Biological MagnificationBiological Magnification

Biological Magnification: The process of a Biological Magnification: The process of a chemical buildup, chemical buildup, increasing in increasing in concentrationconcentration, as it moves up trophic levels , as it moves up trophic levels of a food chain.of a food chain.

  

Why and how do they Why and how do they accumulate?accumulate?

Chemicals, which bioaccumulate in this Chemicals, which bioaccumulate in this way, are stored in the way, are stored in the fatty tissuefatty tissue of of animals. Thus they are stored in the animal, animals. Thus they are stored in the animal, and not used up (like a carbohydrate or and not used up (like a carbohydrate or protein) or passed out as waste.protein) or passed out as waste.

Thus when another animal eats them, that Thus when another animal eats them, that animal will gain the chemical accumulation animal will gain the chemical accumulation from the animal they ate.from the animal they ate.

Food Chain Concentration of DDT in A Long Island Marsh sprayed Food Chain Concentration of DDT in A Long Island Marsh sprayed for Mosquito Control 1967 for Mosquito Control 1967

ppm

Water 00005

Plankton .04

Silverside Minnow .23

Sheephead Minnow .94

Pickerel 1.23

Needlefish 2.07

Heron 3.57

Tern 3.91

Osprey 13.8

Merganser 22.8

Cormorant 26.4

What chemicals biomagnifiy?What chemicals biomagnifiy?

Types of chemicals that biomagnify are Types of chemicals that biomagnify are often chlorinated hydrocarbons that are (or often chlorinated hydrocarbons that are (or were) used to produce pesticides and heavy were) used to produce pesticides and heavy metals and other organic compounds used metals and other organic compounds used in industry. in industry.

Examples are:Examples are:

1.      DDT, chlordane, and lindane. Often 1.      DDT, chlordane, and lindane. Often these types of chemicals are found in these types of chemicals are found in pesticides.pesticides.

2.      Heavy Metals: Mercury and Lead2.      Heavy Metals: Mercury and Lead 3.      PCBs: originally used in electrical 3.      PCBs: originally used in electrical

transformers, it was an excellent electrical transformers, it was an excellent electrical insulator.insulator.

4.      Dioxin4.      Dioxin

POB’sPOB’s These chemicals are sometimes called These chemicals are sometimes called

persistent organic pollutants. (POB’s) persistent organic pollutants. (POB’s) They do not degrade or break down easily They do not degrade or break down easily in the environment. They can last for in the environment. They can last for decades to hundreds of years in an decades to hundreds of years in an ecosystem.ecosystem.

  Consequently, even though some of these Consequently, even though some of these chemical have been banned for years, they chemical have been banned for years, they can still cause problems to the environment.can still cause problems to the environment.

Who is at risk?Who is at risk?

Those most at risk from these chemicals are Those most at risk from these chemicals are those with weakened immune systems, those with weakened immune systems, elderly, pregnant women, and children. elderly, pregnant women, and children.

Health Problems caused by Health Problems caused by biological magnification of these biological magnification of these

chemicals are:chemicals are: 1.      Neurological Damage: Babies and 1.      Neurological Damage: Babies and

young children are most susceptible to the young children are most susceptible to the effects of lead, mercury, and PCBs. Thus effects of lead, mercury, and PCBs. Thus pregnant women are often at risk more due pregnant women are often at risk more due to the chemicals they can pass on to their to the chemicals they can pass on to their babies.babies.

2.      Cancer2.      Cancer 3.      Reproductive Problems/Birth Defects,3.      Reproductive Problems/Birth Defects, 4.      Small hard to detect health effects.4.      Small hard to detect health effects.