Page 3 - report

Sustainability 2022, 14, x FOR PEER REVIEW 3 of 37

• High melting point 62

The toxicity of PFAS and their ubiquitous use, particularly as firefighting foams in the defensive line 63

and mining sectors, have resulted in widespread contamination of soil and groundwater in locations 64
around the world [9]. Because of this strong bond and high melting point, methods for treating PFAS 65

such as thermal treatment, chemical oxidation, and air stripping are difficult [10]. 66

There has been a lot of research done on the toxicity of PFAS, and the results point to a variety of 67

qualities. Animal experiments have revealed that PFAS may cause hepatotoxicity, neurotoxicity, 68
reproductive toxicity, immunotoxicity, thyroid disruption, cardiovascular toxicity, pulmonary toxicity, 69

and renal toxicity [11]. PFASs have sparked widespread concern due to their persistence, 70

bioaccumulation potential, and potential adverse effects on living organisms [12]. They have the ability 71
to travel through water and atmosphere, as a consequence perfluorooctane sulphonate (PFOS) are most 72

widely detected PFASs in the environment [13]. PFOS are extremely persistent and has a high potential 73
for bioaccumulation. They have been identified as complex mixtures that may have a negative impact 74

on autotrophic and heterotrophic food webs, causing acute and long-term impacts at the individual, 75
population, and community levels [14]. Due of their volatile to semi volatile nature, PFAS 76

intermediates are primarily carried via the atmosphere and can eventually be degraded to compounds 77

such as PFSAs (perfluorosulphonic acids) and PFCAs (perfluoroalkyl carboxylates) [15]. PFAS is 78
said to reside in the upper mixed layer in ocean owing to their surfactant property and aqueous solubility 79

[16]. Either downwelling or adsorption to dispersed particles followed by sedimentation are two ways 80
that PFAS might be transported to the deep ocean. It is believed that the deep ocean acts as a long-term 81

sink for these chemicals because of the slow attrition rate of deep ocean water and sediment [16]. The 82
PFAS that are still present in the surface mixed layer are carried over great distances by ocean currents 83

or can reach the atmosphere on marine aerosols produced by choppy seas and breaking waves [17]. 84

Wind currents have the ability to transfer PFAS through the atmosphere far from their emission sources, 85
where they can then either wet or dry depose in the areas, they have travelled [18]. Many biomonitoring 86

investigations use serum or plasma and are based on the physiochemical characteristics of PFAS. To 87

measure human exposure, additional investigations have used whole blood, dried blood spots, milk, 88
urine, hair, and even nails [19]. In the Figure 1, authors have shown the chemical structure of PFAS 89
[20]. 90

91

92