Zusammenfassung der Ressource
safty and suitanablity
- Health and the environment - Ideas about science
- A large number of industrial chemicals exist and
have a range of uses. These uses include consumer
products. The safety of these chemicals must be
checked to identify any risks they may pose to human
health and the environment.
- Some chemicals used in synthetic materials are
harmful in large doses but not in the concentrations
used in the products. Other synthetic materials are
harmful even in these small amounts.
- Persistent organic pollutants (POPs) are a class of chemicals that take
a long time to break down and can harm people and wildlife. Because
they take so long to break down they can be carried over large
distances in air and water. POPs accumulate in the fatty tissues of
animals, including humans. Exposure to POPs can lead to illness and in
severe cases death.
- Many countries have outlawed these chemicals, for
example the UK has banned many of these chemicals
already.
- PVC and plasticisers
- Polyvinyl chloride (PVC) is a widely used plastic containing carbon,
hydrogen and chlorine. It is produced by the process of polymerisation.
Molecules of vinyl chloride monomers combine to make long chain
molecules of polyvinyl chloride.
- This synthetic polymer is relatively cheap and easy to mould.
There are different types of PVC that are manufactured,
serving a range of uses from underground pipes carrying
water, gas and sewage to thinner films used in packaging.
- Plasticisers
- Plasticisers are used to make a material like PVC softer and
more flexible. They are small molecules that can dissolve into
liquids that come into contact with them. The most common
plasticisers used for PVC are phthalates.
- Some argue that phthalates should be banned due to evidence linking
them with health problems such as cancer. Others say that products
containing phthalates have been used for over half a century and no
known cases of harm has been documented due to the use of phthalates.
- Some plasticisers have been banned by regulators in
Europe and the USA.
- Making life cycle assessments
- The articles that we use have three main life stages: manufacture, use and disposal. A life cycle assessment, or
LCA, is a study of the stages in the life of a manufactured product.
- Key features
- Polymers have recycling symbols like this one for PVC to show what they
are The key features of a life cycle assessment include the following
factors:
- the main requirements for energy input the
environmental impact and sustainability of
making the materials from natural resources
- the environmental impact of making the
product from the material
- the environmental impact of using the product
- the environmental impact of disposing of the
product by incineration, landfill or recycling.
- Materials and products
- Different materials
- It is possible to make a product from different materials, for
example. A window frame, for example can be made from
wood or uPVC. The life cycle assessment for a product will
depend on the material that it is made from.
- Different products
- It is possible to use the same material to make different
products. Polythene can be used to make food wrap (cling film)
or a bucket, for example. The life cycle assessment of
different products will be different, even though they are made
from the same material.
- A life cycle assessment can be used to compare and evaluate the impact of:
- the use of different materials for the same job
- the use of the same material for different jobs.
- LCA outcomes- Higher tier
- It is possible to make a life cycle assessment of a material.
The outcome of this life cycle assessment will depend on:
- a consideration of the factors involved in the production of the material
- a consideration of the factors that involve each
of the products that are made from this material.