With reference to named examples, distinguish between a primary and secondary pollutant.

Explain how organic waste may be an effective fertilizer in terrestrial systems but a source of pollution in aquatic systems.

To what extent can different environmental value systems contribute to both causing and resolving the problem of water scarcity?

a primary pollutant is one which is active on emission / directly impacts the environment;
eg CO₂ is released from burning fossil fuels and actively contributes to global warming / CFCs are released from aerosols and actively contribute to ozone depletion;
a secondary pollutant is one formed from a primary pollutant through physical/chemical change;
eg CO₂ combines with sea water to form carbonic acid that leads to impacts on calciferous shelled organisms or corals / NO_x combines with water to form acid precipitation / NO₂ forms PAN/ozone (that contributes to photochemical smog).

Award [2 max] if no examples are given.
Examples of primary pollutants need to include their direct impact (eg NO_x can be either primary or secondary without such specification) and examples of secondary need to include the process leading to their pollutionary impact).
Award [1 max] for example of primary, and [1 max] for example of secondary.

In terrestrial systems [4 max]:
organic waste such as cattle manure/compost can be added to soil as fertilizer;
its decomposition releases nitrates/phosphates/nutrients that promote plant growth;
the slow release will help to prevent run-off/eutrophication/red tide/algal bloom of water bodies;
improves soil quality/structure / making it less prone to erosion/compaction / increases plowability;
it is similar to the natural organic waste in a terrestrial system so may not be a pollutant.

In aquatic systems [4 max]:
organic waste eg sawdust/domestic sewage/agricultural run-off can be discharged into aquatic systems;
increases turbidity/floats on surface/algal growth reduces light penetration and primary productivity of system;
its decomposition leads to bacterial absorption of O₂ / adds high BOD reducing O₂ availability;
this is a limiting factor in aquatic (not terrestrial) systems (negatively) impacting aquatic life;
(decomposition also) releases nitrates/phosphates/nutrients leading to eutrophication/red tide/algal blooms;
domestic sewage/sawmill effluent may contain non-biodegradable organic pollutants/toxins/pathogens;
can pollute drinking water sources for human populations/animal species.

Award [1] for each correct explanation, up to [7 max].

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 demonstrate:

• understanding concepts & terminology of environmental value systems; technocentric; anthropocentric; ecocentric; pro-growth agenda; intensive agriculture; unsustainable extraction; industrialization; water contamination; climate change and rainfall patterns; desalination; rainwater harvesting; water taxes; grey-water cycling; etc
• breadth in addressing and linking range of environmental value systems with impacts of unsustainable extraction; contamination; distribution of water supply and solutions through technology; changes in behaviour; social controls; etc
• examples of value systems; impacts on water availability; specific strategies for
  addressing water scarcity; appropriate technology; etc
• balanced analysis of extent to which different value systems have promoted causes of water scarcity and/or effectively addressed resolving the issue; acknowledging relevant counter-arguments/alternative viewpoints;
• a conclusion that is consistent with, and supported by analysis and examples given eg it is the technocentric pro-growth agenda that has largely contributed to the problem of water scarcity and while technocentric solutions are available to address it, it is only the ecocentric solutions that address the root cause and attempt to curb consumption. NB This is only an example of a possible conclusion. Candidates’ conclusions do not have to agree.

Refer to paper 2 markbands, available under the "your tests" tab > supplemental materials

Question 6 was a popular choice. In part (a) distinctions between primary and secondary pollutants were often valid, though a good number of candidates confused the distinction with point v non-point pollution.

Candidates generally performed well on this question, usually gaining the bulk of their credit from detailed and valid descriptions of eutrophication.

Majority of candidates were able to distinguish environmental value systems and relate their ideologies to issues of water scarcity hence scoring within the 4–6 range. Commonly, there was vague grasp of anthropocentric values and some confusion of these with more cornucopian values. Responses tended to fall short of the higher markband due to a lack of explicit examples, evaluative argument/counterargument or an effective conclusion.