Mevin B. Hooten
Keyword(s):  
Bark Beetle ◽  
Species Distribution ◽  
Species Distribution Models ◽  
Species Distribution Model ◽  
Management Strategies ◽  
Single Species ◽  
Distribution Model ◽  
Subalpine Forest ◽  
Community Effects ◽  
Distribution Models

Abstract Joint species distribution models have become ubiquitous for studying species-habitat relationships and dependence among species. Accounting for community structure often improves predictive power, but can also alter inference on species-habitat relationships. Modulated species-habitat relationships are indicative of community confounding: The situation in which interspecies dependence and habitat effects compete to explain species distributions. We discuss community confounding in a case study of mammalian responses to the Colorado bark beetle epidemic in the subalpine forest by comparing the inference from independent single species distribution models and a joint species distribution model. We present a method for measuring community confounding and develop a restricted version of our hierarchical model that orthogonalizes the habitat and species random effects. Our results indicate that variables associated with the severity and duration of the bark beetle epidemic suffer from community confounding. This implies that mammalian responses to the bark beetle epidemic are governed by interconnected habitat and community effects. Disentangling habitat and community effects can improve our understanding of the ecological system and possible management strategies. We evaluate restricted regression as a method for alleviating community confounding and distinguish it from other inferential methods for confounded models.

Ecotoxicological Effect Indices: A Rapidly Evolving System

1987 ◽  
Vol 19 (11) ◽  
pp. 1-12 ◽  
Author(s):  
John Cairns ◽  
James R. Pratt
Keyword(s):  
Standard Dose ◽  
Biological Effects ◽  
Single Species ◽  
Test System ◽  
Integrated System ◽  
Toxicity Tests ◽  
Hazard Evaluation ◽  
Strong Interactions ◽  
Sensitive Species ◽  
Effective Manner

Ecotoxicology has evolved from a modest number of single species, acute toxicity tests to an integrated system of hazard evaluation for predicting adverse effects of chemicals and complex mixtures on environmental health. The process of screening and regulating chemicals and industrial discharges has improved water quality but has generally not been validated in receiving ecosystems. This deficiency results from the regulation of individual chemicals that rarely occur alone in the environment and from the size of the problem. Many receiving ecosystems have literally hundreds of discharges of complex effluents. Typical single species laboratory tests fail to account for the complexity of ecosystems and the strong interactions that may occur among the component species. Evidence is accumulating that complex test systems such as microcosms and mesocosms can fill this void. Microcosms and mesocosms can be constructed and experiments conducted in a cost-effective manner, and several end points can be measured in complex systems using the standard dose-response paradigm. For example, the current regulation of chlorine discharges is based on three chronic exposures to chlorinated sewage effluent. In a microcosm test, we determined adverse biological effects at nearly an order of magnitude less chlorine (1 μg/1) for the loss of microbial species. To be effective hazard evaluation tools, microcosms and mesocosms must include ecologically meaningful processes and must be useful in making decisions regarding environmental safety and harm. This can only be done with adequate statistical design and intensive sampling. Nevertheless, laboratory ecosystems can be useful in making direct measurements of effects on a large number of interacting species and can be tied to a site-specific problem in a particular ecosystem or can be standardized by using regional type ecosystems as references. By using complex natural communities, the ability to validate test system predictions increases since the test system complexity mimics that found in the real world. Despite hopes that a few sensitive species might be used to make decisions quickly on environmental effects, ecological health will only be maintained when scientists and regulators come to grips with the problem of protecting ecologically important processes as well as sensitive species. This will mean developing tests with increasing environmental realism in which environmentally realistic concentrations of chemicals can be tested without resorting to the use of safety factors or extrapolation from limited data bases. Developing such tests does not mean skyrocketing costs for screening chemicals and effluents, but suggests that regulators and toxicologists will need to deal with new information and learn new skills rather than relying on historically pleasing but ecologically deficient testing programs.

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