Figure 1: The Nadezhda smelting plant in Norilsk opened in 1979
The plant may be a possible source of the water discolouration.
Figure 2: Daldykan River in Norilsk
Describe a practical strategy using a biotic index to provide evidence that the Daldykan River (Figures 1 and 2) is damaged by effluent from the metal processing plant.
Award
- identify sampling sites upstream and downstream of plant/town / sample before and after effluent is released;
- sample invertebrate populations / e.g. using kick samples/nets;
- identify and count numbers of each species;
- determine the absence/presence of indicator species;
- calculate from this data the biotic index for each site / e.g. use BMWP/Simpson’s Diversity Index/Trent Biotic Index;
- repeat sampling throughout the year;
Do not accept ‘use of fish’.
Do not accept only ‘measure biodiversity’.
When measuring levels of pollution, state one advantage of using a biotic index compared to measuring the pollutants directly.
Advantage:
Award
- measures actual impact on living organisms/ecosystem;
- can see if pollution has occurred in the past/in the lifespan of the indicator species even if the water is clean now;
- records seasonal changes in the impact of pollutants;
- does not require complex chemical analysis;
- does not require expensive equipment / is relatively cheap;
Do not accept ‘using a biotic index is quicker than measuring pollutants directly’.
Do not accept ‘provides a numerical value for the level of pollution’.
Do not accept ‘can be used as a reference for future monitoring’.
When measuring levels of pollution, state one disadvantage of using a biotic index compared to measuring the pollutants directly.
Disadvantage:
Award
- does not identify pollutant causing impacts / does not measure the - level of the actual pollutant;
- does not directly measure the level of pollution;
- does not help identify source responsible for impacts;
- inaccurate as populations change naturally (during the season) / impacts could be due to natural changes in environment/other factors;
- requires knowledge of/ability in identification of organisms for area;
requires existence of identification keys;
Do not accept only ‘it is not exact/precise’.
Do not accept ‘method kills organisms’.
