Quantitative modelling of Ostracod bioassay: assigning toxicity index to potentially chemical contaminated swimming pools (original) (raw)
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Protections of aquatic lives from pollution associated hazard are critical to the sustenance of fish pond ecosystem. To determine whether valuable substances such as pond water can pose unacceptable level of risk to fish is the purpose of this investigation. Research has shown that the adverse outcomes of life threatening conditions originate from micro-level events. The use of whole organisms was an alternative approach to integrate and understand the biological substances that can cause toxicity to aquatic organisms. In this research, In vivo Early Life Stage (ELS) testing was conducted on the whole organism in the pond water prior to the independent feeding of ostracod (Heterocypris incongruens). The growth inhibition was also studied to effectively monitor the onset of toxic metabolites in the stationary fish pond. For sampling purpose, fish pond water was collected for five different days after the replacement of old water. It was noted that no further serial dilution was done as the number of days were adopted as dilution one to dilution five. The fish pond has the dimensions of 10×8×7 m, containing 500 liters of water and 200 fish. Fish pond water samples collected from days 1–4 showed average mortality 42 – 47%, while day 5 showed 77% ostracods mortality rate. These results suggested that the onset of fish pond water toxicity starts from day 2 – 5. This implied that toxic metabolites in fish pond water at day five and over can progressively impaired the proper growth and development of fish and other lower organisms.
Journal of Hazardous Materials, 2009
The ostracod Cypris subglobosa Sowerby, 1840 static bioassay test on the basis of a 48 h of 50% of immobilization (EC50) has been used to measure the toxicity of 36 metals and metalloids and 12 reference toxicants. Among the 36 metals and metalloids, osmium (Os) was found to be the most toxic in the test while boron (B), the least toxic. The EC50 values of this study revealed positive linear relationship with the established test models of cladoceran (Daphnia magna), sludge worm (Tubifex tubifex), chironomid larvae (Chironomus tentans), protozoan (Tetrahymena pyriformis), fathead minnow (Pimephales promelas), bluegill sunfish (Lepomis macrochirus), and aquatic macrophyte duckweed (Lemna minor). Correlation coefficients (r2) for 17 physicochemical properties of metals or metal ions and EC50s (as pM) were examined by linear regression analysis. The electronegativity, ionization potential, melting point, solubility product of metal sulfides (pKsp), softness parameter and some other physicochemical characteristics were significantly correlated with EC50s of metals to C. subglobosa. The reproducibility of toxicity test was determined using 12 reference toxicants. The coefficient of variability of the EC50s ranged from 6.95% to 55.37% and variability was comparable to that noticed for D. magna and other aquatic test models. The study demonstrated the need to include crustacean ostracods in a battery of biotests to detect the presence of hazardous chemicals in soils, sewage sludges, sediments and aquatic systems.
Toxicity Assessment and Identification for Protection of Natural Waters
Canadian Water Resources Journal, 2002
Conventional pollution prevention strategies for the protection of natural waters usually entail a comparison of analytical results with water quality guidelines. This comparison is often compromised by the inability to identify fu1ly the toxicants in the environment and the need to reference current toxicological databases containing large datagaps. In light of these shortcomings, we describe examples of an alternative approach based on toxicity testing coupled with chemical manipulation and directed chemical analysis. Advantages of this toxicological approach over traditional methods are illustrated for natural water surveys conducted in North America and Mexico. It is demonstrated that toxicity identification evaluation is well suited to the development of water quality criteria for the protection of aquatic ecosystems. REsUME Les strat6gies traditionnelles de pr6vention de 1a pollution pour la protection des eaux naturelles supposent habituellement la comparaison des rdsultats analytiques avec les lignes directrices en matiCre de qualitd de l'eau. Cette comparaison est souvent compromise par I'incapacitd d'identifier de manidre int6grale les substances toxiques dans I'environnement et le besoin de se r6f6rer iL des bases de donn6es toxicologiques actuelles qui pr6sentent de grandes lacunes statistiques. A la lumidre de ces faiblesses, nous d6crivons des exemples d'une autre approche bas6e sur des essais de toxicit6 combin6s d la manipulation chimique et iL l'analyse chimique dirigde. Les avantages de cette approche toxicologique par rapport aux mdthodes traditionnels sont illustrds pour 1es relev6s hydrologiques (eaux naturelles) 6tablis en Amdrique du Nord et au Mexique. I1 a 6t€ d6montr6 que 1'6valuation des donndes sur la toxicitd est bien adaptde d 1'6laboration des critdres de qualit6 de i'eau pour la protection des 6cosystdmes aquatiques.
Report of the OECD Workshop on Statistical Analysis of Aquatic Toxicity Data
OECD Series on Testing and Assessment, 2002
Why do we have ecotoxicity tests? Ecotoxicity testing can be conducted for several purposes, which can be grouped in different ways: A) Prediction Hazard identification Classification and priority-setting Guidelines, criteria Product development Risk assessment Research B) Control and monitoring Permit compliance (monitoring/standards) Research C) Diagnosis Incidence reports Toxicity Identification and Evaluation (TIE) Research (identification of causal agents) or A) Legal/regulatory New products Re-evaluations Site assessment Criteria, standards Permit-setting and compliance B) Non-regulatory Waste management Product development and safety Market-driven issues Emergency procedures Commercial issues Diagnosis C) Research Mode of action QSARs Some of these applications of ecotoxicity data are beyond the scope of the workshop, which is to deal merely with substances and regulatory issues.
A Toxicologically-Based Framework Can Enhance Urban Aquatic Ecosystem Risk Assessment
This study proposes a toxicologically based algorithm to relate arsenic (As) toxicity to the internal effect concentration (IEC) in tilapia Oreochromis mossambicus. The relationships among As exposure, uptake, accumulation, and toxicity to tilapia are investigated using toxicokinetic (TK) and toxicodynamic (TD) modeling. A 7-d exposure bioassay reveals that the bioconcentration factor (BCF) value of tilapia is 2.88, indicating that the tilapia is capable of accumulating waterborne As. As acute toxicity is analyzed by determining the median external effect concentration (LC 50) at different integration times, indicating that 96-h LC 50 and LC 50 (∞) for tilapia are 28.68 (95% CI: 24.92-32.44) and 12.04 µg mL-1 , respectively. To determine the mode of action (MOA) governing the As toxicity, this study employed the damage-assessment model (DAM) to describe LC 50 s. Result suggests that the DAM characterizes As toxicity well and the intrinsic MOA of As toxicity acts through the reversible reaction between As and specific receptors. This study kinetically links the DAM with IEC-based Hill equation model to derive dose-response relationships between equilibrium As residue and mortality. We suggests that considering MOA in ecotoxicological assessment is useful to improve the construction of environmental quality criteria for protecting rapidly degrading aquatic ecosystems in urban area.
Modeling Aquatic Toxicity through Chromatographic Systems
Analytical chemistry, 2017
Environmental risk assessment requires information about the toxicity of the growing number of chemical products coming from different origins that can contaminate water and become toxicants to aquatic species or other living beings via the trophic chain. Direct toxicity measurements using sensitive aquatic species can be carried out but they may become expensive and ethically questionable. Literature refers to the use of chromatographic measurements that correlate to the toxic effect of a compound over a specific aquatic species as an alternative to get toxicity information. In this work, we have studied the similarity in the response of the toxicity to different species and we have selected eight representative aquatic species (including tadpoles, fish, water fleas, protozoan, and bacteria) with known nonspecific toxicity to chemical substances. Next, we have selected four chromatographic systems offering good perspectives for surrogation of the eight selected aquatic systems, and...