Acute Water Toxicity Research Articles

Bazı Azo Boyalarının QSAR Yöntemi ve Daphnia Magna ile Akut Toksisite Testi ile İncelenmesi

Azo dyes represent the most important class of textile dyes. Biotransformation of azo dyes can release aromatic amines. It is well known that some aromatic amines have genotoxic and/or carcinogenic properties. In this study, it was aimed to investigate the effects of azo dyes, which are composed of aromatic amines, and are widely used in the textile industry, on the environment using acute water toxicity test. The acute water toxicity test using Daphnia Magna was investigated experimentally and theoretically. The OECD QSAR Toolbox program, which has recently attracted attention in theoretical studies and is also used in international regulations, has been preferred. As a result of the studies, it was seen that the experimental and theoretical results gave parallel results. This study showed that theoretical studies can be substituted for experimental studies in order to reduce cost, time, and animal mortality in acute toxicity tests on Daphnia Magna. In addition, according to the results of this study, it was found by experimental and theoretical methods that Basic Yellow 28, Disperse Blue 291, and Disperse Brown 27-1 azo dye are ecotoxicologically toxic.

Surface-enhanced Raman Scattering (SERS) microbial sensor for fresh water acute toxicity monitoring

The substances emerging in environmental water bodies are becoming increasingly complex, causing severe ecotoxicological problems. In addition, the intricate interaction among various chemicals in a water body makes it difficult to accurately evaluate the water quality by simply determining the specie and concentration of the chemicals. Thus, acute toxicity evaluation of water body presents significant importance in environmental monitoring, especially in emergency response. This work proposes a SERS approach for evaluating acute toxicity of fresh water for the first time, where indole, an interspecies signal molecule produced by E. coli strains during regulated spore formation, could be affected by toxic substances, was used as indicator. Several key factors that may affect the evaluation of acute toxicity in water were explored, including the concentration of exogenous L-tryptophan and the incubation time of E. coli with L-tryptophan. Finally, the established system was applied to the acute toxicity evaluation of model chemical Cu2+. The IC50 was determined to be 2.028 mg L-1, better than the results reported in the literature. This study demonstrates the feasibility of using SERS-based microbial sensors to assess acute toxicity in water.

A portable spectroscopic instrument for multiplexed monitoring of acute water toxicity: Design, testing, and evaluation.

The deteriorating water environment worldwide, mainly due to population explosion and uncontrolled direct disposal of harmful industrial and farming wastes, earnestly demands new approaches and accurate technologies to monitor water quality before consumption overcoming the shortcomings of the current methodologies. A spectroscopic water quality monitoring and early-warning instrument for evaluating acute water toxicity are the need of the hour. In this study, we have developed a prototype capable of the quantification of dissolved organic matter, dissolved chemicals, and suspended particulate matter in trace amounts dissolved in the water. The prototype estimates the water quality of the samples by measuring the absorbance, fluorescence, and scattering of the impurities simultaneously. The performance of the instrument was evaluated by detecting common water pollutants such as Benzopyrene, Crystal Violet, and Titanium di-oxide. The limit of detection values was found to be 0.50, 23.9, and 23.2 ppb (0.29 µM), respectively.

Towards regulation of Endocrine Disrupting chemicals (EDCs) in water resources using bioassays – A guide to developing a testing strategy

Endocrine disrupting chemicals (EDCs) are found in every environmental medium and are chemically diverse. Their presence in water resources can negatively impact the health of both human and wildlife. Currently, there are no mandatory screening mandates or regulations for EDC levels in complex water samples globally. Bioassays, which allow quantifying in vivo or in vitro biological effects of chemicals are used commonly to assess acute toxicity in water. The existing OECD framework to identify single-compound EDCs offers a set of bioassays that are validated for the Estrogen-, Androgen-, and Thyroid hormones, and for Steroidogenesis pathways (EATS). In this review, we discussed bioassays that could be potentially used to screen EDCs in water resources, including in vivo and in vitro bioassays using invertebrates, fish, amphibians, and/or mammalians species. Strengths and weaknesses of samples preparation for complex water samples are discussed. We also review how to calculate the Effect-Based Trigger values, which could serve as thresholds to determine if a given water sample poses a risk based on existing quality standards. This work aims to assist governments and regulatory agencies in developing a testing strategy towards regulation of EDCs in water resources worldwide. The main recommendations include 1) opting for internationally validated cell reporter in vitro bioassays to reduce animal use & cost; 2) testing for cell viability (a critical parameter) when using in vitro bioassays; and 3) evaluating the recovery of the water sample preparation method selected. This review also highlights future research avenues for the EDC screening revolution (e.g., 3D tissue culture, transgenic animals, OMICs, and Adverse Outcome Pathways (AOPs)).

A portable instrument for monitoring acute water toxicity based on mediated electrochemical biosensor: Design, testing and evaluation

A water quality early-warning instrument for evaluating acute water toxicity based on the electrochemical biosensor, Model ETOX18-01, was developed and manufactured with the features of low current detection (0.1 nA), precise thermostatic control, self-cleaning as well as remote data transmission. A sensitive integrated microbial electrode, made up of a glass carbon electrode that was modified by an active biofilm consisting of Escherichia coli, thionine, carbon nanodots and chitosan, has been fabricated as the biosensor. To validate the performance, multiple real water samples and artificial water samples were tested by Model ETOX18-01, and compared with ISO standardized luminescent bacterial test simultaneously. The correlation between the Model ETOX18-01 and luminescent bacterial test for these water samples showed good determination coefficient (R2 = 0.9827). In addition, Model ETOX18-01 is more sensitive to colored metal ionic samples. With its characteristics of high sensitivity, excellent repeatability and easy operation, the instrument Model ETOX18-01 provides a promising tool for large-scale water environmental assessment, and has a potential application in evaluating the water quality and early risk warning.

Redox Mediator‐Based Microbial Biosensors for Acute Water Toxicity Assessment: A Critical Review

AbstractWater toxicity assessment is of great importance for monitoring water quality and safeguarding ecological health. Microbial biosensors, which use microorganisms as the bioreceptor, offer a promising complementary method for water quality evaluation. The present Minireview has particular emphasis on microbial biosensors that use redox mediators as signal indicators and their performance for water acute toxicity assessment. The principles, fabrication methods, and recent developments of electrochemical microbial biosensors are systematically summarized. In addition, the application of microbial fuel cells in water biological oxygen demand and biotoxicity determination are also briefly introduced. The main hurdles that hinder the on‐site application of electrochemical microbial biosensors are discussed. With unceasing efforts on improvement of sensitivity and stability, electrochemical microbial biosensors are promising to play more crucial roles in water quality evaluation.

Principles of Hydration

Principles of Hydration

Immobilized bacterial biosensor for rapid and effective monitoring of acute toxicity in water

The use of biosensors by using microorganisms such as bacteria have short life cycles and provide other advantages. One colorimetric biosensor technique that has been developed is the use of a biosensor utilizing the incorporation of Prussian blue formation reactions mediated by E. coli bioreactors with ferricyanide. Immobilization is a method that allows the bacteria can be used for long-term without reducing its ability as bioreceptor. This study aimed to develop a novel and rapid immobilized bacterial biosensor for the detection of toxic compound in water and to evaluate their analytical performances. Immobilization of E. coli performed by trapping method using alginate material support. The bacterial suspension was mixed with sodium alginate (1:1 v/v), and the mixture was continuously dropped in CaCl2 solution to be a form of beads. The beads were used as bioreceptor to detect toxicants regarding cadmium, arsenic, mercury, chromium and lead solutions with Prussian blue as a colorimetric indicator. The linearity and sensitivity of detection of beads to the toxicants were tested, the stability of repeated use and storage were evaluated as well. The results showed that E. coli could be immobilized using alginate with response value was correlated with toxic concentration. The developed biosensor was more stable when used repeatedly and could be stored in a long time. The immobilization of E. coli in calcium alginate bead was successfully performed as a biosensor system for monitoring acute toxicity in water.

Small Microbial Three-Electrode Cell Based Biosensor for Online Detection of Acute Water Toxicity.

The monitoring of toxicity of water is very important to estimate the safety of drinking water and the level of water pollution. Herein, a small microbial three-electrode cell (M3C) biosensor filled with polystyrene particles was proposed for online monitoring of the acute water toxicity. The peak current of the biosensor related with the performance of the bioanode was regarded as the toxicity indicator, and thus the acute water toxicity could be determined in terms of inhibition ratio by comparing the peak current obtained with water sample to that obtained with nontoxic standard water. The incorporation of polystyrene particles in the electrochemical cell not only reduced the volume of the samples used, but also improved the sensitivity of the biosensor. Experimental conditions including washing time with PBS and the concentration of sodium acetate solution were optimized. The stability of the M3C biosensor under optimal conditions was also investigated. The M3C biosensor was further examined by formaldehyde at the concentration of 0.01%, 0.03%, and 0.05% (v/v), and the corresponding inhibition ratios were 14.6%, 21.6%, and 36.4%, respectively. This work provides a new insight into the development of an online toxicity detector based on M3C biosensor.

A novel colorimetric biosensor for monitoring and detecting acute toxicity in water

This work presents a new colorimetric microorganism biosensor for monitoring and detecting acute toxicity in water, where prussian blue (PB) is used as the colorimetric indicator and E. coli as the model bacterial. In this biosensor, the electron mediator, ferricyanide, accepts electrons from E. coli during respiration to produce ferrocyanide, which subsequently reacts with ferric ions to yield PB, a famous material with a blue color. Since toxicants can inhibit the respiratory activity of E. coli and then reduce the ferrocyanide and consequent PB production, toxicity can be easily detected by measuring the decrease in the production of PB induced by toxicants. Three important toxicants, 3,5-dichlorophenol (DCP), As(3+), Cr(6+) are tested and the detection limits are 3.2, 25, and 3.2 ppm, respectively. Moreover, we could identify the yellow green to dark green color change by naked eye even at concentrations as low as 12.5 ppm for both DCP and Cr(6+). Subsequently, the acute toxicities of groundwater and south lake water are successfully determined by this sensor. This biosensor is rapid, sensitive and cost-effective, and can thus be regarded as a promising biosensor for giving an early warning of acute water toxicity.

Water toxicity evaluation in terms of bioassay with an Electronic Tongue

A lot of various applications of the Electronic Tongue (ET) related to the detection and quantification of taste and flavour of different products were reported so far. For obvious reasons, one relies upon human perception and taste panel marks working with ET in this domain. However, there is an unusual, albeit wide, realm of perception-related analysis based on the “marks” produced by other biological species, besides human beings, from different mammals to microorganisms. Thus, a series of methodologies, which are based on an ample variety of species (e.g. Daphnia, algae, unicellular organisms, luminescent bacteria and many others) were applied for the evaluation and monitoring of water quality and detection of acute water toxicity. The present paper deals with the application of the potentiometric multisensor system for water toxicity estimation in terms of the bioassay with three living test organisms: Daphnia magna, Chlorella vulgaris and Paramecium caudatum. The prediction of water toxicity with relative errors 15–26% (depending on the test object) is possible using PLS (projection on latent structures) regression from the data obtained by potentiometric multisensor system.

Use of solid phase microextraction to estimate toxicity: Relating fiber concentrations to toxicity—part I

Use of solid-phase microextraction (SPME) fibers as a dose metric for toxicity testing was evaluated for hydrophobic pesticides to the midge Chironomus dilutus and the amphipod Hyalella azteca. Test compounds included p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT), p,p'-dichlorodiphenyldichloroethane (p,p'-DDD), p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), permethrin, bifenthrin, tefluthrin, and chlorpyrifos. Acute water toxicity tests were determined for 4- and 10-d exposures in both species. Median lethal and sublethal concentrations were expressed both on a water concentration (LC50 and EC50) and on an equilibrium SPME fiber concentration (LC50(fiber) and EC50(fiber)) basis. A significant log dose-response relationship was found between log fiber concentration and organism mortality. It has been shown in the literature that equilibrium SPME fiber concentrations reflect the bioavailable concentrations of hydrophobic contaminants, so these fiber concentrations should be a useful metric for assessing toxic effects from the bioavailable contaminant providing a framework to expand the use of SPME fibers beyond estimation of bioaccumulation.

A novel approach to rapid detection of acute water toxicity and its policy implications for grassroots sustainable environmental monitoring

Unknown chemicals, emerging contaminants, and the resulting reactions among them make early detection and warning of acute water toxicity extremely challenging. The conventional approach using small fish for toxicity monitoring normally requires a designated species of fish and over a week's time to complete, including dilution of the wastewater, a pre-test, and a full test. It often increases chances for error and delays emergency management. This paper reports a novel approach, based on grassroots knowledge and field and lab experience in Jilin, China. This approach uses a combination of different species of aquarium fish to achieve fast and reliable monitoring. It tests the original source water directly without going through the dilution procedure, while paying attention to the time factor. The approach does not require a pre-test and may shorten the time needed for detecting acute toxicity to a few minutes, using a new classification of aquatic toxicity levels. It is inexpensive to use and may be easily adopted by grassroots organizations. The approach is "greener" and more financially and socially sustainable than traditional approaches. The wide use of the approach has the potential to encourage policy innovations for making toxicity monitoring grassroots based and more effective in reducing acute contamination emergencies.

Continuous measurement of acute toxicity in water using a solid state microrespirometer

This work presents the first true solid-state microrespirometer. It consists on a naturally developed biofilm of Pseudomonas aeruginosa over a Nafion modified array of gold microdisc electrodes. Such a device can be used to monitor acute toxicity in water streams based on the oxygen reduction current recorded at the microelectrode array. When a healthy biofilm is exposed to a toxic stream the bacteria conforming stop breathing which results in an immediate increase of the oxygen supply reaching the microelectrode array. The fabrication and use of such a microrespirometer is described, and a possible operation mode for a real application is presented. Given that different waters may contain toxic compounds of diverse nature, the respirometer presented here provides qualitative information only.

Novel Integrated Electrochemical Nano-Biochip for Toxicity Detection in Water

An electrochemical nano-biochip for water toxicity detection is presented. We describe chip design, fabrication, and performance. Bacteria, which have been genetically engineered to respond to environmental stress, act as a sensor element and trigger a sequence of processes, which leads to generation of electrical current. This novel, portable and miniature device provides rapid and sensitive real-time electrochemical detection of acute toxicity in water. A clear signal is produced within less than 10 min of exposure to various concentrations of toxicants, or to stress conditions, with a direct correlation between the toxicant concentration and the induced current.