Biomagnification Speech

Biomagnification speech
DESRIPTION OF THE ISSUE
Biomagnification is the accumulation of substances, especially many chlorinated hydrocarbons that are used as pesticides. Common chlorinated hydrocarbons include DDT, dieldrin, and PCBs. These chemicals are insoluble in water, but highly soluble in organic solvents like animal fats and plant oils. Due to their insolubility, they are persistent in the environment and cannot be broken down by any natural processes.
HISTORY OF THE PROBLEM
DDT was first synthesised in late 1800’s, however was rediscovered by Paul Miller during the start of World War 2 in 1939. It was hailed as a miracle for all people for a number of reasons, including a low toxicity to humans, highly toxic to a wide range of insects, insoluble; so it didn’t have to be applied often and inexpensive.
It was carelessly used during the War to reduce mosquito populations and thus control malaria where the U.S troops were fighting and to prevent the spread of lice in civilian populations in Europe. Its second major accomplishment was to eliminate a typhus epidemic in Naples during 1943.
The World Health organisation estimates DDT helped save the lives of approximately 25 million
CAUSES
As chlorinated hydrocarbons are highly soluble in lipids, and most lipids found in an ecosystem are in biological tissues, the compounds are absorbed and stored in the bodies of consumers. If the consumer is caught and eaten, its fat is digested and the pollutant moves into the fat of the next consumer. It can only become progressively more concentrated as it moves up the food chain, due to the 10 percent law.
IMPACT ON THE ENVIRONMENT
The use of chlorinated hydrocarbons has led to habitat loss and whole species going extinct through unforseen secondary effects
Toxic accumulation of harmful chemicals generally only occurs after it has moved up the food chain to fourth of fifth order consumers. This means a drastic lowering of high order predators that control numbers of lower level species, so naturally an influx of these organisms arises. This results in competition for mates and a higher chance for the spread of disease. If a population reaches carrying capacity it can affect the physical environment in terms of diminishing food sources and habitat destruction.
AN OVERVIEW OF A CASE STUDY OR EXAMPLE
One example of an unintentional effect of biomagnification recently occurred in Malaysia, where the widespread spraying of DDT may have caused the deaths of large numbers of wasps, who preyed on moth pests. The moths fed on straw in roofs of the houses DDT was sprayed on these roofs, in an attempt to get rid of the moths.
The concentration of DDT found in the moths was not enough to be fatal, so instead the chemical was passed on to the wasps who at enough moths for the DDT to become fatal. Without wasps to control the moth population, their numbers increased and many houses were destroyed.
PREVENTIONS/SOLUTIONS TO THE PROBLEM AND THEIR SUCCESS
One of the solutions from the chemical industry to the concern of DDT use is the introduction of new chemicals such as organophosphates that are ‘safer’ because they are not persistent. They are however around 40 times more toxic and insects are developing resistance to them.
Another concept of integrated pest management, or IPM, has been developed to improve the control of pests while decreasing the need for pesticides. Some example of the methods they are using include biological controls, and cultural practices such as timing planting and harvest to avoid periods of peak activity by pest species.
Crops have been introduced with built in insect protection, incorporated into their seeds using modern gene technology. The pesticides are derived from a particular species of plant containing a naturally occurring pesticide. It is estimated that the carbon emission savings from introduction of genetically engineered crops is equal to removing 8.6 million cars from the road for one year. While this is not directly related to solving biomagnification of toxins, by incorporating this technique harmful biomagnification could longer occur.