Background

Monterrey, one of the most urbanized and industrialized cities in Mexico, is facing a serious water crisis that has led to the implementation of a pioneering indirect potable reuse plan by Agua y Drenaje de Monterrey. This project aims to treat and reintegrate wastewater for domestic consumption, a practice that has already been adopted in other countries. However, a new problem arises related to the presence of endocrine disrupting compounds (EDCs), pharmaceuticals and personal care products, which are found in treated wastewater. These contaminants, even in minimal concentrations, have been shown to cause adverse effects on living organisms and contribute to microbial resistance. Given the high industrial activity and population density of Monterrey, the handling and discharge of waste, both domestic, industrial and agricultural, adds to the complexity of the situation, highlighting the need for innovative strategies for the treatment of these waters [1]. The wastewater is treated with a high concentration of these pollutants.

Emerging contaminants (EPs), most of them without adequate environmental regulation, have generated growing concern worldwide due to their persistence, bioaccumulation and the adverse effects they cause in aquatic organisms, which represent a potential risk to human health. Some of these EPs act as endocrine disrupting compounds (EDCs), affecting hormone balance and causing damage to the neuronal, metabolic and reproductive systems [2]. The most recent studies have shown that the use of these compounds in aquatic organisms can have adverse effects on human health.

Environmental impact

Endocrine disrupting contaminants (EDCs), present in wastewater treatment plant (WWTP) effluents, have a significant environmental impact, mainly on inland aquatic ecosystems such as streams, rivers, lakes and marshes. These ecosystems are home to a great biodiversity, including 40% of fish species. The presence of EDC in water affects aquatic life and their distribution in the different aquatic compartments depends on the physicochemical characteristics of these compounds, which can dissolve in water, deposit in sediments, leach into groundwater and bioaccumulate in aquatic and terrestrial organisms. This process represents a risk to public health, as some of these compounds can find their way into drinking water and food [2]. This process is also a risk for public health.

Globally, several CDEs, such as 17b-estradiol (E2), 17a-ethinylestradiol (EE2) and so on, have been detected in surface water and wastewater. These compounds are known to mimic the activity of estradiol, a naturally occurring steroid, which can cause adverse hormonal effects in organisms. Their persistence and toxicity have led to their inclusion on the European Union's list of priority hazardous substances for aquatic ecosystems [2]. In addition, they are known to cause adverse hormonal effects in organisms. In Mexico, recent studies have detected concentrations of CDE in several regions, especially in central states such as Guanajuato, Hidalgo and the Valley of Mexico. However, in the northeastern region, specifically in the Monterrey Metropolitan Area (ZMM), few studies have been conducted on the presence of these contaminants. Recently, worrying levels of BPA and phthalates have been detected in rivers and WWTP effluents in this area, which is one of the most industrialized and populated in Mexico. The environmental effects of these pollutants include the feminization of male aquatic organisms, a consequence that has been observed in waters near WWTPs. Prolonged exposure to these compounds alters the hormonal systems of organisms, affecting their reproductive capacity and, in the long term, endangering biodiversity and the balance of ecosystems [3].

References

[1] Estrada-Arriaga, E. B., Mijaylova-Nacheva, P., Moeller-Chavez, G., Mantilla-Morales, G., Ramírez-Salinas, N., & Sánchez-Zarza, M. (2012). Presencia y tratamiento de compuestos disruptores endócrinos en aguas residuales de la Ciudad de México empleando un biorreactor con membranas sumergidas. Instituto Mexicano de Tecnología del Agua. Recibido en abril de 2012 y aceptado en julio de 2012.

[2] Estrada-Arriaga, E. B., Mijaylova-Nacheva, P., Moeller-Chavez, G., Mantilla-Morales, G., Ramírez-Salinas, N., & Sánchez-Zarza, M. (2013). Presencia y tratamiento de compuestos disruptores endócrinos en aguas residuales de la Ciudad de México empleando un biorreactor con membranas sumergidas. Ingeniería Investigación y Tecnología, 14(2), 275-284. https://doi.org/10.1016/s1405-7743(13)72242-x

[3] Khirbet López-Velázquez, J. L., Guzmán-Marín, H. A., Saldarriaga-Norena, M. A., Murillo-Tovar, L., Hinojosa-Reyes, M., & Villanueva-Rodríguez, M. (2020). Occurrence and seasonal distribution of five selected endocrine-disrupting compounds in wastewater treatment plants of the Metropolitan Area of Monterrey, Mexico: The role of water quality parameters. [Journal Name]. https://doi.org/10.1016/j.jes.2020.12.002