Ecotoxicity evaluation of a liquid detergent using the automatic biotest ECOTOX

Versatile biotechnological applications of Euglena gracilis

Euglena gracilis is a freshwater protist possessing secondary chloroplasts of green algal origin. Various physical factors (e.g. UV) and chemical compounds (e.g. antibiotics) cause the bleaching of E. gracilis cells-the loss of plastid genes leading to the permanent inability to photosynthesize. Bleaching can be prevented by antimutagens (i.e. lignin, vitamin C and selenium). Besides screening the mutagenic and antimutagenic activity of chemicals, E. gracilis is also a suitable model for studying the biological effects of many organic pollutants. Due to its capability of heavy metal sequestration, it can be used for bioremediation. E. gracilis has been successfully transformed, offering the possibility of genetic modifications for synthesizing compounds of biotechnological interest. The novel design of the "next generation" transgenic expression cassettes with respect to the specificities of euglenid gene expression is proposed. Moreover, E. gracilis is a natural source of commercially relevant bioproducts such as (pro)vitamins, wax esters, polyunsaturated fatty acids and paramylon (β-1,3-glucan). One of the highest limitations of large-scale cultivation of E. gracilis is its disability to synthesize essential vitamins B₁ and B₁₂. This disadvantage can be overcome by co-cultivation of E. gracilis with other microorganisms, which can synthesize sufficient amounts of these vitamins. Such co-cultures can be used for the effective accumulation and harvesting of Euglena biomass by bioflocculation.

Applications of advanced neuro-behavioral analysis strategies in aquatic ecotoxicology

Despite mounting evidence of pleiotropic ecological risks, the understanding of the eco-neurotoxic impact of most industrially relevant chemicals is still very limited. In particularly the acute and chronic exposures to industrial pollutants on nervous systems and thus potential alterations in ecological fitness remain profoundly understudied. Since the behavioral phenotype is the highest-level and functional manifestation of integrated neurological functions, the alterations in neuro-behavioral traits have been postulated as very sensitive and physiologically integrative endpoints to assess eco-neurotoxicological risks associated with industrial pollutants. Due to a considerable backlog of risk assessments of existing and new production chemicals there is a need for a paradigm shift from high cost, low throughput ecotoxicity test models to next generation systems amenable to higher throughput. In this review we concentrate on emerging aspects of laboratory-based neuro-behavioral phenotyping approaches that can be amenable for rapid prioritizing pipelines. We outline the importance of development and applications of innovative neuro-behavioral assays utilizing small aquatic biological indicators and demonstrate emerging concepts of high-throughput chemo-behavioral phenotyping. We also discuss new analytical approaches to effectively and rapidly evaluate the impact of pollutants on higher behavioral functions such as sensory-motor assays, decision-making and cognitive behaviors using innovative model organisms. Finally, we provide a snapshot of most recent analytical approaches that can be applied to elucidate mechanistic rationale that underlie the observed neuro-behavioral alterations upon exposure to pollutants. This review is intended to outline the emerging opportunities for innovative multidisciplinary research and highlight the existing challenges as well barriers to future development.

Phytotoxic effects of two commonly used laundry detergents on germination, growth, and biochemical characteristics of maize (Zea mays L.) seedlings

Laundry detergents, a mixture of different compounds, are used as washing agents in houses and cleaning agents in institutions and industries. As a result, industrial and domestic wastewater usually contains detergent contamination in variable amount. In many developing countries, untreated municipal and industrial wastewater is used for irrigation of crops. There is a possibility that laundry detergents and their ingredients present in irrigation water may affect plant growth as reported in several plant species. However, studies on the effects of laundry detergents on important cereal crops like maize can rarely be found in literature. Therefore, the present study was conducted to evaluate the effects of two commonly used commercial laundry detergents on germination, root-shoot length, fresh biomass, leaf number, leaf width, cell viability, cell injury, light-harvesting pigments, protein contents, and ion concentration in maize (Zea mays L.) seedlings. The obtained results revealed that both the detergents in the tested concentration range (1-500 mg L^-1) did not significantly affect seed germination in maize. Similarly, shoot growth, leaf number, and leaf width were not significantly affected by detergents, while in the case of root, one detergent promoted root growth while the other one inhibited it. Both the detergents caused a slight increase in total soluble proteins, and this effect was significant at the highest tested one or two concentrations of detergents (100 and 500 mg L^-1). Chlorophylls a and b and total carotenoids were very sensitive to detergent stress and significantly reduced at detergent concentration above 1 or 10 mg L^-1. Both the detergents caused an increased cell leakage and reduced cell viability, and in most cases, this effect was statistically significant at detergent doses above 10 mg L^-1. Exposure to detergents caused an increased accumulation of Na⁺, K⁺, and Ca²⁺ in maize seedlings. It can be concluded that detergents present in irrigation water at higher concentrations can adversely affect maize by impairing light-harvesting pigments and cell viability.

Toxic effect of commercial detergents on organisms from different trophic levels

The toxic effects of four powder detergents: two laundry detergents (A and B), one household detergent (C), one dishwashing detergent (D), and the surfactant alkylbenzene sulfonate (LAS) were analyzed in this study on organisms from different trophic levels (microalgae, cladocerans, ostracods, amphipods, macrophytes, and fish). LC₅₀ and EC₅₀ values obtained in the toxicity bioassays varied between 0.019 and 116.9 mg L^-1. The sensitivity of the organisms to the detergents was (from most sensitive to least sensitive) Ostracods > microalgae > amphipods > cladocerans > fishes > macrophytes. The toxicity of the commercial products (from most toxic to least toxic) was LAS > D (dishwashing detergent) > A (laundry detergent) > B (laundry detergent) > C (household detergent). When comparing the sensitivity of organisms that inhabit temperate zones (T = 18 °C) to those that are found in tropical zones (T > 25 °C), it was clear that the species that inhabit the tropics are more sensitive to detergents.

Ecotoxicological evaluation of two anti-dandruff hair shampoos using Lemna minor

Hair shampoos, a mixture of various organic and organic compounds, are commonly used personnel care products. Since shampoos are used in almost every household and beauty shop, their ingredients are common components of domestic and municipal wastewater. However, studies on the effect of shampoos to aquatic plants can hardly be found in literature. Therefore, the present study was conducted to investigate the phytotoxic effects of two commonly used anti-dandruff shampoos (named here AD 1 and AD 2) using Lemna minor as a biotest organism. For toxicity assessment, frond number, fresh and dry biomass, and light-harvesting pigments (chlorophyll a, b and total carotenoids) of Lemna were used as end points. Five different concentrations (0.001, 0.01, 0.1, 1, and 5%) of each shampoo were tested in comparison to the control. At lower concentrations of shampoos, some minor and non-significant stimulatory effects were observed in some parameters, but at concentrations above 0.01% both the shampoos significantly inhibited almost all parameters in Lemna. The EC₅₀ values obtained for frond number were 0.034 and 0.11% for AD 1 and AD 2, respectively. The fresh biomass gave EC₅₀ values of 0.07 and 0.066% for AD 1 and AD 2, respectively. Based on the preset study, it can be speculated that shampoo contamination at higher concentrations in water bodies can be a threat to aquatic organisms. This study can be used as a baseline to further investigate shampoo toxicity using other species and to explore the mechanism of shampoo toxicity in aquatic plants.

Daphniatox - Online monitoring of aquatic pollution and toxic substances

The microcrustacean Daphnia is sensitive to many toxic substances and can be cultured easily. The Daphniatox instrument is based on computerized image analysis tracking swimming organisms in real time. The software evaluates 14 endpoints including motility, swimming velocity, orientation with respect to light and gravity as well as cell form and size. The system determines movement vectors of a large number of organisms to warrant high statistical significance and calculates mean values as well as standard deviation. Tests with K dichromate show that the toxin inhibits motility (EC₅₀ 0.75 mg/L), swimming velocity (EC₅₀ 0.70 mg/L) and even causes a significant decrease in length (16% at 4 mg/L) and changes the form of the animals, This bioassay can be used to monitor the toxicity of a large number of dissolved pollutants and toxic substances such as arsenic, dichromate and persistent organic pollutants.

Rational selection of alternative, environmentally compatible surfactants for biotechnological production of pharmaceuticals--a step toward green biotechnology

The biotechnological production of pharmaceutical active substances needs ancillary substances. Surfactants are used at the end of the cell culture as a protection against potential viral or bacterial contamination and to lyse the producing cells for isolation and purification of the products. To find a replacement for a surfactant that had raised environmental concern, environmentally relevant data for potential alternatives were searched for in the literature. Significant data gaps were filled with additional tests: biodegradability, algal growth inhibition, acute daphnid immobilization and chronic daphnid reproduction toxicity, acute fish toxicity, and activated sludge respiration inhibition. The results were used to model removal in the wastewater treatment plants (WWTPs) serving 3 biotechnological production sites in the Roche Group. Predicted environmental concentrations (PECs) were calculated using realistic amounts of surfactants and site-specific wastewater fluxes, modeled removals for the WWTPs and dilution factors by the respective receiving waters. Predicted no-effect concentrations (PNECs) were derived for WWTPs and for both fresh and marine receiving waters as the treated wastewater of 1 production site is discharged into a coastal water. This resulted in a spreadsheet showing PECs, PNECs, and PEC ÷ PNEC risk characterization ratios for the WWTPs and receiving waters for all investigated surfactants and all 3 sites. This spreadsheet now serves as a selection support for the biotechnological developers. This risk-based prioritization of surfactants is a step toward green biotechnological production.

Potential health impact and genotoxicity analysis of drinking source water from Liuxihe Reservoir (P.R. China)

Water from the Liuxihe Reservoir (a source of drinking water for Guangzhou City, P. R. China) was analyzed for semi-volatile organic compounds (SVOCs) and the results were used for a potential health impact assessment and genotoxicity test with the microalgae Euglena gracilis. The SVOCs were tested using USEPA Method 525.2, and the health risk assessment was conducted at a screening level using the hazard quotient (HQ) approach. Alkaline single-cell gel electrophoresis (comet assay) was used to evaluate DNA damage and determine the genotoxicity of the source water. The concentrations of the SVOCs in Liuxihe Reservoir were very low and phthalic acid esters were the main SVOCs present. The mean HQ values of pollutants were all less than one, indicating no risk. However, the lifetime carcinogenic risks (LCRs) were found to be close to the threshold of 1.00E-5. The results show that the water in the Liuxihe Reservoir might pose a potential carcinogenic risk to local residents. The highly concentrated extracts of the water samples could induce DNA damage in the microalgal cells and a dose-effect relationship was identified. These results showed that Liuxihe Reservoir water, as a source of drinking water, could pose a potential LCR to local consumers.

Photosynthesis and photosynthetic pigments in the flagellate Euglena gracilis - as sensitive endpoints for toxicity evaluation of liquid detergents

The present study was designed to validate the applicability of photosynthetic performance using a PAM fluorometer and photosynthetic pigments in Euglena gracilis as endpoint parameters in toxicity assessment of liquid detergents using a dish washing liquid detergent during short- (0-72h) and long-term (7days) exposure. In short-term experiments, the detergent affected the photosynthetic efficiency with EC50 values (calculated for Fv/Fm) of 22.07%, 7.27%, 1.4% and 2.34%, after 0, 1, 24 and 72h, respectively. The relative electron transport rate (rETR) and quantum yield measured with increasing irradiances were also inhibited by the detergent. The most severe effect of the detergent on the light-harvesting pigments (μgmL(-1)) was observed after 72h where chlorophyll a and total carotenoids were decreased at concentrations above 0.1% and chlorophyll b was decreased at concentrations above 0.5%. In long-term experiments, the detergent reduced the photosynthetic efficiency of cultures giving an EC50 value of 0.867% for Fv/Fm. rETR and quantum yield with increasing irradiance were shown to be adversely affected at concentrations of 0.1% or above. A decrease in chlorophyll a and total carotenoids (μgmL(-1)) was observed at concentrations of 0.05% detergent or above. Chlorophyll b was shown to be comparatively less affected by detergent stress, and a significant decrease was observed at concentrations of 0.5% or above. However, there was no prominent decrease in per cell (Euglena) concentration of any pigment. It can be concluded that photosynthesis and light-harvesting pigments in E. gracilis were sensitive to detergent stress and can be used as sensitive parameters in toxicity assessment of detergents in aquatic environments.