Study investigates the presence of contaminants in water

Collaborations between scientists from the State of São Paulo and Texas Tech University are advancing knowledge in fields such as health, the environment and engineering

By Heitor Shimizu, in Lubbock  |  Agência FAPESP – The São Paulo Research Foundation (FAPESP) and Texas Tech University (TTU) have maintained a cooperation agreement since 2014, and have already issued three joint calls for proposals, resulting in the selection of 12 research projects that are currently receiving funding from the institutions. Researchers from all of the projects took part in two sessions of presentations in which they discussed the results of their collaboration during the Lubbock portion of FAPESP Week Nebraska-Texas.

Cassiana Montagner, a professor at the Institute of Chemistry and head of the Environmental Chemistry Laboratory of the University of Campinas (Unicamp) in São Paulo, Brazil, presented findings from the SPRINT project she is conducting with David Klein, a professor of Analytical and Environmental Chemistry at TTU.

The project is attempting to determine emerging contaminants in the environment based on the comparison of water and sewage treatment systems in the United States and Brazil. Samples are being collected from a wide variety of sources such as surface water, groundwater, wastewater, reuse water, sewage water and residential drinking water.

Because there are hundreds of different contaminants that can be found in the water used by the population, the researchers are focusing on a list of compounds of mutual interest, sufficient in number to identify contamination in the source analyzed.

“We are analyzing water samples to determine the presence of industrial compounds, pesticides, personal hygiene products, medicines, caffeine, illegal drugs and several other things,” Montagner said. “The compounds are being isolated, identified and quantified using liquid chromatography coupled with mass spectrometry.”

Caffeine, for example, is one of the substances the group is using to identify the occurrence of sewage contamination in a water source, since it is the product of human consumption and waste. “Contamination in Brazil’s rivers is very high due to wastewater discharge,” she said.

Another emerging contaminant identified by the group are hormones. “Some of these compounds are what are known as endocrine disrupters because they could have an adverse effect on our endocrine system,” Montagner said.

The endocrine system consists of the set of glands responsible for the production of hormones. Some compounds discharged by man into the environment have the potential to deregulate the endocrine system of humans and other animals. It is suspected that this can affect the reproductive system and cause disease.

“Analysis of the presence of these compounds can indicate the level of contamination of the water system by sewage. It is also an indication that the water treatment stations are not efficiently removing emerging contaminants,” Montagner said.

According to the researcher, the presence of contaminants has been identified in drinking water, although at much lower levels than in groundwater or alternative sources of supply.

“Compared to the United States, sanitation conditions in Brazil are quite precarious. Conventional wastewater treatment systems in Brazilian cities are not efficient at removing most of the emerging contaminants, such as bisphenol, used in the production of plastics,” she said.

“The results of our studies indicate that some of the water treatments used in Brazil, if done properly, could remove a portion of these contaminants, but complementary treatments need to be adopted in order to obtain clean water that can be safely consumed,” Montagner said.

In June of 2017, Montagner, Klein and their colleagues published the article “Biophysical Viscosity: Thermodynamic Principles of Per Capita Chemical Potentials in Human Populations”, in the periodical ACS Omega, published by the American Chemical Society, where they present the findings of the SPRINT project.

The article points out that population density is not the only factor involved in determining the flux of contaminants, and that the biophysical viscosity – the resistance of a region to molecular flow under environmental force – is a useful tool in determining the per capita chemical potential of anthropogenic chemical compounds for environmental risk assessments.

Probabilistic dynamics

Aparecido Carlos Gonçalves, a professor in the School of Engineering at São Paulo State University (Unesp) in Ilha Solteira (São Paulo, Brazil), and Stephen Ekwaro Osire, a professor in the Department of Mechanical Engineering at Texas Tech University, talked about the results of their project, “Probabilistic dynamics analysis and lubricant analysis to improve reliability of gearboxes”, in which they conducted a probabilistic analysis of lubricants used in the gearboxes of wind turbines in order to estimate the useful life of this equipment.

“The most common practice of wind turbine drivetrain design, modeling and analyses considers a probabilistic approach to improving system behavior and reliability. However, it is impossible to discuss components or system reliability without considering the uncertainties involved in the design, manufacture, assembly, and load parameters of these systems,” Gonçalves explained.

“Because of this, the current practice of gearbox design for wind turbines needs to be changed so that the process can take into account the uncertainties mentioned. It has been noticed that the uncertainties have an unrelated impact on useful life. In our project, we want to analyze whether the probabilistic approach to dynamic analyses and analyses of lubricants improves gearbox reliability,” he said.

The project by Gonçalves and Osire resulted in publication of the book Probabilistic Prognostics and Health Management of Energy Systems, released in May 2017. There was also a workshop and a symposium organized in Ilha Solteira as well as a workshop in Lubbock attended by researchers involved in the project.