Concentration • of Toxins in successiveTrophiclevels Daniel Seidel EstefanyDuron Alejandro Hernandez Maria Gabriela
Whatis a trophiclevel? Trophiclevels are the feeding position in a food chain such as primary producers, herbivore, primary carnivore, etc. Green plants form the first trophic level, the producers. Herbivores form the second trophic level, while carnivores form the third and even the fourth trophiclevels. In this section we will discuss what is meant by food chains, food webs and ecological pyramids.
Why toxins increase in concentration at each successive tropic level in a food chain? • With the increase of the tropic level, there is a loss of energy. It is averaged that each organism consumes 10% of the energy from the organism that it eats. • Because of this loss of energy, the animals at the higher tropic levels eat more, and hence, eat more toxins. • The toxins accumulate in the fat of the animals, and just continue to increase.
How are higher concentrations of toxins found at the top trophic levels? • The more the animal will eat the more toxin will get accumalated. As high level organisms eat more, the amount of toxin accumalated in them is more. • In other words Biomagnification.
Biomagnification • Biomagnification is the sequence of processes in an ecosystem by which higher concentrations of a particular chemical, such as the pesticide DDT, are reached in organisms higher up the food chain, generally through a series of prey-predator relationships
DDT • DDT (dichlorodiphenyltrichloroethane) isanorganochlorineinsecticidewhichis a colorless, crystallinesolid, tasteless and almostodorlesschemicalcompound. • DDT is a persistent organic pollutant that is readily adsorbed to soils and sediments, which can act both as sinks and as long-term sources of exposure contributing to terrestrial organisms.
Is toxic to a wide range of living organisms, including marine animals such as crayfish, Daphnis, sea shrimp and many species of fish. • It is less toxic to mammals, but may be moderately toxic to some amphibian species, especially in the larval stage.
PcB’s • PolyChlorinatedBiphenyls, are a group of organic chemicals which can be odorless or mildly aromatic solids or oily liquids. They were formerly used in the USA as hydraulic fluids, plasticizers, adhesives, fire retardants, way extenders, de-dusting agents, pesticide extenders, inks, lubricants, cutting oils, in heat transfer systems, carbonless reproducing paper.
Many toxic chemicals travel far from their sources through air, water, and food, and in products we use every day, such as plastics, cleaners, and pesticides. Some of these chemicals remain in the environment for a long time.
Every person on earth carries toxic chemicals in their bodies. Toxic chemicals collect in the fat of people and animals, and in some plants.
When people or large animals (such as bears, owls, hawks, or large fish) eat smaller animals, fish, or plants, toxic chemicals in them are passed along through the food chain or food web and accumulate in the bodies of those eating them. It’s a wholerepeatingcycle, Gettingworse and worsewith Time. Plantsget more toxic, animalseatthetoxicplants, and havedeformedoffspringor die byeatingthem.
Examples: Oil Spill Notonlyharmsthem, butalsotheirfutureoffsprings..
Plastics: Howwilltheyknow Thisis NOT edible? They’revictims of a Biggerpest US.
Pesticides: How can pesticides be harmful to ecosystems? • Pesticide poisonings of people, livestock, and wildlife have occurred when proper care was not taken. Mishandling of pesticides can lead to : Reduced control of the target Injury of non-target plants and animals Environmental damage May disrupt the natural balance in ecosystems