Comparative studies on the acute toxicities of auxiliary chemicals used in textile finishing industry by bioluminescence test and neutral red test

Ecotoxicity evaluation of Cu- and Fe-CNT complexes based on the activity of bacterial bioluminescence and seed germination

The toxic effects of the composites of Fe⁰ and Cu⁰ with different percentages of CNTs were examined based on the activity of bacterial bioluminescence and seed germination. In terms of the EC₅₀ values, the toxic effects of Cu⁰ on bacterial bioluminescence and seed germination were approximately 2 and 180 times greater than that of Fe⁰, respectively. The toxicity increased with increasing CNT content in the Cu-CNT mixtures for both organisms, whereas opposite results were observed with Fe-CNT mixtures. The mean toxic effects of Cu-CNT (6%) were approximately 1.3-1.4 times greater than that of Cu-CNT (0%), whereas the toxic effects of Fe-CNT (6%) were approximately 2.1-2.5 times lower than that of Fe-CNT (0%) for both the bioluminescence activity and seed germination. The causes of this phenomenon are unclear at this point. More research will be needed to elucidate the mechanism of the toxicity of nano-mixture materials and the causes of the different patterns of toxicity with Cu- and Fe-CNT mixtures.

Evaluation of the Effects of Nanoparticle Mixtures on Brassica Seed Germination and Bacterial Bioluminescence Activity Based on the Theory of Probability

Effects of binary mixtures of six metal oxide nanoparticles (NPs; 54 combinations) on the activities of seed germination and bacterial bioluminescence were investigated using the theory of probability. The observed toxicities of various NPs combinations were compared with the theoretically expected toxicities, calculated based on individual NPs toxicities. Different sensitivities were observed depending on the concentrations and the types of NPs. The synergistic mode (67%; observed toxicity greater than expected toxicity) was predominantly observed in the bioluminescence test, whereas both synergistic (47%) and additive (50%) modes were prevalent in the activity of seed germination. With regard to overall analysis, a slightly high percentage (56%) of the synergistic mode of action was (30 out of 54 binary mixture combinations; p < 0.0392) observed. These results suggest that the exposure of an NPs mixture in the environment may lead to a similar or higher toxicity level than the sum of its constituent NPs would suggest. In addition, one organism for assessment did not always show same results as those from a different assessment. Therefore, combining results of different organisms exposed to a wide range of concentrations of binary mixture will more properly predict and evaluate the expected ecotoxicity of pollutants on environments.

Effects of properties of metal-contaminated soils on bacterial bioluminescence activity, seed germination, and root and shoot growth

This study examined the effects of several factors (metal contents and soil properties) on bacterial bioluminescence activity, seed germination and root/shoot growth of Lactuca in metal-contaminated soils. Each bioassay showed different sensitivities to extractants of soil samples. Average sensitivities of the bioassay were in the following order: root growth > bioluminescence ≥ shoot growth ≥ seed germination. Both total and weak acid-extracted metal contents showed no observable correlations with the activity of any bioassays (r(2) < 0.279). However, reasonable correlations were observed between the bioluminescence activity and organics (r(2) = 0.7198) as well as between root growth and CEC (r(2) = 0.6676). Effects of soils were difficult to generalize since they were dependent on many factors, such as soil properties, metal contents, and the organism used in each test. Nonetheless, these results indicated that a battery of bioassays is an effective strategy for assessment of contaminated soils. Furthermore, specific soil factors were shown to more influence on soil toxicity, depending on the type of bioassay.

Interactive Effects of Metal Mixtures on Seed Germination and Bioluminescence Activities based on the Theory of Probabilities

The interactive effects of metal mixtures on seed germination (36 combinations) and bacterial bioluminescence (60 combinations) activities were investigated based on the theory of probabilities. Observed effects were compared with expected effects, which were calculated based on single metal activities. Different responses and sensitivities were observed depending on the types and concentrations of mixture metals as well as the organisms tested. In general, an additive mode of action (observed and expected effects are nearly same) was mostly common in the bioluminescence assay, whereas synergistic and additive inhibition modes were mostly observed in seed germination. Therefore, the mixture effects of the different bioassays could not be generalized because they were dependent on the types and concentrations of chemicals and organisms used. The results indicated that mixture, rather than single, effects by various bioassays and wide ranges of concentration combinations may comprise a better strategy for the bioassessment of contaminated environments.

Joint effects of heavy metal binary mixtures on seed germination, root and shoot growth, bacterial bioluminescence, and gene mutation

This investigation was to assess the joint effects of metal binary mixtures on seed germination, root and shoot growth, bacterial bioluminescence, and gene mutation based on the one toxic unit (1 TU) approach. Different sensitivities and orders of toxicity of metal mixtures were observed among the bioassays. In general, mostly additive or antagonistic effects were observed, while almost no synergistic effects by the binary metal mixtures in all bioassays. Therefore, the combined effects of heavy metals in the different bioassays were difficult to generalize since they were dependent on both chemical type and the organism used in each bioassay. However, these results indicate that a battery of bioassays with mixture chemicals as opposed to just a single assay with single metal is a better strategy for the bioassessment of environmental pollutants.

Acute toxicity assessment of textile dyes and textile and dye industrial effluents using Daphnia magna bioassay

Aquatic toxicity of textile dyes and textile and dye industrial effluents were evaluated in an acute toxicity study using Daphnia magna as an aquatic experimental animal model. The 48-h EC50 value for the azo dyes, Remazol Parrot Green was 55.32 mg/L and for Remazol Golden Yellow was 46.84 mg/L. Whereas 48-h EC50 values for three dye industrial effluents (D1, D2, and D3) were 14.12%, 15.52%, and 29.69%, respectively. Similarly, EC50 value for three textile mill effluents (T1, T2, and T3) were >100%, 62.97%, and 63.04%, respectively. These results also showed linear relationship with high degree of confidence ( r2 = >0.84 to >0.99) between immobility and test concentrations. The ratio of 24 to 48-h EC50 remains to be in between 1.1 and 1.2. The general criteria of toxicity classification showed that both dyes were minor acutely toxic having 48-h EC50 in between 10 and 100 mg/L. Of the six textile and dye industrial effluents tested, one was not acutely toxic (48-h EC50 > 100%) and five were minor acutely toxic (48-h EC50 > 14.12–29.69%). The toxicity classification of effluent based on toxic unit (TU) showed that of the six effluents tested five were found toxic (TU = >1) and one was non-toxic (TU = <1). Thus, dye effluents showed highest toxicity and textile effluents lowest toxicity. The study also suggested that the assay with D. magna was an excellent method for evaluation of aquatic toxicity of dyes and dyes containing industrial effluents.