”fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom (without any H/Cl/Br/I atom attached to it), i.e., with a few noted exceptions (represented by a carbon atom instead having H/Cl/Br/I atoms attached), any chemical with at least a perfluorinated methyl group (−CF3) or a perfluorinated methylene group (−CF2−) is a PFAS” [51].

PFAS substances represent a serious concern for human health potentially inducing alterations in the development, lipid metabolism and endocrine system, cancerogenicity, immunotoxicity, hepatotoxicity and reprotoxicity.

List of typical PFAS uses in industrial and consumers products.

The exceptional strength of the C-F bond confers very high thermal and chemical stability

PFAS have been detected in the air [33,34], groundwater [35,36], freshwater [17,37], marinewater [38,39], drinking water [40,41] and soil [42,43,44]

Common features of PFAS are represented by their chemical stability which causes environmental persistence [10], their high mobility which confers them a long-range transport potential [11] causing their pervasive spreading even into remote regions (e.g., the Arctic’s or Antarctic’s)

Of note, while the PFAS family has rapidly expanded into an impressive number of more than 4700 different substances including both the “legacy PFAS” (i.e., PFOS, PFOA) and the “emerging PFAS” (e.g., GenX)

evidence indicate that these compounds represent also a serious concern for both wildlife and human health as a result of their ubiquitous distribution, their extreme persistence and their bioaccumulative potential

MNPs accumulate within and affect the proper functioning of the placenta – the vital organ of pregnancy responsible for all maternal-fetal exchange

Observations in both maternal mice and rats exposed to PS-NPs during gestation, ranging in size from 20 to 500nm, demonstrated the presence of these particles in fetal liver (96, 108, 109), heart (96, 109), brain (99, 108, 109), lung (108, 109), and kidney (109). Interestingly, a similar exposure using PE-MPs (10-45µm) resulted in MP accumulation exclusively in fetal kidneys (110). In humans, MNPs have been measured in fetal meconium (36, 46, 47) and amniotic fluid (102), and using an ex vivo human placenta perfusion model, a size dependent transfer of MNPs from the maternal to fetal circulation has been described (111, 112).

However, there remain considerable gaps in understanding that prevent a thorough assessment of whether current MNP exposures contribute to significant human infertility or disease.

In rodent models, exposure to phthalates and BPA can induce alterations in DNA methylation patterns (70–73), histone modifications (73, 74), and non-coding RNA expression within the germline. These changes can disrupt normal epigenetic programming during critical windows of spermatogenesis, leading to impaired sperm development, reduced sperm quality, and compromised fertility

elated to cellular growth and development, coupled to poor sperm quality and fertility outcomes

distinct changes in reproductive hormone signalling are observed, with reductions in the circulating concentrations of estradiol (E2) and anti-mullerian hormone (AMH), and increased concentrations of LH, follicle stimulating hormone (FSH) and testosterone

in rodent models leads to reduced sperm quantity and quality (51–54, 57, 59, 61, 64, 65) in addition to reduced testicular androgen production (57) and circulating levels of testosterone

MNPs have been found in a diverse range of biological samples, including blood (30, 31), urine (32), sputum (33), feces (34, 35), and breast milk (36, 37). Further, MNP accumulation has been identified in numerous organ systems including lung (38–43), colon and spleen (44)

MNPs can cross the physiological barriers of the lungs, gut, and skin

There is concern that chemicals contained within MNPs, or those absorbed to their surface, can be carried into the human body and released into various tissue beds (24). In this way, MNPs act as a vehicle for toxic exposure to a number of xenobiotics, which may bypass typical physiological defences such as drug-metabolizing enzymes in the gut and liver and induce direct effects to the cells/tissues surrounding the internalized MNPs (25).

A recent review estimated that over 10,000 unique chemicals are used at various stages in plastics manufacturing, of which roughly 2,400 have been identified as chemicals of regulatory concern (22).

However, polyethylene, polypropylene and polystyrene are the three most common occurring polymers (5), being found in a countless number of household and personal care products (9, 10), cosmetic products (11), toothpaste (10, 12, 13) and plastic food containers (14).

Microplastics are omnipresent in our environment, being found in large quantities in oceans, rivers, ground water, sediments and soil environments, sewage, and even the air we breathe

microplastic accumulation was observed in the human placenta, raising important questions related to the biological effects of these contaminants on the health of pregnancies and offspring