Ecological assessment of the toxicity of nitrogen compounds for aquatic organisms using the Lemna minor L. Biotest

This research is motivated because of increasing eutrophication problems in water bodies. This happens as a result of excess nitrogen and phosphorus. Too many of these nutrients can cause algae to grow, leading to blooms. Harmful algal blooms consume dissolved oxygen in water. As a result, the oxygen level decreases, affecting the aquatic ecosystem. The stenobiont plant, which belongs to the group of the most sensitive bioassays, is the small duckweed Lemna minor L. This plant is sensitive to increasing levels of nutrients and blooms of algae. This research aimed to determine the level of water toxicity using the bioassay of duckweed (Lemna minor L.) to establish dangerous concentrations of nitrogen compounds (NO2-, NO3-, NH4+) (CA) for higher plants of aquatic ecosystems with subsequent risk forecast for Dnipro basin. The research was carried out in accordance with DSTU 32426-2013 “Testing of chemicals of environmental hazard. Lemna sp. Growth Inhibition. Test”. The number of effects associated with nitrogen compounds (NO2-, NO3-, NH4+) on plant growth and development during the testing period was detected. The number of green layers is the main variable that was investigated in the experiment. Changes in the morphological features of duckweed were also studied, in accordance with the standard, the toxicity of water was assessed by changes in leaf colour, manifestations of chlorosis, the transformation of whole plants into individuals, the appearance of young leaves. To estimate the number of effects associated with the nitrogen compounds toxicity, the half-maximal effect (EC50) was studied. It should be noted that studies of water toxicity on NO2- content using the Lemna minor L. test showed that even at the lowest concentration of 0.1 mgNO2-/L aquatic biota will be significantly affected by the toxicity with possible subsequent death. Summarizing the results of the research of the Lemna minor L reaction to the toxicity of water with different concentrations of NO3- came to the conclusion that even the lowest concentration (0.1 mgNO3-/L) will have a negative impact on their growth and development of the plant. Generally, 40.0 mgNO3-/L is considered “safe” for fish farming. However, this is not a case for aquatic vegetation, as shown by this result – such concentration will be toxic and cause death. If we take into account NH4+ salts, the reaction was even more progressive, the deterioration of the leaf layers of duckweed began to occur immediately from the first days of the research, and the number of damaged duckweed was 30% more on day 24 than in salts NO3-, NO2-. For algae of aquatic ecosystems the highest level of toxicity is shown by nitrogen compounds in the form of NO3-, the median concentration of EC50 (96 hours) is 7.7 mg/L. Therefore, the regulation of pollution of aquatic ecosystems by nitrogen compounds should be based primarily on the content of NO3-. To avoid the negative effects of compounds such as NH4+ and NO2- it is necessary to take into account their toxicity level: EC50 (96 hours) NH4+ – 250 mg/L, EC50 (96 hours) NO2- – 720 mg/L. From the above, the free-floating hydrophyte Lemna minor L. is a promising object of testing, as it easily absorbs all the elements and quickly shows the result. It is able to quickly accumulate harmful substances, because in the process of life, its leaves absorb absolutely all the elements that fall into the water.

One Month of Classic Therapeutic Ketogenic Diet Decreases Short Chain Fatty Acids Production in Epileptic Patients

Ketogenic diet (KD), a high fat and very low carbohydrates diet, is used worldwide for the treatment of drug resistant epilepsy but, due to its composition, it might exert an impact on gut health. Even though data of KD effects on intestinal microbiota changes are recently emerging, its influence on the gut environment has been scarcely addressed so far. The aim of this study was to investigate whether 1 month of KD affects the gut environment in epileptic patients, by analyzing short chain fatty acids (SCFA) production and fecal water toxicity. A total of seven patients were enrolled. Stool samples were collected before (T0) and after 1 month of KD (4:1 ketogenic ratio) (T1). SCFA were determined by GC-FID and fecal water toxicity in Caco-2 cell culture by comet assay. Concentrations of SCFA significantly decreased after KD (p < 0.05): in particular, we found a 55% reduction of total SCFA level, a 64% reduction of acetate, 33% of propionate, and 20% of butyrate (p < 0.05). Cytotoxicity of fecal water extracted from stool samples was not significantly altered by diet, while genotoxicity was slightly decreased after KD (p < 0.05). Genotoxicity values were consistent with data previously obtained from a healthy Italian population. The present study suggests that 1 month of KD significantly reduce SCFA production. Since SCFA produced by gut microbiota exert many health promoting effects on either the gut environment or human metabolism, these results open a new branch of investigation into KD effects.

The development of a multifunctional 9,10-dibromooctadecanoic acid-encapsulated heterostructure (Ag@Ag2O) as a nanocatalyst against water toxicity

Fatty acid derivatives capped Ag@Ag2O CSN have been easily synthesized. Comparative catalytic degradation studies against various water contaminants, MB, MO and Cr(vi) have been performed. The experimental results are in favor of CSN, compared to simple fatty acid-coated nanoparticles.

Toxicity Assessment of Treated Sewage Effluent using the Zebrafish Embryo Model

Background: In a context of tremendous economic value, the management and protection of water resources in Qatar has long been a significant issue as part of the global wastewater management plan. The process is based on several stages of treatment in order to deliver high-quality effluent standard. Treated sewage effluent (TSE) can potentially be used for agriculture in Qatar and it should be biologically evaluated before releasing it to the environment. TSE water can be further filtered with techniques that include reverse osmosis, forward osmosis, and nanofiltration. Aim: This project aims to assess the toxicity of differently treated sewage effluent water on the environement using the zebrafish model. Our approach will also be relevant to the assessment of the water quality for agriculture use. Methods: Zebrafish embryos were cultured in different effluent water samples filtered with different techniques. Toxicicity of water was assessed via multiple assasys including: survival rate, tail flicking, and hatching rate. Cardiotoxicity assessment was performed via blood velocity, cardiac output and vessels diameter measurement in major vessels, as well as gene expression for heart failure markers of ANP and BNP by PCR. Results: Samples filtered via Reverse osmosis and nano-filtration resulted in most toxicity. Total dissolved solvent (TDS) measurements were also highest in those samples, suggesting these filteration techniques may result in release of toxic compounds to effluent water. Toxicity assessment is currently ongoing to confirm the findindgs. Conclusion: Utilization of TSE for environmental and agricultural purposes will have an economical value in the nation. It is critically important to determine the most efficient and less toxic ways of water filteration. Zebrafish is a practical model that can be used to assess water toxicity. This project aims to examine toxicity of effluent water filteration techniques using the zebrafish model.