Unit ED13: Hazardous Substances

Question 1

What is Persistence

Answer 1

Persistence is the resistance to breakdown of an environmentally hazardous
substance. This may include chemical, physical and biological mechanisms when
under conditions that would normally be expected. Examples quoted for persistent
substances could include toxic metals (e.g. cadmium) and many chlorinated organic
compounds (e.g. CFCs).

Question 2

What is Bioaccumulation

Answer 2

Bioaccumulation is when a substance has the ability to build up within plants and
animals (e.g. tissues and organs) above the usual background level. This may lead
to further accumulation of the hazardous substance up the food chain. Examples
of hazardous substances that bioaccumulate are mercury, cadmium, pesticides,
polychlorinated biphenyls (PCBs).

Question 3

What is Ecotoxicity

Answer 3

Ecotoxicity is when a particular substance has toxic impacts upon one or more
members of an ecosystem. Any environmentally toxic substances could be referred
to as examples.

Question 4

What is Biotransformation

Answer 4

Biotransformation is the change of a substance into another substance by the
action of an organism (often micro-organisms). Methylation of mercury is one
example which occurred in the Minamata Bay incident. Another example might be
breakdown of hydrocarbons by micro-organisms.

Question 5

What is Half-life

Answer 5

Half-life is classed as the amount of time it takes for a substance to be reduced to
50% of its original concentration. Radioactivity is a good example, although the
concept of half-life could be applied to any substance.

Question 6

What is Point sources of contamination

Answer 6

Point sources - drains, vents and chimneys exhausting to water, air or land.

Question 7

What is Diffuse sources

Answer 7

Diffuse sources - uncontrolled such as runoff of fertilisers and pesticides.

Question 8

Which EU legislation covers the Classification, Labelling and Packaging of Substances and Mixtures covers the classification, information supply and packaging of dangerous substances.

Answer 8

The European Regulation (EC 1272/2008)

Question 9

Which EU Regulation covers the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), dangerous substances and preparations supplied to users must be accompanied by a Safety Data Sheet.

Answer 9

EU Regulation (EC 1907/2006)