Outline, using examples, the differences between primary and secondary pollution.

Explain the causes and effects of acid deposition on natural ecosystems.

To what extent is pollution impacting human food production systems?

Primary pollution:
is active upon emission of pollutant;
eg carbon dioxide/sulphur oxides/ozone/lead/nitrates/phosphates/heat/light;

Secondary pollution:
occurs when primary pollutants undergo some kind of physical or chemical change;
nitrogen/sulphur oxides combining with water to form nitric acid/sulphur acid/acid rain;
nitrogen oxides/VOCs combining to form tropospheric ozone/photochemical smog;

Note: some pollutants (eg ozone/sulphur oxides) can be credited as both a primary and secondary pollutant but to gain credit for the latter there must be an identification of a primary pollutant from which it is derived.

Do not accept eutrophication (eg toxic substances released from algal blooms) as example of secondary pollutant.

Causes:
burning of fossil fuels releases NO_x/SO_x;
the sources of these are mainly coal-burning industries/transportation/electricity generation;
emissions from livestock/use & production of inorganic fertilizers also contribute;
volcanic eruptions can also cause acid rain/release oxides of N/S;
NO_x/SO_x react with water to form acid deposition;
this acid may be deposited locally as dry deposition or dissolve in air moisture and reach ground by wet precipitation;
nitrous oxides produce nitric acid / sulphur oxides produce sulphuric acid;
wind may carry primary pollutants causing ecological damage to be widespread.

Effects:
direct adverse effect of acidity on living organisms eg kills lichens / plankton / fish / soil microbiota;
causing leaf-fall/thinning of waxy cuticle/reduced immunity to disease/root damage in terrestrial plants;
leading to reduced primary production/plant growth;
indirect toxic effect by changing chemistry of soil/water;
eg increased solubility/leaching of plant nutrients/reduced soil fertility;
eg increased solubility/release of toxic metals/aluminium damaging fish/plants;
such toxic metals might undergo bioconcentration/biomagnification;
overall, may therefore cause loss of biodiversity/reduction in food chains/webs etc.

Note: Do not credit biomagnification except in the explicit context of releasing heavy metals. And do not credit impacts of ocean acidification or impacts on limestone/urban infrastructure which are beyond the limits of this question.
Award [5 max] if either causes or effects are not included in response.

Refer to paper 2 markbands, available under “your tests”  tab > supplemental materials

The following guide for using the markbands suggests certain features that may be offered in responses. The five headings coincide with the criteria given in each of the markbands (although ‘ESS terminology’ has been conflated with ‘Understanding concepts’). This guide simply provides some possible inclusions and should not be seen as requisite or comprehensive. It outlines the kind of elements to look for when deciding on the appropriate markband and the specific mark within that band.

Answers may include:

• understanding concepts and terminology of aquatic and terrestrial food production; aquaculture, capture fisheries, aquatic sp. harvesting; provision of food to a growing population; aquatic pollution sources; wide range of parameters lowering water quality; soil content; soil degradation; soil fertility; sustainability of TPSs influenced by industrialization, fossil fuel use, mechanization, fertilizers, pesticides; acid deposition; tropospheric ozone; ozone depletion; eutrophication; dead zones; climate change (Note: Relevant examples will be of pollution affecting food production NOT the other way round);
• breadth in addressing and linking a range of pollutants/polluting activities (fertilizer use/emissions from combustion of fossil fuels/mining/waste disposal etc) and their impacts on food production systems (aquaculture/terrestrial farming systems) and methods of limiting these impacts (alternative sources /regulations/clean-up procedures);
• examples of food production systems; farming practices (aquatic and terrestrial); impacts of pollutants/polluting activities; and methods of limiting impacts;
• balanced analysis of the extent to which a range of pollution events are impacting, or being restored/prevented from impacting, a range of different food production systems;
• a conclusion that is consistent with, and supported by, analysis and examples given eg ‘Terrestrial FPSs are affected by a wider range of pollutants and polluting activities, thus aquatic FPSs show a greater potential for sustainable production feeding the fast-growing global population’.