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Identifying safe plastics and health-hazardous plastics with the use of a number system
Using a number system to classify plastics is a complex subject that still raises a lot of doubts and even myths. Plastics can be classified by numbers, but the problem is not or may not only be the material, but also its additives. In this post we will first talk about categorisation by number and about what has to be taken into account or what safe alternatives can be chosen within the different plastics.
Let's talk about plastic
What is it?
Plastic is a synthetic material produced by means of chemical polymerisation reactions that give rise to macromolecular structures (polymers or plastic resins). A lightweight and flexible material, it can insulate electricity and heat. During its production process, additives are added to give it different textures, stability, gloss, colour and hardness.
Classifying plastics according to their applications
Thermoplastics
These plastics can be melted and moulded several times. They can be recycled by applying heat to them, and they do not lose their properties. These include: Polyethylene (HDPE and LDPE), Polystyrene (PS), Polycarbonates (PC), Polypropylene (PP), Polyvinyl Chloride (PVC), Polyamide (Nylon), Fluorocarbon (Teflon) and Methacrylates (PMMA).
Thermosetting plastics
This type of plastic can only be melted and moulded once. It is a rigid plastic, is temperature resistant and cannot be recycled by heat. These include: Bakelites, Melamine, Plexiglas. Phenols (PF), Amines (MF), Polyester Resins (UP) and Epoxy Resins (EP).
Elastomer plastics
These plastic macromolecules can stretch and contract. Although they are very elastic, they degrade at medium temperatures, so they are not recyclable with heat. Some examples include: rubber, neoprene and silicone.
Classifying plastics according to their nature
Natural origin
These are obtained from natural materials, such as tree latex (rubber), milk casein (galatite), tree cellulose or cotton cellulose (celluloid).
Synthetic origin
These are produced by chemical reactions from compounds derived from petroleum, coal and natural gas.
Classifying plastics according to their degradability
Conventional plastics
When discarded, these plastics end up fragmenting into small particles that are not biodegradable. They must therefore be recycled for reuse, to prevent them from accumulating in the environment and causing damage to the ecosystem.
They are widely used by the population in the form of water containers, food or detergent containers, plastic for disposable packaging, as well as structural materials.
Oxo-degradable plastics
These are conventional plastics with chemical additives. They are self-degradable in the presence of solar radiation and oxygen, by the action of heat and mechanical stress.
This plastic becomes altered in its chemical composition. It is identified with the symbol d2W or with the word 100% degradable. It is mainly used in plastic bags for carrying food and for shopping in supermarkets.
Biodegradables
These are plastics that degrade through the enzymatic action of microorganisms such as bacteria, fungi and algae by aerobic or anaerobic decomposition under natural environmental conditions. Many of these biodegradable plastics, known as Biopolymers, (natural polymers) are obtained from corn, wheat or potato starch through the fermentative action of microorganisms.
The use of a number system to classify plastics according to their composition
Plastic packaging is classified with numbers from 1 to 7 to indicate the type of material from which it is made. These numbers are placed inside a triangle as a recycling symbol, on the base or on the back of the container. These numbers refer to the quality and safety of the plastic used, as well as the chemicals used.
Number 1
The number 1 indicates that it is made of Polyethylene Terephthalate (PET). It is commonly used in the manufacture of water bottles, sodas, juices, sports drinks, mouthwashes, cooking oil bottles, pillow and cushion rubbers, etc.
It is a highly transparent plastic. It can be coloured, can be used with food, but should not be exposed to heat. It is safe for one-time use only, and should then be recycled. The packaging should not be used after its expiry date. This is to avoid the risk of releasing residues of antimony and phthalates, a toxic substance that affects the kidneys, liver, reproductive organs, endocrine system and nervous system.
Plastic number 1 has been found to allow the accumulation of bacteria and the concentration of tastes and odours. Some studies have verified that PET bottled water contains different amounts of Antimony (Sb), Formaldehyde, Acetaldehyde, Bromine (Br), Bisphenol A (BPA), Phthalates (such as Di-2-ethylhexyl phthalate and DEHP), and the concentration of these substances in water increases with the hours of exposure to the sun, time and temperature of storage.
It is recycled to manufacture handle bags, carpets, furniture, coatings, fibres, car parts, and thick and fleece cloths.
Number 2
The number 2 indicates that it is made of High Density Polyethylene (HDPE). This plastic is considered one of the safest plastics for food storage. These plastics can be reused and refilled. It is considered one of the safest plastics for food storage and has a low risk of leakage. It has a high chemical and thermal resistance and is resistant to water, acids and certain solvents.
It is used to manufacture: milk cartons, opaque milk jugs, juice containers, butter containers, yoghurt containers, cereal box liners, toys, baby bottles, packaging bags and film, bottles (shampoo, liquid soap and shower gel), sanitary towels, household cleaner containers, detergent bottles, motor oil containers, plastic bags.
It recycles into pens, picnic tables, detergent and cleaner bottles, containers, water and gas pipes.
Number 3
The number 3 indicates that it is made of Vinyl or Polyvinyl Chloride (V/PVC). PVC is the result of combining chlorine and carbon, plus some toxic additives. This material can be rigid or flexible. It is highly environmentally resistant, meaning that it is not biodegradable, and is therefore harmful to the environment.
Use of this plastic should be avoided, because it contains:
- Diethylhydroxylamine (DEHA), a material whose long-term exposure is carcinogenic.
- Phthalates: plastic number 3 releases phthalates, substances that act as hormone disruptors; they alter sex hormone levels causing males of some species to become female. They are associated with miscarriages, cause low sperm count, infertility, malformations in the human foetus and could have effects on the thyroid, obesity and allergies. PVC flooring or play-mats used in day-care centres have been linked to asthma, allergies and autism in children.
- Vinyl chloride: a carcinogenic substance that is released from PVC when subjected to temperature changes. It easily passes into the food or water it contains, and poses an imminent risk to mankind.
In spite of all these risks, PVC is still frequently used in food wrapping, plumbing pipes, cooking oil bottles, condiment containers, meat and sausage packages, cling film, teething rings, toys, shower curtains and detergent bottles, in bags for bedding products, medicine packages, plastic toys, tablecloths, shoe soles. It is recycled for coatings, flooring, speed bouncers, roofing and road gutters.
Number 4
The number 4 indicates that it is made of Low Density Polyethylene (LDPE). This plastic is strong, flexible and semi-opaque or transparent. It is considered to be one of the most harmless plastics. However, when heated and during decomposition, it releases formaldehyde.
It is found in squeeze bottles, supermarket bags for fruit and vegetables, bags for food such as bread, frozen food, reusable shopping bags, carpets, clothing, straws, rubbish bags, insulation for electrical wiring.
It is recycled to make bins and litter bins, pipes, envelopes, panels, tiles.
Number 5
The number 5 indicates that it is made of Polypropylene (PP). It has a high melting point, and this makes it very useful for heating food and for use as baking pans, as it does not melt under heat. They are opaque, waterproof and resistant.
You will find it in opaque water containers, food storage containers (bread, cereals), yoghurt containers, syrup bottles, medicine containers, ice cream cups, straws, ketchup bottles, plastic tableware, microwave bags, refrigeration containers, disposable nappies and gallon lids.
It is considered one of the safest plastics. It can, however, release Aldehydes, Ketones, Phenol and Carboxylic Acids. These are toxic substances that stimulate sclerosis processes.
It is recycled into car battery boxes, brooms, containers, pallets, signal lights, and bicycle racks, ice scrapers, and ice scrapers.
Number 6
The number 6 indicates that it is made of Polystyrene (PS). It is also known as Styrofoam; it is considered dangerous and deadly. It is therefore recommended to avoid its use or to use it only once, as when heated or reused, it releases Antimony, Bromine, Styrene, Ethylbenzene, Toluene and Benzene.
These substances are highly toxic to health, especially Styrene, which alters the function of the liver and kidneys, and affects the circulatory and nervous system.
This plastic is present in plastic spoons, plastic forks, disposable plates and cups, toys, meat trays, egg cartons, CD cases, water bottles and foam packaging.
It is recycled in foam packaging and insulation, egg cartons, food serving trays, flower pots, office fixtures, vents and trash receptacles.
Number 7
The number 7, indicates that it is made of a mixture of Polycarbonates (PC); Polyamide (PA), Polyurethane (PU) and Bisphenol-A (BPA).
All plastic resins that do not fit into the other categories are grouped here. These plastics are not recycled, as their composition is very varied and unknown.
They are considered deadly plastics because they release toxic chemicals especially when heated, such as Antimony, Bromine and Bisphenol A, a substance catalogued as an ‘endocrine disruptor’, as it has the capacity to alter the hormonal system. It is related to breast and prostate cancer, produces male infertility, causes reproductive problems, hyperactivity, depresses the immune system and increases adipose tissue. It is banned for baby bottles.
These plastics are used in the manufacture of 3- and 5-gallon water bottles, sunglasses, nylon, bottle caps, can liners, iPod cases, computer cases and bulletproof materials.
Others
Currently, products made from Polylactic Acid (PLA) are new plant-based plastics that are biodegradable, durable and resistant to high temperatures. They represent a safer option for health and the environment. They are also included in category No. 7.
The plastic of the Alkanatur Drops jug and filters is number 7. This classification is that of ‘others’, which includes other plastics that do not correspond to any of the other groups. However, it is a 100% safe plastic and certified by the IBS at the University of Granada, directed by Professor Nicolás Olea. To consult the certificate, click on the following button:
Plastics that are not harmful to health
The best plastics are those with the number 2, 4 and 5 in the recycling symbol, which are considered fit for use. They are the only plastics that are safe for storing water, food and other liquids. According to studies, containers made of HDPE (High Density Polyethylene) plastic are recommended because they do not release toxins.
Plastics number 7 are suitable for use only if they bear the acronym ‘PLA’ (Polylactic Acid) or a leaf symbol, because they are plant-based, non-toxic.
Plastics with the number 1 should be used only once. They are also considered suitable for use, but it is NOT recommended to refill plastic water bottles, and these bottles and all number 1 plastic containers should be kept out of the heat and sun.
Plastics that are harmful to health
Bad plastics are those with the number 3, 6 and 7 in the recycling symbol. They are NOT recommended for use and are considered deadly plastics because they release toxic chemicals, especially when heated.
They cause diseases, such as obesity and cancer. These harmful chemicals are released into the air, drinks and food. Drinks and food should not be consumed in number 7 plastics that are not certified as safe, as they are made from a variety of highly toxic materials.
As these are not biodegradable, they accumulate and become a serious environmental pollution problem.
In the ocean, plastic waste accumulates in giant spirals of rubbish, forming a mass of plastic bags, jars, bottles, bottle caps, nets and other plastic rubbish, which are ingested by birds, fish and other marine animals or strangled by plastic bags, causing an increase in deaths of these species due to plastic waste.
Recommendations
- Avoid reusing any type of plastic, especially when it has undergone temperature changes.
- Do not drink bottled water in plastic.
- Use glass containers with HDPE plastic lids for food storage.
- Avoid using Styrofoam (similar to white cork) trays and cups, especially with hot liquids and microwave use.
- Replace the use of cling film with zip-lock bags made of HDPE, a type of plastic that does not release toxins.
- Do not use plastic bags.
- Replace plastic with fabric, wood, bamboo, glass and stainless steel.
- Avoid processed food stored in bags.
- Don't use plastics in the microwave, even if they claim to be microwave safe.
Do you use plastics that are safe for your health?
(*) WARNING
This information is based on available scientific information. These statements have not been evaluated by EFSA. Our water is not intended to diagnose, treat, cure or prevent any disease.
Alkanatur recommends a balanced and varied diet.
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