Search

Environmental pollution is an important issue influencing human health and environmental equilibrium. The range of pollutants is very wide due to industrialization and population growth and the surfactants are one of the most common organic pollutants due to their extensive use and ubiquitous presence from industry to households. Their massive presence in the domestic and industrial wastewater could affect the Wastewater treatment plants by inhibiting the activated sludge used in pollutants biodegradation treatment step. This paper aimed to study the inhibition effect of three classes of surfactants (nonionic, anionic, and cationic) by measuring the respiratory activity of microorganisms with the application of the Oxygen Uptake Rate (OUR) test. This study established that the surfactants could activate or inhibit microorganisms’ activity, depending on surfactant concentration.

An endless list of companies has produced a large amount of pharmaceutical compounds in a year-on-year growth trend. Due to the excessive consumption of these substances and the inappropriate disposal, the environment was contaminated, especially aquatic ecosystems, with quantities of pharmaceuticals (PHACs) so that they have affected the living organisms, leading to decreased biodiversity and ecological degradation. Many studies on PHACs environmental presence and toxic effects were performed, but unfortunately, no limit was establishing for discharging into the environment, especially into the aquatic systems. The aim of this study was to use the bioluminescence of Aliivibrio fischeri bacteria as an indicator of toxical effect of different PHACs in simulated marine mediums. The Microtox® bioassay is based on the PHACs inhibitory effect on the metabolism of bacteria which induced changes in their bacterial bioluminescence. The test organisms were exposed to analgesics and anti-inflammatories such as Diclofenac, Ketoprofen, Naproxen and Ibuprofen. The results showed that based on EC50 values, Naproxen had a very low toxicity but Diclofenac, Ketoprofen and Ibuprofen had a harmful effect on the aquatic organisms.

Surfactants represent the major class of chemicals used in the composition of detergents where the predominant groups are anionic surfactants. Because of the large utilization of detergents in different activities (agricultural, industrial, domestic) an important amount of surfactants can accumulate in the domestic and industrial wastewaters, that are discarded to wastewater-treatment plants (WWTP). Furthermore, surfactants could affect the process of biological wastewater treatment due the inhibition of activated sludge and subsequently the water bodies quality through discharge of WWTPs` effluents. In addition, the soil quality decreased through various modes of sludge applied. The concentrations of organic matters discharged in the wastewater systems from Romania have raised the attention of environmental authorities regarding the toxic impact of their components such as anionic surfactants on the environment. The present paper proposed to highlight the background of organic pollution from Romania through the monitoring of the organics amount in water by Chemical Oxygen Demand (COD) and by the specific indicator � Anionic Surfactants (AS). Temporal (winter, spring and summer, 2019) and spatial (six areas: West, North-West, North-East, East, South and South-West) monitoring of organic matter was performed. It has been found that the spatial and temporal variation of AS concentrations were well correlated with COD load, leading to the conclusion that surfactants represented an important part of the global organic matter.

The widespread use of detergents has raised concern with regard to the environmental pollution caused by their active substances, which are biorefractory, toxic or persistent. Even though anionic and non-ionic surfactants often used in commercial detergents composition are reasonably degradable under aerobic conditions and not particularly toxic at low concentrations, high concentration of surfactants influenced the activated sludge activity and are harmful for the aquatic environment. In the literature, data on the biodegradability and/or ecotoxicity of a certain type of surfactant (anionic, nonionic, cationic) are usually presented. Our study aimed to assess the biodegradability of a mixture of two types of surfactants (anionic mixed with non-ionic) and also, effects caused by their presence of elevated concentrations to the activated sludge micro-organisms, within a batch experiment. We performed a biodegradability test (according Zahn-Wellens method) on 2 synthetic solutions with high concentrations of anionic surfactant �methyl dodecylbenzene sulfonate (15-25 mg/L) and non-ionic surfactant -4-nonylphenyl-polyethylene glycol (10 mg/L). The study established different percent of biodegradability (measured by COD decrease and surfactants removal) depending on initial concentrations of anionic and nonionic surfactants in the tested solutions. High surfactants concentrations modulated the activity and morphology of activated sludge, so its degradation efficiency of the organic substrate has decreased. Surfactant solutions resulting from biodegradability experiment have been tested for toxicity to planktonic crustaceans (Daphnia magna).

Various biocide technologies have been used successfully in water treatment applications for many years, but their constantly increased production and excessive usage has considerable environmental and economic impacts. In addition, the aggressive use of biocides in more and more fields such as agriculture, livestock growth, and fish farming increased the risk to public health. This measures can lead to the selection of pathogens insusceptible to the main available antimicrobials. Antimicrobials resistance is even more significant when cells are embedded in a biofilm especially in water systems. A variety of microorganisms can be found in swimming pool waters which may be introduced in a number of ways. The disinfection of bathing water is generally achieved by chlorine of chlorine-based products, but alternative more eco-friendly methods such as active oxygen are used more frequently. In this paper, compared the biocides efficiency of two compounds based on chlorine or active oxygen. Although it was assumed that the two biocides have the same mechanism of action and efficiency, we showed in this study that biocides efficiency depends on the bacterial membrane structure and the active oxygen had an increased efficacy against microorganisms compared to chlorine.

The market expansion due to globalization generated more anthropogenic contaminants, enhancing their negative impact on the environment. In order to prevent and balanced their negative effect, more rapid, sensitive and eco-friendly ecotoxicological studies as risk assessments were developed. Each country developed national programs to ensure the research infrastructure for implementation and development of new testing methodologies, generating new experimental data transferable to governmental authorities, economic agents and academia. In this review, we intend to highlighted the progress of Romanian researchers in the last 10 years in the field of ecotoxicology and aquatic risk assessment. The studies focused on aquatic systems as a non-targeted system to the anthropogenic pollutants impact. The implemented methodologies according with international requirements for chemical control like REACH Regulation, Detergents Regulation, Biocide Products Regulation or the Aquatic Risk Assessment Guidelines were presented. The ecotoxicological effects of various contaminants such as detergents, pharmaceuticals, pesticides, biocides or heavy metals and environmental polluted samples (surface water, sediment or sludge) were provided. Overall, the studies presented in our studies have a nationally novelty through the variety of test substances, the complexity of laboratory experiments and data processing. The research work has a continue applicability in industry and for control authorities. New accredited testing services that providing useful information about the chemicals and their impact on the environmental were introduced. In addition, the ecotoxicology studies and their challenges were a great source for professional training like PhD and master studies and for impact published papers.