• The water that comes out of the taps in our homes is drinkable because a lot of work goes into it beforehand. Chemistry gives a hand in making the water safe to drink. Here we’ll take a closer look at the water treatment process, and in particular the chemicals used to get clean drinking water to our taps.

• The majority of the water that ends up in our homes is taken from natural sources like rivers and lakes. Another natural resource is groundwater which is water beneath the Earth’s surface, trapped between the pores and cracks in rocks. This water is actually relatively pure, due to natural filtration through chalk and other rocks. The water from rivers, on the other hand, isn't that pure and will need chemical treatment.

• The first step is the “screening” phase where large bits of waste are removed from the water, but this doesn’t help remove smaller pieces or dissolved substances. To solve this problem, coagulants such as aluminium sulfate and iron (II) chloride are added to the solution. Coagulants help neutralise the negative charge on the small particles of organic matter in the water, stopping them from repelling each other and allowing them to clump together. The flocculation process now begins, which means that the particles will increase in size forming a floc.

• In general primary waters rich in organic matter aren’t suitable for domestic uses. If the sludge, formed by the coagulation and flocculation is in a high concentration,it is allowed to settle in the subsequent stage, so that it can be removed from the water, treated, and disposed of.

• After these two processes the water will be filtered into two beds made of sand and gravel which remove any organic matter that wasn't removed in the previous processes.

• Once water has been filtered its acidity may be adjusted. If the water is too acidic it might lead to pipe corrosion and also in toxic metals such as lead getting into the supply. Calcium Carbonate (Limestone) helps to raise the pH of the water, making it less acidic.

• At this point almost all of the solids and dissolved substances in the water have been removed, pathogens such as bacteria and viruses can still be present. As such, the water must be disinfected before it travels through the network of water pipes to private homes. This is often accomplished by adding small amounts of chlorine to the water. Chlorine is a strong oxidising agent, disintegrating cell walls and inactivating enzymes and proteins of pathogens.

FONTE: compoundchem.com

PFAS better known as (perfluoroalkyl substances) are fluorinated substances with a carbon chain structure. In perfluoroalkyl substances, each carbon atom in the chain is fully saturated with fluorine (carbon-fluorine bonds only). A carbon atom can make a maximum of 4 bonds with other atoms; applied to this situation each carbon bonds only 3 fluorine atoms. The fourth bond is taken by another carbon atom and together they form a carbon chain.

The unique characteristic of this organic substance is that it is strongly hydrophilic: which means that PFAS is able to mix well with water, dissolve and/or be attracted by it. To take advantage of this property, this element is used as a part in fire-extinguishing foams.

A scandal which arose in our territory was regarding this precise compound: PFAS. The story goes like this. In the middle of the 1960’s the Rimar society (Ricerche Marzotto) which was located in Trissino, in the Vicenza province, founded a join stock company (Miteni S.p.a) and aimed at the production of high quality leather, and in particular hydrophilic leather.

The production site was situated on top of Europe’s second largest underground water aquiferous.

More than 740.000 inhabitants were using primary water coming from this aquiferous.

In 2013 Arpav Veneto (the public institution entitled for the protection of public health in the Veneto region), reported that water had a concentration of 500 ng/L and exceeded the limit by over 400 ng/L.

In addition, further analysis on the blood of the inhabitants that were trusting that water source was made. The results were shocking, to take into perspective the limit of PFAS in the blood is 0.9 to 3.3 ng/mL, people were found to have an average of 60 ng/mL of that compound in their blood.

The emergency alarm was given because the risks of having these chemicals in our blood are:

• High chance of developing a kidney or testes tumor.

• The development of thyroid diseases, hypertension and ulcerative colitis.

• The organic matter intervenes in the endocrine system, causing a lot of problems to the growth and fertility rate.

The case which was brought to court sustained that Miteni was releasing waste products either illegally or not correctly in the environment. The polluted water reached the fields which contaminated every agricultural product. They also sustained that they were breaking the 4th article of the Legislative Act stipulated on the 2nd of February 2001, n°31, which stated the following: