SIMI 2020

In recent years, the increasing use of biocides has lead to concerns about the development and emergence of biocide resistant microorganisms, due to their adaptation mechanisms. Various biocide technologies have been used successfully in water treatment applications, but their constantly increased production and excessive usage had turned to generate considerable environmental and economic impact. Water is an essential element to preserve life but, at the same time, it is a perfect environment to spread harmful chemical compounds and pathogens. The aquatic systems could be the source of pathogenic microorganisms responsible for an epidemiological risk such as Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The chemical agencies have approved biocides such as chlorine-based products or active oxygen-based on their different molecular targets and efficiency against microorganisms. This study described the differences in the response of tested microorganisms to biocides chlorine-based products or active oxygen at various concentrations (2 ÷ 50 mg/L) and incubation time from 5 minutes and up to 30 minutes.

The hydrosphere represents about 71% of the total surface of the planet of which only 2.8% is represented by freshwater ecosystems. The ecosystem maintains a state of balance between the component populations, throughout its self-control function, maintaining the numerical variations of these populations within certain limits of sustainability. The exceeding of these limits could cause the balance disturbance by changing the structure and functioning of the ecosystem. The complex human activities influence the structure and functioning of ecosystems, transforming the environment and adapting it to its purposes. Microorganisms are present in all types of ecosystems, being endogenous, exogenous or transient due to contamination with various sources of pollution. Water is an essential natural factor of ecological balance increasingly exposed to microbial pollution. Indicators of fecal pollution are used to assess the degree of water contamination and to locate its origin. The continuous and uncontrolled usage of antibacterial agents that contributed to bacterial resistance determined/ caused pollution of aquatic ecosystems with antibiotic resistant microorganisms. The emergence of antibiotic resistant bacteria is predictable in any environment given that the use of antibacterial substances is constantly growing worldwide. Thus, antibiotic resistance induced in the aquatic environment can have an effect both on bacterial populations in the ecosystem and on human health. Aquatic environments are recognized as one of the reservoirs for the transmission and dissemination of antibiotic resistance. The main goal of this paper is to highlight the differences of bacterial communities from anthropogenic and natural aquatic ecosystems and to assess the potential impact they have on the environment and human health.