Content Number: 20
Author Name: Zareen Ghafoor
Author I’d: SBPWNC – A20
Educational Institution: University of the Punjab, Lahore, Pakistan
Content Title: PFAS Forever Chemicals
What are PFAS?
PFAS (polyfluorinated alkyl subsrance ) is group of chemicals that have hydrophobic tail (hydrogen atoms replaced with fluorine atom on carbon backbone) and hydrophilic head (due to functional groups like carboxylic acid and sulfonates). PFAS are aliphatic substances having -CnF2n-1 moiety. Most commonly studied PFAS are Perfluorooctane sulfonate(PFOS) and Perfluorooctanoic acid (PFAS). PFAS possess great chemical inertness, persistence in environment, potential to bioaccumulate and Biomagnify through food chain.
PFAS are considered very toxic chemicals
PFAS are considered very health hazardous. PFAS are persistent in environment having half life >92 years in water. PFAS can cause pre-eclampsia in pragnent ladies, increases total cholestrol level, reduces the antibody response to vaccines, distrurb the thyroid gland by reducing the uptake of iodine, disturb kidney function and causes other hepatic disorder. In soil PFAS enhaces the litter decomposition and soil pH, reduces the soil respiration. PFAS also increases the microbial growth, decrease the level of carbohydrates and effect the mineralization of organic carbon in soil. PFAS taken up by plants are accumulated. Short chain compounds are accumulated in leaves and fruits while long chain are accumulated in roots.
How People are exposed to PFAS?
Human beings are exposed to these via Ingestion, Inhalation, drinking contaminated water and Dermal contact etc.
Sources of PFAS
PFAS are highly mobile, circulate in the environment through ground water, runoff, oceans and landfill leachates etc. PFAS are present in drinking water, ground water, soil, vegetations, human beings and animals. Premiscible level of PFAS in drinking water must be 1ng or below. Major sources of PFAS are fire fighting foams, fluoropolymer industry, batteries, voltaic cells, plastic production, electronic, coating and paint industry. In textile, leather, paper, carpet and apparels, it is used as surface protector due side chain fluorinated polymer. They are present in water proof materials like cosmetics ,water proof bases and water proof maskara etc.
Dismissal of PFAS
Removal of PFAS is very essential to sustain a healthy living. PFAS can be removed from drinking water using Adsorption (biochar, activated carbon), reverse osmosis, ion exchange and nanofiltration methods. Granulated activated carbon and modified graphene oxide can be used to remove PFAS from drinking water. Graphene oxide can be modified using ethanolamine, Diethylene triamine and Diallyldimethylammonium chloride. Biochar can be modified by using ionic liquids to remove PFAS. Ionic liquids have anionic part that is exchanged with PFAS because PFAS anions have high hydration energy. Biochar can be modified in several ways to remove PFAS from drinking water. Ion exchange is a very simple and promising technique for the removal of PFAS from drinking water. Anion exchange resins are mostly used because these resins have negatively charged counter ions that are exchanged with anionic PFAS. Many industries like such as Purolite, DuPont and Calgon Carbon Corporation have started manufacturing PFAS specific resins. Few examples are Purolite A592E (macroporous) and Purofine PFA694E (gel). These all methods remove pfas from drinking water but in future it is expected that we will be able to remove it at low cost.
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Very informative✨
Informative …
You highlight about something that is posing threat to environment …
I appreciate your commitment to raising awareness about this critical issue.
Good work Zareen👍
Very informative and interesting
Very informative and interesting knowledge
Very informative