Biomagnification

bioaccumulation

how pollutants enter a food chain or food web. Involves increase in concentration of pollutants in the tissue of an organism. Smaller organisms towards the bottom of food chain will often absorb these pollutants more easily

biomagnification

refers to pollutants ability to increase in concentration as it moves form one trophic level to the next. Involves increase in concentration from one trophic level to another due to the relative amount each organism in the chain consumes

requirement for biomagnification

pollutants must be:

• long lived and not easily broken down

• mobile in air water etc

• soluble in fats = doesn’t readily dissolve and be excreted so it can be accumulated in fat and retained for long time

• biologically active = can affect living matter

pollutants for biomagnification examples

• DDT

• PCB’s

• Mercury

• Marine plastics

DDT Case study

DDT is a chemical pesticide used in agriculture to kill insects. Bioaccumulation of DDT in earthworms and other insects which are then eaten by birds were poisoned. This is because of biomagnification in which concentration of DDT and as birds eat more and more infected insects. Exposure to humans due to eating, breathing or touching products contaminated by DDT. Low doses unknown impacts but high levels can cause vomiting, tremors and seizures.

Marine Plastic Case Stduy

Marine plastics are tiny plastic fragments from urban and stormwater runoff, sewage overflows, littering and inadequate waste disposal. Effects: blocks digestive tracts, chocking hazard, leach toxic chemicals into marine life.

• laysan albatross = eat plastic in ocean and feed to their chicks which cuts their stomach or take up space and feel full even when starving

• sea turtles = eat plastic as mistake for jellyfish or algae =kill, rupture organs and intestinal blockage