Resources: The handout, scissors and backing card.
Core Handout: A series of games and activities on bioaccumulation.
Revise relevant KS2 learning. The students may be familiar with the different types of pollutants, such as pesticides, herbicides, and heavy metals, and how they can impact the environment and living organisms.
Ask the students: if an oil pipe bursts on the ocean floor, what different organisms would be affected?
Begin the presentation slides by outlining the symptoms and causes of mercury poisoning and ‘Mad Hatter Syndrome’. Then, move on to exploring the pesticide DDT and explain the way it moves along a food chain through bioaccumulation. Use the final slides to prompt the students to critically think about why it can be difficult to accurately manage and use toxic materials.
Expert Film: Piers Warren explains how toxic chemicals can accumulate in the environment.
The students will be play the board game to model bioaccumulation in a food chain. They will need to play in order to complete the handout. It is recommended that students play in groups of four. Print the handout single-sided and give one copy of the board and rules per group and one question sheet per person.
Support: How would the students develop the game? Try playing again with their new rules.
Challenge: Ask the students to find out why pregnant mothers are told not to eat certain types of fish. Which fish are included and why? What damage could those toxins do?
Give students a list of organisms (e.g. grass, mouse, snake, hawk) and a list of contaminants (e.g. DDT, PCBs, mercury, lead). Ask students to rank the organisms in order from least to most contaminated and then explain their reasoning.
Bioaccumulation is the gradual accumulation of substances, such as pesticides, or other chemicals in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost by catabolism (broken down into smaller molecules) and excretion.
Toxins can accumulate within an individual organism and therefore build up within a food chain. As species within an ecosystem are highly interconnected any abiotic changes, this can lead to large knock-on effects. For example, pesticides can build up in an ecosystem, particularly if they do not easily break down in the natural environment or inside organisms.