Aquatic Models: Water Quality and Stability and Other Environmental Factors (original) (raw)
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INTEGRATED CONDITION INDICES AS A MEASURE OF WHOLE EFFLUENT TOXICITY IN ZEBRAFISH (DANIO RERIO
Environmental Toxicology and Chemistry, 2002
Toxic exposure of organisms interferes with organismal integrity at the biochemical level and ultimately gives rise to effects at the individual level. These effects may result in reductions in ecologically relevant characteristics such as growth, reproduction, and survival. A chronic toxicity test with zebrafish (Danio rerio) was conducted where fish were exposed to 50, 75, and 100% effluent for 28 d under flow-through conditions. Effects of effluent exposure were determined using endpoints of physiological (respiration during swimming), growth (condition, length, and weight), and reproductive (spawning and hatching) processes within the same population. Results clearly indicate that the condition and growth of zebrafish is depressed by exposure to the effluent. Also, increased oxygen consumption was found after 14, 21, and 28 d of exposure. Reproduction proved to correlate well with the condition of the motherfish in the control, and spawning and hatching were significantly depressed by effluent exposure. These results indicate that the evaluation of endpoints describing different ecologically relevant processes provides a rational assessment of the cause-effect relationships of effluent toxicity. This approach can quantify effects on different biological processes and can determine the interactions that occur between these different processes.
Chemosphere, 2011
This study analyzed water quality in regions around Patos lagoon (Southern Brazil) that are under anthropogenic pressure. Water samples were collected from five different sites, including one used as a source for human consumption (COR) and others known to be influenced by human activities (IP). Danio rerio (Teleostei, Cyprinidae) organisms were exposed for 24 h to these water samples, plus a control group. It was observed that: (1) reactive oxygen species levels were lower in COR and IP than in the control group; (2) glutamate-cysteine ligase (catalytic subunit) expression was higher in COR than in other sites;
Microchemical Journal, 2019
The Water Framework Directive (WFD) addresses the European Union Member States to achieve a good status of all water bodies. The WFD measures have allowed to reduce and eliminate the discharges, releases, and emissions of several priority substances with the aim of limiting the risks for the ecosystems and public health. Additionally, a Watch List (WL) for the monitoring of emerging contaminants was adopted to assess the environmental risk of new chemicals potentially toxic for water bodies. However, the amount of toxicants widespread in the environment is incredibly high and only a tiny fraction of substances is regularly monitored as established by the European legislation. Furthermore, the WFD does not involve a monitoring plan for chemical mixtures. Chemical analysis of water samples is essential for the monitoring programmes. However, it does not give full answers about the adverse effects of contaminants present in water bodies. In this context, the effect-based methods (i.e. bioassays and biomarkers) are essential tools to implement the monitoring strategies and reach the ambitious goals included in the WFD. Zebrafish early stages, i.e. embryos and early larvae, represent a very successful vertebrate model to assess the toxic effects on aquatic organisms and to subsequently perform a valid ecosystem monitoring. Indeed, this animal model raises many advantages and allows the definition of many toxicant modes of action (MoA). In this review, we report a large number of literature studies that performed experimental analysis using zebrafish embryos and early larvae to investigate the effects of the compounds included into the WFD and the related WL. We show how the zebrafish embryo model is able to detect and identify different toxicity mechanisms and specific effects with a great level of accuracy. Our goal is to promote the use of this effect-based method in the water monitoring strategies and to improve its use for regulatory purposes.
Zebrafish in Toxicology and Environmental Health
Current Topics in Developmental Biology, 2017
As manufacturing processes and development of new synthetic compounds increase to keep pace with the expanding global demand, environmental health, and the effects of toxicant exposure are emerging as critical public health concerns. Additionally, chemicals that naturally occur in the environment, such as metals, have profound effects on human and animal health. Many of these compounds are in the news: lead, arsenic, and endocrine disruptors such as bisphenol A have all been widely publicized as causing disease or damage to humans and wildlife in recent years. Despite the widespread appreciation that environmental toxins can be harmful, there is limited understanding of how many toxins cause disease. Zebrafish are at the forefront of toxicology research; this system has been widely used as a tool to detect toxins in water samples and to investigate the mechanisms of action of environmental toxins and their related diseases. The benefits of zebrafish for studying vertebrate development are equally useful for studying teratogens. Here, we review how zebrafish are being used both to detect the presence of some toxins as well as to identify how environmental exposures affect human health and disease. We focus on areas where zebrafish have been most effectively used in ecotoxicology and in environmental health, including investigation of exposures to endocrine disruptors, industrial waste byproducts, and arsenic.
Secondary stress responses of zebrafish to different pH: Evaluation in a seasonal manner
Stress is one of the most critical factors in fish health. The response to stress in fish is characterized by the stimulation of the hypothalamus, which results in the activation of the neuroendocrine system and a subsequent cascade of metabolic and physiological changes. The present paper deals with the stress responses of water pH on certain biochemical indices and hematological parameters of zebrafish in a seasonal basis. Zebrafish were exposed to different pH e.g., 7.2, 5.0 and 10.0 and the secondary stress responses were observed. The result showed that exposure to pH 5.0 and 10.0 on zebrafish exerted stresses with reference to seasons. Higher values of blood glucose content observed in the month of summer than the month of winter and females showed higher values than males. Chronic effects of pH on the hematological parameters were also significant between these seasons. In conclusion, exposure to pH at sub-lethal concentrations induced biochemical and hematological alterations in zebrafish and offers a simple tool to evaluate the potential risk of polluted water (acid and base) to fish.
CHANGES IN CELLULAR ENERGY BUDGET AS A MEASURE OF WHOLE EFFLUENT TOXICITY IN ZEBRAFISH (DANIO RERIO
Environmental Toxicology and Chemistry, 2003
Organisms exposed to suboptimal conditions face an a priori cost of combating stress in terms of metabolic resources. The energy available for maintenance, growth, and reproduction, based on the biochemical analysis of the energy budget rather than on the direct measurement of those endpoints, may therefore provide a sensitive measure of stress in an organism. The aim of this study was to validate changes in energy budget as an ecologically relevant sublethal parameter by comparing these responses with physiological, growth, and reproductive endpoints. A toxicity test with zebrafish (Danio rerio) was conducted where fish were exposed to a control and 50, 75, and 100% effluent for 28 d under flow-through conditions. Effects of effluent exposure were measured as changes in glycogen, lipid, and protein budgets. Furthermore, the observed effects were linked to different processes like growth, condition, respiration, and reproduction within the same populations. Our results indicate that changes in lipid budgets in exposed fish were the most sensitive endpoint. Excellent relations were found between cellular energy budgets, relative condition factor, and respiration (r 2 ϭ 0.795, p Ͻ 0.001; and r 2 ϭ 0.735, p Ͻ 0.001, respectively), but relations were poorer for reproductive output (r 2 ϭ 0.410, p Ͻ 0.034). As a whole, especially changes in lipid energy budgets provide a sensitive and fast indicator of altered condition in zebrafish under the given exposure regime and allow linking cellular effects to other endpoints within the same exposed populations.
Ecotoxicology and environmental safety, 2018
The Billings reservoir is the largest water-storage facility in the São Paulo Metropolitan Region, with only a small part of the reservoir used for water supply. Recently, the São Paulo Metropolitan Region has experienced the greatest water collapse ever recorded. Thus, the intensification of use of the Billings reservoir should be considered. The objective of this study was to evaluate the quality of the water from different areas of the Billings reservoir related to human consumption (water supply and fishing): Rio Pequeno, Rio Grande, and Bororé rivers. We performed microbiological and physical studies on one water sample collected at each of these sites. Adult zebrafish were exposed to such water samples and their behaviors were evaluated. Finally, we studied central glial fibrillary acidic protein (GFAP) expression, which is related to neuroinflammatory processes. Water samples from Rio Pequeno, Rio Grande, and Bororé presented microbiological contamination for Escherichia coli...
Use of zebrafish (Danio rerio) as a model for research in toxicological studies
Journal of Applied and Natural Science, 2021
Danio rerio, commonly known as zebrafish, is a freshwater aquarium fish and is native to parts of South Asia. It is considered an important organism for analyzing the noxious effects of toxicants and pollutants of the environment. In terms of the molecular signaling pathway, molecular properties, organ functions and structures, and neurogenesis, zebrafish are similar to certain other higher-order vertebrates. The 3Rs, refinement,reduction, and replacement in researchhavegradually evolved with time. The accumulation of toxicants in the environment and the human health conditions from exposure to toxicants present in the environment is a serious concern, and zebrafish serves as an excellent model to research such effects. The three Rs are met by zebrafish, larvae can also be used to discover harmful medication compounds, permitting safer compounds to be explored in model organisms and it could also be used to substitute certain toxicological testing.Also, because embryos are fertilize...
Environmental Science and Pollution Research, 2022
Eco-toxicity profiles for commonly used disinfectants were lacking. Available traditional toxicity techniques have some limitations (assessments and ethical issues). Behaviour toxicology is a promising research area towards early warning and non-invasive approaches. We studied the potential eco-toxic effects of sodium hypochlorite (NaOCl) on the swimming behaviour of zebrafish. Zebrafish were exposed to different concentrations (Treatment I, Treatment II, Treatment III, and Treatment IV) of NaOCl for 360 h. Recovery study (144 h) was conducted for NaOCl treatment groups. The swimming behaviour of zebrafish was quantified efficiently using an online monitoring system (OMS). OMS dataset was processed for determination of behavioural differences by MATLAB and SPSS. Compared to the control group, the swimming strength of zebrafish under NaOCl treatments declined significantly (p < 0.001). Avoidance behaviour has occurred on zebrafish under NaOCl exposure periods. Furthermore, NaOCl toxicity also adjusted circadian rhythms on zebrafish. Zebrafish swimming strength was significantly (p < 0.001) improved under-recovery periods. Moreover, normal diurnal patterns have occurred. NaOCl could cause behavioural abnormalities in non-target organisms. Continuous exposure to common disinfectants could cause external and internal stress on non-target organisms, resulting in behavioural changes and circadian rhythm adjustments. Continuous changes in behavioural and circadian rhythms might reduce organisms' fitness and adaptation capacity. This study highlights (1) the importance of computer-based toxicity assessments, and (2) swimming behaviour is an early warning biomarker for eco-toxicity studies.