Bioaccumulation: Building Up without Breaking Down

What is your favourite food to eat?! 
At the Georgian Bay Biosphere, some of our favourite foods include apples and fish!

Did you know these foods may have chemicals that can be worrying - even the potential to be toxic? These chemicals get into the environment in many ways. Leaking landfills, chemicals for farming, and the exhaust from our cars are all examples of how toxic chemicals could get in the environment!

When chemicals enter the environment they eventually get inside the bodies of plants and animals. This process is called ‘bioaccumulation’ (bio = life and accumulate = increase in number). This is harmful because as one organism eats another, the amount of toxins in their tissues multiply. This process is called ‘biomagnification’ (bio = life and magnify = appear larger).

Let’s do a fun exercise to see how this process works – the answer will be given at the end!

The Bioville Landfill leaks 1 unit of a toxic chemical called mercury into the soil. Once in the soil, it is absorbed by a plant. A grasshopper then eats the plant and absorbs that mercury. 

How much toxin would the grasshopper have accumulated? (1 mercury unit x 1 plant x 1 grasshopper)

A snake, who is also hungry, then eats 10 grasshoppers, and absorbs all their accumulated mercury. 
How much toxins would the snake have accumulated? (1 snake x 10 grasshoppers)

A bird then eats 3 snakes. 
How much toxins would the snake have accumulated? (1 bird x 3 snakes)

Biomagnification exists in all food chains, meaning that people are also part of the process. Being at the top of the food chain, this means that we are at risk for biomagnification.

What can you do to help!?
#1: Don’t pour chemicals down the drain! These chemicals are absorbed into the surrounding environment




#2: Eat organic food when possible! Organic food is grown without the use of chemicals and is generally free of any chemicals that can be potentially harmful. Foods with the symbol below are certified organic.

#3: Eat more vegetables! Foods that are lower on the food chain have lower concentrations of toxins in them. This means it takes longer to accumulate higher levels of toxins than if you ate higher in the food chain.

As for our math exercise, the correct answer is ...

30 units!

Hip Hip Hooray for clean food today!