scholarly journals The predictability of mixture toxicity of demethylase inhibiting fungicides to Daphnia magna depends on life-cycle parameters

2014 ◽  
Author(s):  
Enken Hassold ◽  
Thomas Backhaus
Keyword(s):  
Daphnia Magna ◽  
Mixture Toxicity ◽  
Toxicity Assessment ◽  
Concentration Addition ◽  
Specific Effects ◽  
Predictive Quality ◽  
Dmi Fungicides ◽  
Reproduction Test ◽  
Fecundity Reduction

A variety of different fungicides is found simultaneously in surface waters, among which demethylase inhibitors (DMIs) are a major group. The joint toxicity of four DMIs from different chemical classes (Fenarimol, Prochloraz, Triadimefon and Pyrifenox) was investigated in the reproduction test with Daphnia magna, following an extended protocol according to ISO 10706. We assessed the toxicity of the DMI mixtures across different endpoints and effect levels and evaluated the predictability of their joint action using Concentration Addition (CA) and Independent Action (IA). The mixture reduced fecundity, delayed molting and caused characteristic malformations in offspring in a concentration-dependend manner which is possibly due to an anti-ecdysteroid action, as previously described for individual DMIs. However, also mixture-specific effects were observed: exposed daphnids reached sexual maturity already after the third juvenile molt, and thus significantly earlier than unexposed daphnids, which needed four juvenile molts to reach maturity. This effect is not caused by any of the DMIs alone. Additionally, the percentage of aborted broods was synergistically higher than expected by either CA or IA. IA underestimates the mixture toxicity for all parameters. The predictive quality of CA differed between life history responses, but was always within a factor of two to the observed toxicity. The parameter “fecundity reduction, counting only normally developed offspring” was the most sensitive endpoint, while the parameter “fecundity reduction, counting all living offspring” was slightly less sensitive. The mixture caused a 90% reduction in fecundity at individual concentrations that only provoke 7% effect or less, which calls for a mixture-specific toxicity assessment of DMI fungicides.

scholarly journals The predictability of mixture toxicity of demethylase inhibiting fungicides to Daphnia magna depends on life-cycle parameters

2014 ◽  
Author(s):  
Enken Hassold ◽  
Thomas Backhaus
Keyword(s):  
Daphnia Magna ◽  
Mixture Toxicity ◽  
Toxicity Assessment ◽  
Concentration Addition ◽  
Specific Effects ◽  
Predictive Quality ◽  
Dmi Fungicides ◽  
Reproduction Test ◽  
Fecundity Reduction

A variety of different fungicides is found simultaneously in surface waters, among which demethylase inhibitors (DMIs) are a major group. The joint toxicity of four DMIs from different chemical classes (Fenarimol, Prochloraz, Triadimefon and Pyrifenox) was investigated in the reproduction test with Daphnia magna, following an extended protocol according to ISO 10706. We assessed the toxicity of the DMI mixtures across different endpoints and effect levels and evaluated the predictability of their joint action using Concentration Addition (CA) and Independent Action (IA). The mixture reduced fecundity, delayed molting and caused characteristic malformations in offspring in a concentration-dependend manner which is possibly due to an anti-ecdysteroid action, as previously described for individual DMIs. However, also mixture-specific effects were observed: exposed daphnids reached sexual maturity already after the third juvenile molt, and thus significantly earlier than unexposed daphnids, which needed four juvenile molts to reach maturity. This effect is not caused by any of the DMIs alone. Additionally, the percentage of aborted broods was synergistically higher than expected by either CA or IA. IA underestimates the mixture toxicity for all parameters. The predictive quality of CA differed between life history responses, but was always within a factor of two to the observed toxicity. The parameter “fecundity reduction, counting only normally developed offspring” was the most sensitive endpoint, while the parameter “fecundity reduction, counting all living offspring” was slightly less sensitive. The mixture caused a 90% reduction in fecundity at individual concentrations that only provoke 7% effect or less, which calls for a mixture-specific toxicity assessment of DMI fungicides.

scholarly journals The predictability of mixture toxicity of demethylase inhibiting fungicides to Daphnia magna depends on life-cycle parameters

2013 ◽  
Author(s):  
Enken Hassold ◽  
Thomas Backhaus
Keyword(s):  
Daphnia Magna ◽  
Mixture Toxicity ◽  
Toxicity Assessment ◽  
Concentration Addition ◽  
Specific Effects ◽  
Predictive Quality ◽  
Dmi Fungicides ◽  
Reproduction Test ◽  
Fecundity Reduction

A variety of different fungicides is found simultaneously in surface waters, among which demethylase inhibitors (DMIs) are a major group. The joint toxicity of four DMIs from different chemical classes (Fenarimol, Prochloraz, Triadimefon and Pyrifenox) was investigated in the reproduction test with Daphnia magna, following an extended protocol according to ISO 10706. We assessed the toxicity of the DMI mixtures across different endpoints and effect levels and evaluated the predictability of their joint action using Concentration Addition (CA) and Independent Action (IA). The mixture reduced fecundity, delayed molting and caused characteristic malformations in offspring in a concentration-dependend manner which is possibly due to an anti-ecdysteroid action, as previously described for individual DMIs. However, also mixture-specific effects were observed: exposed daphnids reached sexual maturity already after the third juvenile molt, and thus significantly earlier than unexposed daphnids, which needed four juvenile molts to reach maturity. This effect is not caused by any of the DMIs alone. Additionally, the percentage of aborted broods was synergistically higher than expected by either CA or IA. IA underestimates the mixture toxicity for all parameters. The predictive quality of CA differed between life history responses, but was always within a factor of two to the observed toxicity. The parameter “fecundity reduction, counting only normally developed offspring” was the most sensitive endpoint, while the parameter “fecundity reduction, counting all living offspring” was slightly less sensitive. The mixture caused a 90% reduction in fecundity at individual concentrations that only provoke 7% effect or less, which calls for a mixture-specific toxicity assessment of DMI fungicides.

Zinc and nickel binary mixtures act additively on the tropical mysid Mysidopsis juniae

2016 ◽  
Vol 67 (3) ◽  
pp. 301 ◽  
Author(s):  
Lívia Pitombeira de Figuerêdo ◽  
Jeamylle Nilin ◽  
Allyson Queiroz da Silva ◽  
Évila Pinheiro Damasceno ◽  
Susana Loureiro ◽  
...  
Keyword(s):  
Binary Mixtures ◽  
Conceptual Models ◽  
Anthropogenic Activities ◽  
Mixture Toxicity ◽  
Marine Species ◽  
Toxicity Assessment ◽  
Concentration Addition ◽  
Mortality Data ◽  
Chemical Toxicity ◽  
Single Chemical

Heavy metals may appear in the environment as a result of different anthropogenic activities, such as agriculture practices, industry and mining. They can reach aquatic environments as complex mixtures, and single chemical toxicity as a baseline for risk assessment can underestimate the impairment of ecosystems. The aim of the present study was to evaluate combined toxicity of binary mixtures of zinc and nickel to the tropical mysid Mysidopsis juniae. Acute toxicity was assessed and mixture toxicity was modelled using the conceptual models for concentration addition and independent action to predict whether both metals act additively or whether they interact with each other inside the organism. For that, the observed mortality data were compared with the modelled data. For the single toxicity assessment, results showed that nickel induced higher toxicity than did zinc, with lethal concentrations to 50% of the organisms of 180±30μgL–1 and 260±40μg zinc L–1 respectively. In binary mixtures, both metals acted additively and no interactions were predicted by using the conceptual models. The present study has highlighted the need to fill the gaps in toxicity studies using marine species and approaches that can help improve the assessment of accurate risk in the environment.

scholarly journals Medicines, shaken and stirred: a critical review on the ecotoxicology of pharmaceutical mixtures

2014 ◽  
Author(s):  
Thomas Backhaus
Keyword(s):  
Empirical Data ◽  
Critical Review ◽  
Mixture Toxicity ◽  
Toxicity Assessment ◽  
Concentration Addition ◽  
Ecological Interactions ◽  
Independent Action ◽  
Soil Organisms ◽  
Analytical Monitoring ◽  
Marine Flora

Analytical monitoring surveys routinely confirm that organisms in the environment are exposed to complex multi-component pharmaceutical mixtures. We are hence tasked with the challenge to take this into consideration when investigating the ecotoxicology of pharmaceuticals. This review first provides a brief overview of the fundamental approaches for mixture toxicity assessment, which is then followed by a critical review on the empirical evidence that is currently at hand on the ecotoxicology of pharmaceutical mixtures. It is concluded that, while the classical concepts of Concentration Addition and Independent Action (Response Addition) provide a robust scientific footing, several knowledge gaps remain. This includes in particular the need for more and better empirical data on the effects of pharmaceutical mixtures on soil organisms as well as marine flora and fauna, and exploring the quantitative consequences of toxicokinetic, toxicodynamic and ecological interactions. Increased focus should be put on investigating the ecotoxicology of pharmaceutical mixtures in environmentally realistic settings.

scholarly journals Screening level mixture risk assessment of pharmaceuticals in STP effluents

2013 ◽  
Author(s):  
Thomas Backhaus ◽  
Maja Karlsson
Keyword(s):  
Mixture Toxicity ◽  
Toxicity Assessment ◽  
Concentration Addition ◽  
Individual Risk ◽  
Single Substance ◽  
Rough Approximation ◽  
Realistic Assessment ◽  
Few Data ◽  
Mixture Risk Assessment

We modeled the ecotoxicological risks of the pharmaceutical mixtures emitted into the environment from STP effluents. The classic mixture toxicity concept of Concentration Addition was used to calculate the total expect risk of the analytically determined mixtures, compare the expected impact of seven effluent streams and pinpoint the most sensitive group of species. Single substance-based assessments underestimate the actual risks from pharmaceutical mixtures often by more than a factor of 1 000 in several of the surveyed effluent streams, clearly indicating the need to take the joint presence of pharmaceuticals into consideration in order to provide an environmentally realistic assessment for a given water body. The mixture risk quotients regularly exceed 1, indicating a potential risk for the environment, depending on the specific environmental conditions, in particular the dilution in the recipient stream. The top 10 mixture components explain more than 95% of the mixture risk in all cases. A mixture toxicity assessment cannot go beyond the underlying single substance data. The lack of data on the chronic toxicity of most pharmaceuticals as well as the very few data available for in vivo fish toxicity has to be regarded as a major knowledge gap in this context. On the other hand, ignoring Independent Action or even using the sum of individual risk quotients as a rough approximation of Concentration Addition does not have a major impact on the final risk estimate.

scholarly journals Status Quo in Data Availability and Predictive Models of Nano-Mixture Toxicity

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 124
Author(s):  
Tung X. Trinh ◽  
Jongwoon Kim
Keyword(s):  
Predictive Models ◽  
Computational Models ◽  
Experimental Studies ◽  
Mixture Toxicity ◽  
Quantitative Structure Activity Relationship ◽  
Toxicity Assessment ◽  
Current Data ◽  
Data Availability ◽  
Concentration Addition ◽  
Living Organisms

Co-exposure of nanomaterials and chemicals can cause mixture toxicity effects to living organisms. Predictive models might help to reduce the intensive laboratory experiments required for determining the toxicity of the mixtures. Previously, concentration addition (CA), independent action (IA), and quantitative structure–activity relationship (QSAR)-based models were successfully applied to mixtures of organic chemicals. However, there were few studies concerning predictive models for toxicity of nano-mixtures before June 2020. Previous reviews provided comprehensive knowledge of computational models and mechanisms for chemical mixture toxicity. There is a gap in the reviewing of datasets and predictive models, which might cause obstacles in the toxicity assessment of nano-mixtures by using in silico approach. In this review, we collected 183 studies of nano-mixture toxicity and curated data to investigate the current data and model availability and gap and to derive research challenges to facilitate further experimental studies for data gap filling and the development of predictive models.

scholarly journals Biotesting and phytoindication of aquatic environment quality of urbanized territories

2019 ◽  
Vol 30 (2) ◽  
pp. 101-105
Author(s):  
A. A. Alexeyeva ◽  
O. M. Marenkov ◽  
V. O. Kurchenko ◽  
I. V. Holub ◽  
O. O. Petrovsky
Keyword(s):  
Daphnia Magna ◽  
Aquatic Environment ◽  
Toxicity Assessment ◽  
Snowmelt Runoff ◽  
Environment Quality ◽  
Test Organisms ◽  
Aquatic Environment Quality ◽  
Test Objects ◽  
Wastewater Outfall

Currently, there is a necessity for regular quality control over natural water bodies within the territory of industrial cities. The aquatic environment quality monitoring and the toxicity assessment of the water pollutants, in addition to the hydrochemical analysis data, require integral, biological indicators. In recent times, methods of direct aquatic toxicity assessment, namely biotesting water quality using sensitive hydrobionts and phytoindication with macrophytes, have become increasingly important. In this regard, we have conducted a comparative quality assessment of the water from three different areas of the Saksagan river, influenced by the Ternovska mine in Kryvyi Rih using various test objects. Hydrobiological samples were collected in September 2019 above wastewater outfall (residual rainfall and snowmelt runoff), at wastewater outfall (residual rainfall and snowmelt runoff) and below rwastewater outfall (residual rainfall and snowmelt runoff). In water the basic hydrochemical indicators have been defined: hydrogen index (pH), dissolved gases, biogenic elements, hardness, temperature, electrical conductivity, total mineralization (salinity). The quality of the aquatic environment was assessed by biotesting with daphnid Daphnia magna Straus and phytoindication by modified Mayer`s index. The analysis of the hydrochemical regime has been carried out according to generally accepted methods. Biotesting of water samples was carried out according to CTDC 211.1.4.054-97. In the experiments daphnid Daphnia magna Straus were used as test organisms. For testing the samples toxicity Daphnia youth under the age of 24 hours has been used. The toxicity criterion was the mortality of test organisms in relation to control. The number of dead animals was calculated after 96 hours, then the mortality (or survival) of objects in the samples was calculated. The survey of vegetation has been carried out visually. A rake and a d-shaped net have been used to study the submerged species. The detected algae have been systematized into 3 groups according to the modified Mayer`s index. The average index for the entire monitoring area has reached 15 points, which corresponds to the third quality class (moderately polluted river, β-mesosaprobic zone). It has been revealed that the hydrochemical composition of the water of the Saksagan river is characterized by a sufficiently high mineralization (2.6–3.5 g / l), which is caused by the complex influence of several factors: physiographic conditions, river control (the influence of Makartivske, Krasovske, Saksaganske reservoirs). A naturally simplified structure of the species composition of macrophytes has been noted, which is typical for reservoirs under anthropogenic load. Endangered and listed in the Red book of Ukraine plant species in the study area were absent. The comparison of the results of bioindication methods with hydrochemical analysis has shown that phytoindication by the modified Mayer`s index was more sensitive method with respect to biotesting on daphnid Daphnia magna. However, we consider it impossible to compare these test objects, since each object may have a specific reaction to individual toxicants (Daphnia – to insecticides, macrophytes – to herbicides). Thus, in the future, it is recommended to use a set of methods for rapid assessment of the water quality in urban areas.

scholarly journals Mixture toxicity of six pharmaceuticals towards Aliivibrio fischeri, Daphnia magna, and Lemna minor

2021 ◽  
Author(s):  
Anna Białk-Bielińska ◽  
Łukasz Grabarczyk ◽  
Ewa Mulkiewicz ◽  
Alan Puckowski ◽  
Stefan Stolte ◽  
...  
Keyword(s):  
Daphnia Magna ◽  
Lemna Minor ◽  
Opioid Analgesic ◽  
Mixture Toxicity ◽  
Concentration Addition ◽  
Case Scenario ◽  
Worst Case ◽  
Ca Model ◽  
Inflammatory Drugs ◽  
Aliivibrio Fischeri

AbstractAs the knowledge on the joint effects of pharmaceuticals towards different non-target organisms is still limited, the aim of our study was to evaluate the toxicity of mixtures of pharmaceuticals, as well as their baseline toxicity towards three selected organisms, namely the bioluminescent bacteria Aliivibrio fischeri, the crustacean Daphnia magna, and the duckweed Lemna minor. Different mixtures composed of three up to five pharmaceuticals having the same or different mechanisms of action in terms of their therapeutic activity (non-steroidal anti-inflammatory drugs, opioid analgesic, antibacterial and anti-epileptic drugs) were investigated. The observed EC50s were compared with those predicted using the concentration addition (CA) and independent action (IA) models. In general, the EC50 values for mixtures predicted with the CA model were lower than those obtained with the IA model, although, in some cases, test predictions of these two models were almost identical. Most of the experimentally determined EC50 values for the specific mixtures were slightly higher than those predicted with the CA model; hence, a less than additive effect was noted. Based on the obtained results, it might be concluded that the CA model assumes the worst-case scenario and gives overall closer predictions; therefore, it should be recommended also for modeling the mixture toxicity of pharmaceuticals with different modes of action.

scholarly journals Screening level mixture risk assessment of pharmaceuticals in STP effluents

2013 ◽  
Author(s):  
Thomas Backhaus ◽  
Maja Karlsson
Keyword(s):  
Mixture Toxicity ◽  
Toxicity Assessment ◽  
Species Group ◽  
Concentration Addition ◽  
Individual Risk ◽  
Rough Approximation ◽  
Total Mixture ◽  
Few Data ◽  
Mixture Risk Assessment

We modeled the ecotoxicological risks of the pharmaceutical mixtures emitted from STP effluents into the environment. The classic mixture toxicity concept of Concentration Addition was used to calculate the total expected risk of the analytically determined mixtures, compare the expected impact of seven effluent streams and pinpoint the most sensitive group of species. The risk quotient of a single, randomly selected pharmaceutical is often more than a factor of 1 000 lower than the mixture risk, clearly indicating the need to systematically analyse the overall risk of all pharmaceuticals present. The MCR, which is the ratio between the most risky compound and the total mixture risk, varies between 1.2 and 4.2, depending on the actual scenario and species group under consideration. The mixture risk quotients, based on acute data and an assessment factor of 1 000, regularly exceed 1, indicating a potential risk for the environment, depending on the dilution in the recipient stream. The top 10 mixture components explain more than 95% of the mixture risk in all cases. A mixture toxicity assessment cannot go beyond the underlying single substance data. The lack of data on the chronic toxicity of most pharmaceuticals as well as the very few data available for in vivo fish toxicity has to be regarded as a major knowledge gap in this context. On the other hand, ignoring Independent Action or even using the sum of individual risk quotients as a rough approximation of Concentration Addition does not have a major impact on the final risk estimate.

scholarly journals Medicines, shaken and stirred: a critical review on the ecotoxicology of pharmaceutical mixtures

2014 ◽  
Vol 369 (1656) ◽  
pp. 20130585 ◽  
Author(s):  
Thomas Backhaus
Keyword(s):  
Empirical Data ◽  
Critical Review ◽  
Mixture Toxicity ◽  
Toxicity Assessment ◽  
Concentration Addition ◽  
Ecological Interactions ◽  
Independent Action ◽  
Soil Organisms ◽  
Analytical Monitoring ◽  
Marine Flora

Analytical monitoring surveys routinely confirm that organisms in the environment are exposed to complex multi-component pharmaceutical mixtures. We are hence tasked with the challenge to take this into consideration when investigating the ecotoxicology of pharmaceuticals. This review first provides a brief overview of the fundamental approaches for mixture toxicity assessment, which is then followed by a critical review on the empirical evidence that is currently at hand on the ecotoxicology of pharmaceutical mixtures. It is concluded that, while the classical concepts of concentration addition and independent action (response addition) provide a robust scientific footing, several knowledge gaps remain. This includes, in particular, the need for more and better empirical data on the effects of pharmaceutical mixtures on soil organisms as well as marine flora and fauna, and exploring the quantitative consequences of toxicokinetic, toxicodynamic and ecological interactions. Increased focus should be put on investigating the ecotoxicology of pharmaceutical mixtures in environmentally realistic settings.

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