Life is not risk-free without risk we can't live in world. We all are taking so many risks each day without even thinking about it. We decide to ride a bike rather than drive, even though there's a ten to twenty times greater likelihood per mile of dying in a motorcycle accident than in a car. We decide to walk down stairs rather than take am elevator, even though 7000 people die from falls each year particularly in the United States. Some of us decide to smoke cigarettes, even though it increases our chance of getting cancer by 50%.But what about risks from chemicals like pesticides?
One thing is certain, without pesticides whether they target weeds insecticides or molds and fungicide, crop production would drop significantly, food prices would increase, and famines would occur in less developed parts of the world. Take the herbicide atrazine, for instance. In the United States alone. Approximately 100 million pounds of atrazine, for instance used each year to kill weeds in corn, sorghum, and sugarcane fields, greatly improving the yields of these crops. Nevertheless, the uses of atrazine continues to be a concern because traces persist in the environment, indeed, heavy atrazine exposure can pose health risks to humans and some animals. But the American government (environmental protection agency) (EPA) is unwilling to ban its use because doing so would result in significantly lower crop yields and increased food costs, and because there's no suitable alternative herbicide available.
How we can all the potential hazards from a chemical like atrazine be determined?
Risk evaluation of chemical is carried out by exposing test animals, usually mice or rates to the chemical and then monitoring the animals for signs of harm. To limited and used expense and time needed, the amounts administered are typically hundreds or thousands of times greater than those a person might normally encounter. The results obtained in animal tests, are then distilled into single number called an LD₅₀ the amount of substance per kilogram body weight that is lethal dose for 50% of the test animals. For atrazine, the LD₅₀ value is between 1 and 4 g/kg depending on the animal species. Aspirin, for comparison, has an LD₅₀ of 1.1g /kg and ethanol (ethyl alcohol) has an LD₅₀ of 10.6 /kg.
Some LD₅₀ values :
That lower value the more toxic the substance. Note though, that LD₅₀ values tell only about the side effects of heavy exposure for a relatively short time. the risks of longer -period exposure, such as whether the substance can cause cancer or interfere with development in the unborn.
So, should we still use atrazine? All decisions involves tradeoff, and the answer is rarely obvious. Does the benefits of increased food production outweigh possible health risks of a pesticide? Do beneficial effects of a new drug outweigh a potentially dangerous side effects in small number of users? Different types of people will have different opinions, but an honest evaluation of facts is surely the best way to start. In the current period, atrazine is approved for continued use in the United States because the EPA believes that the benefits of increased food production outweigh possible health risks. At the same time, though, the use of atrazine is being phased out in Europe countries.
Very nice
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