toxicity test Articles
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Toxicity Testing Moves Ahead
Who would have thought that an automated laboratory working around the clock could screen chemical substances for interactions with biological targets at speeds mere mortals could hardly consider — let alone match? Well, this is exactly what is occurring today thanks to a collaborative effort known as “Tox21″ among the U.S. Environmental Protection Agency (EPA), the National ...
By Acta Group
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Use of an exposure chamber to maintain aqueous‐phase nanoparticle dispersions for improved toxicity testing in fish
A novel chamber for maintaining aqueous phase dispersions of nanoparticles (NPs) to enable improved toxicity testing in larval zebrafish was developed. Aqueous concentrations were within 80% of initial NP concentrations, and 96‐h LC50 values were highly reproducible (coefficient of variation <0.16, n=3 tests). Significantly lower toxicity for each NP tested (Ag‐, Cu‐, TiO2‐NPs) in static ...
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Selecting surrogate endpoints for estimating pesticide effects on avian reproductive success
A Markov chain nest productivity model (MCnest) has been developed for projecting the effects of a specific pesticide‐use scenario on the annual reproductive success of avian species of concern. A critical element in MCnest is the use of surrogate endpoints, defined as measured endpoints from avian toxicity tests that represent specific types of effects possible in field populations at ...
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Freshwater Invertebrate Toxicity Tests
Abstract : The first part of the paper addresses the state of the art of standard freshwater invertebrate toxicity tests for regulatory purposes, with details of the characteristics and the test procedures of the acute and chronic tests with Daphnids (Daphnia magna, Daphnia pulexand Ceriodaphnia dubia). Subsequently this review reports on standard tests used for non-regulatory assays, and in ...
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Contrasting effects of chloride on growth, reproduction, and toxicant sensitivity in two genetically distinct strains of Hyalella azteca
The strain of Hyalella azteca (Saussure: Amphipoda) commonly used for aquatic toxicity testing in the US has been shown to perform poorly in some standardized reconstituted waters frequently used for other test species. In 10‐ and 42‐day experiments, we show that growth and reproduction of the US Lab strain of H. azteca varies strongly with chloride concentration in the test water, with ...
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Cyst Based Toxicity Tests. - VIII. Short-Chronic Toxicity Tests with the Freshwater Rotifer Brachionus calyciflorus
Abstract : The development and potential use of a 4-day static renewal test [4-day Life Table (LT) test] and a 3-day static test [3-day Population Growth (PG) test] with the freshwater rotifers Brachionus calyciflorus are described. For both bioassays, test animals are obtained by hatching cysts wich eliminates the need for the culturing and the maintenance of the organisms. The toxicity of ...
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Critical predicted no effect concentrations (PNECs) should not be based on a single toxicity test
Predicted no effect concentrations (PNECs), which represent the concentration of a substance below which an unacceptable effect will most likely not occur, are widely used for risk assessment and in environmental policy and regulation. They are typically based on single species laboratory toxicity tests; often, a single test result for the most sensitive endpoints drives the derivation of a ...
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Microscale Toxicity Testing with Rotifers
Abstract :Toxicity tests are one of the essential tools for evaluating the effects of anthropogenic stress in aquatic ecosystems. Methods using microscale organisms have improved the speed, simplicity, and reduced the cost of making toxicity measurements. The size, ecology, and life cycle of rotifers makes them well suited for microscale assays and toxicity assessment. In the last five years the ...
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Cyst-Based Toxicity Tests. - V. Development and Critical Evaluation of Standardized Toxicity Tests with the Brine Shrimp Artemia (Anostraca, Crustacea)
Abstract : The use of cryptobiotic stages (called cysts of dormant eggs), from which live test organisms can be hatched at will, eliminates the need for continuous stock culturing and opens a promising perspective for better standardization of test methodologies in aquatic toxicology. Although there are several groups of aquatic invertebrates which produce resting stages, the brine shrimp ...
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Assessment of toxicity test endpoints for freshwater mussel larvae (glochidia)
The objectives of our study were to determine if the viability of freshwater mussel larvae (glochidia) is an ecologically relevant endpoint for toxicity tests and to define the appropriate duration of those tests. We assessed 1) how viability (the shell closure response to sodium chloride) compares to infectivity (ability to attach to a host fish and successfully metamorphose to the juvenile ...
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Laboratory algal bioassays using PAM fluorometry: Effects of test conditions on the determination of herbicide and field sample toxicity
Pulse Amplitude Modulation (PAM) fluorometry, based on chlorophyll a fluorescence, is a frequently used technique in algal bioassays to assess toxicity of single compounds or complex field samples. It is known that several test conditions can influence the test results and since a standardized test protocol is currently lacking, it is difficult to link the results of different studies. ...
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A toxicokinetic and toxicodynamic model approach of Myriophyllum spicatum to predict effects caused by short‐term exposure to a sulfonylurea
Toxicokinetic and toxicodynamic models are a promising tool to address the effects of time‐variable chemical exposure. While standard toxicity tests rely, in most cases, on static concentrations, these chemical exposure patterns are unlikely to appear in the field, where time‐variable exposure of chemicals is typical. In this study, we integrated toxicodynamic processes into an existing model ...
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Short‐term toxicity of ammonia, nitrite and nitrate to early life stages of the rare minnow, Gobiocypris rarus
Nitrogenous pollutants including ammonia, nitrite, and nitrate are a widespread concern in natural waters and aquaculture. In the present study, the toxicity of ammonia, nitrite, and nitrate to rare minnow (Gobiocypris rarus) in the early life stage were evaluated by two short‐term toxicity tests. In the short‐term toxicity test conducted on embryo and sac‐fry stage, 30 fertilized eggs with ...
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A Comparison Of Standard Acute Toxicity Tests With Rapid-Screening Toxicity Tests
Abstract: This study compared the relative sensitivity of five inexpensive, rapid toxicity tests to the sensitivity of five standard aquatic acute toxicity tests through literature review and testing. The rapid toxicity tests utilized organisms that require little culturing or handling prior to testing : a freshwater rotifer (Brachnionus calyciflorus); brine shrimp (Artemia salina); lettuce ...
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A Brief Review and Critical Evaluation of the Status of Microbiotests
Abstract : A review is given on some of the current trends in the field of alternative, small-scale aquatic toxicity tests. Examples of recently developed microbiotests with bacteria, algae and invertebrates are used to illustrate potential applications and short-comings of some of these assays. The major drawback of the majority of new microbiotests is the lack of published data on various ...
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