Daphnia Magna Test Research Articles

FeIII–TAML-catalyzed green oxidative degradation of the azodyeOrange II by H2O2and organic peroxides: products, toxicity, kinetics, and mechanisms

Oxidation of Orange II ([4-[(2-hydroxynaphtyl)azo]benzenesulfonic acid], sodium salt) by hydrogen peroxide catalyzed by iron(III) complexed to tetra amido macrocyclic ligands (FeIII–TAML activators) in aqueous solutions at pH 9–11 leads to CO2, CO, phthalic acid and smaller aliphatic carboxylic acids as major mineralization products. The products are non-toxic according to the Daphnia magna test. Several organic intermediates have been identified by HPLC and GC-MS that allowed the detailed description of Orange II degradation. The catalytic oxidation can also be performed by organic oxidants such as benzoyl peroxide, tert-butyl and cumyl hydroperoxides. Kinetic studies of the catalyzed oxidation indicated that FeIII–TAML activators react first with ROOR′ to form an oxidized catalyst (kI), which then oxidizes Orange II (kII). Neglecting the reversibility of the first step, the rate equation is rate = kIkII[FeIII][ROOR′][Dye]/(kI[ROOR′] + kII[Dye]); here FeIII and ROOR′ represent the catalyst and peroxide, respectively. The rate constant kI equals (74 ± 3) × 103, (1.4 ± 0.1) × 103, 24 ± 2, and 11 ± 1 M−1 s−1 for benzoyl peroxide, H2O2, t-BuOOH, and cumyl hydroperoxide at pH 9 and 25 °C, respectively. An average value of kII equals (3.1 ± 0.9) × 104 M−1 s−1 under the same conditions. The unraveling of the kinetic mechanism allows the comprehension of the robust reactivity, and this is discussed in detail using the representative results of DFT calculations.

The applicability of acetylcholinesterase and glutathione S-transferase in Daphnia magna toxicity test

The most commonly used toxicity test worldwide is the acute Daphnia magna test. The relevance of acetylcholinesterase (AChE) and glutathione S-transferase (GST) activity in D. magna exposed to chromium, cadmium, and diazinon was evaluated in connection with this standard test. We found no link between enzyme activities and immobility. Concentrations of Cr 6+ up to 280 μg/L had no effect on AChE and GST activities, while 20% immobility was observed. At concentrations of 20–25 μg/L of Cd 2+ AChE activity was increased by about 50%. The effect of diazinon on both enzymes was insignificant up to concentrations that caused 27% immobility. Consequently, while the use of AChE and GST activities is recommended when the mode of action of chemicals is studied, the value of these biomarkers in routine acute toxicity tests is limited because the relationship between enzyme activities and immobility of D. magna exposed to different chemicals is unclear.

Implications of Pulsed Chemical Exposures for Aquatic Life Criteria and Wastewater Permit Limits

Subacute effects of pulsed copper, zinc, or ammonia exposures were examined, including a range of pulse concentrations, durations, frequencies, and recovery times between pulses, using short-term chronic Pimephales promelas and 21-d Daphnia magna tests. Sublethal effects were rarely observed independent of mortality. Effects were observed only at concentrations near the species continuous exposure 48 h LC50 for each chemical. Daphnia often rebounded from temporary reproduction effects, meeting or exceeding control responses by the end of the test. Effects of 24 h ammonia or copper pulses were diminished soon after the pulse was removed, while 24 h zinc pulses caused continued effects for several days following removal of the pulse, indicating a slower uptake and/or depuration rate for zinc. D. magna exhibited less mortality as copper pulses were spaced further apart, while fish were equally or more affected with longer recovery times between copper pulses, indicative of different adaptation mechanisms between the two species. Responses were not predictable based on either average concentration or a combination of duration and concentration. Chronic water quality criteria and effluent permit limits, expressed as a 4- or 30-d average concentration, respectively, may not be appropriate for protecting against effects of pulsed exposures, depending on the frequency, magnitude, and duration of pulses, as well as the recovery period between events.

Toxicity and intermediates of C.I. Direct Red 28 dye through sequential anaerobic/aerobic treatment

Toxicity and intermediates of C.I Direct Red 28 (DR 28) azo dye was investigated through decolorization and mineralization of DR 28 azo dye in a sequential upflow anaerobic sludge blanket reactor (UASB)/continuous stirred tank reactor (CSTR) system. System performance was determined by monitoring the conventional parameters such as COD, inert COD, TOC, color, ammonia, nitrate, volatile fatty acid (VFA) and total aromatic amine (TAA) analyses. Under steady state conditions color was effectively removed under anaerobic conditions. Total aromatic amines could be mainly removed under aerobic conditions while COD was removed under both anaerobic and aerobic conditions. Samples from effluents of the system were analyzed by high performance liquid chromatography–diode array detection (HPLC–DAD) and gas chromatography–mass spectra (GC–MS) methods to detect the intermediates produced in the effluents of anaerobic and aerobic steps. Benzidine produced under anaerobic conditions was mineralized significantly under aerobic conditions. Simple qualitative analyses, NO − 3–N, HPLC and GC analyses showed that Direct Red 28 could be chiefly mineralized by the anaerobic/aerobic sequential system. Reduction of toxicity was also observed in anaerobic toxicity assays (ATA) respiration/inhibition and Daphnia magna tests through the continuous operation of anaerobic/aerobic sequential treatment system.

Monitoring of toxicity and intermediates of C.I. Direct Black 38 azo dye through decolorization in an anaerobic/aerobic sequential reactor system

An Upflow Anaerobic Sludge Blanket Reactor/Continuous Stirred Tank Reactor was used sequentially to decolorize and mineralize C.I. Direct Black 38 azo dye (3200 mg/L) in a synthetic wastewater containing glucose as co-substrate. At the steady state conditions color was effectively removed under anaerobic condition, while the total aromatic amines and organic fraction could be mainly reduced under aerobic conditions. NO 3 − N, COD, BOD 5, aromatic amine, HPLC and GC analyses showed that Direct Black 38 could be chiefly mineralized by the sequential system. The toxicity levels were determined using three different test organism (ATA-anaerobic toxicity, respiration/inhibition and Daphnia magna tests) through the continuous operation of anaerobic/aerobic sequential system treating Direct Black 38 dye containing synthetic wastewater. Feed and anaerobic effluent had greater toxicity than the aerobic effluent after mineralization of dye.

Toxicity assays applied to wastewater treatment

The utility and validity of toxicity tests for monitoring of wastewater treatment have been assessed. The evaluated acute toxicity tests have been Vibrio fischeri, Selenastrum capricornotum and Daphnia magna tests. The validation studies indicated that the acute toxicity tests can be considered as high sensitivity analytical tools to detect common environmental concentrations of the pollutants at concentration levels as low as ng l −1. The toxicity tests showed to have discriminatory ability to distinguish between different degrees of toxicity, and the toxic specificity of the compounds on target organisms. Synergistic, additive or antagonistic effects were evaluated indicating the capacity of the toxicity test to assess the combined effects of chemicals in wastewaters. The reproducibility of these tests, calculated as relative standard deviation, is acceptable in the range of 5–22.3%. The application of multivariate date analysis proved that toxicity and chemical measures are complementary analytical tools for monitoring of wastewaters quality. The toxicity tests are useful analytical tools for screening of chemical analysis and as an early warning system to monitor the treatment of WWTPs. The use of single toxicity test or battery of tests is the best approach to evaluate the risk because they are reliable indices of the toxic impact of effluents in the aquatic environment. The toxicity tests were applied in the quality control of different European WWTPs.

Complying with Effluent Toxicity Regulation in Canada

Abstract A questionnaire was sent to 75 mills in Canada requesting information on compliance in 1999 with respect to the toxicity regulation for liquid discharges. This regulation requires that at least 50% of rainbow trout and Daphnia magna survive in the discharge from the mill in toxicity tests. Of the 74 mills that responded, 81% and 74% reported no toxicity failures for process effluents in rainbow trout and Daphnia magna tests, respectively. For mills with infrequent or no toxicity episodes during the year (1 or 0 for trout; 1–4 or 0 for Daphnia magna), 89% and 92% of the mills met this criterion for trout and Daphnia magna tests, respectively. In addition to process effluents, 28 mills had separate cooling water discharges and, of these, ten experienced at least one episode of cooling water toxicity. Ammonia and accidental spills were most frequently cited by the mills as likely causes of process effluent toxicity. The most frequent causes cited for cooling water toxicity were chlorine and accidental contamination from other sources.

Aquatic toxicity of acetonitrile and its water quality criteria for the protection of aquatic life in China

The freshwater quality criteria of acetonitrile were studied on the basis of the features of the aquatic biota in China, and with reference to US EPA's guidelines. Acute tests were performed on 13 different species to determine 48h-EC50/96h-EC50 (or 96h-LC50) values for acetonitrile. 2ld survival-reproduction tests with Daphnia magna and growth inhibition tests with Lemna minor were also conducted to estimate lower chronic limit and upper chronic limit values. In the acute tests, Radix plicatula was the most sensitive species to acetonitrile followed by Chironomus sp., Cyprinus carpio and D. magna in turn. The final acute value of acetonitrile was 2290 mg/l. In the chronic tests, reproduction of daphnids was significantly reduced by acetonitrile at 320 mg/l. Acute-to-chronic ratios ranged from 2 to 15.8. A final chronic value of 413.9 mg/l was obtained and a final plant value was 1342 mg/I. A criterion maximum concentration (1145 mg/l) and a criterion continuous concentration (413.9 mg/l) were derived.

Ecotoxicological responses of isolated mitochondrial systems to complex effluents. Are they worthwhile?

In vitro assays with isolated rat liver mitochondria and sub-mitochondrial particles (SMP) of beef heart were compared with acute Daphnia magna test and Microtox®, in order to establish different sensitivities when exposed to complex effluents. Median effective concentration (EC 50) were calculated using the probit analysis, considering several endpoints: immobilisation for D. magna assays, luminescence decrease of the marine bacterium Photobacterium phosphoreum, inhibition of succinate generated potential or the depolarisation caused by ADP addition for rat liver mitochondria by the mithocondrial transmembrane electric potential (TEP) and reduction in the amount of NADH oxidised by the electron transport system to form NAD + in the case of the forward electron transport (FET) or the NADH amount that is reduced to NAD + for SMP, in the case of the reverse electron transfer (RET). The TEP tests showed to be more sensitive than the others one are. The results obtained indicate the convenience of utilising in vitro systems such as the TEP or even SMP to test whole effluent ecotoxicity.

Effects of copper-contaminated sediments on Hyalella azteca, Daphnia magna, and Ceriodaphnia dubia: Survival, growth, and enzyme inhibition

The results of two newly developed sediment toxicity tests were compared to the standard, 48-h acute Daphnia magna and Ceriodaphnia dubia tests. The 14-day Hyalella azteca growth inhibition test is a definitive test of chronic exposure to toxic sediments. The rapid, fluorescent D. magna test, which is based on in vivo inhibition of enzymatic processes, has been suggested as a rapid screening tool. H. azteca mortality was the least sensitive bioassay endpoint, while H. azteca growth, D. magna fluorescence, C. dubia mortality, and D. magna mortality were equally sensitive to the effects of sediments spiked with CuSO4. In sediments collected in copper-contaminated lakes, the standard, acute 48-h D. magna bioassay was the least sensitive test, while the D. magna fluorescence test and H. azteca growth reduction test were the most sensitive bioassays.

Cyst-based toxicity tests X: comparison of the sensitivity of the acute Daphnia magna test and two crustacean microbiotests for chemicals and wastes

This paper statistically evaluates the sensitivity of the acute Daphnia magna bioassay in comparison to that of two crustacean microbiotests: the Streptoxkit F and Thamnotoxkit F, which make use of larvae of the anostracans Streptocephalus proboscideus and Thamnocephalus platyurus respectively, hatched from cysts. Regression equations were calculated for 146 data pairs, taken from 5 different studies dealing with the acute toxicity of pure chemicals, effluents, river sediments, solid wastes and monitoring wells, and sludges. All comparisons show that there is a significant relationship (p< 0.05) between the acute effects found with the D.magna and the two crustacean microbiotests; correlation coefficients ranged from 0.84 to 0.92. In the majority of cases, effect ratios between the conventional D.magna and the microbiotests were within a factor 2 for both pure chemicals and environmental samples. Variation coefficients for repeated tests on the reference chemical potassium dichromate indicate a good precision and hence a good degree of standardization of the microbiotest procedures. The evidence provided in this paper demonstrates that the new crustacean microbiotests can be used as low cost alternatives to the conventional D.magna acute assay.

Human acute toxicity prediction of the first 50 MEIC chemicals by a battery of ecotoxicological tests and physicochemical properties

Five acute bioassays consisting of three cyst-based tests (with Artemia salina, Streptocephalus proboscideus and Brachionus calyciflorus), the Daphnia magna test and the bacterial luminescence inhibition test ( Photobacterium phosphoreum) are used to determine the acute toxicity of the 50 priority chemicals of the Multicentre Evaluation of In Vitro Cytotoxicity (MEIC) programme. These tests and five physicochemical properties ( n-octanol-water partition coefficient, molecular weight, melting point, boiling point and density) are evaluated either singly or in combination to predict human acute toxicity. Acute toxicity in humans is expressed both as oral lethal doses (HLD) and as lethal concentrations (HLC) derived from clinical cases. A comparison has also been made between the individual tests and the conventional rodent tests, as well as between rodent tests and the batteries resulting from partial least squares (PLS), with regard to their predictive power for acute toxicity in humans. Results from univariate regression show that the predictive potential of bioassays (both ecotoxicological and rodent tests) is generally superior to that of individual physicochemical properties for HLD. For HLC prediction, however, no consistent trend could be discerned that indicated whether bioassays are better estimators than physicochemical parameters. Generally, the batteries resulting from PLS regression seem to be more predictive than rodent tests or any of the individual tests. Prediction of HLD appears to be dependent on the phylogeny of the test species: cructaceans, for example, appear to be more important components in the test battery than rotifers and bacteria. For HLC prediction, one anostracan and one cladoceran crustacean are considered to be important. When considering both ecotoxicological tests and physicochemical properties, the battery based on the molecular weight and the cladoceran crustacean predicts HLC substantially better than any other combination.

The Predictive Potential of a Battery of Ecotoxicological Tests for Human Acute Toxicity, as Evaluated with the First 50 MEIC Chemicals

The acute toxicities of the first 50 chemicals (dextropropoxyphene hydrochloride excluded) of the multicentre evaluation of in vitro cytotoxicity (MEIC) programme were determined on four aquatic invertebrates and a bacterial strain (Photobacterium phosphoreum for the Microtox™ test) commonly used in ecotoxicology testing. Three of the aquatic invertebrate tests consisted of cyst-based toxicity tests (Artoxkit M with Artemia salina, Streptoxkit F with Streptocephalus proboscideus, and Rotoxkit F with Brachionus calyciflorus), and the Daphnia magna test. Results of simple linear regression analyses indicated that the rodent tests (rat and/or mouse) were better than the ecotoxicological tests for predicting acute oral lethal doses in man. However, it appears that the batteries of ecotoxicological tests resulting from the partial least squares method appear to be better than the rodent tests for predicting human oral lethal doses.

Assessment of toxicant activity in sediments by the ECHA biocide monitor

The ECHA Biocide Monitor, a dipstick procedure originally designed to test the effectiveness of in situ biocides, was evaluated as a possible environmental toxicity assessment procedure. The dipstick procedure was applied to 94 sediment extracts which were also tested by three well documented toxicant screening procedures; Microtox, Daphnia magna and Spirillum volutans. In these samples the Daphnia magna test proved to be the most sensitive indication of toxicant activity (63 of 94) with the ECHA Biocide Monitor easily being the second most sensitive procedure with 27 of 94 sediments indicating the presence of toxic substances. Results of the investigation are detailed.

Battery of screening tests approach applied to sediment extracts

AbstractThis paper reports the application of a battery of microbiological and toxicant screening tests to sediments collected from the Port Hope area. The sediments were extracted using Milli‐Q water and solvents. The solvent extracts indicated that the whole sampling area has been impacted by toxic chemicals. The Daphnia magna test was the most sensitive screening test in Milli‐Q water extracts. Microbiological studies indicated that the sampling area was, and is continuing to be, impacted by fecal pollution.

Ozonization of Humic Acids. Medium Term Toxicity Towards Daphnia Magna

The ozonation products of humic acids are toxicologically interesting for two reasons: by their actual toxicity, but also because of their complexing capacity vis-à-vis trace metals present in water which are, because of this fact, incompletely eliminated by potabilization techniques. Determination of the ultimate toxicity of ozonized humic acids is achieved with the aid of the medium term Daphnia magnatest. Statistical treatment of the two lethal parameters and of the four sublethal parameters have shown a toxicity for ozonized humic acids in solution, at a concentration of 100 mg−1.