Acute Toxicity Bioassays Research Articles

Toxicity assessment and bioremediation of textile effluent by isolated Pseudomonas Oleovorans PAMD_1 bacteria

Toxic effluents containing azo dyes are discharged from various industries which adversely affect water resources and ecosystem integrity. The objective of this study was to compare the toxicity of untreated as well as treated textile effluent with newly isolated Pseudomonas oleovorans PAMD_1 to Nile Tilapia (Oreochromis niloticus) as the test organism. The acute toxicity bioassay experiments were conducted to determine the median lethal dose (LD50) and hematological changes in O. niloticus. Hematological profile of O. niloticus showed significant elevation (p < 0.05) in RBC count (4.10; 5.42), Hb concentration (8.5; 14.3), and heamtocrit (9.0; 12.5) in the treated effluent when compared to the untreated. The textile effluent was also analyzed for physicochemical parameters, including BOD, COD, TDS, and color intensity prior to and after treatment with P. oleovorans PAMD_1 which showed a substantial reduction in BOD from 371 to 118 mg l−1 (68%), COD from 895 to 220 mg l−1 (76%), and TDS from 4400 to 3730 mg l−1 (15.2%).

Ecotoxicity Evaluation of Industrial Discharge Waters and Metallic Solutions using Two Organisms (Lactuca sativa and Daphnia magna)

Surface treatment industrial discharge water is a complex anthropogenic source of pollutants, including organic pollutants (PAHs, VOCs…) and numerous metal ions. We attempted to identify the main toxicants comparing impact assessment of real polycontaminated effluents and reconstituted polymetallic solutions via ecotoxicological bioassays performed with Daphnia magna immobilization test (24 h) and Lactuca sativa germination test (168 h). We focused first on 2 (Ni and Zn) then on 5 metals (Ni, Zn, Co, Cr, Al). Our results showed differences between metal toxicity order: Zn>Al>Ni>Cr~Co, for daphnids and Ni>Zn>Al~Co>Cr for lettuce. However, discharge waters remained more toxic than synthetic solutions: those 5 metals were not entirely responsible for the discharge water ecotoxicity. We also found D. magna to be more sensitive than L. sativa. This last assessment should be interpreted with care, knowing that immobilization and germination tests are respectively acute and chronic toxicity bioassays. Thus, battery tests are appropriate to evaluate industrial discharge water samples, and should be increasingly used as eco toxicological standards.

Toxic Impact of Phenthoate on Protein and Glycogen Levels in Certain Tissues of Indian Major Carp Labeo rohita (Hamilton)

The organophosphorus pesticide Phenthoate is one of the most widely used insecticide in agriculture sector to control the varieties of pests and ectoparasites. The acute toxicity bioassay tests were conducted at various concentrations ranging from 0.4 and 4.0 mg/l with an interval of 0.4 mg/l on Indian major carp Labeo rohita for 24, 48, 72 and 96 h. The acute toxicity values were determined as 3.0, 2.6, 2.3 and 2.1 mg/l under laboratory conditions respectively. These LC50 values showed that the chemical is highly toxic to the fish. Then the fish were exposed to sub lethal concentrations (1/10 th of 96 h LC50) for 1, 4 and 8 days and studied the significant changes in total proteins and glycogen levels of the fresh wet tissues. The total protein content reduced in various tissues like Liver, muscle, kidney, brain, gill and gut by the percentage of 22.46%,17.91%,12.39%, 8.66%, 8.36% and 8.16 % and glycogen content depletion in the order of kidney, liver, muscle, gill, gut and brain tissues by 57.92%, 49.11%, 48.75%, 34.88%, 32.00% and 28.81% respectively when compared to control group. It was noticed that Phenthoate resulted in the gradual decrease of glycogen and protein levels in the vital organs of fish L. rohita, which led increase in the mortality rate.

Biodegradation of p‐Chloroaniline and Ammonium Removal in Continuous Biofilm Reactors

AbstractIn this investigation, we isolated from an industrial effluent a bacterial community capable of utilizing p‐chloroaniline (PCA) as the sole source of carbon and nitrogen. The isolates were identified as Pseudomonas sp., Achromobacter sp., and Sphingopyxis sp. The bacterial community was employed to set up a continuous system for PCA degradation and ammonium removal. The system consists in two sequential aerobic fixed‐bed reactors, for PCA biodegradation and nitrification respectively, and an anoxic reactor for denitrification. Biodegradation process was evaluated by chemical analysis of PCA, chloride and ammonium, and bacterial count. Nitrification and denitrification processes were evaluated by chemical analysis of ammonium, nitrite and nitrate, and nitrifying bacteria count. Bioassays of acute toxicity using the standard organisms Vibrio fischeri, Pseudokirchneriella subcapitata, and Daphnia magna were performed in order to assess detoxification. An average efficiency of 88.5%, expressed as PCA removal, was achieved in the biodegradation process. The maximum PCA removal rate reached 11.7 g/m3 day. PCA degradation was associated with the release of chloride and ammonium. Ammonium was completely removed by the nitrification/denitrification process. Toxicity was not detected after the biodegradation process.

Exposure to cerium dioxide nanoparticles differently affect swimming performance and survival in two daphnid species.

The CeO2 NPs are increasingly used in industry but the environmental release of these NPs and their subsequent behavior and biological effects are currently unclear. This study evaluates for the first time the effects of CeO2 NPs on the survival and the swimming performance of two cladoceran species, Daphnia similis and Daphnia pulex after 1, 10 and 100 mg.L−1 CeO2 exposures for 48 h. Acute toxicity bioassays were performed to determine EC50 of exposed daphnids. Video-recorded swimming behavior of both daphnids was used to measure swimming speeds after various exposures to aggregated CeO2 NPs. The acute ecotoxicity showed that D. similis is 350 times more sensitive to CeO2 NPs than D. pulex, showing 48-h EC50 of 0.26 mg.L−1 and 91.79 mg.L−1, respectively. Both species interacted with CeO2 NPs (adsorption), but much more strongly in the case of D. similis. Swimming velocities (SV) were differently and significantly affected by CeO2 NPs for both species. A 48-h exposure to 1 mg.L−1 induced a decrease of 30% and 40% of the SV in D. pulex and D. similis, respectively. However at higher concentrations, the SV of D. similis was more impacted (60% off for 10 mg.L−1 and 100 mg.L−1) than the one of D. pulex. These interspecific toxic effects of CeO2 NPs are explained by morphological variations such as the presence of reliefs on the cuticle and a longer distal spine in D. similis acting as traps for the CeO2 aggregates. In addition, D. similis has a mean SV double that of D. pulex and thus initially collides with twice more NPs aggregates. The ecotoxicological consequences on the behavior and physiology of a CeO2 NPs exposure in daphnids are discussed.

Acute Toxicity Bioassays of Cadmium and Mercury on the Juveniles of Asian seabass Lates calcarifer (Bloch)

Acute Toxicity Bioassays of Cadmium and Mercury on the Juveniles of Asian seabass Lates calcarifer (Bloch)

Acute Toxicity Bioassays of Cadmium and Mercury on the Juveniles of Asian seabass Lates calcarifer (Bloch)

The present study was undertaken to investigate the acute toxicity of two heavy metals cadmium and mercury in the juveniles of Asian seabass Lates calcarifer (Bloch) which is considered as an important candidate fish species for brackishwater and freshwater aquaculture. Experiments for the bioassay were performed in static bioassay test condition according to the standard guidelines. The experiment was carried out in the FRP tanks under laboratory condition. The behavioral changes in the fish were observed for all test concentrations of both cadmium and mercury. Median lethal concentrations (LC 50 ) were calculated for 24h, 48h, 72h and 96h by probit analysis. The LC 50 values for 96h and 95% confidence intervals for the juveniles of seabass L. calcarifer showed 6.08 ppm for cadmium and 1.03 ppm for mercury. Furthermore, the exposed specimens showed dose and duration dependent, abnormal behavior and hyperactivity. Mercury indicated more toxic than cadmium for seabass L. calcarifer .

The application of the Lymnaea stagnalis embryo-test in the toxicity bioindication of surfactants in fresh waters

The aim of this study was to assess the efficiency of the new acute toxicity bioassay with the application of embryological criteria, using aquatic invertebrates such as Lymnaea stagnalis L. We were looking for optimal methods of water bio-monitoring, comparing the sensitivity of different biotests. Different forms of snails (embryonic and juvenile) were tested and the tests compared to each other and to the daphnia (EN ISO 6341) test as well. The tested substances were surfactants, which are now regarded global threat to surface waters. The main source of detergent pollution is municipal and industrial wastewater. The tested groups were exposed to various concentrations of diluted surfactant agents known as Brij 32, Brij 58, Bri 72, Brij 76, Brij 78 and the detergent known under the trade name of Ludwik. The results proved that juvenile forms showed higher sensitivity to the tested toxicants. Therefore, they could be used as a potential tool to monitor the acute toxicity of surfactants, which could be presence in aquatic ecosystems.

Acute Toxicity Bioassay with the Amphipod, Grandidierella bonnieroides S. After Exposure to Sediments from an Urban Estuary (Macaé River Estuary, RJ, Brazil)

Acute toxicity to Grandidierella bonnieroides and physicochemical analysis were used for quality assessment of the sediment of the Macaé River urban estuary, located in the Brazilian coast where rapid socioeconomic growth has been induced by offshore oil and gas exploration at the Campos Basin. Sediment samples were collected during four events in four sampling sites of the estuary and also in a control site. Organism mortality after exposure to the estuarine sediments was, on average, 30% a value higher than in the control site where it was 10%. This result together with the physicochemical analysis suggests an initial toxicity condition of the sediments from this aquatic coastal environment.

Acute Toxicity Tests with Cadmium, Lead, Sodium Dodecyl Sulfate, and Bacillus thuringiensis on a Temporary Pond Ostracod

AbstractA complete assessment of effects of pollutants in the environment requires the use of a wide assemblage of test organisms. Crustaceans have been widely used in aquatic environments, but within this group, ostracods have been overlooked, even though they are one of the commonest groups of animals in temporary waters. Within this framework, static acute toxicity bioassays were conducted with heavy metals Cd and Pb, the surfactant SDS and spores of the bacteria Bacillus thuringiensis var. israeliensis using adult parthenogenetic females of the temporary pond ostracod Heterocypris bosniaca. Experiments were run at 20 °C and in a 12 by 12 h photoperiod. The toxicity tests results are expressed as LC50 and EC50 at 48 h and 96 h using probit analysis. The sensitivity of H. bosniaca at 48 h decreased in the following order Cd &gt; Pb &gt; SDS &gt; Bti, while Pb and SDS exchanged their positions at 96 h. Comparison of the LC50 values for this species with information available in the literature reveals that it is generally more resistant than other crustaceans. (© 2012 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Selection of a bioassay battery to assess toxicity in the affluents and effluents of three water-treatment plants

&lt;strong&gt;Objective&lt;/strong&gt;. The assessment of water quality includes the analysis of both physical-chemical and microbiological parameters. However, none of these evaluates the biological effect that can be generated in ecosystems or humans. In order to define the most suitable organisms to evaluate the toxicity in the affluent and effluent of three drinking-water treatment plants, five acute toxicity bioassays were used, incorporating three taxonomic groups of the food chain. &lt;strong&gt;Materials and methods&lt;/strong&gt;. The bioassays used were Daphnia magna and Hydra attenuata as animal models, Lactuca sativa and Pseudokirchneriella subcapitata as plant models, and Photobacterium leioghnathi as bacterial model. To meet this objective, selection criteria of the organisms evaluated and cluster analysis were used to identify the most sensitive in the affluent and effluent of each plant. &lt;strong&gt;Results&lt;/strong&gt;. All organisms are potentially useful in the assessment of water quality by meeting four essential requirements and 17 desirable requirements equivalent to 100% acceptability, except P. leioghnathi which does not meet two essential requirements that are the IC50 for the toxic reference and the confidence interval. The animal, plant and bacterial models showed different levels of sensitivity at the entrance and exit of the water treatment systems. &lt;strong&gt;Conclusions&lt;/strong&gt;. H. attenuata, P. subcapitata and P. leioghnathi were the most effective organisms in detecting toxicity levels in the affluents and D. magna, P. subcapitata and P. leioghnathi in the effluents.&lt;br /&gt;&lt;strong&gt;Key words&lt;/strong&gt;: bioassays, cluster analysis, drinking water, raw water, toxicity.

Response of a freshwater air-breathing fish, Clarias batrachus to salinity stress: an experimental case for their farming in brackishwater areas in Andaman, India

The study was conducted to assess the effects of salinity on growth and biochemical composition of freshwater catfish, Clarias batrachus. A static nonrenewable acute toxicity bioassay test was conducted and LC50 of salinity for 96-h exposure to the fingerling (14.5 cm) was 12.52 ‰. Based on these results, two sublethal salinity levels, viz. 4 and 8 ‰ were selected to study the long-term effects of salinity on C. batrachus for a period of 90 days. From the study, it was found that growth and survival rate were less in saline water (4 and 8 ‰). Maximum growth and survival were recorded in freshwater (0 ‰ salinity) and subsequently at 4 and 8 ‰. To assess the biochemical alteration, few important biomarkers were estimated. At the end of 90 days rearing period, glucose level in the brain and blood of C. batrachus was found to decrease with salinity. The level of liver and muscle glycogen in the fish reared at 4 ‰ was lower than that of control. Ascorbic acid in all organs under study was found to decrease with increasing salinity, which was attributed to stress mitigation effect of vitamin C. Acetylcholine esterase (AchE) activity recorded a gradual decrease with increasing salinity. Metabolic enzymes, alkaline phosphatase (ALP) activity and adenosine triphosphosphtase (ATPase) activity also reduced both in liver and muscle tissues with increasing salinity. From the present investigation, it can be concluded that exposure to higher salinity significantly (P < 0.01) affects the growth and physiological response of Clarias batrachus.

Acute contact toxicity test of insecticides (Cipermetrina 25, Lorsban 48E, Thionex 35) on honeybees in the southwestern zone of Uruguay

Glyphosate-resistant soybean cultivation is expanding rapidly in Uruguay, with its land area having increased by 95 times during the past 10years. Because of the region’s Neotropical conditions, insecticide use is required to ensure adequate soybean productivity. However, in areas shared by soybean crops and beekeepers – such as the southwestern zone of Uruguay (SWZU) – the use of insecticides can increase the risks of honeybee death and honey contamination. Uruguayan commercial and legal guidelines set out practices and field doses designed to prevent acute intoxication with insecticides. However, honeybees in the SWZU are predominantly a polyhybrid subspecies different from that used to set international reference values, and hence they may have a different acute toxicity response, thus rendering such precautions ineffective. The aim of this work was to assess the acute toxicity response of polyhybrid honeybees in the SWZU to cypermethrin (commercial formulation: Cipermetrina 25 Agrin®), chlorpyrifos (commercial formulation: Lorsban 48E®), and endosulfan (commercial formulation: Thionex 35®). Acute toxicity bioassays were conducted to determine the median lethal dose (LD50) of each insecticide for the honeybees. The results indicate that, compared with EU reference values, SWZU honeybees have a higher toxicological sensitivity to chlorpyrifos and endosulfan, and a lower toxicological sensitivity to cypermethrin, based on the commercial formulations tested. However, when these results were adjusted according to their field dose equivalents, only chlorpyrifos emerged as a potential problem for beekeeping, as the maximum recommended field dose of Lorsban 48E® for soybean crops in Uruguay is 23 times the corresponding LD50 for honeybees in the SWZU.

Toxicological response of Amphibalanus amphitrite larvae as an indirect evaluation of antifouling paints’ efficacy

The evaluation of new antifouling paints is usually performed through long and expensive field tests (raft-tests), often depending on the season of exposure. Particularly in the Mediterranean Sea, these tests are representative only if carried out during spring or summer. Therefore, it is strategically important to develop laboratory methods that are able to test and select, during winter, the best formulations to submit to raft-test during the summer. For this reason, an acute toxicity bioassay using larvae (Stage II nauplii) of Amphibalanus amphitrite on paint leaching products obtained with an accelerated ageing system was tested as a tool for the indirect evaluation of antifouling efficacy. Seven experimental paint formulations were selected on the basis of previous obtained field efficacy performances, and were subjected to both laboratory bioassays and to a 12-month raft-test. The data show how paint behaviour (expressed as fouling coverage percentage) after 12 months of immersion in the field could be predicted by the results of laboratory bioassays, expressed as immobilisation percentage of larvae exposed for 48 h to leaching products of artificially aged paints.

Bioassays and biochemical biomarkers for assessing olive mill and citrus processing wastewater toxicity

The toxicity and the biochemical effects of olive mill wastewater and citrus processing wastewater were evaluated using acute toxicity bioassays (Gammarus pulex and Hydropsyche peristerica) and biochemical biomarkers (acetylcholinesterase [AChE] and glutathione S-transferase [GST]). The bioassays indicated toxic properties of olive mill and citrus processing wastewaters. The 24 h LC(50) values of olive mill wastewater ranged from 2.64% to 3.36% for G. pulex and 3.62% to 3.88% for H. peristerica, while the LC(50) of citrus processing wastewater was 25.26% for G. pulex and 17.16% for H. peristerica. Based on a five-class hazard classification system applied for wastewaters discharged into the aquatic environment, olive mill wastewater and citrus processing wastewater were classified as highly toxic and toxic, respectively. Results of the biochemical biomarkers showed that both agroindustrial effluents at increasing sublethal wastewater concentrations could cause inhibition of the AChE and induction of the GST activities. These first results showed that both species as well as their AChE and GST activities have the potential to be used as indicators and biomarkers for assessing olive mill and citrus processing wastewaters quality.

Bioavailability, ecotoxicity, and geological characteristics of trace lead in sediments from two sites on Negro River, Uruguay, South America

Bioassays of two sites along the Rio Negro in Uruguay indicate ecotoxicity, which could be attributable to trace concentrations of lead in river sediments. Monthly samples at two sites at Baygorria and Bonete locations were analyzed for both particle size and lead. Lead was determined by atomic spectrometry in river water and sediment and particle size by sieving and sedimentation. Data showed that Baygorria's sediments have greater percentage of clay than Bonete's (20.4 and 5.8%, respectively). Lead was measurable in Baygorria's sediments, meanwhile in Bonete's, it was always below the detection limit. In water samples, lead was below detection limit at both sites. Bioassays using sub-lethal growth and survival test with Hyalella curvispina amphipod, screening with bioluminescent bacteria Photobacterium leiognathi, and acute toxicity bioassay with Pimephales promelas fish indicated toxicity at Baygorria, with much less effect at Bonete. Even though no lethal effects could be demonstrated, higher sub-lethal toxicity was found in samples from Baygorria site, showing a possible concentration of the contaminant in the clay fraction.

The acute toxicity of fenitrothion on narrow‐clawed crayfish (Astacus leptodactylus Eschscholtz, 1823) in association with biomarkers of lipid peroxidation

The aim of this research was to evaluate the acute toxicity of fenitrothion to the crayfish (Astacus leptodactylus Eschscholtz, 1823), which is chosen as an alternative aquatic organism to fish by using the static test system and evaluate the basic lipid peroxidation parameters for the first 24 h. Crayfish of 27.3 ± 0.56 g mean weight and 10.0 ± 0.72 cm mean length were selected for the bioassay experiments. The experiments were repeated three times in 20 liters of tap water. The temperature of water was 21 ± 1°C. The data obtained were statistically evaluated by using a computer program developed by the United States Environmental Protection Agency, based on Finney's probit analysis method and the 96-h LC(50) value for crayfish was calculated to be 15.75 μg/L. The 95% lower and upper confidence limits for the LC(50) were 9.45 to 25.01 μg/L. In addition to the acute toxicity bioassay experiments, 24-h oxidative stress parameters such as malondialdehyde (MDA) levels and ferrous oxidation assay (FOX HP [hydrogen peroxide] equivalents) were also determined. Only MDA levels of hepatopancreas decreased at 5, 10, and 20 μg/L of fenitrothion doses. We can conclude that fenitrothion is highly toxic to crayfish, a nontarget organism in the ecosystem, and the lipid peroxidation indicators can be easily used for monitoring environmental effects.

Microcystis toxigenic strains in urban lakes: a case of study in Mexico City

Microcystis is a bloom-forming, common cyanobacterium in urban lakes of Mexico City. To assess the presence of potentially cyanotoxin-producing Microcystis, molecular techniques were applied and acute toxicity bioassays were performed with Daphnia magna neonates exposed to cyanobacterial crude extracts. Toxigenic potential of isolated strains was inferred by amplifying the mcyA-Cd genes and their identity as Microcystis was confirmed through the 16S rDNA and phycocyanin operon amplification. Microcystins synthesized under culture conditions were quantified through ELISA. The acute toxicity bioassays revealed that mortality was independent from the cyanotoxin concentration in some strains; this suggests the presence of other metabolites (different from microcystins) that also exerted an important biological effect. Isolated strains had the mcyA-Cd gene and most of them produced variable amounts of microcystins in the culture conditions used, confirming their toxigenic potential. Results warn about possible toxic effect risks for aquatic biota, neighboring areas, visitors and users of these sites, due to the constant presence of these blooms in the studied water bodies.

Dynamic features of ecophysiological response of freshwater clam to arsenic revealed by BLM-based toxicological model

The objective of this study was to use a quantitative process-based damage assessment model (DAM) associated with biotic ligand model (BLM) to examine the ecophysiological responses of freshwater clam Corbicula fluminea to waterborne arsenic. We carried out a 14-day exposure experiment to obtain bioaccumulation parameters and a 7-day acute toxicity bioassay to obtain survival data. To investigate the survival dynamics, we examined 2 key parameters characterizing bioaccumulation and damage regulation: capacity to eliminate body arsenic burden and reversible ability to recover the damage. Results show that uptake rate constant of 2.075 + or - 0.442 (mean + or - SE) ml g(-1) d(-1) during uptake phase and elimination rate constant was estimated to be 0.1995 + or - 0.022 d(-1). The derived bioconcentration factor of 10.401 ml g(-1) suggests that arsenic has a high potential for bioaccumulation in C. fluminea. Our results show that a negative association between bioaccumulation and the fraction of arsenic binding in biotic ligand at 50% mortality, indicating that C. fluminea with higher arsenic binding in gill biotic ligand at 50% mortality level gives a lower capacity to accumulate bioavailable arsenic. We found a linearly positive correlation between elimination rate and recovery rate constants. Yet, a potential tradeoff between ability to eliminate arsenic and ability to recover the damage is not found. We showed that an ecophysiological significance of C. fluminea exposed to arsenic can be revealed by the elimination-recovery regime. This research may also provide mechanistic insights into the development of biomonitoring organism such as C. fluminea mimicking metal bioaccumulation in a real situation.

Short-Term Evaluation in Growing Rats of Diet ContainingBacillus thuringiensisCry1Ia12 Entomotoxin: Nutritional Responses and Some Safety Aspects

The Cry1Ia12 entomotoxin from a Brazilian Bacillus thuringiensis strain is currently being expressed in cotton cultivars to confer resistance to insect-pests. The present study aimed to assess the effects of a diet containing Cry1Ia12 protein on growing rats. A test diet containing egg white and Cry1Ia12 (0.1% of total protein) as a protein source was offered to rats for ten days. In addition, an acute toxicity bioassay was performed in rats with a single oral dose of the entomotoxin (12 mg/animal). No adverse effects were observed in the animals receiving the test diet when compared to those receiving a control diet (egg white). The analysed parameters included relative dry weight of internal organs, duodenum histology, blood biochemistry, and nutritional parameters. The results of the acute toxicity test showed no mortality or behaviour alteration. Thus, Cry1Ia12 toxin at the tested concentration does not cause deleterious effects on growing rats when incorporated in the diet for 10 days.