Human contaminants in water pose reproductive health risks since most of these compounds are endocrine-disrupting substances (EDCs). Endocrine dysfunction negatively affects human development and fertility. The source of chemical pollution in water varies as it comes from byproducts formed during water disinfection processes such as fluorinated compounds, bisphenol A, phthalates, or emissions from industrial and animal activity, or therapeutic medicinal products released into wastewater, pesticides and all these substances Toxicosis has very negative effects on reproduction.
Perfluoroalkyl and polyfluoroalkyl substances
Fluorinated substances are defined as a significant group of organic and inorganic substances that contain one or more fluorine atoms. A subset of these substances contains carbon atoms since all hydrogen atoms have been replaced by fluorine atoms. They are referred to as perfluoroalkyl and polyfluoroalkyl (PFAs). These materials are artificial chemicals that have important properties such as hydrophobic and lipophilic nature and chemical and biological stability. Because of these properties, PFAs are used in a range of consumer products and are very stable in the environment. The presence of these chemicals in the environment is of public health concern since exposure to PFAs has been associated with an increased incidence of neoplasia, endocrine disruption, neurodevelopmental issues, and reproductive problems.
Sources of exposure to PFAs
According to the USEPA, PFAs are found in foods prepackaged with PFAs-containing items, treated with equipment that uses PFAs, or grown in soil or water contaminated with PFAs. These compounds are also found in commercial household products, including stain-resistant fabrics, non-stick products (pots), candles, paints, cleaning products, and fire-fighting foams. In addition, PFAs are found in workplaces, including manufacturing facilities or industries that use these compounds.PFAs can also be found in drinking water, which is usually localized and associated with a specific facility (e.g., manufacturer, landfill, wastewater treatment plant, firefighter training facility).PFAs may also occur in living organisms, including fish and mammals, and these chemicals may accumulate and persist.
The effect of PFAS on humans
PFAs have been associated with reproductive disorders and fecundity in both males and females. An epidemiological study demonstrated that men with high semen levels of PFOs and PFOA had lower numbers of normal sperm compared to men with low semen levels of PFOs and PFOA. In addition, in vitro exposure to PFOA interferes with the penetration of human spermatozoa into synthetic mucus due to excessive ROS, which compromises the penetration ability of human sperm and particle interaction by repealing progesterone-induced Ca2 signaling. Additionally, men exposed to PFOA for up to 2 hours showed a change in sperm motility due to disturbance of the plasma membrane. Maternal exposure to PFAs has been associated with shorter anal-genital distances in boys, demonstrating that PFAs can act as a chemical deoxy to influence male reproductive development. Furthermore, exposure to PFOA and PFOs was associated with decreased sperm quality, testicular size, penis length, and anorectal distance in males.
Studies have also shown that perfluorooctanoic acid (PFOA) acts as an antagonist in the binding of testosterone to androgen receptors, This can result in HPG axis deregulation. In females, exposure to PFAs has been linked to endometriosis. In addition, serum PFOs concentrations were associated with decreased serum levels of estradiol, progesterone, sexual hormone-binding globulin, stimulating follicular hormone (FSH), and testosterone.
Plasma levels of PFAs in pregnant women were associated with lower birth weight. Furthermore, research conducted by mothers and infants as part of the Chemicals Study showed that plasma concentrations of PFOA and PFHxS were associated with decreased fertility.