Water quality and pollutants Section 2.2 Pgs. 76-80 1

The accumulation of pollution p.79 Many different processes release heavy metals (ie. mercury, lead) into the environment. These metals enter the water, and are taken in by organisms like algae. Over time the algae has more and more heavy metal built up in its tissues. This gradual build-up is bioaccumulation. What eats algae? So as we discussed with out food chains and energy pyramids some energy is transferred between levels. This is the same principle with nutrients, minerals, and pollution i.e. mercury in tuna. 2

The accumulation of pollution p.79 The algae can be eaten by other organisms, where more bioaccumulation takes place in the predator organism. This continues down the food chain, with each organism having a higher concentration of the pollutant than the last. This build up of a toxin in a food chain is called biomagnification. 3

Biomagnification: water is polluted i Biomagnification: water is polluted i.e mettalic minerals such as mercury. Producers absorb these access pollutants. Zooplankton or our primary consumer eat the algae and consume the pollutant. Small fish or secondary consumers then large fish or tertiary consumers then fish eating birds or in the case of tuna, humans eat last. Chemical has maginfied from 1 unit up to 10,000,000 units. Toxic enough to harm humans if consumed. 4

Three Causes of Eutrophication Fertilizer or manure runoff from farmland Improper disposal of sewage Chemical and industrial waste